INVASIVE SPECIES IN NATIVE ECOSYSTEMS

Invasive species are a major driver of change in biodiversity and ecosystem functioning. My research seeks to understand how invasive species influence community structure and ecosystem processes and to assist in predicting and mitigating their impacts. I approach this topic using experimental and theoretical techniques. In the field, I've studied the impacts of many invasive species introduced in Patagonia, Argentina, including deer (Cervus elaphus and Dama dama), wild boar (Sus scrofa), yellow jacket wasps (Vespula germanica), cattle (Bos taurus), and pines (Pinus contorta). To gain a global perspective on impacts of invaders, I have reviewed key literature on plant origin and invasiveness, and compared impacts in the native and introduced ranges. These comparisons allow me to identify the mechanisms that promote invasion and help to focus resources on viable management strategies.

WARMING and (species) REMOVAL on MOUNTAINS - WaRM

The amount of carbon in the atmosphere regulates how much warming will occur globally; yet the amount of carbon taken up and released from terrestrial ecosystems under warming remains uncertain in the models that predict future climates. We are studying the ecosystem-level responses to the direct and indirect effects of warming with a coordinated project that combines experimental warming and dominant plant species removal among 12 globally-distributed elevational gradients. We aim to (1) determine the relative influences of climate and interactions among species on biodiversity and ecosystem carbon dynamics. (2) To examine the patterns and processes that shape ecosystem function among disparate ecosystems. (3) To investigate whether the functional composition of plant communities determines how communities respond to warming and dominant species removal.

GENETIC DIVERSITY AND ECOSYSTEM FUNCTION

The importance of within-species genetic diversity on ecosystem functioning is growing in prominence. Genetic variation within a species can have strong effects on population, community, and ecosystem processes. For example, different plant genotypes can have strong effects on the population dynamics of associated arthropods. Moreover, differences in plant genotypes can influence both above- and below-ground ecosystem processes such as primary productivity, litter quality, decomposition rates, and nutrient cycling. Working in collaboration with Greg Crutsinger, we explored the influence of genetic diversity across ecosystem boundaries and under climate change.