The ecological legacies of disturbance events can persist for decades to centuries and past disturbance is important in explaining the present landscape. Ecosystem disturbances are increasing in frequency and severity due in part to global climate change. Our research contributes to an ecological understanding of the consequences of these events and a framework for retrospective study of ecosystem disturbance. Our work is often motivated by a lack of available data that limits our understanding of these processes. We use a combination of tools (remote sensing, field studies, geospatial and statistical analysis) to understand environmental change over broad spatial and temporal scales to inform future natural resource management. Current themes include:
Drought in Forests and Rangelands
Drought is a common feature of semi-arid landscapes, but the frequency and scale at which it occurs appears to be changing. We are engaged in several projects to understand the spatial and temporal effects of recent droughts on local ecotones and regional ecosystems. Collectively these approaches yield management and policy insight into how drought events affect key plant and animal communities at local scales, while enhancing our understanding of ecosystem carbon dynamics at broad scales. Recent projects took place in the aspen ecosystems and sagebrush steppe of southwest Wyoming and we’re starting work on a new project in low elevation aspen communities in the Great Basin.
Fire and Regeneration in Forests
Fire is a primary disturbance agent in many ecosystems and forest response is governed by species life-history traits and post-fire biotic residuals. However, changing fire regimes (increased frequency, higher severity and larger area burned) can trigger a shift in species composition and compromise tree regeneration, ultimately leading to reduced forest resilience. We are engaged in projects investigating burn severity on tree regeneration (Andean Mountains, Chile), quantifying post-fire shifts in plant functional type (Jemez Mountains, New Mexico), and untangling compounded disturbances (e.g. historical insect outbreaks followed by fire) in subalpine forests in the western US.
Extreme Events in Coastal Forests
Although coastal forests are dynamic environments, severe storms compromise photosynthetic capacity and alter forest structure for many years after the event. Furthermore, storm surges push large amounts of saline water up estuaries, flooding riparian forests and inducing tree mortality. We are investigating new ways to quantify the extent and severity of cyclone impacts on vegetation condition in the Sundarbans of Bangladesh in an effort to understand recovery trajectories of mangrove forest at the landscape scale. We’ll soon be starting a project to map tree mortality from Hurricane Sandy in remnant Atlantic white cedar forests that are ecologically important in southern New Jersey.
Habitat Monitoring and Human-Environment Interactions
As biogeographers we are interested in how landscape dynamics and disturbance influence habitat condition and regularly collaborate with wildlife ecologists on species of conservation concern. We use statistical models to develop maps of (often) understudied plant communities that are utilized by natural resource managers in strategic habitat planning. We also work with social scientists, planners and economists to investigate human-environment interactions related to land use change, ecosystem services and rapid ecological assessments. Current projects include monitoring riparian vegetation trends in the Bighorn Mountains, effects of energy development on pygmy rabbits and assessing the legacy of ecosystem services in agricultural fields enrolled in the Conservation Reserve Program.