Characteristics and biodiversity of Oklahoma's Ozark glades

Glades are defined as grassland-like openings in woodlands characterized by exposed bedrock, shallow soils, and drought-tolerant vegetation. Glades provide habitat for numerous species and are found throughout the central United States with many in the Ozarks. Extensive studies in Missouri and Arkansas found that glades support xeric species on the eastern edge of their range, including Eastern collared lizard (Crotaphytus collaris collaris) and greater roadrunner (Geococcyx californianus). While eastern Oklahoma likely has many glades, they have not been studied and may be degraded from their natural state through woody encroachment, land development, and invasive species. The primary goals of this project were to 1) characterize glades in the Ozark Highlands and Boston Mountains ecoregions of Oklahoma, 2) identify new glades using publicly available remotely sensed data, 3) create an inventory of wildlife, and 4) assess biodiversity as a function of glade characteristics. To do this, we used various remotely sensed data layers to characterize eleven glades and fourteen forest sites and used a weighted overlay analysis to predict new glades. For wildlife, we used passive surveys, biodiversity indices, and occupancy models to assess wildlife communities. We found that Oklahoma glades are similar to other Ozark glades in their characteristics but are hard to identify geospatially with publicly available data. From February 2023 to September 2024, we observed 16 mammal, 83 bird, and 30 herptile species using glades. We also identified several protected species or those of conservation concern. Across taxa, we found that richness, diversity, and space use generally responded positively to either short fire intervals, lower levels of woody encroachment, larger glades, or less distance to a glade. In our occupancy models, the highest richness of mammals was on glades and in the spring. This study represents the first inventory and characterization of glades in Oklahoma and provides important insight for managers. Glades provide a variety of important resources, from thermal refuge to foraging and hunting opportunities, for wildlife in Oklahoma. While many glades may have been lost to degradation, prioritizing management to reduce woody encroachment will allow glades to be restored and continue supporting diverse wildlife in Oklahoma.