Volume 88 — Issue 1 (May 2023)

The Richard and Minnie Windler Award recognizes the authors of the best systematics and ecology papers published in Castanea during the previous year. For 2022, authors of two articles were selected as winners: Katherine Culatta, Alexander Krings, Lilian P. Matallana-Ramirez, and Ross Whetten for their article, “Clarifying Taxonomic Boundaries in Nuphar sagittifolia (Nymphaeaceae): Insights from Morphology and Population Genetic Diversity” (Castanea 87[1]:81–104), and Amy Hessl, Andrew M. Liebhold, and Morgan L. Leef for their article, “Dendrochronological Reconstruction of the Historical Invasion of Balsam Woolly Adelgid, Adelges piceae, Feeding on Canaan Fir, Abies balsamea subsp. phanerolepis in the Central Appalachian Mountains” (Castanea 87[1]:1–11).

A floristic checklist of vascular plants was conducted at Shenandoah River State Park (SHSP) in Bentonville, Virginia during the 2021 and 2022 growing seasons. SHSP encompasses 665 hectares (1619 acres) of the northern Shenandoah Valley between the Massanutten Mountains and Shenandoah National Park. The park lies in Warren County which has been botanically underexplored, consistently ranking last in plant collection metrics among the five northern Shenandoah Valley counties. SHSP contains 11 community types that span 165–296 meters above sea level from inland wetlands and river scour communities to upland forests, including endemic Central Appalachian Shale Barrens. A total of 797 collections yielded 536 unique taxa from 109 vascular plant families. These collections were secondarily extended with in-field pictures that were aggregated on an iNaturalist project page. Quick Response (QR) codes were used to link herbarium vouchers to their respective iNaturalist entry. Sixty-four county records of taxa not yet observed in Warren County and one state record, Equisetum laevigatum, were documented. As a first for SHSP, this floristic checklist provides baseline botanical knowledge of the park and expands the available digital data of vascular plants for Warren County by 20%. This augmented knowledge, in tandem with the accompanying iNaturalist project page, will not only be useful to park managers for future development and conservation plans but will also serve as a tool for community scientists to enhance their knowledge of the local flora.

An inventory of the botanical resources of Doe Mountain Recreation Area, comprising 3480 ha on the boundary of the Blue Ridge and Ridge and Valley ecoregions in extreme northeastern Tennessee, was conducted to help guide conservation-based management. A total of 486 species (including subspecies and varieties) was found comprising 95 families, 286 genera, 11 species tracked on the state rare plant list, 153 county records, and 77 exotic species. The relatively high ratio of county records to exotics indicated an area of conservation merit, but the ratio was lower than in floras from comparable areas in eastern Tennessee. The vast majority of county records were of common species, suggestive of an under-collected county. However, some of the noteworthy county records and state-listed species were from unusual habitats such as acid seeps, wetlands, and xeric ridges. Two species, Liatris virgata and Lycopodiella inundata, were new to the state. Water in the seep that supports L. inundata was an order of magnitude more acidic (pH=3.56) than at other sites. An analysis of the wildland–urban interface showed that the periphery of the site had more human impact than the county as a whole with the highest impact on the northern half; only 13% of the area was classified as uninhabited. Management recommendations, some of which were already adopted, targeted protection of acid seeps and xeric roadside slopes, curtailing mowing and herbicide use near a wetland that supports a state endangered species, and reconnaissance for exotic invasions in a biodiverse power line corridor.

Taxa with geographically disjunct distributions and that are endemic or narrowly endemic face the real and immediate threat of local extinction because of inbreeding depression, genetic drift, and environmental stochasticity. These threats are amplified by the predicted changes in climate anticipated within the next 50 years, pointing to the increasing need for population genetic data and translocation experiments to track long-term evolutionary potential in rare plant species. In this study, we assessed population genetic structure within and among natural, augmented, and introduced populations of leafy prairie-clover (Dalea foliosa; Fabaceae) in a geographically disjunct region of the species range (i.e., Illinois) and predicted future potential changes in climate within the study region. Using six novel nuclear microsatellite loci to survey nine populations from Illinois and two from Tennessee, we found extremely limited genetic diversity and no structure among populations within Illinois, with greater genetic diversity within and between populations in Tennessee. Using future climate visualizations, we predict the Illinois portion of the species range will be warmer and wetter within the next 50 years, potentially increasing competition for D. foliosa habitat through woody encroachment. When considered together, these concerns point to the need to prioritize actions that will improve our understanding of the implications of translocations across geographically disjunct regions within the species range.

Fragmented landscapes are a mosaic of ecosystems containing diverse communities of plants and herbivorous arthropods. Plant responses to fire in fire-prone ecosystems are well documented, but less is known about how plant-herbivorous arthropod interactions respond to fires. This study compared the responses of plant communities and their interactions with herbivorous arthropods to fire in a highly fragmented fire-prone glade system. Due to the mosaic landscape of the study site, three habitat types were chosen to delineate communities based on plant species composition, geology, and proximity to each other: small enclosed glade, large open glade, mixed hardwood forest, and pine savanna. From 2016–2019, we observed the interspecific interactions between plant and arthropod communities in the Ketona dolomitic glades of Bibb County in central Alabama. We identified plants to genus or species and recorded evidence of herbivory by seven herbivore guilds of arthropods. We used non-Metric Multidimensional Scaling and Analysis of Similarity to determine patterns of change between the habitats and across years for both plant species and interactions with herbivorous arthropods. Plant communities return to pre-burn species diversity within two years. Plant community composition was grouped strongly by habitat type and year, while interactions with herbivorous arthropods were homogenous across habitats but grouped strongly by year. Tracking herbivorous arthropod guilds using plant association evidence is useful for rapidly and temporally determining overall responses in herbivorous arthropod guild composition. However, it is too coarse to determine changes and responses in herbivorous arthropod guild composition at finer spatial scales.

We have compiled data on 15 taxa (5 woody and 10 herbaceous) as established (9 taxa) or adventivewaif species (6 taxa) in Maryland (2 taxa) and Virginia (13 taxa) that are not considered definitive elements of each state’s extant flora. The woody taxa are Acer ginnala, Corylus avellana, Pyrus betulifolia, Tilia cordata, and Vaccinium virgatum. The herbs include Crocus tommasinianus, Daucus pusillus, Dracocephalum parviflorum, Euphorbia mercurialina, Indigofera hirsuta, Opuntia engelmanni var. lindheimeri, Pilea microphylla, Polycarpon tetraphyllum, Saxifraga stolonifera, and Silene flos–cuculi spp. flos-cuculi. We provide updated taxonomic information, range clarifications, supplemental habitat data, and other details about our voucher specimens and other collections.
Photo credit: John Klinovsky

Chinese privet (Ligustrum sinense) invasion has been found to reduce native species richness and abundance of both herbaceous and woody plants and is a serious threat to wetlands in the southeastern United States. To determine the relationship between privet removal and understory vegetation, we performed surveys on a forested wetland from which L. sinense had been partially removed over a two-year period. Plant community composition, vegetation cover and species richness as well as soil moisture and PAR were recorded in removal and control (Privet-Present) plots in herb, shrub and tree layers. As expected, herb-layer removal plots were wetter and less shady, with more than four times higher cover of native and non-native species. Total species richness and native species richness were both higher in herb-layer removal plots, though non-native species richness did not differ. Shrub-layer removal plots were much less dense, with 1/100 the basal area of shrubs than control plots. Tree-layer plots did not differ in any measure, suggesting that control and removal plot types were historically similar and continued to support comparable overstory vegetation. The composition of woody seedlings in the herb layer did not reflect the mature overstory in either plot type, although several of the most abundant woody seedlings were those of dominant wetland species. We conclude that immediately following L. sinense removal, native species outperform non-natives, both in cover and species richness in the herb layer. The poor recruitment of woody seedlings and saplings as well as the rapid invasion of invasive Japanese stiltgrass (Microstegium vimineum) may thwart restoration efforts, however. To ensure the wetland reaches its pre-invasion community structure, it may be necessary to plant native tree saplings and nurture them through the shrub layer to maturity.

Rhododendron eastmanii is a species endemic to South Carolina and common in the Enoree Ranger District of the Sumter National Forest. A four-year study was undertaken to revisit known populations and to locate new populations. A total of 2,035 individuals in 38 populations were documented, including 663 seedlings, 705 non-flowering adults, and 667 flowering individuals. Plants were most commonly found on mature hardwood slopes above headwater streams. Pollinator visitors included eastern tiger swallowtail (Papilio glaucus), pipevine swallowtail (Battus philenor), and bumblebees (Bombus spp.). Concerns for the future of the species were noted due to deer browsing and subcanopy shading, especially from Acer leucoderme (a native tree) and Elaeagnus umbellata (an introduced shrub). This survey results in a better understanding of the species distribution and documents its demographic changes over time.

Morphometric data were used to investigate the relationship between Cyperus squarrosus and related C. granitophilus, with particular attention to populations of C. granitophilus recently reported from granite outcrops in Texas and Oklahoma. Data for 23 characters (variables) taken from 406 voucher specimens were analyzed using principal component analysis (PCA), discriminate analysis (DA), multivariate analysis of variance (MANOVA), and a Euclidian distance dendrogram. Results (1) strongly support the treatment of C. granitophilus and C. squarrosus as separate species but (2) provide at best weak evidence for formal recognition of C. squarrosus var. runyonii and (3) indicate that the Texas and Oklahoma populations recently reported as C. granitophilus are more closely related to C. squarrosus than C. granitophilus.