Effects of Brush Management on the Reproductive Ecology of Endangered Black-capped Vireos

Abstract

Terrestrial habitats are frequently managed to improve perceived economic or aesthetic value of the land and to improve habitat quality for wildlife species. In central Texas, removal of native Juniperus asheii (Ashe Juniper) is a common landscape-management practice due to the species' propensity for invasion of rangeland, vigorous growth leading to dominance of habitats, and reputation for high water-use. Ashe Junipers provide habitat for wildlife species of economic (e.g., Odocoileus virginianus [White-tailed deer], Meleagris gallopavo [Wild Turkey]) and conservation concern (e.g., the endangered Setophaga chrysoparia [Golden-cheeked Warbler]); however, the relationship between Ashe Junipers and the federally endangered Vireo atricapilla (Black-capped Vireo) is less clear. Blackcapped Vireos breed in early successional shrublands where Ashe Junipers are often able to invade, grow quickly, and shade out the deciduous shrubby vegetation preferred by vireos. Although Ashe Juniper removal in Black-capped Vireo habitat is common practice, relatively little is known about the impacts of brush management on Black-capped Vireo use and reproductive success. Here we present results of a study on the effects of an Ashe Juniper removal treatment, in which juniper trees were removed but surrounding deciduous vegetation was largely left intact, on Black-capped Vireo habitat use and reproductive success. Comparing before and after Ashe Juniper removal, we found that the number of Blackcapped Vireos settling in manipulated habitats remained similar, and we saw no significant changes in the size of the average territory or reproductive success. We conclude that, when the amount of damage to the surrounding deciduous vegetation is limited, selective Ashe Juniper removal is unlikely to negatively affect Black-capped Vireos.