Download Implications of Future Climate for Rocky Reefs

Chapter 3
Implications of Future Climate
for Rocky Reefs
Alecia Bellgrove, Jessica McKenzie, Hayley Cameron
Leather kelp Ecklonia radiata
Photo: Bill Boyle
Citation: Bellgrove, A., McKenzie, J. & Cameron, H. (2013).Chapter 3. Implications of Future Climate
for Rocky Reefs. In Implications of Future Climate for Victoria’s Marine Environment, eds. Klemke, J.
& Arundel, H. Glenelg Hopkins Catchment Management Authority Australia
TABLE OF CONTENTS
Background ................................................................................................................................................... 4
Intertidal reefs ........................................................................................................................................ 5
Shallow subtidal reefs ............................................................................................................................. 5
Deep subtidal reefs ................................................................................................................................. 6
Western Region....................................................................................................................................... 6
Central Region and Embayments............................................................................................................ 6
Eastern Region ........................................................................................................................................ 6
Impact of physiCochemical conditions ............................................................................................................. 7
Mean Sea Level, Astronomical Tides and Storm Surge .......................................................................................... 7
Ocean Currents & Upwellings ............................................................................................................................... 10
Temperature ....................................................................................................................................................... 12
Salinity
....................................................................................................................................................... 17
Waves
....................................................................................................................................................... 20
Carbon Dioxide and Acidification ......................................................................................................................... 23
Rainfall and Runoff ............................................................................................................................................... 26
Interactions & linkages .................................................................................................................................. 29
Major vulnerabilities to climate change ......................................................................................................... 29
References
................................................................................................................................................. 31
BACKGROUND
The Victorian coastline is characterised by expansive areas of temperate reef systems; hard
substrate marine habitats which average temperatures below 18˚C. These reef systems are highly
productive and provide important habitat for a high diversity of marine species, many of which are
endemic to Victoria and temperate Australia (Banaru et al., 2007; Phillips, 2001). They also hold
significant economic value through commercial and recreational fisheries, diving, and tourism
industries (Banaru et al., 2007).
This review focuses on the future climate vulnerabilities of Victorian intertidal, shallow subtidal and
deep subtidal and canyon reef systems (the latter two combined). These reef types are
characteristic of Victorian rocky reef habitats, and are distinguished by differences in exposure to
physical modifiers such as depth, tidal range, hydrodynamics and light; these are factors integral in
structuring benthic marine communities (Coleman et al., 2007; Ferns et al., 2000; O'Hara et al.,
1999).
Figure 1 Distribution of intertidal and shallow subtidal (<20 m) rocky reefs in (a) Western),(b) Central
(including Embayments) and (c) Eastern Regions of the Victorian coastline . Source: Department of Primary
Industries Habitat Ecology Section
4
Hutchinson et al. (2010) described in detail the current state of knowledge of the biogeographic
patterns, oceanographic processes, physical and biological communities, and the ecological and
physical environmental drivers of intertidal, shallow subtidal (<20 m), deep subtidal and canyon
rocky reefs throughout Victoria. They also reviewed the monitoring programs and classification of
marine habitats throughout Victoria (Hutchinson et al., 2010).
This section thus provides only a very brief introduction to Victorian rocky reefs to provide context
for ensuing sections which assess their vulnerability to future climate scenarios.
Intertidal reefs
Intertidal reefs, also known as ‘rocky shores’, occur above the low tide mark and are therefore
directly influenced by tidal cycling; they are periodically exposed to terrestrial conditions during low
tide, and are inundated or directly influenced by seawater at high tide (Hutchinson et al., 2010).
These habitats may differ in aspect, from steep slopes to flat platforms, and can be characterised by
a number of microhabitats such as rock pools, crevices, sandy patches and cobble fields. The
Victorian coast (particularly the Western and Central Regions) is dominated by low-relief, intertidal
rocky reefs with only slight differences in elevation between seaward and landward edges.
The geology of intertidal reefs has been shown to influence species abundances and biotic
community composition (Hope Black, 1971). The geology and substrate type of rocky intertidal reefs
differs along the Victorian coast. The majority of reefs occurring from the SA border to Killarney are
basaltic, while reefs from Killarney to Cape Schanck are predominantly dune limestone/sandstone
(calcarenite), with some mudstone and shale. The lithology of Victorian reefs located to the east of
Cape Schanck becomes more variable, and includes reefs of mudstone, basalt, sandstone and granite
up to 90 Mile Beach which acts as a large expanse of intervening sandy habitat.
Intertidal reefs are expansive and largely continuous for large stretches of the coast in the Western
and Central Regions, but are more sparsely found within the Embayments (where soft-sediment
substrata dominate) and in the Eastern Region.
Intertidal communities on Victorian rocky platforms display distinctive vertical zonation of algal and
invertebrate distributions (King et al., 1971), which has also been extensively documented on
international rocky shores (Mettam, 1994). Vertical zonation on rocky shores has traditionally been
attributed to local gradients in physical and biological structuring factors with changes in shore
height. Physical stressors associated with aerial exposure at low tide (e.g. temperature and
desiccation stress) are generally considered to increase in importance with increasing shore height,
while biological factors such as competition and grazing pressure are generally considered more
influential lower on the shore.
Wave exposure is also an important structuring force on intertidal rocky shores. Species richness of
algae and invertebrates, as well as algal cover, appears to be greater on exposed intertidal reefs
along the Victorian coast than on the sheltered reefs located within Port Phillip Bay (Gilmour and
Edmunds, 2007; Stewart et al., 2007). The severe mechanical stress on organisms living in
wave-swept environments constrains the sizes of intertidal plants and invertebrates such that, for a
given species, larger individuals are generally more abundant on wave-sheltered shores than on
exposed shores (Blanchette, 1997 and references therein; Menge, 1976).
Shallow subtidal reefs
Shallow subtidal reefs are hard substrate environments which remain permanently submerged
during tidal cycles (except during some extreme low tide events) and generally have a bathymetric
profile between 2.5 and 20 m.
Two categories of subtidal habitats have been characterised (Hutchinson et al. 2010):
wave-exposed subtidal reefs (e.g. the open coast and Port Phillip Heads); and
wave-sheltered subtidal reefs (e.g. within Port Phillip Bay).
5
Shallow subtidal reefs predominate in the Western and Central Regions (Figure 1) and the geology of
these reefs generally follows the same patterns as that described for intertidal reefs above.
The flora of Victoria is unique in its diversity and endemism (Phillips, 2001). Fucoid and laminarian
kelps (large brown algae) dominate much of the shallow rocky reefs in Victoria. These species create
habitat and modify the environment (e.g. light, wave action), and support highly diverse
communities of understorey algae, invertebrates (including abalone and southern rock lobster), and
fish. .
Deep subtidal reefs
Deep subtidal reefs are areas of rocky substrate exceeding 20 m depth, and include deep reef
canyons, which are geomorphological formations characterised by steep walls giving way to narrow
chasms. With the decrease in availability of light with depth, there is a concomitant decrease in the
abundance and diversity of algae. At depths below 20 m most algae found are small red species,
including rhodoliths (Ierodiaconou et al., 2011). Whilst the assemblages of deep reefs differ across
Victoria, they tend to be dominated by sessile, filter feeding invertebrates such as sponges,
bryozoans, octocorals and ascidians, but assemblages differ across Victorian deep rocky reefs
(Hutchinson et al., 2010)
There is a paucity of knowledge about the physical and biological environments of deep subtidal
reefs and canyon systems in particular, and the assessment of their future climate vulnerabilities
thus has a high level of uncertainty for most stressors (Hutchinson et al., 2010).
Western Region
The Leeuwin Current (LC) is the predominant oceanographic influence on the coastline of the
Western Region. The LC is a warm water western boundary current that flows strongest in autumn
and winter. In the west of the state, the LC largely influences the eastward coastal current that
drives circulation within Victorian waters (Cirano and Middleton, 2004). The LC and eastern coastal
currents are characterised by warm water, low salinities, and reasonably low nutrients.
Nevertheless, the most prevalent upwelling regions in Australia occur in the Western Region; with
prevailing south-easterly winds driving deep, cool, nutrient-rich waters to the surface, particularly
along the Bonney Coast from Robe in South Australia, to Portland in Victoria. In this region,
upwelling is greatest between November/December and March/April, supporting highly productive
biological systems (Barton et al., 2008).
Central Region and Embayments
The open coast and bays of the Central Region are exposed to the shallow waters of Bass Strait, a
platform mostly 70 m below sea level. Net tidal circulation is generally minimal, although strong
tidal currents are found in some areas, for example the eastern and western entrances of Bass Strait
(Black, 1992). Water movement in this region is primarily determined by wind-driven currents and
trapped coastal waves (Middleton and Black, 1994), and the density profile ranges from well mixed
in winter to highly stratified in summer (Baines and Fandry, 1983). Bass Strait is generally
considered nutrient limited, as areas of upwelling are weak, infrequent and usually quickly diluted
(Hutchinson et al., 2010).
Eastern Region
Oceanographic features in the Eastern Region are majorly influenced by the East Australian Current
(EAC). Although the EAC mostly flows towards the Tasman Sea, some water is directed to eastern
Victoria, particularly during summer. Water transported within the EAC is generally more nutrient
rich than the Leeuwin Current in the west (Connell, 2007) due to numerous areas of upwelling along
the eastern Australian coast (Suthers and Waite, 2007).
6
IMPACT OF PHYSICOCHEMICAL CONDITIONS
Mean Sea Level, Astronomical Tides and Storm Surge
Exposure
Mean sea level (MSL) is expected to rise globally by 0.05-0.15 m by 2030 and 0.18-0.82 m by 2100
with an additional 0.1 m rise in eastern Victoria (WaterTechnology, 2012). Current models of
regional sea level rise may underestimate future MSL projections, due to inadequate observational
data on which they are based and inadequate understanding of several key processes e.g. rates of
ice-sheet outflow and glacial melt (Willis and Church, 2012).
Tidal ranges currently differ along the Victorian coast from approximately 1.2 m in the Western
Region and approximately 1.5 m in the Eastern Region and Port Phillip Bay (PPB) to 2-3 m in the
Central Region and Western Port Bay (WP) (BOM, 2012; WaterTechnology, 2012). Whilst no future
changes to astronomical tides have been modelled for the open coast, the tidal ranges are predicted
to increase slightly (centimetres) in PPB and decrease slightly in WP and Corner Inlet (CI)
(WaterTechnology, 2012).
The impact of mean sea level rise and changes to astronomical tides on intertidal and shallow
subtidal biota must be considered together, along with the potential for increases in extreme storm
surge heights due to the combined effects of mean sea level rise and possible changes to coastally
trapped waves (WaterTechnology, 2012).
Sensitivity
Intertidal
Intertidal rocky reefs in Victoria, particularly in the Western and Central Regions, cover extensive
areas of the coastline (Figure 1) and are generally gently sloping and largely horizontal in aspect
(A. Bellgrove pers. obs.; M. Keough pers. comm.).
Figure shows a schematic profile of intertidal and shallow subtidal rocky reefs typical for much of
the Victorian coastline and their relationship to vertical cliff faces/coastal-protection structures.
Figure 2 Schematic vertical profile of intertidal and shallow subtidal rocky reefs
MHW = mean high water level; MLW = mean low water level
On the seaward edge of these reefs, rocky reefs in the shallow and deep subtidal are more steeply
sloping with a greater proportion of vertical, rather than horizontal, relief surfaces. On the
shoreward edge, intertidal reefs often abut largely vertical cliff faces, particularly on exposed coasts.
Additionally, there are more than 1200 coastal protection structures on the Victorian coast spanning
in excess of 200 km of shoreline, designed to prevent coastal erosion and flooding.
7
These defence structures are largely concentrated in the Embayments (particularly Port Phillip Bay)
and around other important ports and harbours. However, future sea level rise and increased
storminess will likely lead to greater shoreline protection throughout urbanised and economically
important areas of the coast (Thompson et al., 2002).
As a result of the combined effects of mean sea level rise, slight changes to tides, and increased
storm surge, the great majority of rocky substrates currently occupied by intertidal organisms will
become shallow subtidal. Intertidal organisms will be forced into the supralittoral zone (shoreline
above spring tide level), where this is available. However, vertical cliff faces and coastal-protection
structures present physical barriers to the shoreward progression of many intertidal species
retreating from rising sea level (Figure ) and unable to colonise vertical/high-relief surfaces (Vaselli et
al., 2008).
Because of these factors, intertidal reef-dwelling organisms in the vicinity of coastal protection
structures or vertical cliffs are likely to be highly sensitive to mean sea level rises, and shore profiles
will determine the opportunity for shoreward expansion.
Shallow subtidal
Although there is still a level of uncertainty in data used to plot intertidal and shallow subtidal reefs
in Figure 1, it is evident that there is not always pairing of intertidal and subtidal reefs.
As intertidal reefs are flooded due to mean sea level rise, they may be colonised by shallow subtidal
species where current distributions are within dispersal distances. However, the change in vertical
relief as the shallow subtidal moves into the current intertidal (Figure ) will likely affect both the
ability of species to colonise newly available horizontal surfaces (Vaselli et al., 2008) and the degree
of sedimentation and wave exposure.
These factors will alter species composition and abundance in the upper subtidal relative to present.
The mismatch between the distribution of present-day intertidal and shallow subtidal reefs along
the Victorian coast (Figure 1) means there is potential for a large increase in low-relief, shallow
subtidal rocky reefs in the future
Deep subtidal
It is difficult to represent accurately the extent of deep subtidal rocky reefs, as they have not been
mapped for large areas of the Victorian coast (i.e. excluded from Figure 1). However, there is likely
to be more extensive representation of shallow subtidal reef than deep subtidal, with little
differences in vertical relief. This suggests that organisms presently associated with deep subtidal
reefs should be able to move into shallower regions as they become further inundated in the future.
Impact
Intertidal
Mean sea level rise, tidal changes and increases in storm surge will affect the distribution and
orientation of available rocky reef habitat in Victoria (Selkoe et al., 2008). This will be further
influenced in the intertidal by construction of coastal protection structures to mitigate coastal
erosion and flooding (Airoldi et al., 2005; Thompson et al., 2002). With increased vertical surfaces in
the intertidal we may see an increase in the proportion of sessile invertebrates and encrusting
coralline algae at the expense of upright foliose macroalgal cover (Vaselli et al 2008), and this has
potential to threaten the unique diversity of macroalgae that differs between Regions (O'Hara et al.,
2010; Phillips, 2001).
The likely increase in hard, coastal protection structures (Thompson et al., 2002) may counteract the
reduced spatial extent of intertidal reef for species able to colonise vertical/high-relief surfaces,
increase connectivity between populations, and increase the potential for new invasions by
providing ‘stepping stones’ in areas where natural reefs are sparse, such as in the Eastern Region
(Airoldi et al., 2005; Thompson et al., 2002).
8
Shallow subtidal
An increase in the amount of horizontal substrate in the shallow subtidal may lead to an increase in
macroalgal cover (Vaselli et al., 2008). However, higher sedimentation on horizontal surfaces,
exacerbated by coastal erosion and runoff, may favour turfing species over kelps and foliose
understorey species (Airoldi, 1998; Airoldi, 2003; Gorgula and Connell, 2004; Schiel et al., 2005).
Deep subtidal
There is relatively high uncertainty surrounding the availability of deep rocky reef habitat and the
likely impacts from sea level rise. The impacts are assumed to be relatively low if organisms have
the dispersal capacity to colonise shallower reefs.
Adaptive capacity
The adaptive capacities of rocky reef ecosystems to future changes in mean sea level, astronomical
tides and storm surge are likely to be influenced by:
geomorphology (including spatial extent, geology and vertical profile)
dispersal capacity of associated species relative to the rates of change in the environment
mobility of organisms; and
proximity to coastal protection structures in the intertidal.
Generally the adaptive capacity of intertidal reef systems is thought to be relatively low, whereas
that of shallow and deep subtidal reefs should be moderate to high. For the Eastern Region in
particular, the adaptive capacity of reef systems may be compromised further by the low availability
of suitable habitat to move into.
Vulnerability
Table 1 Relative vulnerabilities of rocky reef assemblages to combined changes in sea level,
astronomical tides & storm surge
Habitat
Exposure
Sensitivity
Impact
Adaptive
Capacity
Vulnerability
Western
●
●
●
●
●
Central
●
●
●
●
●
Embayments
●
●
●
Eastern
●
●
●
●
●
Western
●
●●
●
●
●
Central
●
●●
●
●
●
Embayments
●
●●
●
●
●
Eastern
●
●●
●
●●●
●●
Western
●
●●●
●●●
●●
●●●
Central
●
●●●
●●●
●●
●●●
Embayments
●
●●●
●●●
●●
●●●
Eastern
●
●●●
●●●
●●
●●●
Region
Intertidal
Shallow
Subtidal
Deep
Subtidal
●
Relative vulnerabilities are indicated by colours: high=dark blue, medium=light blue, low=green.
Where uncertainty in predictions exists: ●●● = high, ●● = moderate, ●= low level of uncertainty; no dot
indicates relative confidence in prediction
9
Ocean Currents & Upwellings
Exposure
The warm Eastern Australian Current (EAC) is strongest in summer and is extending southward.
The EAC has progressed southward 350km the EAC volume transport is projected to increase in
strength by more than 20% by 2100 (WaterTechnology, 2012). The increased influence of the EAC
will largely be restricted to the Eastern Region, resulting in changes to temperature and salinity in
the region (WaterTechnology, 2012). The bathymetric barrier created by Bass Strait will force EAC
eddies southward (Webster and Petkovic, 2005).
The warm, eastward moving Leeuwin Current (LC) is strongest in late autumn/early winter. The LC
has weakened by 10–30% over recent decades and a further slight weakening is projected for 2100,
although though there is reasonable uncertainty in this prediction (WaterTechnology, 2012).
The weakening/retreat of the LC will affect temperatures in the Western and Central Regions.
The Flinders Current primarily influences the Western Region. The cold, westward moving current is
strongest during summer and autumn. This current has strengthened over the past decade and is
projected to strengthen further by 2100 (WaterTechnology, 2012).
There is limited information available on climate-induced changes to both the Bonney Upwelling in
western Victoria and the eastern Victorian upwelling between Lakes Entrance and Croajingalong
(WaterTechnology, 2012). However, because the upwellings are primarily driven by the prevalence
of longshore easterly winds during summer, predicted increases in the strength and frequency of
these winds (WaterTechnology, 2012) are likely to strengthen the upwellings.
The southward extension of the EAC (WaterTechnology, 2012) will bring warmer water into the
region of the eastern Victorian upwelling and may result in a weakening of this upwelling. The
weakening of the Leeuwin Current and strengthening of the Flinders Current (WaterTechnology,
2012) may also act to strengthen the Bonney Upwelling in particular. There are no significant
upwellings in the Central Region or the Embayments (WaterTechnology, 2012).
Although limited data leads to a high level of uncertainty about potential future changes to the
frequency and magnitude of coastally trapped waves, these waves are important drivers of
variability in currents on the continental shelf (WaterTechnology, 2012), and their influence should
thus be considered as data become available.
Sensitivity
There may be differences in sensitivity (and adaptive capacity) to changes in currents between
west-facing and east-facing rocky reefs. Estuaries with different aspect which are functionally
different in an ecological sense can respond in different ways to external pressures (Barton et al.,
2008).
Planktotrophic larvae are likely more susceptible than lecithotrophic larvae to reductions in
upwelling and/or increases in the EAC, which drives decreases in nutrients and prey availability.
Viability of algal propagules may also be reduced by decreased nutrients particularly in the Eastern
Region. Open coastal regions will be more sensitive to changes in major currents and upwellings
than embayments.
Deep subtidal reefs and canyons in some regions of Victoria provide important feeding and spawning
grounds for commercially valuable fisheries and the links between ocean currents, upwellings, and
flows through Bass Strait are likely to be important for these processes (reviewed in Hutchinson et
al., 2010), making them sensitive to change. However, there is a relatively high level of uncertainty
around the links between oceanographic processes and the functioning of deep reef communities.
10
Impact
Regional changes in ocean temperatures driven by changes to major currents will occur within the
framework of more widespread ocean warming. The effects of changes in temperature and salinity
(as influenced by currents and upwellings) on Victorian reef systems are covered elsewhere in this
review. This section focuses on other influences of changing major currents and upwellings.
For all depth ranges there is likely to be greater arrival of novel propagules in summer to the Eastern
Region, influenced by the extension of the EAC. Increases in the frequency of vagrant sightings are
more likely in the Eastern Region in particular. Because the Eastern Region has relatively few natural
intertidal or shallow subtidal reefs (Figure 1), any increase in the presence of artificial substrata, such
as coastal-protection structures to mitigate flooding and coastal erosion, may be important as
potential hard substrata, providing stepping stones for reef-dwelling propagules (Airoldi et al., 2005;
Thompson et al., 2002) arriving in the EAC. This increases the chance of range extensions of
northern species into the Eastern Region.
Any decrease in strength of the eastern upwelling, overlaid by a strengthening EAC in the Eastern
Region, may limit nutrients and productivity. This may have negative impacts on larval dispersal,
particularly of species with planktitrophic larvae. Conversely, a strengthening of the Bonney
Upwelling may enhance propagule survival and dispersal, and access to food of species in the
Western Region with summer-dispersing propagules or foraging patterns (Kupriyanova and
Havenhand, 2005; Levings and Gill, 2010).
There are reasonably well-documented bioregional boundaries in species distribution and gene flow
in northeastern Victoria, near Merimbula, and at Cape Otway. It is possible that increased gene flow
may occur across these boundaries, with possible range shifts and/or hybridisation driven by future
changes to currents and their influence on propagule dispersal.
Any slackening of the Leeuwin Current may drive extension of central Victorian species westward
from Cape Otway from late autumn to early spring, when the Bonney Upwelling (Middleton et al.,
2007) is expected to contribute less to the barrier at Cape Otway.
Adaptive capacity
The adaptive capacity of reef-dwelling organisms to projected changes to currents and upwellings
will primarily be influenced by:
life history strategy (planktotrophic vs. lecithotrophic larvae)
seasonality in reproduction and dispersal (timed with peaks in upwelling)
dispersal capacity
mobility (relative to strength of currents)
availability of suitable hard substrata for colonisation; and
thermal and osmotic tolerances
11
Vulnerability
Table 2 Relative vulnerabilities of rocky reef assemblages to combined future changes in ocean currents
and upwellings
Exposure
Sensitivity
Impact
Adaptive
Capacity
Vulnerability
Western
●●●
●●
●●●
●●●
●●●
Central
●
●●●
●●
●●
●●
Embayments
●
●
●
●●
●
Eastern
●●
●●●
●●●
●●
●●●
Western
●●●
●●●
●●●
●●●
●●●
Central
●
●
●●●
●●
Embayments
●
●
●
●●●
●●
Eastern
●●
●●●
●●●
●●●
●●●
Western
●●●
●●●
●●●
●●●
●●●
Central
●
●●●
●●
●●●
●●●
Embayments
●
●●●
●●
●●●
●●●
●●
●●●
●●●
●●●
●●●
Habitat
Region
Intertidal
Shallow
Subtidal
Deep
Subtidal
Eastern
Relative vulnerabilities are indicated by colours: high=dark blue, medium=light blue, low=green.
Where uncertainty in predictions exists: ●●● = high, ●● = moderate, ●= low level of uncertainty; no dot
indicates relative confidence in prediction
Temperature
Exposure
Sea surface temperatures (SSTs) in southern Australia have increased by 0.16–0.20°C per decade
since 1950 (WaterTechnology, 2012). This warming has occurred simultaneously with an increase in
the frequency of extreme hot events, a decrease in the frequency of extreme cold events and an
advance in the timing of seasonal warming (Lima and Wethey, 2012).
SST is projected to increase further in the future with up to 1°C increase across Victoria by 2030,
with regional and seasonal differences in the rates of warming (WaterTechnology, 2012). Warming
will generally be greatest in the Eastern Region, influenced by the strengthening of the EAC, and
lower in the Western Region due to the strengthening of the Flinders Current and weakening of the
Leeuwin Current.
Ocean warming is projected to be fastest in autumn (<3°C for Western and Central Regions by 2100
and >3°C by 2100 for Eastern Region) and slowest in summer (<2°C for Western, >3°C for Central and
2– >3°C for Eastern Regions by 2100) and spring (<2.5°C for Western, <1.5°C for Central and
2.5–>3°C for Eastern Regions by 2100). Winter SST’s are projected to increase by <1.5°C in the west
to >3°C in the east. Similarly significant increases in SST are projected for the Embayments.
SST in the nearshore coastal regions and embayments may be further influenced by reductions in
annual rainfall and runoff (WaterTechnology, 2012).
12
Intertidal
Current and projected changes to mean SST are significant, but the most important factors for
intertidal reefs are likely to be changes to air temperatures at low tide and the frequency and
severity of extreme high temperature events. The decrease in the frequency of extreme cold events
(Lima and Wethey, 2012) (likely increasing the number of frost-free days), and coinciding with
seasonal cycles of morning low tides, may also be important for reef-dwelling intertidal organisms.
Shallow subtidal
For shallow subtidal reefs the influence of extreme weather events should largely be buffered by the
water body, such that changes to SST are likely to have the greatest influence on biota (but see
Pearce et al., 2011). However, the upper subtidal area may have greater exposure to increased air
temperatures, particularly if extreme weather events coincide with spring tides (e.g. Durvillaeabased assemblages).
Deep subtidal
Deep subtidal reefs are less likely to be affected by increases in SST. However, there is currently high
uncertainty about temperature increases at depths >20 m. Deep bottom waters on the open coast
generally undergo cyclical summer stratification followed by winter mixing, where temperatures
may differ seasonally (cooler in summer, warmer in winter) by 5–10°C (Levings and Gill, 2010).
Sensitivity
There are significant differences in rocky reef biota across the regions and embayments, with
particularly high endemism (O'Hara et al., 2010; Phillips, 2001). These regional differences in marine
flora and fauna are the result of complex interactions of ecological, biogeographical and
phylogenetic processes occurring on evolutionary time scales (Phillips, 2001; Waters et al., 2010).
Bass Strait may provide a barrier for species at the northern limit of the distribution (Wernberg et
al., 2011a) to retreat to Tasmania, particularly species with limited dispersal (but see McKenzie and
Bellgrove, 2006).
The impact of extreme events (Wethey et al., 2011) and changes to variability in temperature (Lima
and Wethey, 2012) on reef biota may be more important than projected changes to mean
temperature and impacts on reef ecosystems. This may be particularly true for intertidal reefs
(Hawkins et al., 2008; Wethey et al., 2011).
Intertidal
Intertidal environments are naturally highly variable with respect to temperature (and other
physico-chemical parameters) due to tidal cycles of emersion and submersion, with vertical
elevation influencing the period of emersion. Organisms which inhabit rocky intertidal reefs
generally have broad temperature tolerances as a result. However, many populations of intertidal
organisms, particularly those close to their distributional limits, may already experience their
physiological limits under current temperature profiles (Nguyen et al., 2011; Stillman and Somero,
2000). Such species are likely to be highly sensitive to further increases in sea and air temperatures
and increases in extreme temperature events (Hawkins et al., 2008; Lima and Wethey, 2012).
The rate of warming can also greatly influence the capacity of intertidal species to tolerate increased
temperatures (Nguyen et al., 2011). Rock pools may provide refugia from heat stress for some
intertidal species, however sea level rise will influence the availability of suitable rock pools in the
future.
Shallow subtidal
Shallow subtidal reefs in Victoria are often dominated by various species of kelp: large
phaeophycean algae in the orders Laminariales (Macrocystis and Ecklonia) and Fucales (particularly
diverse in temperate Australia (Womersley, 1987) including Durvillaea, Phyllospora, Sargassum and
13
Cystophora species). These kelps are often autogenic ecosystem engineers (Jones et al., 1994; Jones
et al., 1997), providing important habitat e.g. increased structural complexity, and changing the
environment by directly or indirectly modifying abiotic conditions and/or biotic interactions between
species e.g. they reduce light (Reed and Foster, 1984), wave action (Estes and Palmisano, 1974), or
predation risk (Velimirov and Griffiths, 1979), resulting in unique assemblages associated with the
kelps (Smith et al., 1996; Wernberg et al., 2003).
Kelps are sensitive to high temperatures, particularly during reproduction and recruitment, such that
changes in the composition and/or abundance of kelp stands due to temperature may have
significant direct and indirect flow-on effects for associated assemblages (Wernberg et al., 2011c).
Fucoid and laminarian algae are also sensitive to other anthropogenic stressors such as nutrient
inputs and water transparency and quality (Connell et al., 2008; Cormaci and Furnari, 1999).
Sensitivity of native kelps to multiple stressors may open the path for successful invasions by
introduced species (Valentine and Johnson, 2003; Valentine and Johnson, 2004), with a potentially
different suite of consequences for other biota.
The sensitivity of kelp-based, shallow subtidal reef systems will be influenced by extension of the
EAC and the potential to transport novel herbivores into temperature-stressed and over-fished
assemblages (Johnson et al., 2011; Ling, 2008; Ling et al., 2009a).
Deep subtidal
Deep subtidal reefs should generally be less sensitive to increases in SST and extreme events than
shallower reefs. However, it is difficult to assess likely impact and vulnerability because of
uncertainty around projected changes to sea temperature below 20 m.
Impact
Increases in mean SST and an advance in the timing of seasonal warming (Lima and Wethey, 2012)
can drive changes to phenology in a range of ectotherms by boosting metabolism and growth
(Hosono, 2011; Qiu and Qian, 1998; Takasuka and Aoki, 2006), and reducing time to maturity (Dube
and Portelance, 1992; Hosono, 2011; Qiu and Qian, 1998; Smaldon and Duffus, 1984; Tobin and
Wright, 2011). However, increased metabolic demands can cause stress to normal body function
(Neuheimer et al., 2011). These changes may be first evident in the Eastern Region, where the rate
of warming is faster due to the influence of the EAC. Phenological shifts are likely to have both
direct and indirect effects.
There is increasing evidence that species range shifts are already occurring in response to increased
SST (but see Poloczanska et al., 2011). For Australian species this implies contractions at their
equatorial (northern) limits and expansions poleward (southwards) (Johnson et al., 2011; Last et al.,
2011; Ling et al., 2009b; Millar, 2007; Pitt et al., 2010; Wernberg et al., 2011b).
Amongst these species, seaweeds are particularly susceptible (Johnson et al., 2011; Millar, 2007;
Wernberg et al., 2011b), with inevitable loss of biodiversity from significant local and global
extinctions of both seaweeds and associated species of intertidal and shallow subtidal reefs (Schiel
et al., 2004; Wernberg et al., 2011b).
This is brought about by:
lack of potential reef habitat beyond the southern edge of Australia to which to retreat
the apparently poor dispersal capacity of many seaweeds (Bellgrove et al., 2004; Coleman et
al., 2011; Coleman et al., 2009; Santelices, 1990)
significant diversity and endemism in southern Australian marine flora (Phillips, 2001); and
the autogenic engineering role of many vulnerable species (Schiel, 2006; Schiel, 2011;
Wernberg et al., 2011c).
14
Elevated water temperatures may increase susceptibility to disease by compromising immune
responses of hosts, as well as stimulating growth and proliferation of pathogens (Dang et al., 2012;
Lafferty et al., 2004; Sokolow, 2009).
Intertidal
There is evidence from the Central Region that extreme temperature events which occur earlier than
usual, in early spring, can cause significant canopy loss of the intertidal autogenic engineer,
Hormosira banksii, and associated changes to the mid-shore communities (Keough and Quinn,
1998). H. banksii can be slow to recover from such disturbances and the impacts on the whole
community can be long-lasting (Keough and Quinn, 1998; Schiel, 2011).
Changes to extreme hot and cold events along the Victorian coast (Lima and Wethey, 2012) may
result in changes to the vertical distributions of intertidal biota, coupled with the influence of sea
level rise on habitat availability and vertical distributions of species.
Shallow subtidal
Range shifts and loss of biodiversity will have important implications for the structure of shallow
subtidal reef systems as discussed generally above.
Increased temperatures (mean and extreme) and advanced seasonal warming are likely to alter both
timing of reproduction and recruitment success, due to vulnerability of larval development (Byrne et
al., 2010) of reef-dwelling biota, including economically important species. For example, the
southern rock lobster Jasus edwardsii is expected to respond to increased temperature with
decreased recruitment, leading to reductions in biomass, despite predicted higher growth rates (Pecl
et al., 2009). Similarly, increased SST may lead to a reduction in biomass of the commercially
harvested abalone Haliotis rubra (Mellin et al., 2012). H. rubra may be also susceptible to bacterial
pathogens under future SST scenarios (Dang et al., 2012), further impacting biomass.
Increased SST has led to extensive loss of kelp biomass and extent e.g. Macrocystis pyrifera in
Tasmania (Johnson et al., 2011) and range contractions at the northern distributional limits
(Durvillaea potatorum, Ecklonia radiata, Phyllospora comosa (Millar, 2007)). It is likely that
projected temperatures for Victorian waters will stress these species and potentially increase
vulnerability to disease (Lafferty et al., 2004)
Deep subtidal
Range shifts may also be experienced by deep reef biota, although no documented examples are
evident. There are likely to be both direct and indirect effects of displacing cold-water biota, with
changes to community structure and potential loss of diversity. The impact of changes to major
currents on temperature are likely to be important for deep reefs, and impacts may be observed first
in the far east of Victoria, affected by the extension of the EAC.
Adaptive capacity
Changes to the distribution and abundance of autogenic engineers such as Hormosira banksii in the
intertidal, and various laminarian and fucoid kelps in the shallow subtidal, can have cascading effects
on the structure, diversity and resilience of associated communities (Johnson et al., 2011; Schiel,
2006; Schiel, 2011; Schiel and Lilley, 2011; Wernberg et al., 2011b).
Understanding the connectivity and genetic diversity (Coleman et al., 2011; Coleman et al., 2009),
and differences in temperature tolerance (Wernberg et al., 2011c) of Victorian populations of
important intertidal and subtidal habitat-forming species, in the context of their broader
geographical distributions, will be important for assessing the capacity of these species (and their
associated communities) to adapt to future air and sea temperature change scenarios.
15
At all depth ranges, the mobility and behaviour (e.g. avoidance) of organisms will influence their
adaptive capacity. Geomorphology and habitat specialisation may also be important influences in
the subtidal reef systems.
16
Vulnerability
Table 3 Relative vulnerabilities of rocky reef assemblages to future changes in temperature
Habitat
Region
Exposure
Sensitivity
Impact
Adaptive
Capacity
Vulnerability
Western
Central
.
Intertidal
Embayments
Eastern
Shallow
Subtidal
●
Western
●
●
Central
●
●
●
●
●
●
Embayments
●
●
●
Eastern
Deep
Subtidal
Western
●●●
●●●
●●●
●●●
●●●
Central
●●●
●●●
●●●
●●●
●●●
Embayments
●●●
●●●
●●●
●●●
●●●
Eastern
●●●
●●●
●●●
●●●
●●●
Relative vulnerabilities are indicated by colours: high=dark blue, medium=light blue, low=green.
Where uncertainty in predictions exists: ●●● = high, ●● = moderate, ●= low level of uncertainty; no dot
indicates relative confidence in prediction
Salinity
Exposure
Sea surface salinity is expected to decrease by < 0.5 PSU in the Western and Central Regions and
increase by <1 PSU in the Eastern Region by 2100 (WaterTechnology, 2012), influenced by the major
current streams.
There are potentially significant increases in sea surface salinity in the Embayments under all future
climate scenarios due to projected reductions in rainfall and freshwater inflows e.g. 0.2–3 PSU in PPB
by 2030 (WaterTechnology, 2012).
Importantly, there is likely to be greater variability in salinity in the Embayments than in the open
coast due to the influence of reduced annual rainfall on one hand and increased extreme weather
events on the other. This will alter frequency, duration and magnitude of freshwater inflows into
the Embayments (Water Technology, 2012), however this has not been modelled. Extreme rainfall
events are also likely to create localised plumes of reduced-salinity, high turbidity water in the
nearshore open coast. The EAC may drive significant changes in salinity in the Eastern Region.
Sensitivity
Intertidal
Salinity levels in the intertidal can be highly variable and can change rapidly in response to tidal flow,
rainfall, freshwater inflow/runoff and evaporation (Brierley and Kingsford, 2009; Wheatly, 1988). It
is important to note that salinity usually varies in combination with other factors such as
temperature and levels of dissolved gases, and organisms therefore respond to changes in multiple
17
stressors (Wheatly, 1988). As noted for temperature, rocky intertidal organisms generally have
broad salinity tolerances, but may similarly be operating at their physiological limits under current
day profiles (Somero, 2012).
Shallow subtidal
Subtidal reefs have more stable salinities than intertidal reefs, but may experience seasonal
stratification. Increased sea surface salinity in the Embayments may result in increased
stratification, but will also be influenced by mixing.
Deep subtidal
Changes to the salinity of reefs beyond 30 m may not be strongly correlated with sea surface
salinities. Changes to major currents may have greater influence on salinity of deep reefs. The
systems are expected to have low sensitivity to projected changes.
Impact
On the open coast modest reductions of <1 PSU to mean sea surface salinities may not have
dramatic impacts on reef biota. However, more variable salinity profiles driven by increases in
extreme weather events will likely impact both Embayments and open coasts, particularly in the
vicinity of estuaries.
On the open coasts, development and mortality of planktonic dispersive propagules might be most
vulnerable to variations in salinity (Deschaseaux et al., 2011; Fredersdorf et al., 2009).
Intertidal
Parasites (particularly trematodes) commonly infest rocky intertidal invertebrates and can directly
influence both host population numbers and behaviour, and indirectly affect other species through
altered interactions with host species (Mouritsen and Poulin, 2002). There is evidence that changes
in salinity may differentially affect parasites and their hosts, resulting in altered population
dynamics. Reductions in salinity can negatively influence the transmission of trematode parasites,
thereby reducing the prevalence of parasites (Studer and Poulin, 2012). In contrast hypersalinity,
which may occur in tide pools or on emergent reefs due to high evaporation with increased air
temperatures and more extreme hot events, can be favourable for parasite transmission but not for
hosts (Studer and Poulin, 2012).
The habitat-forming fucoid alga, Hormosira banksii, which is ubiquitous on intertidal rocky shores
throughout open coast and Embayments, is sensitive to low salinities (Boyle et al., 2001; Doblin and
Clayton, 1995; Kevekordes, 2000) and high salinities (A. Bellgrove, unpublished data). Increased
exposure to periods of extreme low and high salinity on rocky intertidal shores on the open coast, as
well as increased variability in salinity within the Embayments, will likely compromise health of
established plants, leading to canopy reductions (Boyle et al., 2001) and recruitment failure due to
vulnerability of early life stages to extremes in salinity (Doblin and Clayton, 1995; Kevekordes, 2000;
A. Bellgrove unpublished data). Subsequent changes to other species abundances and distribution
may result (Keough and Quinn, 1998; Schiel, 2006; Schiel and Lilley, 2011).
Shallow subtidal
Whilst black bream Acanthopagrus butcheri are typically estuarine fish, they can also be found on
the open Victorian coast and in the Embayments (T. Matthews, pers. comm.). Recruitment of black
bream has been shown to be affected by water column stratification and freshwater flow (Jenkins et
al., 2010), such that increased salinity and reduced stratification in the Embayments and Gippsland
Lakes may compromise populations of black bream in Victoria (Jenkins et al., 2010).
Changes in sea-surface salinity are also likely to compromise the health and development of
planktonic dispersive stages (Fredersdorf et al., 2009) and negatively affect recruitment of subtidal
reef flora and fauna.
18
Deep subtidal
There is no information on how deep subtidal reef organisms on the Victorian coast are likely to be
affected by modest changes to sea surface salinities. It is likely that changes to major currents may
have greater influence on the salinity of deep reefs. More research is needed to predict with more
certainty future salinities in deep reef systems and potential impacts on the biota.
Adaptive capacity
The adaptive capacity of intertidal and subtidal reef organisms with respect to projected changes to
salinity will be influenced by:
short and long-term osmotic tolerance and/or regulation of both adults and the more
vulnerable planktonic propagules
mobility and behaviour (e.g. avoidance) of organisms
habitat specialisation; and
geomorphology.
Understanding the connectivity and genetic diversity, particularly of autogenic engineers, will also be
critical for understanding resilience of intertidal and subtidal reef communities.
Vulnerability
Table 4 Relative vulnerabilities of rocky reef assemblages to future changes in salinity
Habitat
Exposure
Sensitivity
Impact
Adaptive
Capacity
Vulnerability
Western
●
●●●
●●
●●
●●
Central
●
●●●
●●
●●
●●
Embayments
●
●●●
●●●
●●●
???
Eastern
●●
●●●
●●●
●●
???
Western
●
●●●
●●
●●
●●
Central
●
●●●
●●
●●
●●
Embayments
●
●●●
●
●●●
●●
Eastern
●●
●●●
●●●
●●
●●●
Western
●●
●●●
●●●
●●●
●●●
Central
●
●●●
●●
●●●
●●●
Embayments
●
●●●
●●
●●●
●●●
●●
●●●
●●●
●●●
●●●
Region
Intertidal
Shallow
Subtidal
Deep
Subtidal
Eastern
Relative vulnerabilities are indicated by colours: high=dark blue, medium=light blue, low=green.
Where uncertainty in predictions exists: ●●● = high, ●● = moderate, ●= low level of uncertainty; no dot
indicates relative confidence in prediction
19
Waves
Exposure
There are regional differences in the wave climate along the Victorian coast and Embayments, with
Western Region exposed to some of the highest wave energy experienced anywhere in the world
(WaterTechnology, 2012). The Southern Annular Model (SAM) is projected to increase, leading to
increases in both frequency of large wave events and wave heights, and an anti-clockwise rotation in
wave direction (reducing the frequency of strong westerly winds and increasing the prevalence of
south-easterly winds) (WaterTechnology, 2012). These effects will have the greatest influence in the
Western and Central Regions. The reduction in the frequency of strong westerly winds is predicted
to result in a reduction of wave energy in the Embayments. There are no significant changes in the
wave climate predicted for Eastern Victoria. The Embayments may experience a reduction in wave
energy (WaterTechnology, 2012) which may have consequences for mixing.
Intertidal and shallow subtidal environments, particularly in Western Victoria are likely to have the
greatest exposure to the predicted changes to wave climate. Deep subtidal reefs will be less
influenced by changes to surface waves, but the increase in wave energy at depth, and changes to
wave direction, may still be important.
There is relatively high uncertainty surrounding future wave climates in Victoria (WaterTechnology,
2012).
Sensitivity
As waves break, they rapidly produce complex, highly energetic turbulence, with associated rotating,
stretching and twisting eddies of propagating bores. The primary forces experienced by organisms
in these conditions are drag and impingement of breaking waves (Gaylord et al., 2008). Such
hydrodynamic forces place severe mechanical stress on organisms living in wave-swept
environments and can constrain the sizes of intertidal plants and invertebrates (Blanchette, 1997
and references therein).
However, unlike wave-swept invertebrates, algae are typically weak, compliant and easily dislodged
(Denny and Gaylord, 2002). Intertidal and shallow subtidal sessile and sedentary species that cannot
behaviourally avoid increases in wave energy may be highly sensitive to future wave climates.
Increased wave energy may also disrupt the boundary layer (Denny, 1988) and affect settlement and
recruitment phases (Taylor and Schiel, 2003).
Increases to wave energy may be expected to increase mixing and may reduce vertical stratification
(Levings and Gill, 2010), interacting with temperature and nutrient levels at all depth ranges.
Impact
In the Western and Central Regions, prevailing winds are from the south-west for most of the year,
with south-easterly winds more common during summer. An increase in prevalence of southeasterly winds combined with an increase in wave energy, particularly in the Western Region
(WaterTechnology, 2012), should mean that intertidal and shallow subtidal reefs with
easterly/south-easterly aspect (typically more sheltered in the current wave climate) may
experience greater impacts than reefs with westerly/south-westerly aspects.
Changes in the direction of winds may drive changes in nearshore currents and may potentially
influence delivery of propagules to rocky reefs, leading to altered recruitment patterns (OcchipintiAmbrogi, 2007).
Dislodgement of algae can facilitate long-distance dispersal of fertile fronds which remain
reproductively viable and which disperse propagules (Macaya et al., 2005; McKenzie and Bellgrove,
2009; Stewart, 2006; van den Hoek, 1987). Wave-driven increases in dislodgement of fertile
20
intertidal and subtidal algae have the potential to increase connectivity between populations,
altering gene flow and the potential for range shifts.
Intertidal
Changes to the wave climate (particularly with respect to increased maximum wave height) in
New Zealand, coupled with the wider-ranging effects of ENSO, have been correlated with decreases
in the abundance of the intertidal canopy alga Hormosira banksii (Schiel, 2011). As mentioned
previously, loss of a H. banksii canopy can have long-term direct and indirect effects on other
intertidal species. These effects may be amplified with projected increases in wave energy, as a
canopy of H. banksii has been shown to reduce water flow for other species. The vulnerability of
H. banksii to increases in wave energy is probably, at least in part, due to susceptibility of zygotes to
dislodgement (Taylor et al., 2010; Taylor and Schiel, 2003) and relative ease of dislodgement of
fronds (McKenzie and Bellgrove, 2009).
H. banksii is ubiquitous along the Victorian open coast and Embayments, but tends to be sparsely
distributed on rocky shores in the Western Region (A. Bellgrove pers. obs.) where wave energy is
highest. Projected increases in wave energy and storm surge in the Western Region are likely to
result in proportionally greater canopy loss of H. banksii in this region, and a switch to
turf-dominated assemblages, which may limit potential for recolonisation by H. banksii (Bellgrove et
al., 2010).
Invertebrates which inhabit intertidal rocky shores, particularly in the Western Region, may face
size-selection pressure (Menge, 1976) under future wave climates, leading to a likely reduction in
body size of sessile and sedentary species, e.g. molluscs and barnacles, and likely shifts from grazer
to filter-feeder dominated systems (Brierley and Kingsford, 2009).
Shallow subtidal
Mosaics of habitat patches on rocky reefs have long been recognised (Sousa, 1984), created and
maintained by a number of potential drivers. In temperate south-western Australia, disturbance by
waves has been shown to dislodge significant canopy algae (Ecklonia radiata and Sargassum spp.) to
create open-gap habitats with vastly different assemblage structures (Thomson et al., 2012). It is
highly likely that these kelps and others are equally susceptible to wave exposure on Victorian rocky
reefs. As noted for intertidal reefs, an increase in frequency of large wave events and wave heights,
particularly in the Western Region, may result in increased rates of dislodgement of canopy-forming
algae and creation of open-gap habitats, with subsequent direct and indirect changes to community
structure.
Increases in wave energy may also alter the temporal dynamics of algal canopy loss, and ultimately
reduce species diversity on shallow subtidal reefs (Wernberg and Goldberg, 2008). The scale of
canopy loss may be influenced by synergistic effects of temperature and nutrient sensitivities with
wave exposure. Once created, open-gap patches can persist for decades (Thomson et al., 2012).
In addition to direct and indirect effects of wave-driven, algal canopy loss on shallow subtidal
invertebrates, there are also likely to be direct effects of increased wave energy on invertebrates.
For example, the sea urchin Heliocidaris erythrogramma is sensitive to wave exposure (Thomson et
al., 2012), and population declines may occur in sites which currently are relatively sheltered but
which will experience greater wave exposure in the future.
Deep subtidal
With the high level of uncertainty in understanding of the ecology of deep subtidal reefs in Victoria,
it is difficult to make accurate predictions about how changes in future wave climate may affect
these systems. It is likely that any significant changes to temperature and nutrient cycling (and
seasonality of these), driven by wave-induced increases in mixing and reduced stratification, will
result in changes to structure and function of deep reef assemblages, with potential consequences
for biodiversity. More research is needed to accurately assess potential impacts.
21
Adaptive capacity
The adaptive capacity of canopy algae-based communities to future wave climates on intertidal and
shallow subtidal rocky reefs will be influenced by:
the algal biomechanics and associated risk of dislodgement (Blanchette, 1997; Denny, 1988;
McKenzie and Bellgrove, 2009) and ecomechanics (Denny and Gaylord, 2010) more broadly
dispersal and recruitment dynamics and capacity to recolonise disturbed areas (Bellgrove et
al., 2004; Macaya et al., 2005; McKenzie and Bellgrove, 2009; Santelices, 1990; van den
Hoek, 1987)
the influence of existing or new herbivores on canopy algae and persistence of open-gap
patches (Johnson et al., 2011; Ling, 2008; Thomson et al., 2012); and
direct and indirect effects of the presence/loss of an algal canopy on other biota in the
system (e.g. Johnson et al., 2011; Schiel, 2006; Schiel, 2011; Wernberg and Goldberg, 2008;
Wernberg et al., 2003).
The adaptive capacity of reef fauna will also be influenced by:
mobility and behaviour (e.g. avoidance) and habitat specialisation of species
geomorphology and reef orientation
fecundity, dispersal dynamics and generation time (with respect to size-selection pressures).
Vulnerability
Table 5 Relative vulnerabilities of rocky reef assemblages to future changes in wave climate
Habitat
Exposure
Sensitivity
Impact
Adaptive
Capacity
Vulnerability
Western
●●●
●
●●
●●
●●
Central
●●●
●
●●
●●
●●
Embayments
●●●
●
●●
●●
●●
Eastern
●●●
●
●●
●●
●●
Western
●●●
●
●●
●●
●●
Central
●●●
●
●●
●●
●●
Embayments
●●●
●
●●
●●
●●
Eastern
●●●
●
●●
●●
●●
Western
●●●
●●
●●●
●●
●●●
Central
●●●
●●
●●●
●●●
●●●
Embayments
●●●
●●
●●●
●●●
●●●
Eastern
●●●
●●
●●●
●●●
●●●
Region
Intertidal
Shallow
Subtidal
Deep
Subtidal
Relative vulnerabilities are indicated by colours: high=dark blue, medium=light blue, low=green.
Where uncertainty in predictions exists: ●●● = high, ●● = moderate, ●= low level of uncertainty; no dot
indicates relative confidence in prediction
22
Carbon Dioxide and Acidification
Exposure
Ocean pH is projected to decrease (become more acidic) by ~0.1 pH units by 2030 and by ~0.3 pH
units by 2100, with a slightly greater reduction in the Western Region moving to the Eastern Region
(WaterTechnology, 2012). This equates to approximately 100% increase in the concentration of
hydrogen ions by 2030 (Orr et al., 2005). The pH levels in Embayments are projected to decrease by
>0.1 and >0.3 pH units by 2030 and 2100, respectively, although there is greater uncertainty around
projections for Embayments than Ocean (WaterTechnology, 2012).
The oceans have absorbed ~50% of anthropogenically derived carbon dioxide (CO2) in the past
200 years (Sabine et al., 2004). Atmospheric carbon dioxide is directly related to ocean pH (Caldeira
and Wickett, 2003), and pH interacts with carbonate availability (Brierley and Kingsford, 2009). This
means that increases in atmospheric CO2 lead to a simultaneous increase in aqueous CO2, and a
decrease in the concentration of carbonate ions and pH (Fabry et al., 2008; Orr et al., 2005).
Sensitivity
Many marine organisms from diverse taxa (e.g. molluscs, echinoderms, crustaceans, fish, coralline
algae, phytoplankton) have calcified skeletons or other structures which are formed from calcium
carbonate derived from primarily (in order of decreasing solubility) magnesium-calcite (Mg-calcite),
aragonite, or calcite crystals (Andersson et al., 2008; Fabry et al., 2008). The Southern Ocean is
predicted to be undersaturated in aragonite by 2100, and in calcite within a further 50–100 years
(Orr et al., 2005). Mg-calcite undersaturation will precede that of aragonite due to higher solubility
(Andersson et al., 2008). As a result, calcifying reef organisms, particularly those dependent on
Mg-calcite or aragonite, may have highest sensitivity to ocean acidification (Andersson et al., 2008;
Brierley and Kingsford, 2009; Ries et al., 2009).
The decrease in carbonate availability is matched by an increase in aqueous CO2 (Orr et al., 2005),
which has the potential to drive increased rates of photosynthesis of photoautotrophs, as CO2 is the
substrate for photosynthesis (Beardall et al., 1998). Intertidal macroalgae may be least sensitive/
responsive to increased CO2, because most are already at CO2 saturation (Beardall et al., 1998).
However, photosynthesis in many subtidal macroalgae has been shown to be limited by dissolved
inorganic carbon (Holbrook et al., 1988) so they may be more responsive to elevated CO2 with
enhanced photosynthetic rates (Beardall et al., 1998). Photosynthesis is unlikely to be greatly
enhanced in species with carbon-concentrating mechanisms because they largely rely on an ability
to use bicarbonate ions, which will not change greatly in the future (Beardall et al., 1998; Israel and
Hophy, 2002).
Conversely, marine fauna may show physiological sensitivity to hypercapnia (increased partial
pressure of CO2 in seawater) through disruption of the cellular acid-base balance and reduced
oxygen transport capacity (Fabry et al., 2008). Species with high pH-buffering capacity (such as
active fish and rockpool inhabitants), high tolerance to bicarbonate accumulation, and/or effective
ion transport mechanisms may be most robust to hypercapnia, but more research is needed (Fabry
et al., 2008).
Although the greatest changes to ocean pH are likely to occur in shallow waters, deep reef biota may
be highly sensitive to even small pH changes (Seibel and Walsh, 2001). The relatively stable
environmental conditions and reduced oxygen at depth, combined with low rates of metabolism of
deep reef biota may limit the capacity for ion exchange and acid-base regulation and may increase
sensitivity to hypercapnia (Fabry et al., 2008; Seibel and Walsh, 2001).
23
Impact
Research into the likely impacts of elevated CO2 and ocean acidification is only in its infancy.
Consequently there is a high level of uncertainty, particularly in understanding the indirect
community interactions that might flow from direct impacts of elevated CO2 and ocean acidification
on individual species. Most research has focused on the effects of acidification on corals and
coccolithophores, with less emphasis on temperate rocky reef biota.
Several studies (Andersson et al., 2008; Brierley and Kingsford, 2009; Fabry et al., 2008; Orr et al.,
2005) have suggested that projected decreases in ocean pH will compromise the calcified structures
of marine organisms due to dissolution of Mg-calcite and aragonite in particular, and disruption of
the mineralisation process with potential to impact on growth and survival. However, it appears
that the story is more complex, with other examples where calcification and growth of organisms
were enhanced under acidification scenarios (Doney et al., 2009; Ries et al., 2009). The same has
also been seen for the planktonic coccolithophores (Beaufort et al., 2011)
Ocean acidification can negatively affect the early life history phases of calcifying taxa in complex
ways, with direct and indirect effects on multiple processes e.g. metabolism, fertilisation, larval
development, growth, settlement (Albright and Langdon, 2011; Fabry et al., 2008). Molluscs and
echinoderms whose larval skeletal structures are composed of highly soluble, unstable, transient,
amorphous calcium carbonate may be particularly vulnerable (Fabry et al., 2008). It is possible, and
perhaps likely, that vulnerable early life history stages of non-calcifying organisms are also affected
by acidification through physiological stress and disruption (Fabry et al., 2008).
Intertidal and shallow subtidal
Molluscs, echinoderms, crustaceans, serpulid worms and fish are ubiquitous and diverse on
Victorian intertidal and shallow subtidal rocky reefs, and provide a diversity of ecosystem services
(Hutchinson et al., 2010). Species within these taxa have calcified skeletal/protective structures or
other potential vulnerable calcified parts e.g. otoliths in fish. Calcified algae, particularly species
within the Corallinaceae, are also abundant and diverse on Victorian reefs, providing both important
habitat e.g. turfing species in the intertidal (Kelaher, 2002; Kelaher et al., 2001) and settlement cues
for commercially important abalone (encrusting coralline species and Haliotis spp.) (de Viçose et al.,
2010; Roberts and Watts, 2010).
Recruitment limitation and changes in abundance of calcified species may have community and/or
ecosystem scale effects (Albright and Langdon, 2011; Beardall et al., 1998; Fabry et al., 2008; Ries et
al., 2009), with possible reductions in diversity, structural complexity and resilience of systems
(Fabricius et al., 2011).
Shallow subtidal reefs in Victoria are largely dominated by canopy-forming fucoid and laminarian
kelps, with coralline algae a conspicuous component of the understorey (Hutchinson et al., 2010).
These kelps are suggested to have functioning carbon-concentrating mechanisms (CCMs) and are
therefore predicted to show little response to elevated CO2 (Hepburn et al., 2011).
Algal species without CCMs have been shown to be more abundant with increasing depth on
New Zealand rocky reefs, although occupying <10% of the substratum (Hepburn et al., 2011). These
species accounted for more than 50% of non-calcifying red algae (Hepburn et al., 2011). It is
reasonable to assume that at least a similar proportion of the highly diverse, red algal flora on
Victorian reefs are also without CCMs due to phylogenetic conservation of CCMs (Beardall et al.,
1998). These species are suggested to benefit from increased CO2 (Beardall et al., 1998; Hepburn et
al., 2011; Israel and Hophy, 2002). Mesocosm experiments on the South Australian coast showed
that understorey algal turfs doubled in biomass and quadrupled occupation of space under future
CO2 and temperature scenarios (Russell et al., 2009). Field manipulations showed that these turfing
algae inhibited recruitment of the laminarian kelp Ecklonia radiate (Connell and Russell, 2010).
24
Deep subtidal
Non-calcifying red algae may become a more conspicuous component of deep subtidal reefs, at least
to depths for which there is sufficient light (Hepburn et al., 2011; Russell et al., 2009). Deep reef
communities may be further altered by physiological stress to dominant fauna (Fabry et al., 2008;
Seibel and Walsh, 2001) and dissolution of calcareous structures of important space occupiers such
as sponges. Unique and extensive rhodolith beds on the Victorian coast (Ierodiaconou et al., 2011)
may also be vulnerable to demineralisation of cell walls.
Adaptive capacity
The adaptive capacity of marine algae to elevated CO2 and lowered pH may depend on:
the presence/absence of CCMs (Beardall et al., 1998)
the capacity for positive effects on photosynthesis to counteract negative effects of
acidification, particularly for vulnerable early life history stages (Roleda et al., 2012); and
direct and indirect interactions with other species (Russell et al., 2009).
The capacity of reef fauna to adapt to elevated CO2 and lowered pH will be largely influenced by:
their ability to tolerate and/or regulate the physiological stress concomitant with
hypercapnia (Fabry et al., 2008)
the carbonate chemistry of any calcified structures (Andersson et al., 2008; Ries et al., 2009)
the level of protection to their outer shell layer afforded by an organic covering (Ries et al.,
2009)
synergistic effects of other stressors; and
direct and indirect interactions with other species(Doney et al., 2009).
Vulnerability
Table 6. Relative vulnerabilities of rocky reef assemblages to combined future changes in CO2 & acidification
Habitat
Sensitivity
Impact
Adaptive
Capacity
Vulnerability
Western
●●
●
●●●
●●
Central
●●
●
●●●
●●
●●
●
●●●
●●
Eastern
●●
●
●●●
●●
Western
●●
●
●●●
●●
Central
●●
●
●●●
●●
●●
●
●●●
●●
Eastern
●●
●
●●●
●●
Western
●●●
●●
●●●
●●
Central
●●●
●●
●●●
●●
●●●
●●
●●●
●●
●●●
●●
●●●
●●
Region
Exposure
Intertidal
Embayments
Shallow
Subtidal
Deep
Subtidal
Embayments
Embayments
Eastern
●
●
●
Relative vulnerabilities are indicated by colours: high=dark blue, medium=light blue, low=green.
Where uncertainty in predictions exists: ●●● = high, ●● = moderate, ●= low level of uncertainty; no dot
indicates relative confidence in prediction.
25
Rainfall and Runoff
Exposure
The Victorian coastline has an extensive network of catchments draining into the ocean, with
approximately 108 estuaries across the state, half of which are intermittently open (Barton, 2006).
Consequently, predicted changes to rainfall and storm events will result in large changes to coastal
runoff. Annual runoff is projected to decrease by 2030 by as much as 22% in the Western Region,
and by 18% and 14% in the Central and Eastern Regions, respectively (WaterTechnology, 2012).
By 2060, runoff is expected to decrease by up to 26–36% along the Victorian coast. The
Embayments are projected to experience 12–16% reductions in annual runoff by 2030 and up to
29% by 2060, with the greatest reduction in Port Phillip Bay (WaterTechnology, 2012).
Reductions in annual runoff will influence temperatures, salinities, and delivery of nutrients and
sediments into coastal waters, and particularly into the Embayments (WaterTechnology, 2012).
Additionally, changes to the timing, magnitude and duration of storm events will impact coastal
runoff processes (WaterTechnology, 2012) and may increase variability in nearshore
physico-chemical parameters, particularly in the Embayments.
Reductions in rainfall will interact with changes to the ocean wave climate to affect the frequency
and duration of estuarine mouth openings, which will affect the amount of runoff entering the
marine environment.
Sensitivity
Intertidal
Intertidal reefs are sensitive to changes in delivery of nutrients, sediments and freshwater into the
coastal environment as a result of rainfall, runoff and wastewater discharge (Airoldi, 1998; Brown et
al., 1990; McKenzie et al., in prep). High concentrations of nutrients not only provide valuable food
sources for intertidal algae, invertebrates and fishes, but can also affect recruitment abilities of some
intertidal algal species (Dagg et al., 2004; Doblin and Clayton, 1995; Grimes and Kingsford, 1996b;
Schlacher and Connolly, 2009). Freshwater runoff also reduces salinity levels of the intertidal zone.
Shallow subtidal
With sea level rise, an increase is likely in the relative proportion of low relief reef in the shallow
subtidal on the Victorian coast (Figure 2). We may thus expect greater rates of sedimentation in the
future, particularly when associated with large and prolonged, episodic flood events. Reef biota are
expected to be highly sensitive to increases in the magnitude and variability (Airoldi, 1998) of
sedimentation events. Shallow subtidal flora may also be sensitive to changes to nutrient delivery
(Brown et al., 1990; McKenzie et al., in prep), however more research is needed to fully understand
potential impacts, particularly with regards to interactions with upwelling events.
Deep subtidal
Little is known about the influence of rainfall and runoff on deep subtidal reef systems, but they are
assumed to be less sensitive than shallower reef systems.
Impact
With greatest (22%) reductions in annual rainfall and runoff predicted for the Western Region by
2030 (WaterTechnology, 2012), it would be expected that intertidal and subtidal reefs would be
most impacted in this region, compared to the rest of Victoria. The extent and influence of estuarine
discharge on coastal systems will depend on wind, tidal regimes, topography of the entrance of the
estuary along with the nature of the ocean currents (Gillanders and Kingsford, 2002).
26
Intertidal
Estuarine discharge from large, permanently open river systems has been shown to deliver high
concentrations of nutrients and organic matter to the marine receiving environment, stimulating
primary productivity, increasing pelagic invertebrates, fish recruitment and altering water quality of
adjacent coastal waters (Banaru et al., 2007; Dagg et al., 2004; Lane et al., 2007; Liu and Dagg, 2003;
Lohrenz et al., 1999; Lu et al., 2010; Rabalais et al., 2000). Similar patterns have been shown for
intermittently open systems, where intermittent estuaries release high nutrient loads to coastal
waters, changing water quality and reducing salinity and temperature (McKenzie et al., in prep).
Predicted future reductions in rainfall and runoff are likely to contribute to a reduction in nutrients
and organic matter inputs to the marine environment. This would affect nearshore coastal
productivity, possibly benefiting nutrient-sensitive fucoid algae (Brown et al., 1990; Chapman, 1995),
but reducing food availability for invertebrates (Hill et al., 2008; Hill et al., 2006). A reduction in
runoff is also likely to increase the frequency of estuary mouth closure, resulting in less fresh and
marine water exchange to regularly occur.
Future changes to the timing, magnitude and duration of storm events are likely to cause intertidal
communities to be exposed to large pulse flooding events which deliver high concentrations of
nutrients and freshwater. The impacts of large pulses may override reductions in annual runoff, but
there is high uncertainty in both exposure and sensitivity of biota/ecosystems to such pulses.
Changes are likely in intertidal algal communities, where evidence shows greater abundance of
opportunistic ephemeral green algae to inhabit areas of high nutrients (Bellgrove et al., 2010; Brown
et al., 1990; McKenzie et al., in prep). High nutrient waters also provide food sources for higher
trophic levels of invertebrates and fish, with high runoff areas contributing to some of the most
productive areas of the ocean (Dagg and Breed, 2003; Grimes and Kingsford, 1996a; Hill et al., 2008;
Hill et al., 2006; Lohrenz et al., 1999; Schlacher and Connolly, 2009; Smith and Demaster, 1996).
However, increased runoff could have detrimental effects on recruitment abilities of fucoid algae
such as Hormosira banksii, due to high nutrients and reduced salinities (Boyle et al., 2001; Doblin
and Clayton, 1995). Unpredictable periods of high runoff will not only affect macroalgae
communities but may also indirectly affect invertebrate fauna via reductions in suitable habitat
(Schiel and Lilley, 2011). Additionally, there is evidence that runoff can increase the chance of
disease in corals due to introduction of terrestrial pathogens (Lafferty et al., 2004; Sokolow, 2009).
The same may be true for temperate reef systems, although further research is required.
Extreme, episodic rainfall and runoff events will also increase sediment loads, resulting in increased
turbidity, deposition and burial in intertidal and newly low relief shallow subtidal reefs affected by
sea level rise. High turbidity will decrease light penetration, and may compromise photosynthetic
ability of primary producers. Sedimentation can cause abrasion, anoxia, and reductions in light, and
has been shown to affect intertidal assemblage structure, usually driving a switch to a less complex
assemblage, although effects can be variable (Airoldi, 2003; Airoldi and Cinelli, 1997; Airoldi et al.,
1996; Airoldi and Virgilio, 1998; Santelices et al., 2002).
A large pulse event may have a negative impact on intertidal communities through increasing
sedimentation, however a small flood may not be so detrimental to the system, and may have a
positive impact by providing nutrients and organic matter to the system (Gaston 2006). Thus a shift
from regular but small volumes of runoff to periodically large volumes may be expected to drive
changes in reef systems. More research is needed to investigate the effects of different size floods
on rocky reef systems, including pulse versus press discharge events.
Shallow subtidal
Little research has been undertaken to investigate effects of rainfall and runoff on shallow subtidal
communities. However it would be assumed that shallow subtidal areas may show similar responses
to the intertidal systems.
27
Deep subtidal
With limited knowledge and understanding on the effects of runoff on deep subtidal reefs in
Victoria, it is difficult to make accurate predictions about how decreased runoff may affect these
reef systems. It is likely, however that impacts will be less than those experience by intertidal and
shallow subtidal systems. Deep waters are usually nutrient rich relative to shallower surface waters
such that deep reef benthos may be more tolerant of nutrient pulses than shallower species.
Similarly the runoff driven effects of salinity and temperature are expected to be less pronounced.
Sedimentation, however, may still be a problem in deep reefs, particularly within the Embayments,
where mixing regimes may change with rainfall reductions. Upwelling-driven patterns of circulation
may be more important to deep reefs than rainfall and runoff (Levings and Gill, 2010).
Adaptive capacity
It is difficult to predict whether increases in episodic pulse events will be more important than
reductions in annual flow, and any assessment of adaptive capacity has high uncertainty.
For flora and fauna at all depths, their adaptive capacity with respect to rainfall and runoff will be
influenced by:
their ability to withstand periodic sediment accretion and removal (Santelices et al., 2002)
their ability to withstand periods of low light (influencing photosynthesis, prey capture, mate
choice etc) associated with plumes
nutrient limitation (which may interact with temperature and be more severe in the Eastern
Region due to the strengthening EAC); and
ability to withstand/benefit from pulses of high nutrients and freshwater in an otherwise low
nutrient environment.
Vulnerability
Table 7 Relative vulnerabilities of rocky reef assemblages to combined future changes in rainfall and
runoff
Habitat
Exposure
Sensitivity
Impact
Adaptive
Capacity
Vulnerability
Western
●●
●●●
●●●
●●●
●●●
Central
●●
●●●
●●●
●●●
●●●
Embayments
●●
●●●
●●●
●●●
●●●
Eastern
●●
●●●
●●●
●●●
●●●
Western
●●
●●●
●●●
●●●
●●●
Central
●●
●●●
●●●
●●●
●●●
Embayments
●●
●●●
●●●
●●●
●●●
Eastern
●●
●●●
●●●
●●●
●●●
Western
●●●
●●●
●●●
●●●
●●●
Central
●●●
●●●
●●●
●●●
●●●
Embayments
●●●
●●●
●●●
●●●
●●●
Eastern
●●●
●●●
●●●
●●●
●●●
Region
Intertidal
Shallow
Subtidal
Deep
Subtidal
28
Relative vulnerabilities are indicated by colours: high=dark blue, medium=light blue, low=green.
Where uncertainty in predictions exists: ●●● = high, ●● = moderate, ●= low level of uncertainty; no dot
indicates relative confidence in prediction
INTERACTIONS & LINKAGES
The climate change projections reviewed above will not happen in isolation. It is generally agreed
that it will be the cumulative effects from a range of interacting processes that will have the greatest
impacts on existing ecosystems but will also be hardest to predict (Russell et al., 2012; Russell et al.,
2009). For example the effects of temperature or salinity on the physiology of organisms will affect
their responses to extreme events such as storms, which might include storm surges and flooding
and increased turbidity, large runoff events with associated water quality changes as well as physical
disturbance caused by increased wave action.
Similarly, the ability to recover or recolonise an area following the combined effects of such climate
related events might depend on the delivery of propagules by the prevailing currents, food
availability which might be impacted by seasonal changes to upwellings, and the effects of ocean
acidification on specific larval stages of available organisms.
Climate driven changes also need to be considered in the context of other anthropogenic stressors,
such as overfishing (Ling et al., 2009a), invasive species, pollution, urbanisation, and engineered
coastlines (Airoldi et al., 2005). The potential synergies amongst such multiple stressors are only just
beginning to be examined. It is also critical that we have a better understanding of the links
between catchments and our coasts in order to understand the downstream effects which may flow
from climate driven impacts upstream.
MAJOR VULNERABILITIES TO CLIMATE CHANGE
This review has assessed the vulnerabilities of intertidal, shallow and deep subtidal reefs across
Victoria, based on an integrated assessment of the current understanding of the exposure,
sensitivity, impact and adaptive capacity of these reef systems to climate-associated stressors.
It is important to understand that different species within these systems will undoubtedly have
individual vulnerabilities to each stressor, and potentially different interactions and synergies with
other climate and anthropogenic stressors. Assessment of the vulnerability of reef systems has
attempted to integrate individual vulnerabilities in the context of current understanding of the direct
and indirect interactions amongst species, and the relative strength in those interactions.
There is relatively high uncertainty in most of the predictions (as summarised in Table 8) a dearth of
knowledge, both physical and ecological, of deep subtidal reefs in Victoria and more generally.
As more ecological research is conducted, and we gain improved understanding of interactions
between species, and between species and the environment, we will likely be able to improve levels
of certainty in the predictions made, and potentially change our assessment of vulnerability of
Victorian rocky reefs to the projected future climate.
29
Table 8 Summarised relative vulnerabilities of rocky reef assemblages to each climate stressor
Habitat
Sea level &
Tides
Ocean currents
& Upwelling
Temperature
Salinity
Waves
CO2 &
Acidification
Rainfall &
Runoff
Western
●
●●●
●
●●
●●
●●
●●●
Central
●
●●
●
●●
●●
●●
●●●
Embayments
●
●
●
●●●
●●
●●
●●●
Eastern
●
●●●
●
●●●
●●
●●
●●●
Western
●
●●●
●
●●
●●
●●
●●●
Central
●
●●
●
●●
●●
●●
●●●
Embayments
●
●●
●
●●
●●
●●
●●●
Eastern
●●
●●●
●
●●●
●●
●●
●●●
Western
●●●
●●●
●●●
●●●
●●●
●●
●●●
Central
●●●
●●●
●●●
●●●
●●●
●●
●●●
Embayments
●●●
●●●
●●●
●●●
●●●
●●
●●●
Eastern
●●●
●●●
●●●
●●●
●●●
●●
●●●
Region
Intertidal
Shallow Subtidal
Deep Subtidal
Relative vulnerabilities are indicated by colours: high=dark blue, medium=light blue, low=green.
Where uncertainty in predictions exists: ●●● = high, ●● = moderate, ●= low level of uncertainty; no dot indicates relative confidence in prediction
30
REFERENCES
Airoldi, L., 1998. Roles of disturbance, sediment stress, and substratum retention on spatial
dominance in algal turf. Ecology, 79: 2759-2770.
Airoldi, L., 2003. The effects of sedimentation on rocky coast assemblages. Oceanography and
Marine Biology: an Annual Review, 41: 161-236.
Airoldi, L. et al., 2005. An ecological perspective on the deployment and design of low-crested and
other hard coastal defence structures. Coastal Engineering, 52(10-11): 1073-1087.
Airoldi, L., and Cinelli, F., 1997. Effects of sedimentation on subtidal macroalgal assemblages: an
experimental study from a mediterranean rocky shore. Journal of Experimental Marine
Biology and Ecology, 215: 269-288.
Airoldi, L., Fabiano, M., and Cinelli, F., 1996. Sediment deposition and movement over a turf
assemblage in a shallow rocky coastal area of the Ligurian Sea. Marine Ecology Progress
Series, 133: 241-251.
Airoldi, L., and Virgilio, M., 1998. Responses of turf-forming algae to spatial variations in the
deposition of sediments. Marine Ecology Progress Series, 165: 271-282.
Albright, R., and Langdon, C., 2011. Ocean acidification impacts multiple early life history processes
of the Caribbean coral Porites astreoides. Global Change Biol, 17(7): 2478-2487.
Andersson, A.J., Mackenzie, F.T., and Bates, N.R., 2008. Life on the margin: implications of ocean
acidification on Mg-calcite, high latitude and cold-water marine calcifiers. Marine EcologyProgress Series, 373: 265-273.
Baines, P.G., and Fandry, C.B., 1983. Annual cycle of the density field in Bass Strait. Australian
Journal of Marine and Freshwater Research, 34: 143-153.
Banaru, D., Harmelin-Vivien, M., Gomoiu, M.-T., and Onciu, T.-M., 2007. Influence of the Danube
River inputs on C and N stable isotope ratios of the Romanian coastal waters and sediment
(Black Sea). Marine Pollution Bulletin, 54: 1385-1394.
Barton, J.L., 2006. Indicators of estuarine health in south-eastern Australian estuaries. PhD thesis
Thesis, Flinders University, Adealaide, Australia, Adelaide.
Barton, J.L., Pope, A.J., Quinn, G.P., and Sherwood, J.E., 2008. Identifying threats to the ecological
condition of Victorian estuaries, Department of Sustainability and Environment Technical
Report.
Beardall, J., Beer, S., and Raven, J.A., 1998. Biodiversity of marine plants in an era of climate
change:.Some predictions based on physiological performance. Botanica Marina, 41(1): 113123.
Beaufort, L., I. Probert, T. de Garidel-Thoron, E. M. Bendif, D. Ruiz-Pino, N. Metzl, C. Goyet, N.
Buchet, P. Coupel, M. Grelaud, B. Rost, R. E. M. Rickaby, and C. de Vargas. 2011. Sensitivity
of coccolithophores to carbonate chemistry and ocean acidification. Nature 476:80-83
Bellgrove, A., Clayton, M.N., and Quinn, G.P., 2004. An integrated study of the temporal and spatial
variation in the supply of propagules, recruitment and assemblages of intertidal macroalgae
on a wave-exposed rocky coast, Victoria, Australia. Journal of Experimental Marine Biology
and Ecology, 310: 207-225.
Bellgrove, A., McKenzie, P.F., McKenzie, J.L., and Sfilgoj, B.J., 2010. Restoration of the habitatforming fucoid alga Hormosira banksii at effluent-affected sites:competitive exclusion by
coralline turfs. Marine Ecology Progress Series, 419: 47-56.
Black, K.P., 1992. Evidence of the importance of deposition and winnowing of surficial sediments at a
continental shelf scale. Journal of Coastal Research, 8: 319-331.
Blanchette, C.A., 1997. Size and survival of intertidal plants in response to wave action: A case study
with Fucus gardneri. Ecology, 78(5): 1563-1578.
BOM, 2012. National Tidal Center. Australian Government, Bureau of Meteorology.
Boyle, M.C., Jillett, J.B., and Mladenov, P.V., 2001. Intertidal communities in Doubtful Sound, New
Zealand: changes over time. New Zealand Journal of Marine and Freshwater Research, 35(4):
663-673.
Brierley, A.S., and Kingsford, M.J., 2009. Impacts of Climate Change on Marine Organisms and
Ecosystems. Current Biology, 19(14): R602-R614.
Brown, V.B., Davies, S.A., and Synnot, R.N., 1990. Long-term monitoring of the effects of treated
sewage effluent on the intertidal macroalgae community near Cape Schanck, Victoria,
Australia. Botanica Marina, 33: 85-98.
Byrne, M. et al., 2010. Fertilization in a suite of coastal marine invertebrates from SE Australia is
robust to near-future ocean warming and acidification. Marine Biology, 157(9): 2061-2069.
Caldeira, K., and Wickett, M.E., 2003. Anthropogenic carbon and ocean pH. Nature, 425(6956): 365365.
Chapman, A.R.O., 1995. Functional ecology of fucoid algae: twenty-three years of progress.
Phycologia, 34(1): 1-32.
Cirano, M., and Middleton, J.F., 2004. Aspects of the mean wintertime circulation along Australia's
southern shelves. Journal of Physical Oceanography, 34: 668-684.
Coleman, M.A. et al., 2011. Connectivity within and among a network of temperate marine reserves.
PLoS ONE, 6(5).
Coleman, M.A., Gillanders, B.M., and Connell, S.D., 2009. Dispersal and gene flow in the habitatforming kelp, Ecklonia radiata: relative degrees of isolation across an east-west coastline.
Marine and Freshwater Research, 60(8): 802-809.
Coleman, M.A., Vytopil, E., Goodsell, P.J., Gillanders, B.M., and Connell, S.D., 2007. Diversity and
depth-related patterns of mobile invertebrates associated with kelp forests. Marine and
Freshwater Research, 58(7): 589-595.
Connell, S.D., 2007. Subtidal temperate rocky habitats: Habitat heterogeneity at local to continental
scales. In: Connell, S.D., Gillanders, B.M. (Eds.), Marine Ecology. Oxford University Press,
South Melbourne, pp. 378-401.
Connell, S.D., and Russell, B.D., 2010. The direct effects of increasing CO2 and temperature on noncalcifying organisms: increasing the potential for phase shifts in kelp forests. Proceedings of
the Royal Society B-Biological Sciences, 277(1686): 1409-1415.
Connell, S.D. et al., 2008. Recovering a lost baseline: missing kelp forests from a metropolitan coast.
Marine Ecology-Progress Series, 360: 63-72.
Cormaci, M., and Furnari, G., 1999. Changes of the benthic algal flora of the Tremiti Islands (southern
Adriatic) Italy. Hydrobiologia, 398/399: 75-79.
Dagg, M.J., Benner, R., Lohrenz, S., and Lawrence, D., 2004. Transformation of dissolved and
particulate materials on continenetal shelves influenced by large rivers: plume processes.
Continental Shelf Research, 24: 833-858.
32
Dagg, M.J., and Breed, G.A., 2003. Biological effects of Mississippi River nitrogen on the nothern gulf
of Mexico- A review and syntheis. Journal of Marine Systems, 43: 133-152.
Dang, V.T., Speck, P., and Benkendorff, K., 2012. Influence of elevated temperatures on the immune
response of abalone, Haliotis rubra. Fish Shellfish Immunol., 32(5): 732-740.
de Viçose, G.C., Viera, M., Bilbao, A., and Izquierdo, M., 2010. Larval settlement of Haliotis
tuberculata coccinea in response to different inductive cues and the effect of larval density
on settlement, early growth, and survival. J Shellfish Res, 29(3): 587-591.
Denny, M., and Gaylord, B., 2002. The mechanics of wave-swept algae. J Exp Biol, 205(10): 13551362.
Denny, M.W., 1988. Biology and the Mechanics of the Wave-Swept Environment. Princeton
University Press, Princeton, NJ.
Denny, M.W., and Gaylord, B., 2010. Marine Ecomechanics. Annu Rev Mar Sci, 2: 89-114.
Deschaseaux, E., Taylor, A., and Maher, W., 2011. Measure of stress response induced by
temperature and salinity changes on hatched larvae of three marine gastropod species.
Journal of Experimental Marine Biology and Ecology, 397(2): 121-128.
Doblin, M., Clayton, M.N., 1995. Effects of secondarily treated sewage effluent on the early life
history stages of two species of brown macroalgae: Hormosira banksii and Durvillaea
potatorum. Marine Biology, 122: 689-698.
Doney, S.C., Fabry, V.J., Feely, R.A., and Kleypas, J.A., 2009. Ocean acidification: the other CO2
problem. Annu Rev Mar Sci, 1(1): 169-192.
Dube, P., and Portelance, B., 1992. Temperature and photoperiod effects on ovarian maturation and
egg-laying of the crayfish, Orconectes limosus. Aquaculture, 102(1-2): 161-168.
Estes, J.A., and Palmisano, J., 1974. Sea otters: their role in structuring nearshore communities.
Science, 185: 1058-1060.
Fabricius, K.E. et al., 2011. Losers and winners in coral reefs acclimatized to elevated carbon dioxide
concentrations. Nature Climate Change, 1(3): 165-169.
Fabry, V.J., Seibel, B.A., Feely, R.A., and Orr, J.C., 2008. Impacts of ocean acidification on marine
fauna and ecosystem processes. ICES Journal of Marine Science: Journal du Conseil, 65(3):
414-432.
Ferns, L.W., Hough, D., and Caitlin, J., 2000. Chapter 1 Synthesis of stage 3. Describing marine
biodiversity through mapping and quantitative analysis of biological data: A classification
system for Victoria's intertidal and nearshore sub-tidal marine waters. In 'Environmental
inventory of Victoria's Marine Ecosystems Stage 3 (2nd Ed.): Understanding Biodiversity
Representativeness of Victoria's Rocky Reefs'. (Eds L. W. Ferns and D. Hough). Parks, Flora
and Fauna Division, Department of Natural Resource.
Fredersdorf, J., Muller, R., Becker, S., Wiencke, C., and Bischof, K., 2009. Interactive effects of
radiation, temperature and salinity on different life history stages of the Arctic kelp Alaria
esculenta (Phaeophyceae). Oecologia, 160(3): 483-492.
Gaylord, B., Denny, M.W., and Koehl, M.A.R., 2008. Flow Forces on Seaweeds: Field Evidence for
Roles of Wave Impingement and Organism Inertia. Biological Bulletin, 215(3): 295-308.
Gillanders, B.M., and Kingsford, M.J., 2002. Impact of changes in flow of freshwater on estuarine and
open coastal habitats and the associated organisms. In: Gibson, R.N., Barnes, M., Atkinson,
R.J.A. (Eds.), Oceanography and Marine Biology, Vol 40. Oceanography and Marine Biology.
Taylor & Francis Ltd, London, pp. 233-309.
33
Gilmour, P., and Edmunds, M., 2007. Victorian intertidal reef monitoring program: The intertidal reef
biota of Central Victoria's Marine Protected Areas (Volume 2). Parks Victoria, Melbourne.
Gorgula, S.K., and Connell, S.D., 2004. Expansive covers of turf-forming algae on human-dominated
coast: the relative effects of increasing nutrient and sediment loads. Marine Biology, 145(3):
613-619.
Grimes, C.B., and Kingsford, M.J., 1996a. How do Riverine Plumes of Different Sizes Influence Fish
Larvae: do they Enhance Recruitment? Marine and Freshwater Research, 47: 191-208.
Grimes, C.B., and Kingsford, M.J., 1996b. How do riverine plumes of different sizes influence fish
larvae: Do they enhance recruitment? Marine and Freshwater Research, 47(2): 191-208.
Hawkins, S.J. et al., 2008. Complex interactions in a rapidly changing world: responses of rocky shore
communities to recent climate change. Clim Res, 37(2-3): 123-133.
Hepburn, C.D. et al., 2011. Diversity of carbon use strategies in a kelp forest community: implications
for a high CO2 ocean. Global Change Biol, 17(7): 2488-2497.
Hill, J.M., McQuaid, C.D., and Kaechler, S., 2008. Temporal and spatial variability in stable isotope
ratios of SPM link to local hydrography and longer term SPM averages suggest heavy
dependence of mussels on nearshore production. Marine Biology, 154: 899-909.
Hill, J.M., McQuaid, C.D., and Kaehler, S., 2006. Biogeographic and nearshore-offshore trends in
isotope ratios of intertidal mussels and their food sources around the coast of southern
Africa. Marine Ecology Progress Series, 318: 63-73.
Holbrook, G.P. et al., 1988. Photosynthesis in marine macroalgae - evidence for carbon limitation.
Can J Bot, 66(3): 577-582.
Hope Black, J., 1971. Benthic communities. Memoirs of The National Museum of Victoria Melbourne
32, 129-170.
Hosono, T., 2011. Effect of temperature on growth and maturation pattern of Caprella mutica
(Crustacea, Amphipoda): does the temperature-size rule function in caprellids? Marine
Biology, 158(2): 363-370.
Hutchinson, N., Hunt, T., and Morris, L., 2010. Seagrass and reef program for Port Phillip Bay:
temperate reefs literature review.
Ierodiaconou, D., Monk, J., Rattray, A., Laurenson, L., and Versace, V.L., 2011. Comparison of
automated classification techniques for predicting benthic biological communities using
hydroacoustics and video observations. Continental Shelf Research, 31(2, Supplement): S28S38.
Israel, A., and Hophy, M., 2002. Growth, photosynthetic properties and Rubisco activities and
amounts of marine macroalgae grown under current and elevated seawater CO2
concentrations. Global Change Biol, 8(9): 831-840.
Jenkins, G.P., Conron, S.D., and Morison, A.K., 2010. Highly variable recruitment in an estuarine fish
is determined by salinity stratification and freshwater flow: implications of a changing
climate. Marine Ecology-Progress Series, 417: 249-261.
Johnson, C.R. et al., 2011. Climate change cascades: Shifts in oceanography, species' ranges and
subtidal marine community dynamics in eastern Tasmania. Journal of Experimental Marine
Biology and Ecology, 400(1-2): 17-32.
Jones, C.G., Lawton, J.H., and Shachak, M., 1994. Organisms as ecosystem engineers. Oikos, 69: 373386.
34
Jones, C.G., Lawton, J.H., and Shachak, M., 1997. Positive and negative effects of organisms as
physical ecosystem engineers. Ecology, 78(7): 1946-1957.
Kelaher, B.P., 2002. Influence of physical characteristics of coralline turf on associated macrofaunal
assemblages. Marine Ecology Progress Series, 232: 141-148.
Kelaher, B.P., Chapman, M.G., and Underwood, A.J., 2001. Spatial patterns of diverse macrofaunal
assemblages in coralline turf and their associations with environmental variables. Journal of
the Marine Biological Association of the United Kingdom, 81(6): 917-930.
Keough, M.J., and Quinn, G.P., 1998. Effects of periodic disturbances from trampling on rocky
intertidal algal beds. Ecological Applications, 8(1): 141-161.
Kevekordes, K., 2000. The effects of secondary-treated sewage effluent and reduced salinity on
specific events in the early life stages of Hormosira banksii (Phaeophyceae). Eur J Phycol, 35:
365-371.
King, R.J., Hope Black, J., and Ducker, S.C., 1971. Intertidal ecology of Port Phillip Bay with systematic
list of plants and animals. Memoirs of The National Museum of Victoria Melbourne, 32: 93128.
Kupriyanova, E.K., and Havenhand, J.N., 2005. Effects of temperature on sperm swimming
behaviour, respiration and fertilization success in the serpulid polychaete, Galeolaria
caespitosa (Annelida : Serpulidae). Invertebr Reprod Dev, 48(1-3): 7-17.
Lafferty, K.D., Porter, J.W., and Ford, S.E., 2004. Are diseases increasing in the ocean? Annu. Rev.
Ecol. Evol. Syst, 35: 31-54.
Lane, R.R. et al., 2007. The effects of riverine discharge on temperature, salinity, suspended
sediment and chlorophyll a in a Mississippi delta estuary measured using a flow-through
system. Estuarine, Coastal and Shelf Science, 74: 145-154.
Last, P.R. et al., 2011. Long-term shifts in abundance and distribution of a temperate fish fauna: a
response to climate change and fishing practices. Global Ecology and Biogeography, 20(1):
58-72.
Levings, A.H., and Gill, P.C., 2010. Seasonal winds drive water temperature cycle and migration
patterns of southern Australian giant crab Pseudocarcinus gigas. In: Kruse, G.H. et al. (Eds.),
Biology and Management of Exploited Crab Populations under Climate Change. Alaska Sea
Grant, University of Alaska Fairbanks.
Lima, F.P., and Wethey, D.S., 2012. Three decades of high-resolution coastal sea surface
temperatures reveal more than warming. Nature Communications, 3.
Ling, S.D., 2008. Range expansion of a habitat-modifying species leads to loss of taxonomic diversity:
a new and impoverished reef state. Oecologia, 156(4): 883-894.
Ling, S.D., Johnson, C.R., Frusher, S.D., and Ridgway, K.R., 2009a. Overfishing reduces resilience of
kelp beds to climate-driven catastrophic phase shift. Proceedings of the National Academy of
Sciences of the United States of America, 106(52): 22341-22345.
Ling, S.D., Johnson, C.R., Ridgway, K., Hobday, A.J., and Haddon, M., 2009b. Climate-driven range
extension of a sea urchin: inferring future trends by analysis of recent population dynamics.
Global Change Biol, 15(3): 719-731.
Liu, H., and Dagg, M., 2003. Interactions between nutrients, phytoplankton growth, and micro- and
mesozooplankton grazing in the plume of the Mississippi River. Marine Ecology Progress
Series, 258: 31-42.
35
Lohrenz, S.E. et al., 1999. Nutrients, irradiance, and mixing as factors regulating primary production
in coastal waters impacted by the Mississippi River plume. Continental Shelf Research, 19:
1113-1141.
Lu, Z., Gan, J., Dai, M., and Cheung, A.Y.Y., 2010. The influence of coastal upwelling and a river plume
on the subsurface chlorophyll maximum over the shelf of the northeastern South China Sea.
Journal of Marine Systems, 82: 35-46.
Macaya, E.C. et al., 2005. Presence of sporophylls in floating kelp rafts of Macrocystis spp.
(Phaeophyceae) along the Chilean Pacific coast. Journal of Phycology, 41(5): 913-922.
McKenzie, J.L., Bellgrove, A., Quinn, G.P., and Matthews, T.G., in prep. Influence of intermittent
estuarine discharge on intertidal macroalgal assemblages.
McKenzie, P.F., and Bellgrove, A., 2006. No outbreeding depression at a regional scale for a habitatforming intertidal alga with limited dispersal. Marine and Freshwater Research, 57: 655-663.
McKenzie, P.F., and Bellgrove, A., 2009. Dislodgment and attachment strength of the intertidal
macroalga, Hormosira banksii (Fucales, Phaeophyceae). Phycologia, 48(5): 335-343.
Mellin, C., Russell, B.D., Connell, S.D., Brook, B.W., and Fordham, D.A., 2012. Geographic range
determinants of two commercially important marine molluscs. Divers Distrib, 18(2): 133-146.
Menge, B.A., 1976. Organization of the New England rocky intertidal community: role of predation,
competition and environmental heterogeneity. Ecol Monogr, 46: 355-393.
Mettam, C., 1994. Intertidal zonation of animals and plants on rocky shores in the Bristol Channel
and Severn Estuary-the northern shores. Biological Journal of the Linnean Society, 51: 123147.
Middleton, J.F. et al., 2007. El Nino effects and upwelling off South Australia. Journal of Physical
Oceanography, 37(10): 2458-2477.
Middleton, J.F., and Black, K.P., 1994. The low frequency circulation in and around Bass Strait: a
numerical study. Continental Shelf Research, 14: 1495-1521.
Millar, A.J.K., 2007. The Flindersian and Peronian Provinces. In: McCarthy, P.M., Orchard, A.E. (Eds.),
Algae of Australia: Introduction. CSIRO publishing, Canberra, pp. 554-559.
Mouritsen, K.N., and Poulin, R., 2002. Parasitism, community structure and biodiversity in intertidal
ecosystems. Parasitology, 124: S101-S117.
Neuheimer, A.B., Thresher, R.E., Lyle, J.M., and Semmens, J.M., 2011. Tolerance limit for fish growth
exceeded by warming waters. Nature Climate Change, 1(2): 110-113.
Nguyen, K.D.T. et al., 2011. Upper temperature limits of tropical marine ectotherms: Global warming
implications. PLoS ONE, 6(12).
O'Hara, T., McShane, P.E., and Norman, M., 1999. Victoria. In 'Under Southern Seas, the ecology of
Australia's Rocky Reefs'. (Ed. N. Andrew.). (UNSW: Sydney.).
O'Hara, T.D., Addison, P.F.E., Gazzard, R., Costa, T.L., and Pocklington, J.B., 2010. A rapid biodiversity
assessment methodology tested on intertidal rocky shores. Aquatic Conservation: Marine
and Freshwater Ecosystems, 20(4): 452-463.
Occhipinti-Ambrogi, A., 2007. Global change and marine communities: Alien species and climate
change. Marine Pollution Bulletin, 55(7-9): 342-352.
Orr, J.C. et al., 2005. Anthropogenic ocean acidification over the twenty-first century and its impact
on calcifying organisms. Nature, 437(7059): 681-686.
36
Pearce, A. et al., 2011. The “marine heat wave” off Western Australia during the summer of
2010/11. Fisheries Research Report No. 222. Department of Fisheries, Western Australia.
40pp.
Pecl, G. et al., 2009. The east coast Tasmanian rock lobster fishery – vulnerability to climate change
impacts and adaptation response options. Report to the Department of Climate Change,
Australia.
Phillips, J.A., 2001. Marine macroalgal biodiversity hotspots: why is there high species richness and
endemism in southern Australian marine benthic flora? Biodiversity and Conservation, 10:
1555-1577.
Pitt, N.R., Poloczanska, E.S., and Hobday, A.J., 2010. Climate-driven range changes in Tasmanian
intertidal fauna. Marine and Freshwater Research, 61(9): 963-970.
Poloczanska, E.S. et al., 2011. Little change in the distribution of rocky shore faunal communities on
the Australian east coast after 50 years of rapid warming. Journal of Experimental Marine
Biology and Ecology, 400(1-2): 145-154.
Qiu, J.W., and Qian, P.Y., 1998. Combined effects of salinity and temperature on juvenile survival,
growth and maturation in the polychaete Hydroides elegans. Marine Ecology-Progress
Series, 168: 127-134.
Rabalais, N.N. et al., 2000. Gulf of Mexico biological system responses to nutrient changes in the
Mississippi River. In: Hobbie, J.E. (Ed.), Estuarine Science: A Synthetic Approach to Research
and Practice. Island Press, Washington DC, pp. 241-268.
Reed, D.C., and Foster, M.S., 1984. The effects of canopy shading on algal recruitment and growth in
a giant kelp forest. Ecology, 65: 937-948.
Ries, J.B., Cohen, A.L., and McCorkle, D.C., 2009. Marine calcifiers exhibit mixed responses to CO2induced ocean acidification. Geology, 37(12): 1131-1134.
Roberts, R.D., and Watts, E., 2010. Settlement of Haliotis Australis Larvae: Role of Cues and
Orientation of the Substratum. J Shellfish Res, 29(3): 663-670.
Roleda, M.Y., Morris, J.N., McGraw, C.M., and Hurd, C.L., 2012. Ocean acidification and seaweed
reproduction: increased CO2 ameliorates the negative effect of lowered pH on meiospore
germination in the giant kelp Macrocystis pyrifera (Laminariales, Phaeophyceae). Global
Change Biol, 18(3): 854-864.
Russell, B.D. et al., 2012. Predicting ecosystem shifts requires new approaches that integrate the
effects of climate change across entire systems. Biology Letters, 8(2): 164-166.
Russell, B.D., Thompson, J.A.I., Falkenberg, L.J., and Connell, S.D., 2009. Synergistic effects of climate
change and local stressors: CO2 and nutrient-driven change in subtidal rocky habitats. Global
Change Biol, 15(9): 2153-2162.
Sabine, C.L. et al., 2004. The oceanic sink for anthropogenic CO(2). Science, 305(5682): 367-371.
Santelices, B., 1990. Patterns of reproduction, dispersal and recruitment in seaweeds. Oceanography
and Marine Biology: an Annual Review, 28: 177-276.
Santelices, B., Aedo, D., and Hoffmann, A., 2002. Banks of microscopic forms and survival to
darkness of propagules and microscopic stages of macroalgae. Revista Chilena de Historia
Natural, 75: 547-555.
Schiel, D.R., 2006. Rivets or bolts? When single species count in the function of temperate rocky reef
communities. Journal of Experimental Marine Biology and Ecology, 338: 233-252.
37
Schiel, D.R., 2011. Biogeographic patterns and long-term changes on New Zealand coastal reefs:
Non-trophic cascades from diffuse and local impacts. Journal of Experimental Marine Biology
and Ecology, 400(1-2): 33-51.
Schiel, D.R., and Lilley, S.A., 2011. Impacts and negative feedbacks in community recovery over eight
years following removal of habitat-forming macroalgae. Journal of Experimental Marine
Biology and Ecology, 407(1): 108-115.
Schiel, D.R., Steinbeck, Jr., and Foster, M.S., 2004. Ten years of induced ocean warming causes
comprehensive changes in marine benthic communities. Ecology, 85(7): 1833-1839.
Schiel, D.R., Wood, S.A., Dunmore, R.A., and Taylor, D.I., 2005. Sediment on rocky intertidal reefs:
effects on early post-settlement stages of habitat-forming seaweeds. Journal of
Experimental Marine Biology and Ecology, 331: 158-172.
Schlacher, T.A., and Connolly, R.M., 2009. Land-ocean coupling of carbon and nitrogen fluxes on
sandy beaches. Ecosystems, 12: 311-321.
Seibel, B.A., and Walsh, P.J., 2001. Carbon cycle - potential, impacts of CO2 injection on deep-sea
biota. Science, 294(5541): 319-320.
Selkoe, K.A., Halpern, B.S., and Toonen, R.J., 2008. Evaluating anthropogenic threats to the
Northwestern Hawaiian Islands. Aquat Conserv, 18(7): 1149-1165.
Smaldon, P.R., and Duffus, J.H., 1984. The effects of temperature, pH and salinity on the maturation
of gametes and fertilization in Patella vulgata L. J Mollus Stud, 50(FAL): 232-235.
Smith, S., Simpson, R., and Cairns, S., 1996. The macrofaunal community of Ecklonia radiata
holdfasts: description of the faunal assemblage and variation associated with difference in
holdfast volume. Australian Journal of Ecology, 21: 81-95.
Smith, W.O., and Demaster, D.J., 1996. Phytoplankton biomass and productivity in the Amazon River
plume: correlation with seasonal river discharge. Continental Shelf Research, 16(3): 291-319.
Sokolow, S., 2009. Effects of a changing climate on the dynamics of coral infectious disease: a review
of evidence. Diseases of Aquatic Organism, 87: 5-18.
Somero, G.N., 2012. The Physiology of Global Change: Linking Patterns to Mechanisms. Annual
Review of Marine Science, Vol 4, 4: 39-61.
Sousa, W., 1984. Intertidal mosaics: patch size, propagule availability and spatially variable patterns
of succession. Ecology, 65: 1918-1935.
Stewart, H.L., 2006. Ontogenetic changes in buoyancy, breaking strength, extensibility, and
reproductive investment in a drifting macroalga Turbinaria ornata (Phaeophyta). Journal of
Phycology, 42(1): 43-50.
Stewart, K., Judd, A., and Edmunds, M., 2007. Victorian intertidal reef monitoring program: The
intertidal reef biota of Victoria's Marine Protected Areas. Parks Victoria, Melbourne.
Stillman, J.H., and Somero, G.N., 2000. A comparative analysis of the upper thermal tolerance limits
of eastern Pacific porcelain crabs, genus Petrolisthes: Influences of latitude, vertical
zonation, acclimation, and phylogeny. Physiol Biochem Zool, 73(2): 200-208.
Studer, A., and Poulin, R., 2012. Effects of salinity on an intertidal host-parasite system: Is the
parasite more sensitive than its host? Journal of Experimental Marine Biology and Ecology,
412: 110-116.
Suthers, I.M., and Waite, A., 2007. Ecological Oceanography. In: Connell, S.D., Gillanders, B.M. (Eds.),
Marine Ecology. Oxford University Press, South Melbourne, pp. 199-226.
38
Takasuka, A., and Aoki, I., 2006. Environmental determinants of growth rates for larval Japanese
anchovy Engraulis japonicus in different waters. Fish Oceanogr, 15(2): 139-149.
Taylor, D., Delaux, S., Stevens, C., Nokes, R., and Schiel, D., 2010. Settlement rates of macroalgal
algal propagules: Cross-species comparisons in a turbulent environment. Limnol. Oceanogr,
55(1): 66-76.
Taylor, D.I., and Schiel, D.R., 2003. Wave-related mortality in zygotes of habitat-forming algae from
different exposures in southern New Zealand: the importance of 'stickability'. Journal of
Experimental Marine Biology and Ecology, 290: 229-245.
Thompson, R.C., Crowe, T.P., and Hawkins, S.J., 2002. Rocky intertidal communities: past
environmental changes, present status and predictions for the next 25 years. Environmental
Conservation, 29(2): 168-191.
Thomson, D.P., Babcock, R.C., Vanderklift, M.A., Symonds, G., and Gunson, J.R., 2012. Evidence for
persistent patch structure on temperate reefs and multiple hypotheses for their creation
and maintenance. Estuarine Coastal and Shelf Science, 96: 105-113.
Tobin, D., and Wright, P.J., 2011. Temperature effects on female maturation in a temperate marine
fish. Journal of Experimental Marine Biology and Ecology, 403(1-2): 9-13.
Valentine, J.P., and Johnson, C.R., 2003. Establishment of the introduced kelp Undaria pinnatifida in
Tasmania depends on disturbance to native algal assemblages. Journal of Experimental
Marine Biology and Ecology, 295(1): 63-90.
Valentine, J.P., and Johnson, C.R., 2004. Establishment of the introduced kelp Undaria pinnatifida
following dieback of the native macroalga Phyllospora comosa in Tasmania, Australia.
Marine and Freshwater Research, 55(3): 223-230.
van den Hoek, C., 1987. The possible significance of long-range dispersal for the biogeography of
seaweeds. Helgolander Meeresuntersuchungen, 41: 261-272.
Vaselli, S., Bertocci, I., Maggi, E., and Benedetti-Cecchi, L., 2008. Assessing the consequences of sea
level rise: effects of changes in the slope of the substratum on sessile assemblages of rocky
seashores. Marine Ecology-Progress Series, 368: 9-22.
Velimirov, B., and Griffiths, C.L., 1979. Wave-induced kelp movement and its importance for
community structure. Botanica Marina, 22: 169-172.
Waters, J.M. et al., 2010. Australia's marine biogeography revisited: Back to the future? Austral Ecol,
35(8): 988-992.
WaterTechnology, 2012. Implications of Future Climate to Victoria’s Marine Environment: Physical
Conditions. Report for Glenelg-Hopkins Catchment Management Authority, Hamilton,
Victoria.
Webster, M.A., and Petkovic, P., 2005. Australian bathymetry and topography grid. Geoscience
Australia, Canberra, Australia.
Wernberg, T., and Goldberg, N., 2008. Short-term temporal dynamics of algal species in a subtidal
kelp bed in relation to changes in environmental conditions and canopy biomass. Estuarine
Coastal and Shelf Science, 76(2): 265-272.
Wernberg, T., Kendrick, G.A., and Phillips, J.C., 2003. Regional differences in kelp-associated algal
assemblages on temperate limestone reefs in south-western Australia. Divers Distrib, 9(6):
427-441.
39
Wernberg, T. et al., 2011a. Impacts of climate change in a global hotspot for temperate marine
biodiversity and ocean warming. Journal of Experimental Marine Biology and Ecology, 400(12): 7-16.
Wernberg, T. et al., 2011b. Seaweed Communities in Retreat from Ocean Warming. Current Biology,
21(21): 1828-1832.
Wernberg, T., Thomsen, M.S., Tuya, F., and Kendrick, G.A., 2011c. Biogenic habitat structure of
seaweeds change along a latitudinal gradient in ocean temperature. Journal of Experimental
Marine Biology and Ecology, 400(1-2): 264-271.
Wethey, D.S. et al., 2011. Response of intertidal populations to climate: Effects of extreme events
versus long term change. Journal of Experimental Marine Biology and Ecology, 400(1-2): 132144.
Wheatly, M.G., 1988. Integrated Responses to Salinity Fluctuation. Am Zool, 28(1): 65-77.
Willis, J.K., and Church, J.A., 2012. Regional Sea-Level Projection. Science, 336(6081): 550-551.
Womersley, H.B.S., 1987. The marine benthic flora of southern Australia, Part II. South Australian
Government Printing Division, Adelaide.
40