Enhancing Tropical Forest Restoration in Abandoned Pastures in Lieu of Climate ChangeEPA Grant Number: F07F20240
Title: Enhancing Tropical Forest Restoration in Abandoned Pastures in Lieu of Climate Change
Investigators: Townsend, Patricia A.
Institution: University of Washington
EPA Project Officer: Michaud, Jayne
Project Period: September 1, 2007 through September 1, 2010
RFA: STAR Graduate Fellowships (2007) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Fellowship - Biology/Life Sciences , Fellowship - Tropical Ecology , Global Climate Change
Tropical forests have been cleared throughout Latin America for pasture and agriculture. Pastures frequently become degraded, then abandoned, and subsequently lapse into a state of arrested succession. There are many ecological barriers to succession in abandoned pastures, and global climate change is compounding the problem. The research site for this project is in Monteverde, Costa Rica, more dry days and less mist are having a significant impact on the cloud forest. Because pastures lead to highly fragmented forest, habitat connectivity must be re-established so that species can shift ranges as the climate changes.
This research tests three hypotheses regarding factors that may limit tree establishment in abandoned pastures, and hence limit succession: (1) highly competitive non-native grasses inhibit seed germination and seedling growth; (2) seed predation limits seed germination; and (3) adverse physical conditions lead to high rates of seed and seedling desiccation.
Experiments started in 2005 with seeds from seven native trees seek to evaluate limiting factors by eliminating grass with soil solarization, reducing grass with cutting, and adding logs to improve microsite conditions. Seed predation and seedling herbivory are also being monitored. Additional experiments will be started with at least three native tree species in 2007 and 2008 to further evaluate seed predation and seedling survival and growth rates. Two additional grass reduction techniques will be tested as well as vegetative propagation to provide immediate shade to mitigate seedling desiccation. Finally to plan for climate change, selection of species for restoration will be evaluated, as it may be beneficial to use plants from lower elevations that better tolerate hot dry conditions, preferably those with high growth rates to aid in carbon sequestration.
This research will aid in understanding succession and provide suggestions for how to enhance plant recruitment to facilitate tropical forest restoration. Management techniques will depend on the plant’s life stage and on differing pasture conditions. Preliminary results indicate that logs may be used to assist seed germination in areas with natural seed rain and soil solarization may be useful to eliminate invasive grasses to reduce competition with native species. This research will also provide insight into how restoration can be done in anticipation of climate change.