Grantee Research Project Results

Breeding Ecology Response of Songbirds to Forest Disturbance

EPA Grant Number: F6F70558
Title: Breeding Ecology Response of Songbirds to Forest Disturbance
Investigators: Wick, Jill
Institution: Alabama A & M University
EPA Project Officer: Hahn, Intaek
Project Period: September 1, 2006 through September 1, 2008
Project Amount: $63,880
RFA: GRO Fellowships for Graduate Environmental Study (2006) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Terrestrial Ecology

Objective:

Many migratory songbird species have experienced population declines over the past four decades, in part due to habitat loss in both the breeding and wintering grounds. One of the factors contributing to the loss of suitable habitat for many bird species in the United States is forest management practices that prevent natural disturbances (i.e., fire suppression), leading to the breakdown of ecological processes and “unhealthy” forest ecosystems. To restore forest ecosystem health, canopy reduction and prescribed burning have been used to simulate natural disturbance. This study will examine the effect of two types of disturbance (prescribed burning and forest thinning) on the songbird community and individual avian fitness (an individual's contribution to the next generation’s breeding population).

Approach:

This research is based on the theory that forest disturbances such as prescribed burning and canopy thinning mimic natural habitat disturbances and will alter resource abundance and availability. Research techniques will include breeding bird surveys, territory mapping, radio tracking, nest monitoring, arthropod sampling, and habitat surveys. Two Neotropical migratory species, the hooded warbler (Wilsonia citrina) and the worm-eating warbler (Helmitheros vermivorus), will be used as focal species. Experimental design consists of a before-and-after control-impact (BACI) randomized complete block design with two factors – three thinning levels (no thin, 11 m2 ha-1 residual basal area (BA), and 17 m2 ha-1 residual BA) and two burn treatments (no burn and burn). Each treatment will be replicated three times. The experiment will be conducted at the Bankhead National Forest in northwestern Alabama. It is my hope that the results of this research will aid forest resource managers in understanding how forest disturbance affects bird populations.

Expected Results:

I anticipate that early successional bird abundance will increase in thinned plots, whereas ground and shrub nesting species abundance will decrease in burned plots. Territory size will be directly related to arthropod availability and indirectly related to forest disturbance. Nest success will be correlated with food availability, presence of predators, and presence of brood parasites. An increase in the presence of predators and in brood parasitism will be seen in thinned plots due to a more open canopy.

Supplemental Keywords:

anthropogenic disturbance, Bankhead National Forest, bird community, canopy thinning, ecology, forest disturbance, forest ecology, habitat disturbance, hooded warbler (Wilsonia citrina), northwestern Alabama, prescribed fire, silviculture, songbirds, terrestrial ecosystems, worm-eating warbler (Helmitheros vermivorus),, RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Monitoring/Modeling, Habitat, Environmental Monitoring, Biology, biodiversity, community composition, avian habitat quality, habitat loss, anthropogenic, avian community dynamics, breeding habitat, forest fragmentation, forest interior songbird

Progress and Final Reports:

2007

Final