Playas are landscape depressions commonly found in semi-arid environments that serve as important wetland habitat for wildlife, as recreational areas for human activity, sites for storm water retention, and provide a source of recharge for groundwater systems. Due to their high prevalence in semi-arid regions such as the Texas Southern High Plains (SHP), they are also commonly subjected to agricultural and urban runoff and development, which threatens the capacity of ephemeral playas to deliver critical ecosystem services such as improving quality and storage of groundwater resources, providing habitat for plants, insects, and animals, and sequestering carbon. Despite our heavy dependence on and interactions with playas, we know surprisingly little about soil biogeochemical dynamics in these systems, especially regarding the activities and distribution of soil microbial communities in these habitats that play an important role in water quality and nutrient cycling. Without characterizing how microbial communities and activities are generally distributed across ephemeral playas, and how these are regulated by environmental drivers such as soil and vegetative properties, we cannot understand or investigate how playa management and surrounding land-use change can impact ecosystem functioning and delivery of ecosystem services.
Results/Conclusions
Three ephemeral playas in Lubbock, TX were selected according to their predominant surrounding land use (urban residential, urban parking lot, or native rangeland), and three landscape zones (basin, annulus, and bench) were subdivided within each playa. Twenty soil samples were collected to a 15 cm depth from each location in a fishnet grid pattern. We measured microbial biomass, community composition, and selected chemical and physical soil properties of each sample. Non-metric multidimensional scaling ordinations (NMS) were used to compare the community composition between the playas and playa zones, with significant differences between groups determined by multi-response permutation procedure (MRPP, α = 0.05). Results were spatially analyzed and illustrated in ESRI ArcGIS. Soil microbial community composition significantly differed between playa sites (p < 0.05) and between landscape zones across all playa types (basin vs annulus and bench p < 0.05). The influence of environmental drivers such as soil pH, moisture, bulk density, and soil organic matter (SOM) will be analyzed. The results of this research reveal how soil microbial community dynamics vary across playa basins and how these dynamics are altered by land use, which will impact how land managers, producers, and urban residents interact with these ecosystems in the future.