Liza S. Comita   Krithi K.   Karanth   Eleni   Nikitopoulos   Patricia      Adame   Hernando

Liza S. Comita   Postdoctoral Research Scientist Columbia University, Department of Ecology, Evolution and Environmental Biology 1200 Amsterdam Avenue New York, NY 10027-5557 Phone: 212-854-8253 Fax: 212-854-8188 Email: lsc2125@columbia.edu I am broadly interested in patterns of diversity, dynamics, and species distributions in both pristine and human-altered tropical forests. My current research focuses on the regeneration ecology of tropical tree species and how spatial and temporal variation in seedling dynamics act to maintain diversity and determine species composition in tropical forests. Seedling recruitment, growth and survival are among the most critical demographic rates driving forest regeneration following human or natural disturbance. Nevertheless, determinants of tropical seedling dynamics and the relative importance and interactions of various biotic and environmental drivers are not well understood, even in undisturbed forests. My current postdoctoral research focuses on how forests regenerate following large natural disturbances, namely hurricanes, and how regeneration pathways and post-disturbance community composition change as a result of human alterations to landscapes. For this project, I am utilizing a 15-year record of tree and seedling dynamics in the 16-ha Luquillo Forest Dynamics Plot in the Luquillo mountains of northeastern Puerto Rico. The plot encompasses areas of differing intensities of past human disturbance. In addition, the region has been hit by two major hurricanes since 1989. Thus, the site provides an excellent opportunity to study forest regeneration and community stability following large-scale natural and human disturbance. I am currently analyzing patterns of seedling dynamics to assess shifts in the relative importance of land-use history, biotic interactions (e.g., competition, herbivory), and abiotic variables (e.g., light, soil resources) as the forest recovers from hurricane damage. Analyses of this forest plot will be used to predict the future of this forest and will have implications for forests throughout the tropics that will likely experience increases in hurricane disturbance and human impacts in the coming decades. Past and ongoing research projects include: -Long-term dynamics of the seedling layer on Barro Colorado Island, Panama -Cross-site comparisons of tropical forest dynamics -Effects of spatial and temporal variation in water availability on tropical tree species distributions -Impacts of long-term research on vegetation dynamics and composition   top of page Krithi K. Karanth   Research Fellow Columbia University, Department of Ecology, Evolution and Environmental Biology 1200 Amsterdam Avenue New York, NY 10027-5557 Phone: Fax: 212-854-8188 Email:krithi.karanth@gmail.com Dr. Krithi K. Karanth is a post doctoral scientist with Dr. Ruth DeFries. She obtained a Ph.D in Environmental Science and Policy from Duke University (2008). She has a master's from Yale in Environmental Science (2003), B.S (Environmental Science ) and B.A (Geography) from the University of Florida (2001). Research Interests I am broadly interested in human-environment interactions, particularly focusing on protected areas and their relationship to people and biodiversity. The central themes to my research are: 1. Protected areas and their relationship to people living around them; 2. Biodiversity patterns and factors that drive the persistence of wildlife; 3. Societal impacts of conservation interventions and policies. I am particularly interested in human-wildlife interactions, land use change, livelihood dependence of local communities, resettlement of people, and tourism impacts.   top of page   Eleni Nikitipoulos   Research Fellow Columbia University, Department of Ecology, Evolution and Environmental Biology R. 609 Schermerhorn 1200 Amsterdam Avenue New York, NY 10027-5557 Phone: 212-854-9707 Fax: 212-854-8188 Email: en2142@columbia.edu I study socio-sexual behavior in non-human primates. As a behavioral ecologist, I am interested in how behavior functions to impact an individual’s direct and indirect fitness. In order to understand social and sexual interactions between individuals it is important to unravel processes in competition and cooperation. My particular fields of study include male and female sexual strategies, collective action and public goods, and cooperation between kin and between non-kin. My dissertation work focused on female mating preferences and the effects of female sexual strategies on male-male competition. I empirically investigated how female copulation calls and mating preferences influenced male mating success in captive long-tailed macaques (Macaca fascicularis). Traditionally, females were thought to express mate choice by mating selectively with males. However, promiscuous females might exert choice through selection on male ejaculate after copulation. Furthermore, females might mate with multiple partners as a counterstrategy to infanticide by males or to avoid nonviable fertilizations. While promiscuous mating is notable in long-tailed macaques, the alpha male monopolizes copulations with females for at least a portion of the mating period. The proportion of paternity monopolized by the alpha male, however, depends on female cooperation with his mating efforts, female efforts to mate with other males, and the alpha male’s timing of monopolized copulations in relation to the female’s ovulation. My current research project with Dr. Marina Cords investigates patterns of cooperative behavior in a wild guenon, Cercopithecus mitis, focusing on communal territory defense as a public good and pair-wise grooming as a private exchange. A public good is a behavioral service provided by one or more individuals that benefits the entire group, even group members who don’t participate in its provision. Collective action models offer an approach to investigate how distribution of benefits within a group motivates individual action and decreases cheating. Cheating occurs when individuals contribute less than their fair share toward the collective good, and a collective action problem arises if free-riding results in sub-optimal levels of the collective good. As a commodity, grooming offers hygienic and hedonic value. In the absence of within- and between-group competition, grooming can only be traded for itself and reciprocal grooming bouts are expected. When grooming can be traded for something else, shifts away from reciprocal exchange are expected. Kin selection, reciprocal altruism, and mutualism have been identified as three major mechanisms that can bring about the evolution of cooperation, and each predicts characteristic patterns of interaction among social partners. In general, the degree to which individuals participate in cooperative activities through any of these mechanisms should reflect a positive balance of benefits minus costs. Predicting who cooperates and when is thus a matter of identifying and assessing those benefits and costs for potential cooperators.   top of page   Patricia Adame Hernando   Visiting Scientist Columbia University, Department of Ecology, Evolution and Environmental Biology R. 1020 Schermerhorn Extension 1200 Amsterdam Avenue New York, NY 10027-5557 Phone: 212-854-8253 Fax: 212-854-8188 Email: pa2281@columbia.edu I am a visiting research scientist from Spain at Columbia University's department of Ecology, Evolution and Environmental Biology. My doctorate research, completed at the University of Madrid (Spain), focused on individual-tree growth modeling of a mediterranean oak using Spanish National Forest Inventory. The recognition of different problems in wide areas, and the increasing interest in using these stands for either direct production (such as wine barrels) or indirect production (such as silvopastoral uses, recreation, and environmental preservation) justifies the urgent need to guarantee a sustainable management of oak stands. Considering the high environmental and silvicultural variability of these stands in Spain, it is necessary to typify and characterize them in order to optimize their management. I am interested in the mathematical modeling process, which integrates theoretical and field ecology concepts and methodologies, and in the ecosystem/human dynamics. Current work focuses on abiotic characteristics (hurricanes, topography, basin, etc...) of permanent plots in Puerto Rico between 1990-2000.   top of page