CLIMATE CHANGE: IMPACTS AND ADAPTATION

         Climate change is rapidly becoming a major threat to global biodiversity, drastically altering natural ecosystems. A growing body of research examines the impacts of changing climate on individual populations or on the distributions of habitat types. Yet natural communities are complex; in order to fully comprehend, and potentially mitigate, the effects of climate change we must understand the impacts, not just on single species, but on ecological interactions. How a given species responds to climate change will be strongly affected by concurrent impacts on its predators, prey, mutualists, and parasites. Our understanding of the effects of changing climate on interspecific interactions is only in its infancy.
         Moreover, despite the vast literature on the ecological impacts of climate change, very few scientists to date have asked “what can we do about it?” Clearly we need to immediately and drastically reduce humanity’s carbon footprint. But even if we were to stop emitting fossil fuels tomorrow, climate change would continue. The time lag between emissions and atmospheric response ensures that our past discharges have not yet caught up with us. It is therefore critical that we develop on-the-ground means of alleviating and adapting to the impact of climate change on species and ecosystems.
         My work on climate change is on three fronts:

1) CLIMATE CHANGE IN TROPICAL FORESTS
        The impacts of climate change on tropical forests -the greatest storehouse of terrestrial biodiversity on earth- are critical to understand.  Tropical trees are hit with the "double whammy" of climate change, being affected directly by rising temperature & altered precipitation, and indirectly by the fact that as abiotic conditions change, human behavior could change in ways detrimental to biodiversity.  For example, the direct ecophysiological impacts of warming on tropical trees are compounded by increased logging and anthropogenic fires as forests dry.  Efforts are underway to expand protected areas and control destructive fires.  Along with Eric Post and Bill Laurance, I argue that these initiatives should be coordinated at regional and international levels to explicitly increase the climate-change resilience of remaining forests and forest-dependent taxa.

A major new policy instrument for mitigating carbon releases, Reducing Emissions from Deforestation and Forest Degradation (REDD), could be made much more effective when integrated into such resilience-enhancing strategies. Currently, REDD is intended to reduce carbon emissions by helping to protect forests, but it lacks explicit mechanisms for increasing forest resilience. We suggest that REDD projects, new protected areas, and fire-control efforts should be collectively focused on two goals: (i) increasing large-scale connectivity of tropical forests, especially across latitudinal and elevational gradients, to facilitate range shifts by tropical species in response to future climate change, and (ii) reducing or halting agricultural expansion in areas of rapid deforestation, especially when such areas are also susceptible to drying, as with the Amazon’s arc of deforestation.

The biodiversity benefits of REDD projects and new protected areas would be augmented by strategically locating them to protect connectivity between major eco-zones, for example between the Amazon lowlands and the uplands of the Brazilian and Guyana Shields, or by spanning large-scale moisture gradients as with the Central Amazonian Conservation Corridor.

              In tropical Asia, strategic use of REDD projects could help to link existing protected areas into large-scale conservation networks in central Borneo, the forests along the Thailand-Myanmar border, and in the Annamite Mountains of Laos and Vietnam. While fire-control education and regulation will always be important in Southeast Asia, we can predict when their need will be especially acute: El Niño events can generate strong drying in the equatorial forests of Indonesia and Malaysia, often leading to massive increases in burning. If El Niño events increase in intensity in response to anthropogenic activities, fire will become an ever more critical issue in Southeast Asia and elsewhere in the tropics. 

2) ELK, ASPEN, AND SNOW IN YELLOWSTONE
        I am examining how declining snow levels in the Yellowstone Ecosystem affect the interaction between elk (Cervus elaphus) and aspen (Populus tremuloides). Funding from the David H. Smith Conservation Research Fellowship has allowed me to examine the impacts of climate on the elk-aspen interaction, and to begin to assess how to help mitigate such impacts. I conducted extensive winter field work in Yellowstone involving large-scale correlative studies and controlled field experiments, combined with meta-analysis and quantitative population modeling. This
is in collaboration with Joel Berger and Eric Post. Read more about this project here.

3) STRATEGIES AND SOLUTIONS

        I am helping bring experts together to find ways to adapt wildlife management to climate change. Along with Eric Post and Daniel Doak, two of the world's leading climate change ecologists, I am editing a book called "Wildlife conservation in a changing climate". This book is under contract with the University of Chicago Press and is due for publication in 2011. Read more about the book here.