Research Interests
My research is currently focused on the population biology of the rare and endangered wildflower Senna hebecarpa (wild senna).  Very little is known about the biology of this species, and therefore I have begun to document the plant's basic reproductive biology, life-history parameters (rates of birth, growth, and death), and population viability.
     This summer I am investigating different aspects of S. hebecarpa's reproductive biology.  Specifically, I am documenting the plant's flowering phenology and conducting an experiment to quantify the level of inbreeding within the population (see directed research studies).  It is not uncommon among rare species that are distributed in small and isolated populations such as S. hebecarpa to experience a loss in fitness due to higher than normal levels of inbreeding, a phenomenon known as inbreeding depression.

I have spent several years investigating the population biology of a threatened understory palm, Chamaedorea radicalis, which grows in the Montane cloud forests of northeastern Mexico. Leaves of this palm are harvested by local collectors called palmilleros, and there is a concern that over-harvesting is causing a decline in wild C. radicalis populations.
     As part of my research, I have constructed mathematical models that project the affects of leaf harvest and other disturbances such as livestock grazing on long-term population growth rates (Endress et al. 2006, Berry et al. 2008). These results are currently being used to develop management strategies that promote sustainable leaf harvest practices.
     I have also examined the reproductive biology of C. radicalis to determine its pollination vector and what factors influence reproductive success in a population (Berry & Gorchov 2004).  Chamaedorea radicalis has the rare breeding system dioecy, where each individual is either male and produces only staminate flowers or female and produces only pistillate flowers.  Such a breeding system requires a vector to transfer pollen from males to females.  I examined the role of population density and male abundance on female fecundity to determine if leaf harvest or other factors have reduced population sizes to the point where pollination is limited (Berry & Gorchov 2006).

Left: Staminate flower

Middle: Pollen

Right Pistillate flower

Directed Studies Projects
Research in my lab is primarily focused on plant population ecology and conservation.  Students interested in conducting an independent research project are welcome to work with me on the pollination biology and population dynamics of wild senna, or other local plant species that are rare, invasive, or otherwise ecologically important.

Current student projects include a controlled pollination experiment  to test for the effects of inbreeding depression in wild senna.  This research involves constructing pollinator exclusion bags (below left), emasculating flowers to prevent self-pollination (below middle), and conducting hand-pollinations of select flowers (below right). 
     After pollination treatments are complete, students will be quantifying the initial affects of inbreeding on the plant's reproductive success by measuring fruit set (number of fruits per flower) between self- and cross-pollinated plants.  Seeds from these fruits will be collected to measure the effect of inbreeding on the fitness of offspring by measuring seed germination, seedling survival, and seedling size.  These experiments will be conducted during the school year in the newly constructed greenhouse.

 Research Publications

Berry E.J., Gorchov D.L., Endress B.A., and Stevens M.H.H. 2008. Source-sink dynamics within a plant population: the impact of substrate and herbivory on palm demography.  Population Ecology. 50:63-77 ( PDF Document / 650kb)

Berry E. J. & Gorchov D. L. 2006. Female fecundity is dependent on substrate, rather than male abundance, in the wind-pollinated, dioecious understory palm Chamaedorea radicalis.  Biotropica. 39:186-194. (PDF Document / 200kb)

Endress B. A., Gorchov D. L., & Berry E. J. 2006. Sustainability of a non-timber forest product:  Effects of alternative leaf harvest practices over six years on yield and demography of the palm Chamaedorea radicalis.  Forest Ecology and Management 234:181-191 (PDF Document / 350kb).

Berry E. J. & Gorchov D. L. 2004. Reproductive biology of the dioecious understory palm Chamaedorea radicalis in a Mexican cloud forest: pollination vector, flowering phenology, and female fecundity.  Journal of Tropical Ecology 20:1-8. (PDF Document / 900kb)