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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]

Because ectotherm activity and metabolism are sensitive to temperature, terrestrial arthropods may be especially responsive to ongoing climatic warming. Here, we quantified responses of arthropod abundance to two years of warming in an outdoor temperature manipulation experiment at Duke Forest, North Carolina, USA. Nine open‐top chambers were individually heated year‐round from 1.5° to 5.5°C above ambient temperature. From two years of monthly pitfall trapping, we collected and identified 4,468 arthropods representing 24 orders. We initially predicted that arthropods would experience the greatest negative effects of experimental warming during the summer months, when temperatures reach their yearly maximum and arthropods may be close to their maximum thermal tolerance limits. Instead, we found that the strongest negative effects on arthropod abundance occurred during the winter and spring, when ambient temperatures are relatively cooler, whereas the effects of experimental warming on abundance were not significant during the summer or fall. During the spring of 2012, the warmest spring on record for the southeastern USA, total arthropod abundance declined 20% per °C of experimental warming. Abundance declines were driven largely by flies (Diptera), which were the most abundant insect order, representing approximately a third of all arthropods collected. The most abundant arthropod family, Mycetophilidae (fungus gnats), declined 64% per °C of warming during the spring of 2012. Although previous research on climatic warming has focused on the impact of maximum yearly temperatures on organismal performance, our results are more consistent with the cool‐season sensitivity hypothesis, which posits that arthropods adapted for cooler conditions are likely to face the strongest negative effects of warming during the cooler seasons. [ABSTRACT FROM AUTHOR]

The goal of elucidating the primary mechanisms constraining the assembly and distribution of biodiversity remains among the central unresolved challenges facing the field of ecology. Simulation studies and experimental manipulations have focused on how patterns in community assembly result from bivariate relationships along productivity or environmental gradients. However, the joint influence of multiple resource gradients on the distribution of species richness in natural communities remains understudied. Using data from a large network of multiscale vegetation plots across forests and woodlands of the southeastern United States, we find significant evidence for the scale‐dependent, joint constraints of forest structure and soil resources on the distribution of vascular plant species richness. In addition to their significant partial effects on species richness, understory light levels and soil fertility positively interact, suggesting a trade‐off between the two limiting resources with species richness peaking both in high‐light, low‐fertility conditions as well as low‐light, high‐fertility settings. This finding provides a novel perspective on the biodiversity–productivity relationship that suggests a transition in limiting resources from soil nutrients to light availability when enhanced productivity results in reduced light resources for subordinate individuals. Results likewise have meaningful implications for our understanding of scale‐dependent community assembly processes as size‐asymmetric competition replaces environmental filtering as the primary assembly mechanism structuring temperate forest communities along an increasing soil fertility gradient. [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]

Aims The latest China Vegetation Classification System (China-VCS) for natural/semi-natural vegetation has eight hierarchical levels: Association < Association-group < Subformation < Formation < Formation-group < Vegetation-subtype < Vegetation-type < Vegetation-type-group. The classification is based on dominant species and their growth forms and has been completed at the formation level. The principal challenge today in Chinese vegetation classification is to develop the China-VCS at levels below the formation in a way that is consistent with current international standards. We explored the following question: how can existing vegetation plot data help develop the China-VCS and improve its compatibility with other international classification systems? Methods We compiled 401 plots having plant cover and/or aboveground biomass measurements collected in six Stipa steppe formations and divided them into those with cover data (299 plots) and/or biomass data (283 plots). We applied a combination of hierarchical clustering and ordination to partition the cover and biomass data sets into formations and constituent associations. We then used supervised noise clustering to improve the classification and to identify the core plots representing each association. Diagnostic species were also identified at both association and formation levels. Finally, we compared the classification results based on cover and biomass data sets and combined these results into a comprehensive classification framework for the six formations. Important Findings Our results using cover data were comparable with those using biomass data at both formation and association levels. Three Stipa formations were classified into associations based on cover data, two based on biomass data and one based on both biomass and cover data. Twenty-seven associations were defined and proposed within the six formations, using cover or biomass data as consistent classification sections (CCSs). Both dominant species in the dominant stratum and diagnostic species from multiple strata of the core plots were used to characterize vegetation types at both formation and association levels, improving the compatibility of our classification with the International Vegetation Classification. Temperature and precipitation were found to be important climatic factors determining the distribution pattern and species composition of Stipa -dominated vegetation. We propose a framework for plot-based vegetation classification in the China-VCS, using our work with Stipa -dominated steppe vegetation as an example. We applied the concept of CCS to make optimal use of available data representing both plant cover and biomass. This study offers a model for developing the China-VCS to the association level in a way that is consistent with current international standards. [ABSTRACT FROM AUTHOR]

The movement of plant species across the globe exposes native communities to new species introductions. While introductions are pervasive, two aspects of variability underlie patterns and processes of biological invasions at macroecological scales. First, only a portion of introduced species become invaders capable of substantially impacting ecosystems. Second, species that do become invasive at one location may not be invasive in others; impacts depend on invader abundance and recipient species and conditions. Accounting for these phenomena is essential to accurately understand the patterns of plant invasion and explain the idiosyncratic results reflected in the literature on biological invasions. The lack of community‐level richness and the abundance of data spanning broad scales and environmental conditions have until now hindered our understanding of invasions at a macroecological scale. To address this limitation, we leveraged quantitative surveys of plant communities in the USA and integrated and harmonized nine datasets into the Standardized Plant Community with Introduced Status (SPCIS) database. The database contains 14,056 unique taxa identified within 83,391 sampling units, of which 52.6% have at least one introduced species. The SPCIS database includes comparable information on plant species occurrence, abundance, and native status across the 50 U.S. States and Puerto Rico. SPCIS can be used to answer macro‐scale questions about native plant communities and interactions with invasive plants. There are no copyright restrictions on the data, and we ask the users of this dataset to cite this paper, the respective paper(s) corresponding to the dataset sampling design (all references are provided in Data S1: Metadata S1: Class II‐B‐2), and the references described in Data S1: Metadata S1: Class III‐B‐4 as applicable to the dataset being utilized. [ABSTRACT FROM AUTHOR]

Perseaborbonia and Persea palustris are two species in the Lauraceae family, native to the southeastern USA. Because of their similar morphologies, many authorities treat these two species as varieties of a more broadly defined group, Persea borbonia. Consequently, the species and communities associated with P. borbonia and P. palustris are not well defined. Extensive mortality has occurred in both species because of laurel wilt disease. Our objectives were to (a) determine whether P. borbonia and P. palustris are associated with different communities, (b) describe the communities and associated species in which P. borbonia and P. palustris occur, and (c) determine which communities support larger individuals of Persea spp. We analyzed data collected from 1988 through 2012 by the Carolina Vegetation Survey. To test differences among plant communities with natural growth of P. borbonia and P. palustris, we used ordination and analysis of similarities. We used cluster analyses and species-indicator analyses to group 388 plots into distinct communities. Results were verified by random forest analyses. We compared basal area of Persea spp. in each community with Kruskal-Wallis multiple comparisons. Persea borbonia and P. palustris communities were significantly different in species composition. Persea borbonia was limited almost exclusively to maritime coastal forests, whereas P. palustris had a larger geographical range, extending from near-coastal settings inland through the fall-line of the sandhills. The cluster and indicator species analyses identified eight unique groups, one for P. borbonia, and seven for P. palustris. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the Carolina Vegetation Survey (CVS) is to provide a framework for characterization of natural plant communities throughout North and South Carolina and adjacent US states. The resulting classification supports scientific interpretation of vegetation pattern, biodiversity inventory, biodiversity monitoring, conservation efforts, and identification of restoration targets. Application of the approach: The CVS classification approach will lead to a synthetic treatment of the vegetation of the Carolinas. Although regional in its scope, the approach is generalizable to other geographic regions. It will support further development of the US National Vegetation Classification (USNVC), providing a model for similar work in other regions, thereby leading to more rapid improvement and application of the USNVC. Main features and protocols: Our protocols were developed for use with a large database of vegetation-plot records inventoried using a consistent, published methodology. Plot sizes typically range from 100 to 1000 m2, although data from smaller subplots are also collected. Each record has a full list of vascular plant species and includes cover-class estimates and tallies of woody stems. Species concepts and nomenclature are regularly updated to a consistent standard. Supporting data include soil chemical and physical properties and other site attributes. Class definition procedures employ node-based agglomerative hierarchical algorithms, informed by ordination procedures and by a priori assignment of records to vegetation classes. Advantages and limitations: Classification protocols draw on widely- used, well-established procedures and algorithms. Typological resolution aims to conform to one or more of the lower levels of the USNVC hierarchy. A limitation is that most plots were located using preferential sampling, which has the potential for incorporating selection biases. However, this approach captures rare or unanticipated types that would otherwise be missed. To date CVS data collection has been restricted to natural communities and consequently cannot inform classification of semi-natural or cultural vegetation. [ABSTRACT FROM AUTHOR]

We studied lichen communities on bole and base tree trunk segments along forest edge-to-interior gradients on opposite sides of a major highway and a control site in central North Carolina, U.S.A., to investigate if these two communities differ and if so, do they differ in response to highway pollution. At each site we measured various environmental parameters including ambient air NO2 concentrations, and sampled lichens on 5-7 trees along each of five parallel transects established at the forest edge and at 25, 60, 100 and 150 m into the forest. We compared lichen communities between the two trunk segments via species richness and composition by habit, photobiont type, and reproductive strategy. We then ran dual (bole and base) NMS ordinations with subsequent correlation/regression analyses to explore/test relationships of lichen parameters with environmental variables among the 15 sample transects combined. Species richness was similar between trunk segments at transect and site levels as well as overall. Bole and base communities were more compositionally similar to each other at the highway sites than they were at the control site, based on Bray-Curtis similarity indices ( BC). Tree base communities differed in terms of functional groupings, with greater proportions of squamulose, cyanolichen and sterile species than found in tree bole communities, but varyingly so among sites. Patterns of bole-base BC values with distance from the forest edge were not apparent in any of the sites. Ordination analyses resulted in Axis 1 representing most of the variation for each trunk segment. Along this axis, correlations were similar between boles and bases, with the strongest ones involving lichen species richness (negative) and NO2 concentrations (positive); notably weak correlations involved tree species number, canopy cover and DBH. Similar patterns were found when lichen species number was correlated with environmental parameters directly, with NO2 concentration correlating strongest at each trunk segment. Among functional groups, % crustose and % fertile species on bases correlated significantly with NO2. Lichen species-NO2 relationships on boles and bases were both found to be highly significant quadratic relationships with base lichen richness being stronger. [ABSTRACT FROM AUTHOR]

We studied lichen communities along forest edge-to-interior gradients on opposite sides of a major highway and along a remote lakeshore in central North Carolina, U.S.A., to investigate highway pollution effects on this sensitive ecosystem component. At each site we sampled lichens on trees at 10 m intervals along each of five parallel transects established at the forest edge and at 25, 60, 100, and 150 m into the forest in the highway sites, with a similar layout along a nonlinear lakeshore in a similar forest type, from which transect distances from the forest edge were estimated using average tree distances from the nearest shoreline. Lichen communities were inventoried on tree trunks from the base up to 1.5 m height, then compared both among and within sites. Species richness was highest in the control site, and did not differ between the two highway sites. The highway sites were more similar to one another than either was to the control site, based on Bray-Curtis similarity indices. No associations were detected among sites and sampled lichen biotic components in terms of growth form, photobiont type or reproductive mode. In the highway sites, total transect species richness increased from the forest edge to 150 m distant. In the control site, species richness decreased from the forest edge to the most distant transect. Findings suggest a negative effect of highway pollution on species richness of lichen communities, but not on species composition by habit, photobiont type or reproductive mode. Despite the elevated NOx concentrations recorded along the highway, known nitrophilous species were largely absent, suggesting that other factors, including other pollutants, were affecting community structure near the highway. [ABSTRACT FROM AUTHOR]

Several studies have demonstrated that floras of the New World contain larger proportions of alien species than those of the Old World; however, the differences in fine-scale invasion patterns are poorly known. We compared the levels of invasion in analogous habitats of two environmentally similar regions in temperate North America and Europe (the Carolinas and the Czech Republic), using comprehensive vegetation-plot databases. Native and alien vascular plant species were identified within 4165 vegetation plots assigned to 12 habitats occurring in both areas. The level of invasion was calculated for each habitat (1) as the proportion of aliens recorded cumulatively across multiple plots (habitat scale) and (2) as the mean proportion of aliens per plot (plot scale), both separately for all alien species and for the subgroup of aliens originating in one region and invading the other. The proportions of species native on one continent and invading the other were also calculated for each habitat to compare the alien species exchange between continents. Habitat levels of invasion showed remarkably similar patterns on the two continents. There were significant positive relationships for the levels of invasion, both for all alien species (habitat-scale R2 = 0.907; plot-scale R2 =0.676) and for those that originated on the opposite continent (habitat-scale R2 =0.624; plot-scale R2 =0.708). In both regions, the most and the least invaded habitats were the same, but on average, North American habitats showed higher habitat-scale levels of invasion than their European counterparts. At the same time, a larger proportion of alien species was provided by European habitats for invasion to North America than vice versa. The consistent intercontinental pattern of habitat levels of invasion suggests that these levels are driven by similar mechanisms in distant regions. Habitat conditions are likely to have stronger effect on the level of invasion than the identity of alien species, as shown by similar levels of invasion in analogous habitats despite different geographical origins of alien species. The higher flux of alien species from Europe to North America is consistent with a generally higher level of invasion of North American habitats. [ABSTRACT FROM AUTHOR]

Aim We hypothesize that the level of plant invasion at the scale of vegetation plots is affected by the different sizes of regional species pools of alien plants adapted to particular habitats. We test these species-pool effects in the context of alien species exchange between analogous habitats on two continents. Location North and South Carolina, and the Czech Republic (both as native and invaded range). Methods We identified native and alien vascular plant species within 6059 vegetation plots from 27 habitats of eastern North America and Central Europe. We compared the habitats' level of invasion, expressed as the proportion of alien species in a representative sample of vegetation plots from each habitat, with the contribution of each habitat to the alien species pool, calculated as the proportion of species of this habitat that are native to one continent and donated as aliens to the other. Results A habitat's level of invasion on one continent increases with the proportion of alien species donated to its regional species pools by analogous habitats on the other continent, i.e. the more of its native species a habitat contributes as aliens, the more of them establish in analogous recipient habitats (direct species-pool effect). The habitat's level of invasion on the same continent also increases with the proportion of native species that those habitats themselves donate to regional species pools on the other continent, i.e. a habitat that gives many aliens also receives many aliens (reciprocal species-pool effect). Main conclusions We demonstrate that when a habitat on one continent donates more of its native species to the alien species pool, the analogous habitat on the recipient continent also contains a greater number of aliens. The same donor habitat is itself also the recipient of more alien species invading from the analogous habitats of other continents. [ABSTRACT FROM AUTHOR]

Establishing the phylogenetic and demographic history of rare plants improves our understanding of mechanisms that have led to their origin and can lead to valuable insights that inform conservation decisions. The Atlantic coastal plain of eastern North America harbours many rare and endemic species, yet their evolution is poorly understood. We investigate the rare Sandhills lily ( Lilium pyrophilum), which is endemic to seepage slopes in a restricted area of the Atlantic coastal plain of eastern North America. Using phylogenetic evidence from chloroplast, nuclear internal transcribed spacer and two low-copy nuclear genes, we establish a close relationship between L. pyrophilum and the widespread Turk's cap lily, L. superbum. Isolation-with-migration and coalescent simulation analyses suggest that (i) the divergence between these two species falls in the late Pleistocene or Holocene and almost certainly post-dates the establishment of the edaphic conditions to which L. pyrophilum is presently restricted, (ii) vicariance is responsible for the present range disjunction between the two species, and that subsequent gene flow has been asymmetrical and (iii) L. pyrophilum harbours substantial genetic diversity in spite of its present rarity. This system provides an example of the role of edaphic specialization and climate change in promoting diversification in the Atlantic coastal plain. [ABSTRACT FROM AUTHOR]

This study provides quantitative ecological targets for restoring degraded peat-based Carolina Bays in the Carolina Flatwoods Ecoregion. Cluster analysis of vegetation data from three Carolina Bay reference sites in Bladen County, North Carolina, indicated four plant communities present: pond pine (Pinus serotina) woodland, non-riverine swamp forest dominated by swamp gum (Nyssa biflora), high pocosin dominated by evergreen shrubs with scattered pond pine, and bay forest dominated by loblolly bay (Gordonia lasianthus). We classified bay soils according to surface organic layer thickness (OLT) into mineral, histic, shallow organic, and deep organic types. We monitored the water table of each soil type in one bay throughout one growing season. The soil types with corresponding water table regimes were: mineral (9.4 cm mean OLT with a rooting zone water table [RZWT] 39% of the monitoring period), histic (27.5 cm OLT and 76% RZWT), shallow organic (63.9 cm OLT and 84% RZWT), and deep organic (102.5 cm OLT and 57% RZWT). Pearson residual analysis and correspondence analysis revealed that pond pine woodland was positively associated with mineral and histic soils, non-riverine swamp forest with shallow organic soil, bay forest with deep organic soil, and high pocosin with deep organic soil. We concluded that peat-based Carolina Bay restoration in the Carolina Flatwoods Ecoregion should be gauged against reference data which suggests: 1) pond pine woodland be established on mineral and histic soils; 2) non-riverine swamp forest be established on shallow organic soils; and 3) high pocosin and bay forest be established on deep organic soils. [ABSTRACT FROM AUTHOR]

The general phylogeographical paradigm for eastern North America (ENA) is that many plant and animal species retreated into southern refugia during the last glacial period, then expanded northward after the last glacial maximum (LGM). However, some taxa of the Gulf and Atlantic Coastal Plain (GACP) demonstrate complex yet recurrent distributional patterns that cannot be explained by this model. For example, eight co-occurring endemic plant taxa with ranges from New York to South Carolina exhibit a large disjunction separating northern and southern populations by >300 km. Pyxidanthera (Diapensiaceae), a plant genus that exhibits this pattern, consists of two taxa recognized as either species or varieties. We investigated the taxonomy and phylogeography of Pyxidanthera using morphological data, cpDNA sequences, and amplified fragment length polymorphism markers. Morphological characters thought to be important in distinguishing Pyxidanthera barbulata and P. brevifolia demonstrate substantial overlap with no clear discontinuities. Genetic differentiation is minimal and diversity estimates for northern and southern populations of Pxyidanthera are similar, with no decrease in rare alleles in northern populations. In addition, the northern populations harbour several unique cpDNA haplotypes. Pyxidanthera appears to consist of one morphologically variable species that persisted in or near its present range at least through the latter Pleistocene, while the vicariance of the northern and southern populations may be comparatively recent. This work demonstrates that the refugial paradigm is not always appropriate and GACP endemic plants, in particular, may exhibit phylogeographical patterns qualitatively different from those of other ENA plant species. [ABSTRACT FROM AUTHOR]

A continuous, 13-yr record of environmental data and phytoplankton species and assemblage structure in the mesohaline Neuse River Estuary (biweekly, April-October; monthly, November-March) was used to evaluate phytoplankton assemblage responses to changing environmental conditions. Ordination techniques including nonmetric multidimensional scaling, indicator species analysis, and BIO-ENV software were used to investigate potential environmental predictors of phytoplankton assemblage patterns under chronic eutrophication. Phytoplankton assemblages were strongly related to temperature and total nitrogen : total phosphorus ratios, with expected seasonal changes in species composition. Interannual changes in river discharge influenced whether phytoplankton assemblages were dominated by diatoms and phototrophic flagellates or by mixotrophic and heterotrophic dinoflagellates. Increasing ammonium concentrations also have been an important influence on phytoplankton assemblages. Raphidophytes (including the potentially toxic species Heterosigma akashiwo), haptophytes, chlorophytes, and the bloom-forming dinoflagellate Heterocapsa rotundata have increased in more recent years (2000-2006), concomitant with increasing ammonium concentrations. Abundance of the potentially toxic dinoflagellates Prorocentrum minimum and the grouping Pfiesteria spp., 'pfiesteria-like' dinoflagellates, and Karlodinium veneficum remained stationary over time and rarely exceeded 103 cells mL−1. Abundance of P. minimum was positively related to dissolved organic nitrogen and suspended solids concentrations, whereas the highest abundance of the grouping Pfiesteria spp., 'pfiesteria-like' dinoflagellates, and K. veneficum occurred during summer and fall, related to high total phosphorus concentrations, temperature, and salinity. Overall, this study provides new species-level insights to advance understanding about anthropogenic influences on phytoplankton assemblages. The data suggest an increasingly important role of ammonium in controlling phytoplankton assemblage structure, including increased abundance of some harmful species, in eutrophic estuaries. [ABSTRACT FROM AUTHOR]

Cool Springs Environmental Education Center (CSEEC), owned by Weyerhaeuser Company, includes a 591 ha State Significant Natural Area. It is located in Craven County, North Carolina, in the floristically rich Atlantic Coastal Plain. A vascular flora inventory documented the occurrences of 567 species and sub-specific taxa and 303 genera in 118 plant families, including populations of the Atlantic Coastal Plain endemics Pondspice (Litsea aestivalis) and LeBlond's Coastal Goldenrod (Solidago villosicarpa). We identified twenty plant community types, including the uncommon Longleaf Pine (Pinus palustris) Woodland, Bald Cypress-Tupelo Gum (Taxodium distichum -- Nyssa aquatica) Swamp, a number of small depression wetland communities, and the novel Sand Laurel Oak-Labially Pine (Quercus hemisphaerica -- Pinus taeda) Woodland. Soils ranged from excessively drained sands to very poorly drained organics. The order of the soil mapping units according to the number of plant taxa they supported per unit area was TaB > PO > Ln > Mu > DO, MM > Se > KuB. Among five of 12 floristic study sites having positive residuals in the regression of log species richness on log area, CSEEC had the third largest residual. There was no relationship between the residuals from regressions of log species on log area and soil drainage heterogeneity on log area. The occurrences of two rare plant species, a species-rich flora, ten natural plant community types, and an assemblage of wet and dry soils in a variety of geomorphic settings are objective factors justifying the recognition of CSEEC as a State Significant Natural Area. [ABSTRACT FROM AUTHOR]

Because of ongoing debate over the long term impacts of logging, we conducted a study to assess if second growth (70 ± 10 years) rich coves differ from old growth rich coves (> 125 years) in species diversity or composition. We sampled twenty-six 0.1 ha plots, representing these two age classes. We distributed the plots amongst three randomly selected mountain ranges in the southern Appalachians of North Carolina, and sampled each mountain range in separate years. We used nested subplots of 0.01 m², 0.1 m², 1 m², 10 m², 100 m², and 1000 m² to establish species-area relationships (SARs) for each age class. We found no significant differences between the SARs for the two age classes, nor did we find significant differences between age classes using the Simpson, Shannon-Wiener, or Sorensen indices of species diversity. However, we found that total cover of all plant species was greater in aid growth rich coves, and that 10% of the tested species had lower abundance in second growth. No species were present in old growth and absent in second growth, but species with lower second growth abundance may warrant future study. [ABSTRACT FROM AUTHOR]

Resin flow is the primary means of natural defense against southern pine beetle (Dendroctonus frontalis Zimm.), the most important insect pest of Pinus spp. in the southern United States. As a result, factors affecting resin flow are of interest to researchers and forest managers. We examined the influence of fertilization, artificial wounding and fungal inoculation on resin flow in 6- and 12-year-old stands of loblolly pine (Pinus taeda L.) and determined the extent of that influence within and above the wounded stem area and through time. Fertilization increased constitutive resin flow, but only the younger trees sustained increased resin flow after wounding and inoculation treatments. An induced resin flow response occurred between 1 and 30 days after wounding and inoculation treatments. Wounding with inoculation resulted in greater resin flow than wounding alone, but increasing amounts of inoculum did not increase resin flow. Increased resin flow (relative to controls) lasted for at least 90 days after wounding and inoculation. This increase appeared to be limited to the area of treatment, at least in younger trees. The long-lasting effects of fungal inoculation on resin flow, as well as the response to fertilization, suggest that acquired resistance through induced resin flow aids in decreasing susceptibility of loblolly pine to southern pine beetle. [ABSTRACT FROM AUTHOR]

Historically, fire and the southern pine beetle (Dendroctonus frontalis) have interacted in a manner that maintains the stability of pine-dominated forests in the southern Appalachians. Fire suppression has recently been implicated in the disruption of the integrity of these forests and their shift toward hardwood dominance. This study examined the influences of fire and southern pine beetle infestation on stand structure and resin flow of pines in pine-dominated forests in the Linville Gorge Wilderness of North Carolina. Resin flow in most pine species increases in response to various types of wounding and is a pine tree's primary defense against insect pathogens. Pine-dominated stands in this study decreased in both basal area and density after exposure to fire and/or southern pine beetle infestation. Decreases in basal area and density of Pinus pungens were strongly associated with infestation, while decreases in Pinus rigida were influenced primarily by exposure to fire. Resin flow was substantially higher in trees that were exposed to fire, but not infested, than in trees experiencing any other combination of fire exposure and infestation (including trees that were neither exposed to fire nor infested). This elevated resin flow was still present 18 mo after burning. Since resin flow is the primary means of host defense against southern pine beetle, it is suspected that fire could confer an acquired resistance to future southern pine beetle infestations through elevated resin flow. [ABSTRACT FROM AUTHOR]

This study reports on a three-semester model project designed to assess the impact of enriched content related to Women's and Gender Studies on students enrolled in an undergraduate ecology course. The two constructs of interest were (a) students' attitudes toward women in science and society and (b) students' assessment of the classroom climate for women. The data included 398 matched pretest and posttest survey responses from a control group, a minimal enrichment group, and an increased enrichment group. Findings indicated that, although small course revisions did not influence students' attitudes toward women in science and society, such revisions had a positive influence on students' assessments of the classroom climate. [ABSTRACT FROM AUTHOR]

Exotic species research has generated several paradigms about the effects of invasion on native ecosystems and the site characteristics that promote invasibility. We are interested in translating these theoretical paradigms into management recommendations. Using vegetation surveys of urban riparian forests in central North Carolina, we tested the competition and resource availability paradigms. We assessed the association between exotic and native species and identified potential resources that promote invasion. Exotic and native species richness was negatively correlated (r = -0.66, p = 0.0009), conforming to the predictions of the competition paradigm. In particular, native woody species were negatively associated with several exotic growth forms. Two of the most common exotic species, Hedera helix (English ivy) and Microstegium vimineum (Japanese stilt grass), did not co-occur with several native woody plants, suggesting that they may preclude the establishment and regeneration of native woody plant communities. Our results have less direct implications for the resource availability paradigm. There were no correlations between light availability (indexed by canopy cover) and either cover or richness of exotic species. However, exotic species richness was generally positively correlated to soil fertility. These results suggest that the competition and resource availability paradigms are useful for understanding the dynamics of urban riparian forests that are invaded by a suite of exotic species. Removal efforts should focus on two of the most common invasive plants, H. helix and M. vimineum, and native woody plants should be re-established. While soil fertility is difficult to manage at a site level, we urge managers to lobby for strict regulations on nutrient inputs from upstream and adjacent development. [ABSTRACT FROM AUTHOR]

Although the rate that species accumulate with area has long been regarded as an important component of fine-scale community structure and several studies have examined this rate in meta-analyses, few if any studies have systematically examined fine-scale species-area relationships using a consistent survey protocol over a large region. We examined fine-scale species-area relationships using the extensive database of the Carolina Vegetation Survey (North Carolina, South Carolina, Georgia, and Tennessee, USA), including 1472 plots wherein vascular plant richness was recorded for each of six subplot sizes regularly spaced on a log10 scale, from 0.01 to 1000 m². Contrary to prevailing theory, our data closely and consistently fit an Arrhenius (power law) species-area model, echoing broader-scale patterns. Species accumulation rate (Z) values fell within a narrow range (95% between 0.2 and 0.5) despite a 30-fold range in 1000-m² richness. When we added regional- and global-scale richness estimates to our results, a Preston-type triphasic curve emerged. We suggest that (1) fine-scale species-area relationships are remarkably consistent and (2) full-scale species-area curves reveal scale dependencies in diversity data that are not accounted for by current species-area theory. [ABSTRACT FROM AUTHOR]

Recent scholarship about women and science is a good source of material for addressing the under-representation of women in science. This review is the result of an interdisciplinary fusion of science and women's studies to critically assess teaching tools in undergraduate ecology education. We examine: (1) the representation of women and the coverage of social and cultural context in introductory ecology textbooks, and (2) student learning about women's contributions to ecology. Discipline demographics reveal that women are presented in textbooks less often than expected, and that explicit discussions of the social and cultural context of science are rare. When course content is enriched with material about women's contributions, student's awareness of women scientists improves. Such knowledge can play a critical role in proactively challenging students' perceptions of ecology and ecologists, creating a more positive classroom climate for all students, and introducing novel avenues of questioning and discovery. [ABSTRACT FROM AUTHOR]

We examined factors likely to be important in management of rare flora of the long-leaf pine-wiregrass ecosystem on Fort Bragg and Camp Mackall Military Reservations in North Carolina, USA. We documented 1,268 occurrences of thirty-six rare plant species during two inventories conducted from 1991 to 1993 and 1998 to 1999. Of these occurrences, 891 (70.3%) persisted, 258 (20.3%) went extinct, and 119 (9.4%) colonized between the first and second inventories; extinctions exceeded colonizations by 139 occurrences. We used analyses of contingency table frequencies and logistic regressions to test hypotheses about temporal responses of local occurrences of rare flora. We found statistically significant effects of fire frequency on the colonization and extinction of rare flora; extinctions declined and colonizations increased with increasing fire frequency. There were statistically significant effects of both area occupied and stem number on the persistence and extinction of rare flora; extinctions declined and persistences increased with increasing area occupied and stem number. Our analyses emphasize the importance of fire and population size for the conservation of rare flora in this landscape. [ABSTRACT FROM AUTHOR]

In the southeastern USA, harvest of pine straw sometimes involves mechanical raking of natural Pinus palustris (longleaf pine) communities. Little is known about the effects of raking nor how these effects may vary in time and space. In a two yr experiment, we examined the effects of mechanized raking on Pinus palustris dominated communities (scrub oak, dry savanna, and mesic savanna) by monitoring vegetation at seven spatial scales (0.01-100 M²). We measured floristic similarity and the proportion of species initially present that were gained (i.e. new species) or lost during four sampling periods. Relationships between spatial scale and these community attributes were analyzed using a repeated measures approach and functional response curves. Spatial scale clearly affected observed rates of species loss and floristic similarity; losses declined and floristic similarity increased as scale increased. We relate these patterns to expanding population sizes with scale and our inability to detect species reductions in large populations. Scale had little influence on species gains. The effects of raking did not differ across scales, but raking caused greater mean losses of species and greater mean changes in floristic similarity when mean values were calculated over all scales. Raking also increased the mean rate of species gains in the mesic savanna during one period. Otherwise, interaction effects of community and raking were largely absent from both mean values and response curves. Despite significant short-term effects of raking, changes in species richness were minor. [ABSTRACT FROM AUTHOR]

Presents information on a study which assessed genetic discontinuity and variability of chloroplast microsatellite loci in eastern North American Abies using fluorescent DNA fragment analysis. Experimental procedures; Results and discussion.

BSTRACT: Weighted averages (WA) was investigated as a vegetation-based method for wetland designation, to be used in conjunction with the wetland indicator status of plants from Wetland Plants of the United States of America 1986 (Reed, 1986). Ecological indices were assigned to indicator groups and were used to compute weighted averages for quantitative data obtained from four studies of wetland vegetation conducted in various regions of the United States. Weighted averages of vegetation data proved to be a useful tool for assessing wetland status of the vegetation types included in our study: (1) rankings of vegetation stands or types by WA correlated well with their positions on environmental moisture gradients; and (2) the results of WA could be used, together with a wetland/upland break-point, to designate vegetation types as wetland or upland in a way that agreed well, in three of the four studies, with an alternative classification of wetland habitats. The variation of weighted averages among the sampling units representing a vegetation type was generally small relative to the range of ecological indices assigned. However, designations based on weighted average scores close to the break-point should be considered provisional and must be verified with supplementary data on soils and hydrology. [ABSTRACT FROM AUTHOR]

Gradient analysis was employed to determine vegetation pattern in relation to environment on limestone and granite in the Mule Mountains, Cochise County, Arizona, USA, using data obtained from 175 0.1-ha (20 x 50 m) quadrats located over ranges of elevation and topographic position. Sequences of major community types from mesic to xeric positions on the mountain slopes were pygmy conifer-oak scrub, open oak woodland, and desert grassland on granite and Cercocarpus breviflorus scrub, mesic phase Chihuahuan desertscrub, and xeric phase Chihuahuan desertscrub on limestone. Calcareous bajadas (alluvial plains) southwest of the Mule Mountains support a disturbed Chihuahuan desertscrub type. An environmental scalar was developed to quantify site position along complex-gradients of elevation and topographic position. The scalar was correlated with indirect ordination axes from reciprocal averaging, principal components analysis, and Wisconsin polar ordination. Over similar ranges of elevation and topographic position, granitic sites have higher species richness, greater importance of herbaceous and arborescent species, and lower importance of shrubby species than limestone sites. Both rock types support vegetation rich in widely distributed southwestern species but the vegetation on limestone has a distinctly Chihuahuan character, while that on granite is Madrean. Investigation of species distributions indicated a modal shift toward more mesic environments on limestone as compared to granite. This shift complemented other observations which suggested more xeric conditions on limestone. The low-elevation plant communities on limestone represent the northwesternmost occurrence of the Chihuahuan Desert formation. This may be due to three factors: (1) limestone habitats are arid (as judged from observations of vegetation); (2) increased aridity favors desert species, but the local climate (particularly cool winter temperatures) selects for Chihuahuan, rather than Sonoran, species; and (3) among desert species the Chihuahuan are better adapted to calcerous soils, which occur widely in the Chihuahuan Desert. [ABSTRACT FROM AUTHOR]

An obituary for ecologist and professor Ernest Davis Seneca is presented.

A letter to the editor is presented in response to a previously published article which comments on how current undergraduate ecology text books portray the role of women scientists.