Volume 84 – Issue 2 (Nov 2019)

JoVonn G. Hill and John A. Barone, eds. 2018. Southeastern Grasslands: Biodiversity, Ecology, and Management. Published by The University of Alabama Press, Tuscaloosa, 344 p. Hardbound, $54.95. ISBN 978-0-8173-1988-5

Southeastern Grasslands: Biodiversity, Ecology and Management is a collection of 20 research and review articles that focus on the floristics, conservation, and ecological history of grassland prairies in the southeastern United States. The volume “was inspired by the” 2012 Southeast Prairie Symposium and is a varied tribute to a unique and disappearing biome that has been reduced to less than 10% of its original range. Human encroachment, climate change, and invasive species have virtually eradicated the open grasslands that once dotted the USA from east Texas to the Atlantic Coast.

The book was written “with a broad audience in mind,” however, each chapter is written in a research format with Introduction, Methods, Results, and Discussion sections suggesting the more likely audience comprises academic and conservation scientists. Because each chapter was inspired by a 15 minute research talk, chapters are concise with discussion sections closer in length to an abstract. And although this book is not directly marketed as a textbook, the hardcover has the weight and dimensions of a standard textbook at 9 × 12 inches and 5.4 pounds, so it is a rather large book to lug around and after carrying the book between my office and home more than a few times the binding started to fray and a few pages came loose. The text is rather large with wide spacing and broad margins, so there is a lot of white on each page. Although the publishers designed the book to mimic a university text, the density of the material does not merit such a large and cumbersome tome. By comparison, Raven: Biology of Plants, 8th edition, is the same dimension and weight but with twice the number of pages and information. For the sake of the consumer, the publisher could have been more economical by publishing this work with a smaller type, paper size, and gauge.

As an old-school taxonomist, I found it disappointing that the editors chose not to maintain nomenclatural consistency throughout the text. For example, in chapter 5, “Floristics of the Louisiana Cajun and Inland Priaries,” and chapter 7, “Vegetation and Flora on Lowlands in the Central Black Belt of Mississippi,” Sambucus nigra is treated under the Caprifoliaceae; however, in chapter 6, “The Native Flora of Grasslands and Associated Woodlands in the Grand Prairie Ecoregion of Eastern Arkansas,” S. nigra is treated in the Adoxaceae. Also in chapter 5, Acer is treated in the Aceraceae, and in chapters 6 and 7, it is placed in the Sapindaceae. Similarly, in chapters 5, 6, and 7, Thyrsanthella difformis is referred to under the genus Trachelospermum which was demonstrated over a decade ago to be polyphyletic (Livshultz et al. 2007) with the New World species T. difforme clearly distinct from the Asian taxa. There are numerous other taxonomic inconsistencies throughout the book. I find this troublesome, considering that this book emphasizes the pressing need to conserve our nation’s grasslands, and yet a backbone of endangered species management is precise species identification. The failure to maintain taxonomic consistency in a research focused text only helps to solidify the pervading thought that taxonomy is an archaic science subject to arbitrary rules not worthy of serious academic attention.

Overall, I found the individual chapters interesting and informative (especially chapter 8 exploring the historical distribution of Osage Orange). However, other than sharing geography, the collected works lack synthesis. Just like the presentations at the symposium on which the volume is based, the chapters are individual units that require no prior knowledge or understanding of the previous unit. I would not recommend this book as a standalone textbook for a course on grasslands. However, given the broad range of subjects and chapter lengths, this volume would provide a wonderful text to a senior seminar course on the Conservation and Ecology of Grasslands, and it should definitely be a standard reference for any conservationist working to preserve the Grasslands of the Eastern United States.

American ginseng (<i>Panax quinquefolius</i>) roots have long been harvested for use in herbal medicine. Overharvesting has threatened long-term viability of wild American ginseng populations. Research has been ongoing to determine factors affecting the variation of ginsenosides in roots. Given the conservation concerns regarding wild American ginseng, we began experimenting with a partial-root harvest method in 2014 for extracting tissue for ginsenoside analysis without killing individual plants or causing long-term declines in wild populations. We took partial-root harvest samples from 57 plants in four wild populations throughout western North Carolina and monitored morphological attributes of these and 56 paired, unharvested plants of similar size for four years after harvest. Partial-root samples were taken from an additional 162 plants from 16 new populations in 2015 and 2016. Morphological attributes of these plants were monitored annually or biannually. In the paired plant study, annual reemergence did not differ between harvested and unharvested plants in any year after harvest. Leaf area was significantly lower in harvested plants than unharvested controls in the first year postharvest, but these differences did not persist after the first year. In the unpaired study, preharvest-postharvest comparisons were more variable, likely due to different harvest years and interannual variation in weather. Our results demonstrate that partial-root harvest could be an effective way for ginsenoside researchers to reduce their impact on wild and cultivated American ginseng populations and it may represent a non-destructive harvest protocol for root tissue phytochemical analysis.

Thompson Pond, a bog lake in Pine Plains, New York, has flora indicative of both ombrotrophic and minerotrophic conditions. Distinct community types within this wetland system include a peripheral moat, hummock swamp, floating vegetation mats, peat rafts, aquatic floating-leaved and submergent macrophytes, and open water. A false-bottom of unconsolidated peat overlies the lake bed. Vegetation composition is typically diverse in such lakes, which support species of both acidic and calcareous habitat affinities. We repeated a 1973–74 survey to assess changes in wetland flora after four decades. The recent survey yielded 218 vascular plant species, representing 66 families and 134 genera. The largest genus was Carex with 26 species. Forty species from the original survey were not relocated, and 97 species were found in the recent survey that had not been found in the original survey. Eriocaulon aquaticum, usually associated with oligotrophic waters, was common in the original survey and not found in the recent survey. Aerial photos were used to calculate the change in vegetation cover, revealing that floating vegetation mats and peat rafts expanded between 1970 and 2016. Nutrient loading from agricultural and residential land use within the watershed, in addition to the installation of a dam across the lake’s surface water outlet have likely contributed to the floristic and community structure changes seen in Thompson Pond.

Purple loosestrife (Lythrum salicaria) is documented for the first time for Louisiana in Plaquemines Parish, extending its range southward about 310 km. Three species of Lythrum are now known for Louisiana, and four species have been recorded for the central Gulf and lower Mississippi valley regions. A key to species and regional distributional data are provided for L. salicaria.

ABSTRACT:

Chevreulia acuminata is reported for the first time in North America from recent collections in the southeastern United States. Populations from Lee County, Alabama, and one in Troup County, Georgia, were found growing in lawns or grassy areas along with other weeds. Photographs and a description of C. acuminata are provided.

ABSTRACT

Geum radiatum is a federally endangered high-elevation rock-outcrop endemic herb that is widely recognized as a hexaploid and a relic species. Little is known about G. radiatum genetic diversity, population interactions, or the effect of past augmentations of populations. This study sampled every known population of G. radiatum and used microsatellite markers to measure genetic diversity and population structure. The analysis demonstrates that there is interconnectedness and structure among populations. In addition, the analysis was able to differentiate transplanted individuals and identify putative anthropogenically admixed individuals within augmented populations. Geum radiatum exhibits diversity within and among populations and current gene flow connects the northern populations. This information provides a greater understanding of the genetic sustainability of G. radiatum and what conservation efforts will most help this imperiled species to survive.

Please note that the initial PDF issued was paginated incorrectly.  The correctly paginated article appears at this link.

ABSTRACT:

The dwarf sundew (Drosera brevifolia) occurs from Uruguay to Virginia. Disjunct populations occur in the southeastern U.S. with the northernmost in Kentucky. Despite this wide distribution, relatively little is known about the biology of this species. It has been described as both annual and biennial. The endangered Kentucky population is considered biennial, but occasionally, live, mature plants have dead flower stalks in early autumn suggesting some may be perennial. In 2013, 40 sundews that germinated in the fall of 2012 were marked as they flowered in 2013. They were observed into a third growing season in 2014 until the end of July. Sixteen plants (40%) died after setting seeds in their second growing season, while nine (22.5%) remained alive, flowered, and set seeds again the following year. Seven of these were still alive at the end of July 2014. Fifteen plants were puzzling as the leaves were dead after setting seeds in their second growing season, but were alive May 2014, of which 12 flowered. This study confirms that at least a portion of the Kentucky population of D. brevifolia is perennial. This is probably facultative perenniality because some plants only survive to a third growing season when precipitation falls evenly over the growing seasons and when no hot, dry periods occur. Mild winters without extensive snow cover may contribute to facultative perenniality as well.

Please note that the initial PDF issued was paginated incorrectly.  The correctly paginated article appears at this link.

ABSTRACT:

Gentiana autumnalis (pine barren gentian) is a rare, fall-flowering perennial that is endemic to pine barren habitat from New Jersey to South Carolina. This disturbance-adapted, early successional species is at risk in New Jersey as a result of human interactions, namely growing season mowing and fire suppression. We used a repeated measures design to compare the differences between managed (mowing and prescribed fire) and unmanaged G. autumnalis populations for density, life stage, mortality, and fecundity. Managed populations had a greater gentian density, proportion of reproductive individuals, and seedlings compared to unmanaged populations. Implementing prescribed burns and mowing at previously unmanaged sites prior to spring growth increased gentian density, flowering, and seed set the same year. Our data support that prescribed burning and mowing can be beneficial management tools for the conservation of G. autumnalis and other disturbanceadapted species that require open early-successional habitat. However, their implementation can have negative consequences if conducted during the growing season, especially for roadside populations that are periodically mowed. Declining rare plant populations have the potential to benefit from management practices that facilitate ideal growing conditions and influence life stage transitions that will best improve population growth rate over time.

ABSTRACT:

The biodiversity of freshwater springs in the Arkansas Ozarks is poorly described and has received relatively little attention from researchers. Information on the biodiversity of springs is crucial for their management and conservation. This study describes the aquatic and semi-aquatic plant communities and key habitat features of several springs located at Buffalo National River, Arkansas. We report 58 taxa from among all springs, including eight genera of algae, one species of horsetail, three marchantiophytes, and one bryophyte. Among angiosperms, we found 21 species of monocots and 24 species of eudicots. Six non-native species occur among the springs and none are considered to be invasive. Data show that impounded springs tend to have higher plant diversity than springs with primarily lotic geomorphologies. Cluster analysis showed that the springs with a prominent lentic structure were most similar to each other with respect to shared taxa, while the springs with well defined, long spring-runs and no functional impoundments shared the most taxa. Geographic proximity in the watershed does not appear to play a substantial role in similarity of plant populations, indicating other factors are involved. An NMDS analysis of habitat and water chemistry data corroborated the cluster analysis and showed that habit structure plays a key role in plant community composition. Springs at Buffalo National River occurring within the Boston Mountains and Springfield Plateau appear to have lower taxonomic diversity compared to the larger springs occurring on the adjacent Salem Plateau, which is likely because of their low magnesium concentrations.

ABSTRACT:

Marshallia mohrii (Asteraceae) is a perennial forb endemic to grasslands in the southeastern United States. Despite having been listed as federally threatened for three decades, little is known about its biology and life history. In this study, we examined the role of light, temperature, seed age, and cold stratification on seed dormancy break and germination in M. mohrii. We also quantified soil temperatures in a Ketona glade population of M. mohrii to infer dormancy breaking and germination phenologies under natural conditions. Relatively high proportions (>65%) of cold stratified seeds germinated across a range of temperature regimes in both light and darkness, whereas nonstratified seeds only germinated to high proportions in light at high temperatures. Germination proportions of laboratory stored seeds were slightly greater than freshly matured seeds, but remained much lower than those of cold stratified seeds. According to laboratory experiments, both autumn and spring germination phenologies are possible depending on the temperature and light conditions seeds experience after dispersal. Seeds of M. mohrii exhibited type 3 non-deep conditional physiological dormancy, which has been found in other members of Asteraceae from temperate grasslands. Overall, the germination niche of M. mohrii is defined by conditional seed dormancy, reduced dormancy levels following cold stratification, dark germination after dormancy loss, seasonal germination cueing, and seed traits consistent with short-term persistence in soil. Results from our study are useful for future conservation and recovery actions with M. mohrii and represent the first known published report of germination traits in this genus, which contains several other rare and range-restricted species.