Download Climate change adaptation in Scotland Indicator

Climate change adaptation in Scotland
Indicator Card 2014
Generalist species more able to cope with climate change
than specialist species: snow-bed species
This is one in a series of climate change adaptation 'indicator cards' which has
been developed for the natural environment in Scotland.
Using indicators, each card communicates the latest evidence about current and
past trends in adaptation actions - activity which aims to help Scotland to better
cope with climate change. They also report the latest evidence about the climate
change risks, opportunities and impacts these actions address.
The cards will enable decision-makers to better understand the influence of
adaptive actions upon critical climate change issues for Scotland , and help them
to identify adaptation options available for the future.
Using the example of snow-bed species, this card explains how Scotland is
managing the risk to biodiversity that generalist species will be more able to cope
with climate change than specialist species.
Other indicator cards and further information about ClimateXChange's work can
be found at www.climatexchange.org.uk
A snow-bed in the Scottish mountains. Copyright: Chris Ellis, RBGE.
Understanding the information in this card
Monitoring adaptation using indicators
Three types of indicators are presented in this card:
Indicators of action show the current status and trends in the adaptation actions being taken to
address the risk/opportunity.
To set these actions in context and to help us better understand their contribution, the card also
presents indicators for the risks/opportunities and impacts which the actions address (see Fig 1):
Indicators of risk/opportunity show the current status and trends in the vulnerability and
exposure to the risk/opportunity.
Indicators of impact show the current status and trends in felt impacts of the risk/opportunity.
The indicator trends are shown using coloured arrows, and the level of need for improved
indicator data is highlighted, as follows:
Generalists species more able to adapt than specialists:
snow-bed species
Level of risk*
2020s
2050s
2080s
M
M
H
Level of
confidence*
Thumbnail image
L
* From the Climate Change Risk Assessment for Scotland 2012
Moerckia blytii (liverwort) – a snow-bed
bryophyte. Copyright: Dave Genney, SNH.
Adaptation at a glance
Information on the status of snow-bed mosses and liverworts (bryophytes) provides one example we can use to
understand the risk that generalist species may be more able to cope with climate change than specialist species.
Snow bed vegetation found in Scottish mountain ranges includes species of bryophytes which are snow bed specialists
dependent upon the late-lying snow which occurs in these areas. These snow-bed bryophytes include species of
conservation priority (such as Andreaea nivalis and Marsupella arctica, and Gymnotrium apiculatum).
It is expected that a long-term trend towards a reduction in the size and length of snow-lie will cause changes in the
composition of snow-bed vegetation; with conservation-priority snow-bed specialist vegetation communities
expected to move towards a widespread ‘generalist’ vegetation type typical of more open montane conditions.
Current evidence tentatively indicates a change away from snow-bed specialist bryophytes towards generalist species
in snow-beds. However trends in occurrence are not consistent, with some snow-bed specialist bryophytes
decreasing in frequency whilst others are increasing in frequency. This may demonstrate a reorganisation
of snow-bed vegetation community structure.
Adaptation actions to address the risk to snow-bed specialist bryophytes are currently focussed on management
Actions for Sites of Special Scientific Interest (SSSIs) with bryophytes as a Notified Feature. Snow-bed specialist
bryophytes, a component of the Eastern Cairngorms SSSI, were considered to be in ‘Unfavourable’ condition during
the last round of Site Condition Monitoring (2010) possibly due to climate change. If further declines occur as a result
of external pressures such as climate change, it could result in the removal of snow-bed bryophytes from the SSSI
citation – an example of ‘managed retreat’.
Indicators of risk
Extent and distribution of montane snow
Forth-coming: Snow Survey of Great Britain data.
Latest figure
Not yet available
Trends
Not yet
available
Data
need
Not yet
available
There is direct vulnerability of snow-bed species to a decline in montane snow cover, with impacts extending to areas
of late-lying snow. UK climate projections (UKCP09 scenarios) show a decline in mean snowfall of 65-80% over
montane areas generally by the 2080s, with regional assessments also strongly suggesting a reduction in snow cover
across mountain ranges in Scotland.
Indicators of impact
Frequency of specialist and generalist
species in snow-bed communities
Latest figure
Trends
Specialist
snow-bed
bryophytes
All
bryophytes
Western
Scotland
10%
decrease
18%
decrease
Eastern
Scotland
4%
increase
18%
increase
Data need
Not yet
available
A comprehensive survey of snow-bed vegetation was carried out in 1989-1990, for 58 areas of late-lying snow across
Scotland. Scottish Natural Heritage commissioned a repeat survey of 22 of the original 58 snow-beds during 20072008 (Fig. 1, Table 1); these were located across western and central mountain ranges, and within the eastern and
relatively more continental Cairngorm Mountains. Analysis of the composition of bryophyte assemblages and the
frequency with which species occur has demonstrated only very tentative evidence for change in snow-bed
communities. This included a statistically significant 13% decline in the frequency of the snow-bed specialist liverwort
Moerckia blytii (pictured). However, trends in frequency of occurrence were not consistent across the snow-bed
bryophytes, with some species showing a decrease and some an increase . This may demonstrate a reorganisation of
snow-bed vegetation structure, or may reflect the fact that the repeat sampled plots were not strictly replicates.
A separate analysis for the purposes of this Card focussed on broad measures of vegetation structure: vascular plants,
with grasses as a specific example, and bryophytes generally, with snow-bed bryophyte specialist species as
indicators. The analysis (see Fig. 2) demonstrated a decline in the frequency of snow-bed specialist bryophyte species
and bryophytes generally for the snow-beds in western areas, implying structural change in the vegetation. In
contrast, both snow-bed specialist bryophytes and other bryophytes increased in frequency in snow-beds across
Eastern Scotland. There is therefore preliminary evidence that change in the snow-bed vegetation may show regional
variation.
Condition of Notified Feature
bryophytes in SSSIs with snow-beds
Eastern Cairngorms SSSI: Unfavourable declining (2010)
Cairngorms SSSI: Favourable maintained (2005)
Not yet
available
Ben Nevis SSSI: Favourable (2005)
Bryophytes are a Notified Feature of the Eastern Cairngorms SSSI, Cairngorms SSSI and Ben Nevis SSSI. Snow-bed
bryophytes, a component of the Eastern Cairngorms SSSI, were considered to be in ‘Unfavourable’ condition during
the last round of Site Condition Monitoring (SCM), possibly as a direct consequence of climate change. In contrast,
bryophytes in the Cairngorms SSSI and Ben Nevis SSSI were found to be in ‘Favourable’ condition in the last round of
SCM. However, in the latter two SSSIs, the condition score relates to all bryophytes not the snow-bed specialist
bryophytes in particular (as is the case for the Eastern Cairngorms SSSI).
Indicators of adaptation action
Latest figure
Trends
Data
need
No indicator at present
Currently adaptation to address the climate change risk to snow-bed bryophytes is focussed on the management
actions for SSSIs. As noted above, a component of the Eastern Cairngorms SSSI - snow-bed specialist bryophytes were considered to be in ‘Unfavourable’ condition during the last round of Site Condition Monitoring (SCM), possibly
as a direct consequence of climate change. The condition of snow-bed specialist bryophytes will be assessed over
several cycles of SCM, and if further decline in condition is confirmed as a consequence of external pressures (such as
climate change) it could trigger their removal from the SSSI citation. This is an example of an adaptation action
consistent with ‘managed retreat’. In contrast, bryophytes in the Cairngorms SSSI and Ben Nevis SSSI were found to
be in ‘Favourable’ condition in the last round of SCM. The lack of a specific condition status for snow-bed specialist
bryophytes in the latter two SSSIs may suggest a need for monitoring of snow-bed specialist species within the overall
bryophyte populations of these sites . Alternative adaptation options include the reduction of other environmental
pressures through to experimental infrastructure projects, including: (a) snow-fences to encourage drifting and to
retain late-lying snow, (b) textile blankets as used in the Alps to prevent glacier melt, or (c) artificial snow blowing to
augment natural deposits. Currently, none of these options are under consideration as a formal approach to
conservation of snow bed bryophytes in Scotland.
Adaptation in perspective
Information on the status of snow-bed specialist bryophytes provides a valuable assessment of the condition of snowbed vegetation and provides one example through which we can understand the risk that generalist species may be
more able to cope with climate change than specialist species. Snow-bed species are particularly useful in
understanding this and wider climate change risks because:
(1) They are niche specialists, and monitoring their status is especially relevant during a period when observational
data indicates an increasing homogenisation of the mountain flora, through an expansion of generalists.
(2) They occur at the edge of their range (latitudinal and altitudinal) in Scotland, capturing a scenario in which species
are unable to track climate change through migration e.g. via inter-connected habitat.
(3) Areas of late-lying snow provide ecosystem services in addition to their unique biodiversity, for example by
sustaining the baseflow of streams and rivers following the main period of snowmelt.
Adaptation in focus: impact
Figure 1: The location of 22 repeat-survey
snow-beds for which data was made
available by Scottish Natural
Heritage. Snow-beds were grouped into
two regions for analysis: Region 1 (red
box), with snow-beds 1.-8., representing
more western and central mountain
ranges, and Region 2 (blue circle), with
snow-beds 9.-22., representing the
eastern and relatively more continental
Cairngorm snow-beds . The data collected
from these sites in 1989-1990 and 20072008 was analysed to calculate changes in
the frequency of snow-bed vegetation
(see indicators of impact).
Region
Western
Table 1: Names of snow bed sites used
in the repeat survey (illustrated in
Figure 1).
Site Code
Site Name
S1.
S2.
S3.
S4.
Beinn Dearg
Ben Wyvis, North Coire
Mam Sodhail, Lochan Uaine
White Mounth, Coire Boidheach
S5.
S6.
S7.
S8.
White Mounth, Glas Allt
Creag Meagaidh, West Coire
Ben Lawers, An stuc
Ben Lawers, NE Face
S9.
S10.
S11.
S12.
Cairngorm, Ciste Mhearad
Carn Lochan, Coire Domhain
Carn Lochan, Coire Domhain
Ben Macdui, Lower Garbh Uisge Beag
S13.
Ben Macdui, Upper Garbh Uisge Beag
S14.
S15.
Ben Macdui, North Slope
Ben MacDui, Upper Garbh Uisge Mor
S16.
S17.
S18.
Ben MacDui, Bealach 1232m
Braeriach, Garbh Coire Mor
Braeriach, Garbh Coire Mor E Gully
S19.
Beinn a Bhuird, Coire an t'Snaechda
S20.
S21.
S22.
Beinn a Bhuird, Dubh Lochan
Beinn a Bhuird, North Top
Beinn a Bhuird, Garbh Coire
Eastern
Adaptation in focus: impact
Western Snow-beds
(sites 1.-8., n = 20 plots)
Eastern Snow-beds
(sites 9.-22., n = 83 plots)
100
INCREASING
80
60
40
20
NO CHANGE
Range of the response
0
-20
-40
-60
DECREASING
s
yo
ph
yt
Al
es
lb
ry
op
hy
te
s
sn
ow
-b
ed
br
la
nt
s
la
rp
ss
e
ra
sc
u
G
Va
N
VC
s
yo
ph
yt
Al
es
lb
ry
op
hy
te
s
la
nt
N
VC
sn
ow
-b
ed
br
la
rp
Va
sc
u
G
ra
ss
e
s
-80
Fig. 2: Change in the frequency of snow-bed vegetation: comparison between 1989/90-2007/8 in the percent cover of
four vegetation categories – (i) grasses, (ii) all vascular plants (including ferns), (iii) NVC snow-bed dominant bryophytes
(Kiaeria starkei, Polytrichum alpinum, Polytrichum sexangulare and Racomitrium heterostichum), and (iv) all bryophytes.
Further information
SNH Site Condition Monitoring: www.snh.gov.uk/protecting-scotlands-nature/protected-areas/sitecondition-monitoring
Rothero, G.P., Grytnes, J.-A., Birks, H.J.B. & Genney, D. (2008) Effects of climate change on bryophytedominated snowbed vegetation. Scottish Natural Heritage 104 pp.
Acknowledgements
The analysis underpinning the information in this card was carried out by Chris Ellis, Royal Botanic Garden Edinburgh
and Dave Genney, Scottish Natural Heritage using data provided by Rothero, G.P., Grytnes, J.-A., Birks, H.J.B. &
Genney, D. (2008)
Glossary
Adaptation Actions: adjustments aimed at helping society and the environment cope with the risks of a
changing climate, or responses which exploit the opportunities of climate change.
Bryophytes: a group of non-vascular plants that include mosses, liverworts and hornworts.
Climate Change Risk Assessment: an independent assessment of the latest evidence about the threats and
opportunities posed to the UK by climate change.
Impact: the felt consequences of climate change. These may be economic, structural, social, and
environmental.
Managed retreat: an adaptation response to climate change in which the decision is made to accept change
rather than to try to maintain the status quo.
National Vegetation Classification: a comprehensive classification and description of the plant
communities of Britain.
Risk/opportunity: the potential impacts of climate change assessed according to their likelihood, magnitude
of potential impact and urgency.
Site Condition Monitoring: the condition of features on designated sites e.g. SSSIs, in Scotland is
determined by Scottish Natural Heritage’s (SNH) Site Condition Monitoring (SCM) programme. SCM is a 6
year rolling programme of monitoring which assesses the condition of designated natural features using the
following reportable condition categories: favourable maintained; favourable recovered; favourable
declining; unfavourable recovering; unfavourable no change; unfavourable declining; part destroyed and
destroyed.
Sites of Special Scientific Interest: areas of land and water that Scottish Natural Heritage (SNH) considers to
best represent Scotland’s natural heritage - its diversity of plants, animals and habitats, rocks and
landforms, or a combinations of such natural features. SNH designates SSSIs under the Nature Conservation
(Scotland) Act 2004.
SSSI Citation: details the 'features of interest' for which a SSSI has been notified.
UKCP09: the UK Climate Projections. Published in 2009, they provide the most authoritative evidence of
potential changes in climate for Scotland from the present to 2100.
Vulnerability: the degree to which a system e.g. the natural environment, is susceptible to, or unable to
cope with, adverse effects of climate change.