Volume 85 – Issue 2 (December 2020)

Geum geniculatum (Rosaceae), bent avens, is a perennial herb restricted to the high elevations of three mountaintops near the North Carolina/Tennessee border (USA). Although geographically restricted, occurrences on these mountaintops can have up to hundreds and occasionally thousands of individuals. While Geum geniculatum has been censused thoroughly, some sites have not been visited in over a decade, and formal biological studies are lacking. To understand genetic variation within the species and connectivity among populations, individuals were sampled from each of three extant mountain locations and were genotyped using 14 microsatellite markers previously developed for other congeners. Results show that G. geniculatum displays high genetic diversity, and that each mountain acts as a highly structured metapopulation with moderate interpopulation differentiation. Based on the high numbers of private alleles and results of an M-ratio test, genetic drift is likely driving structure and differentiation among metapopulations. Results will inform management of the species, and suggest that transfer of seeds or genetic material among sites should be minimized.

Local floras are a basis of biogeography, ecology, evolution, and systematics, and they add value to research sites. Mountain Lake Biological Station is located between 1,150 and 1,319 m elevation in southwestern Virginia on infertile, acidic soils supporting a second-growth forest strongly dominated by Quercus rubra about 150 years old. We sampled vascular vegetation on 352 randomly distributed plots 10m in diameter with 8 subplots of 1 m2 each. The plots contained 175 taxa (including 7 taxa that included 16 lumped species); other fieldwork added 43 species for a total of 227 species in the forest. We excluded disturbed areas around buildings, roadsides, and ponds that harbor many ruderal and invasive species. Average detection probability of a species on a plot was estimated to be 75%. We recorded binary occurrence (present or absent on a plot) and prevalence (occurrence on 0, 1, 2, … 8 subplots per plot) and a set of environmental variables measured in the field or laboratory, or estimated from LIDAR data collected by NEON. Nonmetric multidimensional scaling ordination rejected the null hypothesis of random distributions of herbaceous species among plots. Cluster analysis defined eight groups of plots based on prevalence of herbaceous species to illuminate rejection of the null hypothesis. The environments of these clusters, determined only by their floras, demonstrated the importance of rock type, soils, solar radiation, canopy height, and topography in determining the local distribution of species. Significant differences among assemblages and their environments occurred within a superficially homogeneous forest.

We present the results of a floristic inventory and qualitative descriptions of the forest communities occurring in Malanaphy Springs State Preserve (MSSP), located in the Paleozoic Plateau of northeastern Iowa. Most of the 25.9-ha preserve is a mature mesic to dry-mesic deciduous forest community occurring on a steep slope adjacent to the Upper Iowa River. The preserve also contains a small floodplain forest as well as a small highly disturbed forest on the upland. We documented 422 plant taxa in our surveys, including 52 non-vascular taxa, 14 seedless vascular taxa, 3 gymnosperms, and 353 angiosperms. Eighty-seven percent of the vascular plant taxa are native, and 21% of the species have an Iowa coefficient of conservatism score of 7 or higher. Five species are listed by the Iowa Department of Natural Resources as endangered, threatened, or of special concern in the state. This survey provides critical baseline data needed to document future changes in the plant communities of MSSP. We conclude that this preserve is an important example of high-quality mesic deciduous forest communities in Iowa. We further conclude that the species diversity of the preserve is threatened by the cumulative impacts of habitat loss, high levels of deer herbivory, invasive species, nitrogen deposition, and climate change and that active management and strategic policy decisions will be needed to preserve native plant species diversity.

We report the first record of Portulaca amilis in Tennessee. A native of South America, P. amilis is a weedy plant that has been introduced to and naturalized in the southeastern United States. Previously this species has only been reported from the Atlantic Coastal Plain and Piedmont. This suggests a range expansion either west over the Appalachian Mountains from the Carolinas, or north from Georgia, Alabama, or Mississippi into the Ridge and Valley region of east Tennessee.