Group size mediates effects of intraspecific competition and forest structure on productivity in a recovering social woodpecker population
Abstract
Conservation of endangered social wildlife in disturbance‐prone forests is challenging because direct and indirect effects of management strategies developed at the time of species’ listing when population density is low may change under high‐density conditions in locally recovered populations. Here, we used piecewise structural equation modeling to evaluate direct and indirect drivers of productivity in the federally endangered cooperatively breeding red‐cockaded woodpeckerDryobates borealis(RCW) on Savannah River Site, South Carolina, USA. We estimated direct and indirect relationships among group size, neighboring group sizes, fledgling production, density of cavity tree clusters occupied by RCWs, area satisfying threshold criteria of ≥22 stems ha−1of pines ≥35.6 cm diameter at breast height (dbh), 2 ha−1basal area (BA) of hardwoods 7.6–22.9 cm dbh, and −1of pines ≥35.6 cm dbh and 2 ha−1BA of hardwoods 7.6–22.9 cm dbh, and area treated with prescribed fire, but not area with −1≥35.6 cm dbh and 2 ha−1BA of hardwoods 7.6–22.9 cm dbh will promote large group sizes, which in turn improve fledgling production and offset costs of heightened competition with neighboring groups under high‐density conditions. Additionally, positive effects of area treated with prescribed fire on RCW group size and fledgling production indicate prescribed fire has unique contributions to woodpecker productivity, likely via direct effects on forest structure and potentially indirect effects on arthropod prey available to foraging RCWs. By simultaneously accounting for multiple drivers of productivity in social wildlife, our study contributes to the understanding of how increases in social wildlife population sizes can alter previously documented habitat‐fitness relationships.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 20, 2021
- Source ID
- 10.1111/acv.12757
Entities
People
- C. E. Moorman
- James E. Garabedian
- John C. Kilgo
- M. N. Peterson
Organizations
- North Carolina State University
- Savannah River Operations Office
- United States Forest Service