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Historical accounts describe savanna-like conditions over portions of the Piedmont of the southeastern United States dating at least as far back as the 1500s. These open habitats are thought to have declined because of human development, Fire suppression, and loss of native grazing animals. Unfortunately, conservation efforts to restore and sustain Piedmont savanna are hampered by our current rudimentary understanding of community assembly and maintenance dynamics. Such understanding would be facilitated by a robust classification of species into specialist and generalist guilds related to canopy openness, a classification that is currently unavailable on a broad scale. Consequently, our objective was to develop a shade-tolerance classification for the upland Piedmont herbaceous flora of the Carolinas and Virginia, based on quantitative plot data from the region. To achieve this objective, we utilized a dataset of plot records (representing natural and semi-natural vegetation) from the Carolina Vegetation Survey. These are permanent plots on public and private land that were surveyed between 1977 and 2015. Following quality control, the dataset contained 1300 plots and 1550 species (including 835 native herbaceous species after single occurrences were removed), with species abundances in plots reported in cover classes. We estimated the canopy cover of each plot from the cover codes of its tree species and assigned each plot to habitat shade classes: open (75% canopy cover; n = 1097). We calculated point biserial correlation coefficients ([r.sub.pb]), which provided a positive or negative value for each species, dependent on its abundance and habitat association. We considered single (open, semi-open, or closed) and combined (open+semi-open, closed+semi-open, or open+closed) habitat classes during our analysis. Of the 835 native herbaceous species in the dataset, we found 141 (17%) to be heliophytes (specialists of open habitats with canopy cover 75%), despite 84% of plots in the dataset being classified as closed habitats. Our work suggests that open and semi-open habitats may contain a disproportionate diversity of regional herbaceous flora and provides the first quantitative shade-tolerance classification for over 800 herbaceous species. This work provides a resource that can be used by field biologists and land managers to identify heliophyte communities, and to assess the success of habitat restoration and creation efforts., INTRODUCTION Eastern United States Piedmont upland prairies, savannas, and woodlands with a heliophytic flora of Midwest prairie affinity trace an arc beginning with the Blackland prairies of Mississippi and Alabama [...]

Although vegetation succession in the Piedmont of eastern North America favors closed-canopy forest in the absence of disturbance, historical evidence suggests upland vegetation of the region was, in near history, characterized by areas of heliophilic vegetation, such as prairies, savannas, and woodlands. While some work has been undertaken to characterize putative remnant communities at the local and subregional level, there has been no comprehensive, quantitative study to characterize the breadth of heliophilic vegetation commonly referred to as "Piedmont prairies" in the mid-Atlantic portion of the Piedmont, despite evidence that more than one community type is likely represented. We fill this gap by assessing Piedmont prairie communities in the present-day landscape using the best quantitative vegetation data currently available from the Carolina Vegetation Survey vegetation-environment database. We extracted records for 195 permanent vegetation plots representative of upland, terrestrial, open or semi-open vegetation in the Piedmont of the Carolinas and Virginia, a region coinciding with 17th- and 18th-century accounts of historical savannas. Through hierarchical clustering (flexible-β) and stride analysis (plotting the PARTANA ratio and silhouette width), we determined the optimal partition for our dataset to be 12 clusters. The R package optpart was used to move plots between clusters to further ensure plots are members of their best-fit cluster. Nonmetric multidimensional scaling ordination was used to visualize compositional trends in the dataset. We identified 12 major types of heliophilic vegetation that can be categorized into five larger groupings: Piedmont Oak-Hickory and Red Cedar Woodlands, Piedmont Glades, Piedmont Pine Woodlands, Piedmont Savannas and Grasslands, and Piedmont River Terrace Glades. [ABSTRACT FROM AUTHOR]

Question: Understanding the mechanisms determining species composition is one of the central goals in ecology. The limestone landscape of southwestern China is one of the most widely known landscapes developed on carbonate bedrock in the world. We explored the following question: What are the patterns of species composition and phylogenetic structures of the communities developed on the acid and limestone soils? Location: Southwestern China. Methods: Using 536 plots on acid and limestone soils, we identified distinct vegetation types on both soil types based on hierarchical clustering and ordination. Variation partitioning partitioned the effects of climate, geographic distance and soil on species composition. Generalized linear models determined the effects of climate and soil on phylogenetic diversities. Results: The typical vegetation on acid soils is evergreen broad‐leaved forests characterized by Castanopsis species, while typical vegetation on limestone soils is mixed evergreen and deciduous forests characterized by a high proportion of deciduous trees and calciphytes. Soil type was much more important in driving species composition than climate and spatial distance. The standardized mean pairwise phylogenetic distance (ses.MPD) and mean nearest taxon distance (ses.MNTD) were significantly lower on limestone soils than on acid soils, indicating a more clustered phylogenetic structure. The effect of soil on ses.MPD was stronger than on ses.MNTD, and ses.MNTD increased with increasing annual temperature and precipitation seasonality on acid soils but decreased on limestone soils, suggesting that soil affected phylogenetic structure at relatively deep branches, while climate combined with soil mainly affects the relatively recent branches, as ses.MPD measures phylogenetic structure at deep branches and ses.MNTD that at shallow branches. Conclusions: This study highlights the importance of soil in shaping community structure at a regional scale, and it also reveals the unique features of limestone vegetation and supports the validity of limestone vegetation types in the Chinese vegetation classification system. [ABSTRACT FROM AUTHOR]