Barriers to Forest Regeneration on Abandoned Central Amazonian PasturesEPA Grant Number: U915577
Title: Barriers to Forest Regeneration on Abandoned Central Amazonian Pastures
Investigators: Feldpausch, Ted R.
Institution: Cornell University
EPA Project Officer: Michaud, Jayne
Project Period: August 1, 1999 through August 1, 2002
Project Amount: $99,960
RFA: STAR Graduate Fellowships (1999) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology and Ecosystems
The objective of this research project is to investigate revegetation dynamics as a function of biophysical variables across a regenerating successional gradient of abandoned pasture to forest. Questions to be answered include: (1) How do biophysical conditions impact germination rates and seedling growth/survival? (2) How do agro-forestry and common native successional species respond to changing environmental conditions? (3) How do biophysical conditions vary with succession and how do these conditions inhibit or accelerate forest fallow succession?
Two important considerations in woody species invasion of pastures and the development of forest fallows are whether species can be established and how growth proceeds. The revegetation dynamics of fallow vegetation will be tested under four successional pasture chronosequences in a converted rainforest located in the central Amazon near Manaus, Brazil. Successional treatments include: (1) grass dominated pasture; (2) grasses and woody shrubs; (3) shade intolerant open canopy woodlot; and (4) late successional forest. Under these four chronosequence treatments the investigator will: (1) determine the germinability of desirable and undesirable forest fallow species; (2) test revegetation dynamics (e.g., LAI, survival, net assimilation rate) of planted agroforestry and natural successional species; and (3) assess above and below ground biophysical dynamics of the four treatments over time. The species introduction tests will be divided into two components, germinability and transplanted species tests. To better understand germination success, several common early and late successional woody species will be planted and germination will be recorded across the four treatments. Two species of woody agroforestry seedling species and two species of woody native indigenous successional species will be transplanted into the four treatments, and growth will be monitored over time to better understand fallow succession. Potential agroforestry tree species are Cupuacu (Theobroma grandiflorum) and Teca (Tectona grandis) because of their high economic value and Cecropia spp. and another indigenous, late successional species. Soil water flux will be monitored with a Trime TDR probe. Vegetation water potential will be measured over time to determine water uptake and stress using the pressure bomb technique. A CID, Inc., CI-110 canopy analyzer will be used to assess leaf area, canopy architecture, and solar radiation interception. The experiment terminates with destructively harvesting vegetation on the preceding treatments for leaf area, net assimilation, carbon sequestration, and soil and total site nutrient stock analysis.
Obtain answers to key questions regarding germination rates and seedling growth survival, the effects of changing environmental conditions on agro-forestry and native successional species, and effect of biophysical conditions on forest fallow succession.