Download CCAMLR - Antarctic and Southern Ocean Coalition

COMMISSION POUR LA CONSERVATION
DE LA FAUNE ET LA FLORE MARINES
DE L'ANTARCTIQUE
________________________________________________
COMMISSION FOR THE CONSERVATION
OF ANTARCTIC MARINE LIVING RESOURCES
_____________________________________________
КОМИССИЯ ПО СОХРАНЕНИЮ
МОРСКИХ ЖИВЫХ РЕСУРСОВ АНТАРКТИКИ
CCAMLR
COMISIÓN PARA LA CONSERVACIÓN DE
LOS RECURSOS VIVOS MARINOS
ANTÁRTICOS
CCAMLR-XXXII/BG/15
21 September 2013
Original: English
Agenda Item No. 5.6
SC Agenda Item No. 8
Climate Change, Marine Ecosystems, and Non-Native
Species: The view from the Southern Ocean
Submitted by ASOC
_______________________
This paper is presented for consideration by CCAMLR and may contain unpublished data, analyses, and/or
conclusions subject to change. Data in this paper shall not be cited or used for purposes other than the work
of the CAMLR Commission, Scientific Committee or their subsidiary bodies without the permission of the
originators and/or owners of the data.
Climate Change, Marine Ecosystems, and Non-Native Species:
The view from the Southern Ocean
Abstract
Climate change is already affecting parts of Antarctica, including the Antarctic Peninsula and portions of the
Southern Ocean. Some of the occurring and projected effects include changes in temperature, ocean
circulation, stratification, nutrient availability, oxygen levels and acidification. The challenge for CCAMLR
is to gain an adequate understanding of climate change impacts in the Southern Ocean at both large and
small scales on a timely basis. This will require the integration of data from a wide variety of sources and
disciplines. Specific actions that CCAMLR should undertake include the designation of MPAs that can act as
climate change reference areas, the integration of climate change considerations into decisionmaking
processes, and an increase in research into climate change impacts.
1. Introduction
Scientific research clearly demonstrates that parts of Antarctica, including the Antarctic Peninsula and
portions of the Southern Ocean, are experiencing the effects of anthropogenic climate change, including but
not limited to global warming. These effects will have profound implications for the region. To manage
ecosystems in a precautionary way, CCAMLR must integrate information on these effects into its
decisionmaking processes as encouraged by CCAMLR resolution 30/XXVIII. Although it is not possible
for CCAMLR to halt or reverse climate change, CCAMLR can take actions that will mitigate climate change
impacts, and perhaps slow or stop cascading environmental effects from occurring. Currently, information
about climate change and climate change impacts is not considered in a systematic fashion by the Scientific
Committee or its working groups. This paper focuses on the effects of climate change on the marine species
and ecosystems of the Southern Ocean, and suggests ways to better integrate climate change information into
CCAMLR processes.
2. General climate change impacts on marine ecosystems
Anthropogenic climate change is impacting marine ecosystems. Some of the occurring and projected effects
include changes in temperature, ocean circulation, stratification, nutrient availability, oxygen levels and
acidification.1 These changes are having and will continue to have profound effects on ecosystems, including
the possibility of emerging, novel ecosystems. 2
It is important to note that, in this discussion, we are concerned about what has been called “multiscale
regime shifts,” that is, where entire biogeographical boundaries change.3 Managers often view regime shifts
from the end effects—such as increases in and arrivals of new predators or disease outbreaks. These
phenomena are not the primary problem; they are ecological responses to broader signals in the earth
system. 4
In the Southern Ocean, tracking and responding to ecosystem changes are critical. However, these effects are
expected to amplify and diversify as global climate change intensifies. Furthermore, the resilience of native
species to increased temperatures or to more regular occurrences of El-Nino Southern Oscillation (ENSO)
events is not expected to be very high. 5 Many species, not just krill, will experience these impacts. 6
3. Non-native Species/ biodiversity changes
1
Doney et al. 2012. Climate Change Impacts on Marine Ecosystems. Annual Reviews of Marine Science. 4:11-17.
Doi:10.1146/annurev-marine-041911-111611.
2
Doney et al, 2012.
3
Terry P. Hughes, Stephen Carpenter, Johan Rockström, Marten Scheffer, Brian Walker, Multiscale regime shifts and
planetary boundaries, Trends in Ecology & Evolution 28: 389-395. http://dx.doi.org/10.1016/j.tree.2013.05.019.
4
Hughes et al. 2013, pg 392.
5
Clarke, A., Murphy, E. J., Meredith, M. P., King, J. C., Peck, L. S., Barnes, D. K. A. & Smith, R. C. 2007 Climate
change and the marine ecosystem of the western Antarctic Peninsula. Phil. Trans. R. Soc. B 362, 149–166.
6
Clarke et al.
A recent study characterized how marine organisms respond to climate change at a global scale. The authors
found that “characteristics common among marine organisms, such as high rates of propagule production
and dispersal by ocean currents, might lead to faster expansions in distribution than observed for plants and
animals on land, even at latitudes where velocities of isotherm migration over the ocean and land surfaces
(1960-2009) have been comparable.” 7,8
Because of the natural history of marine organisms, therefore, it is possible that expansions of some life
forms—namely phytoplankton, bony fish, and invertebrate zooplankton—will be faster at sea than on land.9
The effects of ecological expansion on the Southern Ocean would be dramatic, since the areas to move
further south are geographically limited. We could expect to see increased arrivals of non-native species and
invasive species replacing indigenous Antarctic life forms. Research suggests that this will have particularly
severe impacts in the Southern Ocean, with high levels of species turnover. Species turnover is defined as a
combination of invasion and local extinction, and will be highest in sub-polar regions, and around the West
Antarctic Peninsula. 10
4. Sea Ice impacts on marine ecosystems
Sea ice is an incredibly important component of the Antarctic environment, playing “a critical role in
structuring the biodiversity of the polar oceans.” 11 Thus any changes in sea ice extent can have a wide range
of impacts beyond those most commonly discussed. Declines in sea ice can work along with other changes in
the ocean and the atmosphere to intensify warming. 12 Understanding these complex changes is central to
understanding climate change impacts on marine ecosystems.
The western Antarctic Peninsula is rapidly warming, with a winter temperature increase of 6°C since the
1950s, which corresponds with a sea ice season that has shortened by 90 days since 1978. 13 With the loss of
sea ice, phytoplankton stocks have decreased by 80% in the northern section of the western Antarctic
Peninsula, while they have increased to the south, along the sea ice margin. 14 Changes in the cryosphere
open and close new areas for species to live in, affecting those already present and destabilizing conventional
wisdom about appropriate areas in which to fish and related to establishing catch limits that meet
CCAMLR’s Article II requirements.
The impact of climate change on krill is a particular concern, due to the importance of krill for many
Antarctic species. A recent review of climate change impacts on krill highlighted the likely impact of
important drivers of climate change on krill and Antarctic ecosystems. This review showed that current rates
of warming and sea ice loss are fastest in the southwest (SW) Atlantic sector, thus affecting key nursery
habitats and feeding grounds of krill. 15 Additionally, the review concluded that “sea ice has multiple benefits
for krill, and reductions in duration, extent and geographical distribution of this winter habitat will likely
have additive cumulative negative effects, all impacting the reproductive success and survival of krill, with
7
Burrows, M. T. et al. The pace of shifting climate in marine and terrestrial ecosystems. Science 334, 652–655 (2011).
Poloczanska et al. 2013 “Global imprint of climate change on marine life” Nature Climate Change. August 4. Doi:
10.1038/NCLIMATE1958.
9
Poloczanska et al., 2013
10
Cheung, W. W., Lam, V. W., Sarmiento, J. L., Kearney, K., Watson, R., & Pauly, D. (2009). Projecting global
marine biodiversity impacts under climate change scenarios. Fish and Fisheries, 10(3), 235-251.
11
Hoegh-Guldberg O, Bruno JF. 2010. The impact of climate change on the world’s marine ecosystems. Science
328:1523–28.
12
Schofield O, Ducklow HW, Martinson DG, Meredith MP, Moline MA, Fraser WR. 2010. How do polar marine
ecosystems respond to rapid climate change? Science 328:1520–23
13
Schofield et al 2010.
14
Montes-Hugo M, Doney SC, Ducklow HW, Fraser W, Martinson D, et al. 2009. Recent changes in phyto-plankton
communities associated with rapid regional climate change along the western Antarctic Peninsula. Science 323:1470–
73.
15
Flores, H. Atkinson, A., Kawaguchi, S., Krafft, B. A., Milinevsky, G., Nicol, S., Reiss, C., Tarling, G. A., Werner, R.,
Bravo Rebolledo, E., Cirelli, V., Cuzin-Roudy, J., Fielding, S., Groeneveld, J. J., Haraldsson, M., Lombana, A.,
Marschoff, E., Meyer, B., Pakhomov, E. A., Rombolá, E., Schmidt, K., Siegel, V., Teschke, M., Tonkes, H., Toullec, J.
Y., Trathan, P. N., Tremblay, N., Van de Putte, A. P., van Franeker, J. A., and Werner, T.. Impact of climate change on
Antarctic krill. Marine Ecology Progress Series 458: 1–19, 2012.
8
possible cascading effects on food web structure.” 16 Thus if predicted declines in sea ice continue, we will
see decreases in the krill population. 17 This situation would likely have very negative consequences for krill
predators.
In models, non-native species invasions in the Southern Ocean are limited by the availability of ice free
areas. 18,19While the Bellingshausen/Amundsen Sea areas are losing sea ice in terms of area as well as length
of ice season, some other areas of the Antarctic are gaining ice. Overall, Antarctic sea ice has been increasing
at the rate of 0.9% per decade since the 1970s, particularly in the Ross and Weddell Seas and Indian Ocean
sectors. These changes are likely related to broader scale changes of ocean and air circulation related to
climate change, and are likely to intensify over time. 20 Areas around the West Antarctic Peninsula, however,
will be increasingly ice-free and have been predicted to be areas where relatively high levels of invasions
will occur. 21 Both increases and decreases in sea ice will likely have significant implications for CCAMLR
management.
5. Conclusions and Recommendations
CCAMLR should take a more proactive approach to the potential impacts of climate change. In recent years,
discussions about climate change in the Scientific Committee and its Working Groups have been relatively
limited in scope. It would enhance the process of providing timely scientific information if climate change
were more thoroughly analysed and discussed annually by the SC and its Working Groups, and it would be
useful for CCAMLR to consider establishing a sub-group focusing only on climate issues.
Presently the number of Members involved with significant climate research on the Southern Ocean marine
environment is modest.
16
•
The development of the Southern Ocean Observing System (SOOS) offers an excellent source of
data on climate change. ASOC urges CCAMLR scientists to take an annual look at SOOS updates to
ensure that they are able to incorporate any new, relevant information into their working group and
Scientific Committee discussions.
•
Efforts currently underway to estimate the ecological status of the Southern Ocean (SC-CAMLR
XXXI, paragraph 8.3), including the application of the conservation tool RACER (Rapid
Assessment of Circum-Arctic Ecosystem Resilience), should be used in conjunction with other
work, such as expanding on the work of Cheung et al. (2009) in modeling potential invasions and
local extinctions in the West Antarctic Peninsula and sub-polar regions. Such work will be important
for helping CCAMLR determine what climate change issues will impact management the most.
•
Instead of being a standalone agenda item, climate change considerations should become a regular
part of CCAMLR deliberations. In that context, when proposals for opening areas to fishing and
quotas are discussed, climate change realities must become an integral part of the decision-making
process.
•
CCAMLR should create Marine Protected Areas (MPAs) based on their potential as climate change
reference or refuge areas. MPAs can be used to assist scientists in determining whether changes in
an ecosystem are the result of climate change or human activities. Such MPAs should be no-take and
should have similar ecosystem characteristics to areas in which fishing occurs. Comparisons
Ibid.
Ibid.
18
Cheung, W. W., Lam, V. W., Sarmiento, J. L., Kearney, K., Watson, R., &Pauly, D. (2009). Projecting global marine
biodiversity impacts under climate change scenarios. Fish and Fisheries 10(3), 235-251.
19
Intergovernmental Panel on Climate Change (IPCC). 2007. Climate Change 2007: The Physical Science Basis.
Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change,
edited by Susan Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Avery, M. Tignor and H.L. Miller.
Cambridge, UK, and New York: Cambridge University Press.
20
Parkinson, CL and DJ Cavalieri. 2012. Antarctic sea ice variability and trends: 1979-2010. The Cryosphere 6:931956.
21
Cheung et al. 2009.
17
between MPAs and areas under no protection will be extremely useful for understanding changes to
marine ecosystems and how to better mitigate them.
•
CCAMLR should take steps to increase scientific research and monitoring about climate change
phenomena and impacts in the Southern Ocean, which is a burden that should be more widely shared
among Members.
Climate change has the potential to render much of the good work done by the Scientific Committee and its
Working Groups moot. It is no longer sufficient to simply include climate change as a regular agenda item
for discussion – it must be an integral part of decisionmaking processes.