Relationships of soil and climate features with plant community assembly, phylogenetic diversity and functional traits in South Dakota’s Black Hills and Great Plains — 52a — April Dunn, Sage Robinson, Maddy Reichert, Tara Ramsey, Justin Ramsey

Physical and chemical features of soil are a major factor affecting terrestrial plants. Here we describe soil traits (particle size distribution, pH, electroconductivity) at sites that we recently characterized for species composition (presence/absence and % ground cover), phylogenetic diversity (inferred from chloroplast DNA sequences), and functional traits (representation of major functional groups in communities as well as phenotypic traits for a widespread plant species, wild yarrow). The study sites span an elevational transect through the Black Hills and Great Plains (~2,500′ to 7,200′ elevation) and represent contrasting climate zones (~2-3-fold differences in mean annual temperature and precipitation) and habitat types (prairies, badlands, open pine and deciduous forests, wet meadows, mountain summits, etc.).

Soils were sampled using a 12″ corer at four haphazardly selected locations at each of 37 study sites (50 m x 50 m plots). Soils were air-dried and sieved prior to measurement.  We assessed texture using a Bouyoucos sedimentation assay and calculated percent sand and clay for samples; pH and EC were measured with a digital probe. Site climate data were inferred from BioClim.

Soil features varied widely across samples and study sites (range of site averages, 1.5 to 70.5% sand, 7.8 to 79.3% clay, 5.1 to 8.2 pH, 50.6 to 1842.8 µS conductivity); all soil traits showed a strong site-of-origin effect (ANOVAs, R²>0.5, P<0.001). However, soil features showed more complex spatial and habitat patterns than annual temperature and precipitation, which varied in predictable ways with elevation and geography. In PCA and other multivariate analyses, climate factors were primary factors associated with plant community composition and functional traits while the measured soil features were secondary factors. These results highlight the complexity of soil traits and their connection to localized geology and erosion processes.

Black Hills State University
Justin Ramsey