Effects of oak barrens habitat management for Karner blue butterfly (Lycaeides samuelis) on the avian community Eric M. Wood a,⇑ , Anna M. Pidgeon a , Claudio Gratton b , Timothy T. Wilder c a Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, USA b Department of Entomology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, USA c Fort McCoy Military Installation, WI 54656, USA article info Article history: Received 5 May 2011 Received in revised form 3 October 2011 Accepted 11 October 2011 Available online 8 November 2011 Keywords: Avian community Habitat management Karner blue butterfly Adjacent habitat Oak barren Savanna abstract The federally endangered Karner blue butterfly (Lycaeides samuelis) is the focal species for a conservation plan designed to create and maintain barrens habitats. We investigated whether habitat management for Karner blue butterflies influences avian community structure at Fort McCoy Military Installation in Wis- consin, USA. From 2007 through 2009 breeding bird point count and habitat characteristic data were col- lected at 186 sample points in five habitat types including two remnant barrens types, barrens habitat restored from woodland and managed specifically for the Karner blue butterfly, and two woodland hab- itat types. Although the bird community of managed barrens was not identical to the communities of remnant barrens, the Field Sparrow (Spizella pusilla), a species of conservation concern, and sparse canopy associated bird species, such as the Baltimore Oriole (Icterus galbula) and Eastern Bluebird (Sialia sialis) were predicted to occupy managed barrens and remnant barrens in similar proportions. Adjacent habitat was the most influential factor in determining the community of bird species using the managed barrens. In Wisconsin, and likely throughout the range of the Karner blue butterfly, management for the butterfly creates habitat that attracts a bird community similar to that of remnant barrens, and benefits several avian species of conservation concern. Additionally, the landscape context surrounding the managed hab- itat influences avian community composition. Managed barrens that are adjacent to remnant barrens, rather than adjacent to woodland habitats, have the highest potential for conserving barrens breeding birds. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction In the United States, federal, state, and private agencies have established conservation plans for species recovery, which often involve restoring or maintaining habitat through active manage- ment. Managing habitat to promote populations of wildlife species is a science that has evolved from altering the structure of habitat for single game species (Leopold, 1933) to complex ‘active adaptive management’ approaches that optimize decision-making processes (Walters and Hilborn, 1978; Wilhere, 2002). Although habitat management planning that takes into account all species is a de- sired goal, practically there may be enough resources to address the needs of only the most vulnerable species. Vulnerability arises for many reasons, one of which is dependence on a specific habitat type that has declined in extent. The degree to which the vulnera- ble species functions as a surrogate for other species (i.e., a species for which management benefits other species, Caro and O’Doherty, 1999) is usually unknown (Simberloff, 1998; Loyola et al., 2007). In the northeastern and central portions of the United States, conservation and recovery plans have been implemented for the federally endangered Karner blue butterfly (Lepidoptera: Lycaeni- dae, Lycaeides samuelis, hereafter Karner blue, US Fish and Wildlife Service, 2003). Across their range, which extends from Minnesota east to New York, Karner blue populations have severely declined, due primarily to the loss of barrens habitat (Nuzzo, 1986; Heikens and Robertson, 1994). Barrens are a type of savanna, classified by sparse tree canopies (5–50% cover), with a diverse forb and grass understory, typically found on poor soils (Curtis, 1959; Bray, 1960). Barrens were historically maintained by fire (Wolf, 2004) and large native grazers (Ritchie et al., 1998). However, following European settlement, anthropogenic modifications, such as plow- ing and clearing for agriculture as well as fire suppression reduced the extent of barrens to highly localized regions (Nuzzo, 1986; Anderson and Bowles, 1999; Leach and Givnish, 1999). The Karner blue needs barrens habitat because the host plant of Karner blue larvae, wild blue lupine (Lupinus perennis) along with ant species needed by larvae to reach pupation (Pierce et al., 2002) occur in these habitats (Grundel et al., 1998, 2000). Additionally, the spa- tially heterogeneous tree canopy cover and sandy soils of barrens 0006-3207/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.biocon.2011.10.010 ⇑ Corresponding author. Tel.: +1 608 265 9219; fax: +1 608 262 992. E-mail address: emwood@wisc.edu (E.M. Wood). Biological Conservation 144 (2011) 3117–3126 Contents lists available at SciVerse ScienceDirect Biological Conservation journal homepage: www.elsevier.com/locate/biocon