Download Climate change: a cause for new biodiversity conservation

Climate change: a cause for new biodiversity conservation objectives but let’s not throw
the baby out with the bathwater
Suzanne Prober1 & Michael Dunlop2
CSIRO Climate Adaptation Flagship and CSIRO Ecosystem Sciences
1
2
Private Bag 5, Wembley WA 6913
GPO Box 284, Canberra ACT 2601, Australia
The likelihood of dramatic climate change impacts on Australia’s biodiversity is increasingly
recognized, and with this, the need to adjust the goals of biodiversity management and policy.
In particular, it will be important to shift our focus from preserving species and current
species composition, towards maintaining ecological and evolutionary processes (Dunlop &
Brown 2008; Bennett et al 2009; Steffen et al. 2009). We may need to accept that gradually
the giant tingle trees will disappear from the south-west forests, and that snow gums may
invade areas we currently value as alpine herbfield. But we can reasonably hope that current
biota will be replaced by functioning, diverse ecosystems that effectively capture limiting
ecological resources and provide ecosystem services, including beautiful places for human
enjoyment.
This proposed shift from goals focusing on species and ecological communities towards goals
focusing on processes is pragmatic and offers primary directions for policy and
implementation. It could favour a low-intervention philosophy: letting nature take its course
but ensuring that the stage is effectively set for adaptation, especially in environments
impacted by human activity. It suggests we might invest less in single-species conservation
efforts, and concentrate more on ecological resilience and adaptability. At the ecosystem
scale this might include minimizing non-climatic stressors and conserving species diversity to
optimize availability of species to maintain ecological functions (redundancy). At the
landscape scale it means conserving a diversity of habitats to provide options for species to
shift and reassemble, and in some cases, restoring connectivity that will facilitate these shifts.
The latter in particular has already entered the policy agenda and has gained public popularity
in implementation through ambitious projects such as GondwanaLink (NRMMC 2010).
On the other hand, in this shift towards process-based goals, we must also avoid throwing the
baby out with the bath water. In accepting that the mix of species will change in any
particular place and that we may lose some or many species, do we accept anything that
grows? Why restore native ecological communities that are legacies of the past, why control
boxthorns when they could provide critical bird habitat? Why not construct our new
ecosystems from species of practical utility; is it worth investing in expensive translocations?
These questions arise because it is more than processes that many of us value. We identify
with our unique flora and fauna; it contributes to diversity on the world stage. What would
Australia be without the gum tree, marsupials, its diversity of colourful parrots? We can or
must accept some change: indeed something we value is the representation of our changing
environmental history in the Australian biota – our links with the southern hemisphere
continents through the Gondwanan plant families such as the Proteaceae, or to even earlier
times through the ancient Araucarias. However, once we’ve crossed the line from managing
for what we know to managing for what might be, it is no longer straightforward to define
objectives and targets for biodiversity conservation. To avoid an ‘anything goes’ response,
we need to be more explicit about what we value in our biodiversity, and encapsulate those
values in new conservation goals.
Establishing these goals requires a philosophical debate that is only just beginning. Clear
answers may take a decade or more to emerge but here we offer a few ideas. We might, for
example, aim to maintain the evolutionary character of the Australian biota. Over 85% of
Australian vascular plant species are endemic to the continent, and this might offer a target to
aim for. This approach supports a goal of ecological re-assembly by Australian native species
rather than species originating from outside Australia, promoting ongoing or increasing
support for exotic species management. Similarly, it favours the conservation or restoration
of environments and processes that have driven the evolution of our distinct biota. This might
include conserving remnants with natural (low) soil nutrient levels in otherwise nutrientenriched agricultural landscapes, maintaining areas grazed by native marsupials rather than
livestock, or allowing fire regimes to evolve in response to changes in litter dynamics and fire
weather.
As well as continental endemics, Australia’s biogeographic history has endowed us with
many regional endemics. Thus within the broad bounds of maintaining the evolutionary
character of the Australian biota, we might propose a ‘proximity principle’, favouring
community reassembly by proximate rather than distant Australian species. This might be
especially important in the biodiversity hotspot of south-western Australia for example, to
maintain its evolutionary distinctness from the east. On the other hand, it should allow
flexibility at the local to regional scale dependent on the extent of likely stress. This would
permit, for example, considered inclusion of drought-tolerant native species or genetic stock
in revegetation.
Another goal might simply be to minimize native species loss at the national scale – allowing
for movements and adjustments across the continent (or smaller defined regions) but
managing for maximum diversity and species turnover. For better or worse, this may
encourage a focus on species-level conservation or translocations. However, a more critical
ingredient is to conserve a very wide diversity of Australian environments, including climatic
refugia. While the latter is consistent with approaches suggested by process-focused goals,
this will not always be the case. For example, an unexpected option might be to limit
connectivity in selected unique or diverse areas. This could increase the potential for
climatically marginalised native species to survive, by isolating them from invasion by exotic
or even native species, or protecting them from fire.
In changing our conservation goals, indeed in the haste to adopt new ones, there is also a real
risk of prematurely discarding the biodiversity conservation tools that we have painstakingly
established over the past half-century. Many of these tools are well-placed to help us meet
these new challenges. A network of perpetual conservation reserves, designed according to
principles of comprehensiveness, adequacy and representativness (CAR), remains a highly
appropriate mechanism for conserving a diversity of natural environments. Some adjustments
(e.g. another R to emphasize resilience and the need for a wider margin in all of our
conservation efforts) will add value, but the fundamental principles are not broken by the
phenomenon of species coming and going. Similarly, threatened ecological community
listings highlight those environments that are most under threat, development controls and
listing of threatening processes will be increasingly relevant for reducing non-climatic
stressors on our biota; and the importance of community awareness and education in
achieving conservation goals has never been more critical. Hence, while current approaches
are increasingly questioned, we should also ask whether we risk more in disabling them than
in working with and adapting what we have.
To conclude, managing biodiversity under climate change will largely be about facilitating
nature’s response. We will need to accept much change, but we do have some capacity to
influence outcomes through policy and on-ground action: we should not stop short of goals
that target the essence of what we value in Australia’s biodiversity.
References
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Quinn G.P., Radford J.Q., Robinson D., Watson J.E.M. and Yen A. (2009). Ecological
processes: a key element in strategies for nature conservation. Ecological Management
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Dunlop M., Brown P.R. (2008) Implications of Climate Change for Australia’s National
Reserve System. A Preliminary Assessment. Report to the Department of Climate Change.
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http://www.climatechange.gov.au/~/media/publications/adaptation/nrs-report.ashx
Natural Resource Management Ministerial Council (2010). Australia’s Biodiversity
Conservation Strategy 2010-2030. Australian Government, Department of Sustainability,
Environment, Water, Population and Communities, Canberra.
Steffen W., Burbidge A., Hughes L., Kitching R., Lindenmayer D., Musgrave W., Stafford
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