Using a natural reference system to evaluate songbird habitat restoration

Abstract

ABSTRACT. The Golden-winged Warbler (Vermivora chrysoptera) is an imperiled songbird that breeds in early-successional plant communities of eastern North America. Conservation efforts on the breeding grounds have become a priority because population declines are thought to be driven, in part, by the loss of breeding habitat. Although the species is known to use a variety of upland and wetland cover types, the majority of previous research on the species has been conducted in uplands. Although patterns of Goldenwinged Warbler habitat use within anthropogenic upland communities are well understood, such information within naturally occurring habitats are scant. We compared Golden-winged Warbler densities in natural shrub-wetlands and nearby upland timber harvest that conformed to species-specific habitat guidelines of the Poconos Region of Pennsylvania. We also identified vegetation characteristics of natural shrub-wetlands associated with high warbler abundance. Our analyses suggest that timber harvests and natural shrubwetlands of the Poconos supported similar densities of Golden-winged Warblers. N-mixture models suggested that natural shrubwetlands with low canopy cover and high densities of 1-2 m tall woody stems hosted more Golden-winged Warblers. Wetland complexes comprising more edge and those with more emergent wetland types supported the highest warbler abundances. This suggests that the species requires edges when it occurs within shrub-wetlands, a pattern not observed within our timber harvests, which were designed to have adequate tree cover throughout. Findings from our study combined with those from concurrent research evaluating Goldenwinged Warbler reproductive success suggests that timber harvests following Golden-winged Warbler habitat guidelines have similar capacity as natural shrub-wetlands to support breeding populations. A future effort to quantify the potential of different wetland types to host breeding Golden-winged Warblers is warranted. Such information used in combination with timber harvest planning will provide insight for landscape-level conservation that considers maintaining appropriate amounts of nesting habitat to sustain Goldenwinged Warblers in this region.Utilisation d'un système de référence naturel pour évaluer la restauration de l'habitat d'un passereau RÉSUMÉ. La Paruline à ailes dorées (Vermivora chrysoptera) est un passereau en danger qui niche dans les communautés végétales de début de succession de l'est de l'Amérique du Nord. Les efforts de conservation sur les aires de nidification sont maintenant prioritaires parce qu'on pense que les baisses de population sont imputables, en partie, à la perte d'habitat de nidification. Même si cette espèce est connue pour fréquenter une variété de milieux se trouvant en terrains secs ou humides, la majorité des recherches antérieures sur l'espèce ont été menées sur des hautes terres. Si on connait bien les tendances de l'utilisation de l'habitat par cette paruline dans les milieux d'origine anthropique se trouvant en terrain sec,...

Multiscale drivers of restoration outcomes for an imperiled songbird

“…Among the most efficient habitat restoration tools recommended by the Conservation Plan are overstory removal timber harvests (Bakermans et al 2015;McNeil et al 2018). Overstory removal harvests (2.2-8.9 m 2 /ha residual basal area; Bakermans et al 2011) are rigorously demonstrated to provide quality habitat for GWWA territorial establishment (Bakermans et al 2015), pairing (Roth et al 2014), andnesting (McNeil et al 2017), created from mature forest otherwise unsuitable for nesting.…”

Early Successional Forest Management on Private Lands as a Coupled Human and Natural System

“…At the time of biological monitoring, the managed properties were either under a current NRCS contract or had recently finished an NRCS contract to create early successional forest. Within each early-successional forest, we randomly placed 1-2 point sampling locations at which birds were surveyed (see McNeil et al [36] for point placement protocols). At each location, we conducted both American Woodcock and Golden-winged Warbler point count surveys in 2015 and 2016.…”

“…We also used point count surveys to quantify Golden-winged Warbler (and other songbird) presence but sampled during the times (early mornings) and dates (mid-May-June) when Golden-winged Warblers are best detected. See McNeil et al [36] for a full description of warbler survey methods. Our final dataset for each property included American Within each early-successional forest, we randomly placed 1-2 point sampling locations at which birds were surveyed (see McNeil et al [36] for point placement protocols).…”

“…See McNeil et al [36] for a full description of warbler survey methods. Our final dataset for each property included American Within each early-successional forest, we randomly placed 1-2 point sampling locations at which birds were surveyed (see McNeil et al [36] for point placement protocols). At each location, we conducted both American Woodcock and Golden-winged Warbler point count surveys in 2015 and 2016.…”

“…We also used point count surveys to quantify Golden-winged Warbler (and other songbird) presence but sampled during the times (early mornings) and dates (mid-May-June) when Golden-winged Warblers are best detected. See McNeil et al [36] for a full description of warbler survey methods. Our final dataset for each property included American Woodcock naïve occupancy (1/0), Golden-winged Warbler naïve occupancy (1/0), and avian species richness (not including American Woodcock/Golden-winged Warbler).…”