Variation of Prokaryotic and Fungal Soil Communities across a Vegetative Transect Sarah E Shawver 1 , Jeff A Brady 2 and Donald G McGahan 1,2 * 1 Department of Wildlife, Sustainability and Ecosystem Sciences, Tarleton State University, USA 2 Texas A&M AgriLife Research, USA Submission: March 09,2018; Published: April 11, 2018 * Corresponding author: Donald G McGahan, Department of Wildlife, Sustainability, and Ecosystem Sciences, Tarleton State University, Box T-0050, Stephenville, TX 76402, USA, Email: Agri Res & Tech: Open Access J 15(3): ARTOAJ.MS.ID.555953 (2018) 0069 Research Article Volume 15 Issue 3 - April 2018 DOI: 10.19080/ARTOAJ.2018.15.555953 Agri Res & Tech: Open Access J Copyright © All rights are reserved by Donald G MCGahan Introduction Soil microbial communities are affected by a number of biotic and abiotic factors including pH, nitrogen (N), carbon (C), and vegetation. Soil pH is one of the primary influences on microbial communities. Soil chemical properties, especially pH, rather than spatial effect, land use, climate, or soil physical properties, explain the largest amount of variance in microbial communities [1]. Soil pH impacts microbial and fungal diversity, but temperature and latitude do not, and greater diversity is found where soil pH is more basic [2]. Additionally, Arbuscular mycorrhizal communities are dependent on pH, carbonate content, base saturation, and phosphorus [3]. In addition to pH, nutrient availability impacts microbial communities. Microbial biomass is directly related to soil organic carbon content [4,5]. Not surprisingly, spatial distribution of denitrifying organisms within a field is related to nitrates, dissolved organic C, and dissolved organic N [6]. While pH and nutrients can individually impact distribution and abundance of microbial communities, these factors can also have a synergistic effect. Soil pH affects the availability of nutrients. Wetter climates tend toward greater base cation leaching, acidity, and fungi:bacteria ratios [7]. With less moisture available for leaching, soil pH and base cation content are typically greater. Vegetation also impacts soil microbial communities. Globally, microbial communities are impacted by biome and belowground plant net primary production [8] while soil microbial community composition varies with ecosystems [2]. For example, ratios of fungi:bacteria are lower in grasslands due to differences in pH and moisture. While both plants and soils impact soil microbial communities [5], grassland type plays a major role in explaining variability in soil microbial communities of grasslands [9]. When considering both biotic and abiotic habitats, the predictive fit of models in grazing pastures improves when plant traits are included [7], and microbial communities can be quite plant- specific [10]. Given that plants and soil microbes are intricately related, we would expect that changing one would alter the other. Microbial communities can be shaped by the presence of species-specific root exudates, which can provide C and growth factors for auxotrophic organisms [11]. In Texas, Ashe juniper (Juniperus ashei) has been overtaking savannas previously dominated by live oak (Quercus virginiana). This is a major management concern for water-limited Texas Abstract Soil microbial communities depend on pH, texture, and available nutrients. Ashe juniper (Juniperus ashei) is encroaching on live oak (Quercus virginiana) savannas. Litter differences may alter soil microbial communities and therefore the ability of the soil ecosystem to cycle nutrients. The objective was to determine whether soil microbial communities differ under the canopies of Ashe juniper and live oak. At each of three transects we collected four surface soil samples under live oak canopy, overlapping canopies of live oak and Ashe juniper, under Ashe juniper canopy, and in grass away from the trees. We characterized soils by pH, texture, calcium carbonate equivalence, total nitrogen, and total carbon. Microbial communities were analyzed using massively parallel DNA sequencing and analyzed within QIIME using Kruskal-Wallis ANOVA, Mann-Whitney U, and Spearman’s rank correlations. Prokaryotic communities differed along the transect, while fungal communities did not. Soil pH increased from live oak to grass. Trends in taxa were mostly associated with vegetation, pH, and CCE. Many prokaryotic genera associated with soil properties were important nutrient cyclers. Many fungal genera associated with pH and vegetation were mycorrhizal fungi, suggesting a plant-specific relationship. Keywords: 16S; ITS; Sequencing; Juniperus; Quercus; Vegetation; Rangeland; Soil health