COLUMBIA UNIVERSITY THE
URIARTE LAB Department of Ecology, Evolution &
Environmental Biology |
Impacts of landscape
configuration on plant recruitment in Amazonia Collaborators Emilio Bruna, University
of Florida John Kress,
Smithsonian Institution Marina Anciães,
Instituto Nacional de Pesquisas Amazônicas Marina Côrtes, University of São
Paulo, Rio Claro The diversity, composition, and dynamics of vegetation during
succession are highly dependent on relationships with frugivorous
animals. Birds are among the principal animal dispersal agents of tropical
forest plant species. We are working on the Biological Dynamics of Forest
Fragments Project (BDFFP) located 70
km north of Manaus, Brazil, to determine how
forest fragmentation, secondary forest regeneration, and interspecific
variation in avian foraging behavior influence the
recruitment of Heliconia acuminata,
a common understory plant in primary forests. By using a combination of empirical and modeling
approaches, we have elucidated the degree to which biotic and abiotic factors acting at various spatial and temporal
scales contribute to recruitment of H. acuminata in this human-modified landscape. By mapping and measuring seedlings in
long-term plots at high spatial resolution, radio-tracking bird dispersers,
conducting feeding experiments to estimate seed gut passage rates,
quantifying the abiotic environment (e.g., light
availability), and developing detailed GIS vegetation maps of the area
surrounding the fragments, we can integrate the necessary data in
sophisticated spatially-explicit models of seed rain and seedling
recruitment. Marina Cortes, a former graduate student,
developed microsatellite primers for H.
acuminata and has genotyped over 2,500 individuals
within this landscape at two time points, 1998 and 2005. These snapshots in time represent
fine-scale genetic structure before (1998) and after (2005) secondary forest
re-growth in the matrix surrounding the forests. These data provide us with
unique empirical and theoretical insights into the effects of landscape
fragmentation and the characteristics of the surrounding landscape on
disperser behaviour and population genetic structure, a vital contribution to
ecology. |