Responses of a Federally Endangered Songbird to Understory Thinning in Oak-Juniper Woodlands

• Published in: Environmental management (New York) Vol. 59; no. 4; pp. 684 - 692
• Main Authors: Long, Ashley M., Marshall, Mike E., Morrison, Michael L., Hays, K. Brian, Farrell, Shannon L.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.04.2017; Springer Nature B.V
• Subjects: Animals; Aquatic Pollution; Armed forces; Atmospheric Protection/Air Quality Control/Air Pollution; Conservation of Natural Resources - methods; Earth and Environmental Science; Ecology; Ecosystem; Endangered & extinct species; Endangered Species; Environment; Environmental Management; Environmental Monitoring - methods; Environmental protection; Environmental regulations; Forestry Management; Forests; Hardwoods; Juniperus - growth & development; Military; Military bases; Military personnel; Military readiness; Military training; Natural resources; Nature Conservation; Plant species; Private lands; Public lands; Quercus - growth & development; Setophaga; Songbirds; Songbirds - growth & development; Songbirds - physiology; Species composition; Success; Texas; Thinning; Threatened species; Trees; Understory; Vegetation; Waste Water Technology; Water Management; Water Pollution Control; Wildlife conservation; Wildlife management; Woodlands; United States > US; ASW, USA, Texas; Understory thinning; Golden-cheeked warbler; Oak-juniper woodland; Military training; Ecological site description; Setophaga chrysoparia
• ISSN: 0364-152X; 1432-1009
• DOI: 10.1007/s00267-016-0810-3

Wildlife conservation and management on military lands must be accomplished in the context of military readiness, which often includes ground-based training that is perceived to conflict with wildlife needs and environmental regulations. From 2008‒2012, we examined territory density, pairing success, and fledging success of the federally endangered golden-cheeked warbler ( Setophaga chrysoparia ; hereafter warbler) in relation to removal of small-diameter trees from the understory of mature oak-juniper ( Quercus-Juniperus ) woodland at the 87,890 ha Fort Hood Military Reservation in central Texas. Understory thinning created troop maneuver lanes, but left canopy vegetation intact. Warbler density, pairing success, and fledging success were similar across thinned and control sites. We found that warbler pairing and fledging success were best predicted by Ecological site (hereafter Ecosite), an indicator of hardwood tree species composition. Warbler pairing and fledging success were about 1.5 and 1.6 times higher, respectively, for territories dominated by the Low Stony Hill Ecosite than territories dominated by the Redlands Ecosite. Our results indicate that understory thinning for military training purposes did not have a negative effect on warblers at Fort Hood in the manner tested, and suggest that removal of smaller trees from the understory in a way that replicates historic conditions may elicit neutral responses from this forest-dependent songbird. Quantifying wildlife responses to military activities provides the Department of Defense and US Fish and Wildlife Service with data to guide conservation of threatened and endangered species on Department of Defense facilities while maintaining the military mission, and supports wildlife management efforts on other public and private lands.