Plant Community Trait-by-Environment Relationships in the Greater Cape Floristic Region
The Greater Cape Floristic Region (GCFR) of South Africa is a region of incredible plant diversity. My work at UConn is part of a larger project that is investigating parallel evolutions that contributed to this diversity. Most of my work focuses on the relationships between plant communities, the functional traits of the plants that make up those communities, and the environmental conditions where those communities occur.
The Invasion of Frangula alnus
Though the usefulness and value of distinguishing native and non-native species is currently a topic of lively debate, it is clear that some non-native species have substantial negative effects on biodiversity and human health. The seriousness of these threats justifies research into the ecological and evolutionary processes governing the establishment and spread of non-native species. Additionally, several researchers (e.g. Sax et al. 2007, Trends in Ecol. Evol. 22:465-471) have pointed out that studying species invasions may yield insights into ecological and evolutionary processes in general. With these two ideas in mind, I set out early in my graduate career to study a non-native species of concern in a geographic region and ecosystem of great importance to me, the deciduous forests of northeastern North America. Following discussions with researchers and land managers, I decided to focus my dissertation research on the non-native invasive species Frangula alnus (Glossy Buckthorn). F. alnus is a woody plant native to Eurasia. It has a rapid growth rate, the ability to thrive in nutrient poor soils, produces abundant fruits, and benefits from bird assisted seed dispersal - all factors that likely contribute to its successful invasion. For my Ph.D. research, I examined the temporal and spatial ecological processes governing the invasion of F. alnus in a quantitative modeling framework that comprised (1) a demographic model based on data I am collecting during a multi-year field study; (2) a statistical model of the spread rate of F. alnus and the effects of land-use change, based on herbarium records and historical landscape reconstruction; and (3) a species distribution model (SDM), based on occurrence data from multiple sources. I integrated the results of these models, linking information on dynamic processes (e.g., results from the demographic model) with information on ecological patterns (e.g., results from the SDM), to gain an understanding of what processes contributed to the rapid spread of F. alnus throughout northeast North America. This work is currently being prepared for publication.
Impacts of Global Climate Change
I have worked on several projects that focus on examining the impacts of global climate change on species, some of conservation concern. In my future research, I will continue to investigate the effects of climate change on species demography and ecosystem processes.
Sea-level Rise Effects on Shore Birds
From 2009 to 2012 I worked with a collaborative research group that included scientists from the University of Florida and the Army Corp of Engineers to examine the effects of projected sea-level rise on shore-birds along the Gulf Coast of Florida. My primary role in this project was to gather relavent biological information on three bird species of interest (Snowy Plover, Piping Plover, and Red Knot), and to construct a demographic model for the Snowy Plover (Charadrius nivosus). We linked this demographic model to a spatial model of the effect sea-level rise is projected to have on shore-bird habitat along the Gulf Coast, and examined what impacts on the risk of population decline and extinction such changes may have for this species. Several publications have come out of this project, but my work on linking the demographic and spatial models was published late in 2011 in Global Change Biology (Aiello-Lammens et al. 2011). (Image of Snowy Plover under Creative Commons Attribution 2.0 Generic from Wikipedia; photo by Mike Baird, bairdphotos.com)
Systematic Review of the Causes of Local Extinction Due to Climate Change
Another project I have worked on is a systematic review of the proximate causes of local extinction due to climate change. This review was in part the result of a seminar lead by Professor John J. Wiens at Stony Brook University. The key question we set out to address in this review was "for observed local extinctions connected to climate change, are the proximate causes of extinction related to abiotic or biotic factors?" The results of our systematic review support the idea that biotic interactions are more often involved in the proximate cause of local extinction than abiotic factors (i.e. physiological limits). I have discussed our findings and my thoughts on the literature review process in blog post here. The article, which I co-lead, can be found here (Cahill et al. 2012, Proceedings of the Royal Society B).