Wildlife habitat condition in open pine woodlands: Field data to refine management targets

Abstract

Open pine ecosystems of the southern United States are a conservation priority for many agencies, organizations, and private landowners. These woodlands, characterized by moderately-stocked overstories, low cover of midstory, and grass-dominated herbaceous groundcover, provide important habitat for a suite of rare and declining wildlife species. To provide guidance for land managers engaged in habitat restoration in open pine ecosystems, ranges of desired conditions for elements of vegetation structure have been developed using literature survey and expert opinion. We compared empirical data on habitat occupancy for 17 wildlife species from second-growth longleaf pine woodlands in southwestern Georgia with recommended ranges for basal area (BA) of all pine, BA of pine ≥ 35.5 cm dbh, percent canopy cover, percent herbaceous cover, and percent shrub cover. Vegetation data were taken from 864 monitoring plots and Mahalanobis distance models were used to develop habitat suitability indices from the wildlife data. Recommendations for shrub cover and BA of pines ≥ 35.5 cm fit well with model predictions for all wildlife species. However, mean BA of all pines at sites used by wildlife were at the low end of the recommended range. Herbaceous cover at sites used by wildlife was well below the recommended range, whereas canopy cover was well above recommendations, suggesting these ranges should be expanded. These modifications could provide managers of open pine ecosystems greater flexibility, allowing them to incorporate a broader suite of objectives in their management while still providing habitat for wildlife species of concern. Moreover, our models suggest that monitoring presence of open pine indicator bird species may be an efficient method to assess restoration or management progress of open canopy pine systems.