Understanding species interactions in a novel community: Anolis and Phelsuma in Hawaii

Hawaii's non-native herpetofauna provide a unique opportunity to study community dynamics. We use experimental enclosures to study interactions between the convergent Anolis (anoles) and Phelsuma (day geckos) that have been introduced to Hawaii. Enclosures allow us to control resource availability and manipulate the lizard species assemblage. The first experiment (2015-2019) was a substitive competition experiment aimed at determining functional trait differences, patterns of resource use (structural, thermal, diet) and fitness effects in response to  varying the lizard assemblage. We also looked for evidence of interspecific interference (Kennedy-Gold 2019). Functional morphology aspects of this work are in collaboration with Tim Higham, see here for a blog post on one of our papers at Functional Ecology. 

The second experiment (2021-2022) is looking for evidence for resource partitioning in an R* framework (i.e., do different species suppress different prey populations?), as well as spatial heterogeneity in competitive ability (i.e., does prey capture success vary based on trait-performance relationships in different microhabitats)? We are also looking at where the species fall along a slow-fast life-history gradient and differences in foraging behavior. 

Disease ecology of introduced mammals in Hawaii

Emerging infectious diseases are of increasing concern for both public and ecosystem health. Leptospirosis is a zoonotic EID of global importance that occurs in Hawaii. The disease is caused by a bacterium that is transmitted by a wide range of mammalian hosts, with human infection due to contact with animals or contaminated water or soil. Hawaii provides an ideal system for studying leptospirosis because 1) we have a relatively simple host community comprised of a small number of largely introduced mammals, and 2) our natural climate gradients from wet to dry allow for testing of climatic drivers of disease. In collaboration with Matthew Medeiros we are studying leptospirosis in small mammal hosts and the environment over time to better understand the ecology of this zoonotic disease in Hawaii. This work has also lead to collaboration with Rob Cowie on rat lungworm. 

Resource pulses and pulsed subsidies

Resource pulses are a prime example of spatio-temporal variation in resource abundance and provide windows into how animals cope with natural resource variation. We (Jonah Piovia-Scott, Louie Yang, Dave Spiller, Tom Schoener, et al.) have been studying the effects of resource pulses on island food webs in the Bahamas, including the sequence of cascading effects from both an above-ground lizard pathway and below-ground plant pathway, changes in the strength of top-down control over the course of the pulse, and how individual changes in lizard foraging behavior and life history lead to impacts at the population and community level. 

Historical resurveys of lizard communities in the Mojave Desert

The Mojave Desert has experienced a warming climate, increased development, and the spread of introduced species over the last several decades. To evaluate the impact of these changes, we (Bob Thomson, Greg Pauly, Anthony Barley, Levi Gray, et al.) have been resurveying lizard communities at sites originally surveyed by Eric Pianka in the 1960s as well as some additional sites. Using both line transect distance surveys and specimen collection, we are evaluating changes in species traits, diversity, and abundance.