Susan G Letcher

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Rates of change in tree communities following major disturbances are determined by a complex set of interactions between local site factors, landscape history and structure, regional species pools and species life histories. Our analysis focuses on vegetation change following abandonment of agricultural fields or pastures, as this is the most extensive form(More)
The phylogenetic structure of ecological communities can shed light on assembly processes, but the focus of phylogenetic structure research thus far has been on mature ecosystems. Here, I present the first investigation of phylogenetic community structure during succession. In a replicated chronosequence of 30 sites in northeastern Costa Rica, I found(More)
We develop a novel statistical approach for classifying generalists and specialists in two distinct habitats. Using a multinomial model based on estimated species relative abundance in two habitats, our method minimizes bias due to differences in sampling intensities between two habitat types as well as bias due to insufficient sampling within each habitat.(More)
To gain insight into the ecological processes driving community reassembly in disturbed ecosystems, we assessed the phylogenetic dispersion of earlyand late-successional tree species occurring in lowland forests of northeastern Costa Rica. Early-successional species were more closely related than expected by chance, whereas late-successional species tended(More)
Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic(More)
Recent evidence suggests that liana abundance and biomass are increasing in Neotropical forests, representing a major structural change to tropical ecosystems. Explanations for these increases, however, remain largely untested. Over an 8-yr period (1999–2007), we censused lianas in nine, 24 9 36 m permanent plots in old-growth and selectively logged forest(More)
The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate(More)
Land-use change occurs nowhere more rapidly than in the tropics, where the imbalance between deforestation and forest regrowth has large consequences for the global carbon cycle. However, considerable uncertainty remains about the rate of biomass recovery in secondary forests, and how these rates are influenced by climate, landscape, and prior land use.(More)
Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth(More)
Susan G. Letcher*, Jesse R. Lasky, Robin L. Chazdon, Natalia Norden, S. Joseph Wright, Jorge A. Meave, Eduardo A. P erez-Garc ıa, Rodrigo Mu~ noz, Eunice RomeroP erez, Ana Andrade, Jos e Luis Andrade, Patricia Balvanera, Justin M. Becknell, Tony V. Bentos, Radika Bhaskar, Frans Bongers, Vanessa Boukili, Pedro H. S. Brancalion, Ricardo G. C esar, Deborah A.(More)