Plant Systematics, Conservation Biology, and Ethnobotany


Sebastián Tello

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Assistant Scientist
Ecology Center for Conservation and Sustainable Development

Sampling effects, regional species pools, and the role of unseen species. Two of the most pressing challenges to biodiversity science are 1) to identify the forces that control the structure of ecological communities (the composition and abundance of species within sites), and 2) to understand how these forces might change across space or time. Individual communities, however, are embedded within larger regions (landscapes) and are connected by dispersal of species and movement of materials. Thus, communities can be strongly influenced by their broader ecological context. Recent research highlights the role of “regional sampling effects”, and the need to account for these effects when studying other potential forces structuring communities. Regional sampling effects refer to the variation in in ecological communities that is expected simply from random drawing of species from a broad species pool. Null models (statistical tools based on data randomization) have been used to account and control for regional sampling effects in recent studies. However, a criticism of past studies is that regional species pools used in analyses do not consider the effects of unobserved species. These species are important players in the landscape dynamics that produce real communities, but are not observed in empirical data because of limited information. The objective of this study will be to test the hypothesis that unobserved diversity in regional species pools has biased results of previous research regarding the role of sampling effects. For this project, students will learn the R programming language and use it to conduct computer simulation experiments that will test predictions of the research hypothesis. Furthermore, students will re-analyze empirical data to confirm or modify the conclusions of previous research. Students in the project will learn and put in practice concepts in community ecology, tropical plant biogeography, statistical programming and null model analysis of ecological data.

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