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Forest Area to Support Landbird Population Goals for the Mississippi Alluvial Valley

Open-File Report 2020-1097
Prepared in cooperation with the Lower Mississippi Valley Joint Venture
By:  and 
https://doi.org/10.3133/ofr20201097

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Abstract

Historically, the Mississippi Alluvial Valley (MAV) (Partners in Flight Bird Conservation Region #26) was predominantly bottomland hardwood forest, but natural vegetation has been cleared from about 80 percent of this ecoregion and converted primarily to agriculture. Because most bird species that are of conservation concern in this region are dependent on forested wetlands, bottomland hardwood forest is the habitat of greatest conservation concern in the MAV. Past conservation planning for forest-dwelling birds in this region has focused on habitat objectives with presumptions regarding bird population goals being met through habitat provision. To better define population objectives, we estimated current populations of silvicolous birds on the basis of detections during 10 years of North American Breeding Bird Surveys (BBS). For each species, we used their estimated population and historical (1966–2015) change in their relative abundance, as assessed from BBS data, to establish regional population goals. We used the variance associated with historical BBS trends to estimate the minimum forest area required to sustain greater than or equal to (≥) 25 breeding pairs, which we combined with predicted probability of occupancy to identify sustainable forested habitat. For 54 species, we used published empirical density estimates, as affected by forest management, to estimate the proportion of the population objective that could be provisioned within sustainable forest patches. The area of presumed population-sustaining habitat, under existing forest management, was sufficient to support the species’ population objective for 23 species. We estimated that the target populations of seven additional species (Black-and-white Warbler, Brown Thrasher, Cerulean Warbler, Eastern Towhee, Indigo Bunting, Wood Thrush, and Yellow-breasted Chat) could be supported by current forest area through widespread changes in forest management. Target populations of seven other species (American Robin, Barred Owl, Boat-tailed Grackle, Chipping Sparrow, Eastern Phoebe, Mississippi Kite, and Red-headed Woodpecker) were accommodated within the MAV when populations in both forest and nonforest habitats are considered. For the remaining 20 species, we estimated the population increase needed to achieve their population goals. For these species, we estimated the additional area of forest restoration required to achieve their population goal within sustainable forest patches or, alternatively, the additional area of occupied habitat required to support their population goal within both forest and nonforest habitat. An additional 700,000 hectares of sustainable forest habitat may be enough to attain the forest-dependent population goals for most bird species within the MAV.

Suggested Citation

Twedt, D.J., and Mini, A., 2021, Forest area to support landbird population goals for the Mississippi Alluvial Valley (ver. 1.1, August 2021): U.S. Geological Survey Open-File Report 2020–1097, 84 p., https://doi.org/10.3133/ofr20201097.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Study Area
  • Methods
  • Results
  • Discussion
  • Summary
  • References Cited
  • Appendix 1. Bird species
  • Appendix 2. Bird detections during North American Breeding Bird Surveys
  • Appendix 3. Locations of stops on North American Breeding Bird Survey routes
  • Appendix 4. Model covariates
  • Appendix 5. Most supported occupancy models
  • Appendix 6. Model parameter weights
  • Appendix 7. Predicted avian species occupancy
  • Appendix 8. Area of sustainable forest habitat
  • Appendix 9. Area of forest and nonforest occupied habitat
Publication type Report
Publication Subtype USGS Numbered Series
Title Forest area to support landbird population goals for the Mississippi Alluvial Valley
Series title Open-File Report
Series number 2020-1097
DOI 10.3133/ofr20201097
Edition Version 1.1: August 2021; Version 1.0: February 2021
Year Published 2021
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Patuxent Wildlife Research Center, Eastern Ecological Science Center
Description Report: vi, 75 p.; 2 Appendixes; Version History
Country United States
State Arkansas, Kentucky, Louisiana, Mississippi, Missouri, Tennessee
Other Geospatial Mississippi Alluvial Valley
Online Only (Y/N) Y
Additional Online Files (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details