Occupancy and abundance of wintering birds in a dynamic agricultural landscape

Journal of Wildlife Management
By: , and 



Assessing wildlife management action requires monitoring populations, and abundance often is the parameter monitored. Recent methodological advances have enabled estimation of mean abundance within a habitat using presence–absence or count data obtained via repeated visits to a sample of sites. These methods assume populations are closed and intuitively assume habitats within sites change little during a field season. However, many habitats are highly variable over short periods. We developed a variation of existing occupancy and abundance models that allows for extreme spatio‐temporal differences in habitat, and resulting changes in wildlife abundance, among sites and among visits to a site within a field season. We conducted our study in sugarcane habitat within the Everglades Agricultural Area southeast of Lake Okeechobee in south Florida. We counted wintering birds, primarily passerines, within 245 sites usually 5 times at each site during December 2006–March 2007. We estimated occupancy and mean abundance of birds in 6 vegetation states during the sugarcane harvest and allowed these parameters to vary temporally or spatially within a vegetation state. Occupancy and mean abundance of the common yellowthroat (Geothlypis trichas) was affected by structure of sugarcane and uncultivated edge vegetation (occupancy = 1.00 [equation image = 0.96–1.00] and mean abundance = 7.9 [equation image = 3.2–19.5] in tall sugarcane with tall edge vegetation versus 0.20 [equation image = 0.04–0.71] and 0.22 [equation image = 0.04–1.2], respectively, in short sugarcane with short edge vegetation in one half of the study area). Occupancy and mean abundance of palm warblers (Dendroica palmarum) were constant (occupancy = 1.00, equation image = 0.69–1.00; mean abundance = 18, equation image = 1–270). Our model may enable wildlife managers to assess rigorously effects of future edge habitat management on avian distribution and abundance within agricultural landscapes during winter or the breeding season. The model may also help wildlife managers make similar management decisions involving other dynamic habitats such as wetlands, prairies, and even forested areas if forest management or fires occur during the field season.

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Publication type Article
Publication Subtype Journal Article
Title Occupancy and abundance of wintering birds in a dynamic agricultural landscape
Series title Journal of Wildlife Management
DOI 10.1002/jwmg.98
Volume 75
Issue 4
Year Published 2011
Language English
Publisher Wiley
Publisher location Hoboken, NJ
Contributing office(s) Southeast Ecological Science Center
Description 11 p.
First page 836
Last page 847
Time Range Start 2006-12-01
Time Range End 2007-03-31
Country United States
State Florida
Other Geospatial Everglades Agricultural Area
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