Southern Appalachian Research Articles

Subduction initiation recorded in the Dadeville Complex of Alabama and Georgia, southeastern United States

Abstract The Dadeville Complex of Alabama and Georgia (southeastern United States) represents the largest suite of exposed mafic-ultramafic rocks in the southern Appalachians. Due to poor preservation, chemical alteration, and tectonic reworking, a specific tectonic origin for the Dadeville Complex has been difficult to deduce. We obtained new whole-rock and mineral geochemistry coupled with zircon U-Pb geochronology to investigate the magmatic and metamorphic processes recorded by the Dadeville Complex, as well as the timing of these processes. Our data reveal an up-stratigraphic evolution in the geochemistry of the volcanic rocks, from forearc basalts to boninites. Our new U-Pb zircon crystallization data—obtained from three amphibolite samples—place the timing of forearc/protoarc volcanism no later than ca. 467 Ma. New thermobarometry suggests that the Dadeville Complex rocks subsequently experienced deep, high-grade metamorphism, at pressure-temperature conditions of >7 kbar and >760 °C. The data presented here support a model for formation of the Dadeville Complex in the forearc region of a subduction zone during subduction initiation and protoarc development, followed by deep burial/underthrusting of the complex during orogenesis.

Black Appalachia's Oldest Old: Untold Stories of Experienced Racism and Coping With Religious Practices/Beliefs.

Racism and religion are recognized as prevailing Social Determinants of Health (SDoH). To explore ways in which racism and religion looms in the daily lives of African Americans, we analyzed the experiences of African Americans born during the Jim Crow years and living in the Southern Appalachian Region of the United States. Twenty-seven African Americans participated in this qualitative descriptive study that utilized criterion sampling, open-ended semistructured interviews, and content analysis to identify a typology of categories related to experienced racism and ways in which religion was used in response to those experiences. Participants were an average age of 82.22 years (SD = 5.07); primarily women (n = 19, 70.4%); married (n = 11, 40.7%); junior high school (n = 6, 22.2%), high school or general educational diploma (n = 7, 25.9%), completed college or professional school (n = 6, 22.2%); were retired (n = 27, 100.0%); and affiliated with Baptist churches (n = 18, 66.7%). Experiences with racism included inequities in healthcare and education, and racially motivated physical violence. Religious practices/beliefs included forgiveness, humility, and humanity. Racism experienced by African American participants was likely countered by religious practices/beliefs inspired through intergenerational teachings with affiliations to the Black Church. These experiences of the oldest old ) African Americans living in communities of the Southern Appalachia, United States, illustrate the pervasive nature of racism. The religious beliefs that are frequently transmitted intergenerationally through the Black Church are relevant to understand present-day encounters with racism among African Americans and possibly other communities of color.

The Manhattan project: Isotope geochemistry and detrital zircon geochronology of schists in New York City, USA

The geology of New York City (USA) consists primarily of metasedimentary rocks that were deformed during the series of orogenies between ca. 470 Ma and ca. 300 Ma that culminated in the amalgamation of Pangea. The rocks in New York City play a key role in understanding the tectonic history of these orogenies because they lie at a critical location at the boundary between the Northern and Southern Appalachian Mountains. The primary question addressed here is where these metasedimentary rocks originated prior to the assembly of Pangea. Through detrital zircon and whole-rock Nd isotope analyses, we show that all the metasedimentary rocks of New York City, mapped as the Manhattan Schist and the Hartland Group, are primarily derived from Laurentia as indicated by detrital zircon populations dominated by 1200−900 Ma grains and εNd values between −7 and −13. The results presented here do not necessitate an exclusively Laurentian source for the detrital material found in New York City, but the data strongly suggests protoliths represent sedimentary units that are primarily derived from the Laurentian margin. Another important result from this study is the limited contributions from any rift volcanics and/or Gondwanan material(s). There is some subtle variability across our zircon sample suite, but there is no convincing evidence for major changes in bulk provenance signal that would be consistent with derivation from vastly different continental sources for these rocks. The shared provenance signal observed here is counter to the previous suggestions that a major terrane boundary, often called Cameron’s Line, exists in New York City, separating Laurentian rocks from those of a Gondwanan affinity.

Postglacial phylogeography, admixture, and evolution of red spruce (Picea rubens Sarg.) in Eastern North America.

Climate change is a major evolutionary force that can affect the structure of forest ecosystems worldwide. Red spruce (Picea rubens Sarg.) has recently faced a considerable decline in the Southern Appalachians due to rapid environmental change, which includes historical land use, and atmospheric pollution. In the northern part of its range, red spruce is sympatric with closely related black spruce (Picea mariana (Mill.) B.S.P.), where introgressive hybridization commonly occurs. We investigated range-wide population genetic diversity and structure and inferred postglacial migration patterns and evolution of red spruce using nuclear microsatellites. Moderate genetic diversity and differentiation were observed in red spruce. Genetic distance, maximum likelihood and Bayesian analyses identified two distinct population clusters: southern glacial populations, and the evolutionarily younger northern populations. Approximate Bayesian computation suggests that patterns of admixture are the result of divergence of red spruce and black spruce from a common ancestor and then introgressive hybridization during post-glacial migration. Genetic diversity, effective population size (Ne) and genetic differentiation were higher in the northern than in the southern populations. Our results along with previously available fossil data suggest that Picea rubens and Picea mariana occupied separate southern refugia during the last glaciation. After initial expansion in the early Holocene, these two species faced a period of recession and formed a secondary coastal refugium, where introgressive hybridization occurred, and then both species migrated northward. As a result, various levels of black spruce alleles are present in the sympatric red spruce populations. Allopatric populations of P. rubens and P. mariana have many species-specific alleles and much fewer alleles from common ancestry. The pure southern red spruce populations may become critically endangered under projected climate change conditions as their ecological niche may disappear.

Natural area visitors’ willingness to pay for amphibian conservation in a global biodiversity hotspot

Transfer of harmful pathogens from imported pet animals to natural populations of wildlife is a new challenge in protected area management. Understanding visitors’ preferences for, and value they place on, protecting biodiversity from such disturbances is important in developing effective management interventions. By conducting a visitor survey at two natural areas in the Southern Appalachian region of the United States, a global hotspot of amphibian biodiversity, this study examined natural area visitors’ willingness to pay (WTP) to conserve wild amphibian populations under two different assumptions for the distribution of WTP – normal and log-transformed. Results from the retained model assuming a normal distribution for WTP showed that visitors were willing to pay US$10.55 (95% CI US$9.61—US$11.50) per visit in donation to ensure the persistence of healthy amphibian populations. Determinants of individual WTP under both model specifications included the perceived threat to amphibians from pathogen transmission in natural areas they visit, their self-assessed familiarity with general knowledge about amphibians, the level of importance they placed on the benefits to humans from amphibian biodiversity, and annual household income. These findings are useful in understanding the economic value of amphibian diversity to natural area visitors, and in assessing the viability of a visitor-supported mechanism to fund projects mitigating anthropogenic threats to amphibian biodiversity.

Acute Health Effects of Wildfire Smoke Exposure During a Compound Event: A Case-Crossover Study of the 2016 Great Smoky Mountain Wildfires.

In 2016, unprecedented intense wildfires burned over 150,000 acres in the southern Appalachian Mountains in the United States. Smoke from these fires greatly impacted the region and exposure to this smoke was significant. A bidirectional case-crossover design was applied to assess the relationship between PM2.5 (a surrogate for wildfire smoke) exposure and respiratory- and cardiovascular-related emergency department (ED) visits in Western North Carolina during these events. For 0-, 3-, and 7-day lags, findings indicated a significant increase in the odds of being admitted to the ED for a respiratory (ORs: 1.055, 95% CI: 1.048-1.063; 1.083, 1.074-1.092; 1.066, 1.058-1.074; respectively) or cardiovascular event (ORs: 1.052, 95% CI: 1.045-1.060; 1.074, 1.066-1.081; 1.067, 1.060-1.075; respectively) for every 5μg/m3 increase in PM2.5 over a chosen cutpoint of 20.4μg/m3. For all endpoints assessed except for emphysema, there were statistically significant increases in odds from 5.1% to 8.3%. In general, this increase was most pronounced 3days after exposure. Additionally, individuals aged 55+ generally experience higher odds of heart disease at the 3- and 7-day lag points, and Black/African Americans generally experience higher odds of asthma at the 3-day lag point. In general, larger fires and increased numbers of fires within counties resulted in higher health burden at same day exposure. In a secondary analysis, the odds of an ED visit increased by over 40% in several cases among people exposed to days above the Environmental Protection Agency 24-hr PM2.5 standard of 35μg/m3. Our findings provide new understanding on the health impacts of wildfires on rural populations in the southeastern US.

Habitat niche dynamics of the sicklefin redhorse: a southern Appalachian Mountain habitat specialist

AbstractHistorically, suckers (Catostomidae) have been largely neglected in conservation efforts. Due to pervasive lotic habitat degradation and loss throughout North America, sucker habitat knowledge is urgently needed for conservation. The sicklefin redhorse (Moxostoma sp.) is an undescribed, imperiled sucker, endemic to a small geographic range in the southern Appalachian Mountains (USA). We described adult sicklefin redhorse seasonal and spawning microhabitat suitability, quantified spawning substrate composition, identified seasonal and spawning habitat niches (i.e., macrohabitats), and characterized foraging habitat. We combined radiotelemetry and visual observations of Hiwassee River basin adult sicklefin redhorses during March–January (2006–2008) to address our objectives. Sicklefin redhorses occupied seasonal and spawning microhabitats non-randomly, and we developed season- and spawning-specific habitat suitability criteria (HSC) using a Bayesian approach. Adult sicklefin redhorses occupied habitats with swift midchannel currents, moderate depths, and coarse substrates supporting hornleaf riverweed (Podostemum ceratophyllum). In contrast, suitable spawning sites were located in near-bank shallow depths, slow currents, over intermediate-sized substrates near cover, but free of riverweed. Annually, principal component analyses indicated that sheet and run macrohabitats were predominantly occupied, while pocket-water riffles near depositional, edgewater zones provided spawning sites. Spawning substrate composition was predominantly small cobble (40.9%) and very coarse gravel (21.3%), but fines (3.0%) were also prevalent within interstitial spaces. Mean Fredle index was 28.2, indicating spawning substrate permeability at half potential. Annually, bedrock covered with hornleaf riverweed was the dominant foraging substrate. Our adult sicklefin redhorse annual, seasonal, and spawning HSCs, multivariate habitat niche characterizations, spawning substrate analyses, and foraging habitat descriptions can guide habitat conservation and restoration throughout the species’ geographic range.

Seasonal and sex-specific changes in the gastrointestinal tracts of Peromyscus maniculatus.

Functional traits are phenotypic characteristics that contribute to fitness of individuals in dynamic and changing environments. In mammals, both categorical and continuous (e.g., quantitative) functional traits have been extensively utilized as proxies for diet, locomotion, and other aspects of species ecology, but there has been less focus on form and function of soft tissues. This is particularly true for the digestive system, which varies in size and complexity across Class Mammalia and plays a major role in the energetics of species. To guide more effective utilization of gastrointestinal (GI) morphology as a functional proxy in small mammal ecology, we examined how GI tracts (lengths and masses of four GI sections) varied within a population of deer mice (Peromyscus maniculatus) in the Southern Appalachian Mountains of North Carolina, United States. We collected samples of adult P. maniculatus monthly for 1 year and measured GI tracts to quantify variation with respect to seasonality and trophic level, providing insight into plasticity in this soft tissue trait over time. We found that season had a significant effect on the total length and wet mass of the GI tract, with January mice having the longest GI tracts and lengths being shortest in the summer. The relative shortening of the GI tract in summer corresponded with a partial trophic increase detected by stable isotope signatures. GI length and wet mass also were affected by reproduction, but males and females responded in sex-specific ways to demands of reproduction, with reproductively active males having shorter and lighter GI tracts than nonreproductively active males. Our study provides proof-of-concept for understanding population-level plasticity in a rarely collected soft tissue trait, which may also be complementary to standard craniodental measurements as a functional dietary proxy to understand mammalian ecology and community assembly.

Examining how risk diversification for conservation is influenced by the probability assigned to uncertainty scenarios

SummaryDespite the progress in conservation risk management, conservation organizations are reluctant to interface usable risk-diversification strategies with their decision-making processes. One reason for this reluctance is that the empirical models used to develop risk-diversification strategies need the expected returns on investment (ROIs) of target assets and their variances and covariances, and the probabilities of occurrence of the scenarios needed to calculate those statistics are almost always unknown. We examine how risk diversification for conservation is influenced by the probabilities assigned to uncertainty scenarios using a case study involving the conservation of biodiversity at the county level in the central and southern Appalachian region within the framework of modern portfolio theory. A comparison of risk-mitigating portfolios with bootstrapped and fixed probability distributions shows that introducing the flexibility of an unknown probability distribution of uncertainty scenarios allows conservation organizations to spread bets more than with the inflexibility of the fixed probability distribution, while also achieving higher expected ROIs per unit of risk on average. The improvement becomes more significant when conservation organizations are less risk averse.

The Heterogeneity of Social Network and Institutional Covariance in the American Southeast

AbstractSocial, political, and economic institutions covary with one another in heterogenous ways across space and time. Social Network Analysis (SNA) offers a set of analytical tools and conceptual frameworks that have allowed for formal comparisons of interactions, affiliations, and relationships in reconstructing historical trajectories of institutional change. Although archaeologists have made full use of a range of metrics that describe the structural variation of social networks, formal approaches to analyzing the covariance of networks, and the institutions that structured networks in the past, remain undertheorized. In most cases, descriptive metrics are compared between networks built from different datasets or networks separated in time. Using quadratic assignment procedure (QAP) correlations to compare matrices of archaeological data, I draw on a ceramic dataset of approximately 350,000 sherds from the Southern Appalachian region to investigate how decisions related to manufacture choice and to stylistic design covaried with one another between roughly AD 800 and 1650. I explore how material attributes may or may not vary independently of one another and what that means for our analyses of the institutions they reflect. The results contribute to broader comparative analyses of institutional change and perennial discussions of social evolution.

Evaluating Informal Science Education Centers in the Southern Appalachians

abstract: The southern Appalachian region is a hotspot of ecological biodiversity that is under increasing threat from climate change and rapid population growth. We posit that informal science education is uniquely adapted to foster environmental stewardship in the region, but the current state of informal science education within the southern Appalachians is poorly understood. We reviewed current informal science education centers (ISECs), which we define as centers for science learning outside of structured curriculum ( n = 166). For each of these centers, we compiled information on geographical location, programs offered, and funding sources. We found large geographic gaps in ISEC coverage that often aligned with low-population, low-income counties. The most common program type in our dataset was field trips, followed by public programming, while research and virtual programming were the least often offered. ISECs that had funding from multiple organizations generally had the most diverse and robust programming.

White-tailed deer (Odocoileus virginianus) fawn survival and the influence of landscape characteristics on fawn predation risk in the Southern Appalachian Mountains, USA.

In the Southern Appalachian region of the United States, harvest data has indicated the occurrence of low deer densities while exposing a trend of declining white-tailed deer (Odocoileus virginianus) populations over the past several decades in northern Georgia. A triumvirate of increasing fawn predator populations reside in the Southern Appalachian Mountains including coyotes (Canis latrans), black bears (Ursus americanus) and bobcats (Lynx rufus). This region is also characterized by a homogenous landscape composed of mature forests and sparse understory vegetation, likely lacking adequate cover to offer fawns refugia from predators. Our objectives were to estimate survival and cause-specific mortality rates of fawns while assessing a possible link between mortality risk, intrinsic fawn characteristics (i.e., birth mass, Julian birth date, sibling status), and landscape features within fawn usage areas. During 2018-2020, we radio-collared 71 fawns within the Chattahoochee National Forest of northern Georgia, USA and monitored survival to 12 weeks of age. We observed low fawn survival (cumulative = 0.157, 95% CI = 0.091-0.273; vaginal implant transmitter = 0.196, 95% CI = 0.096-0.403) with predation as the leading cause of all known mortalities (45 of 55 mortalities; 82%) due primarily to coyotes (n = 22), black bears (n = 12), and bobcats (n = 7). Relationships between landscape features and fawn predation risk were minimal with only one informative covariate. Increasing amounts of early successional land cover within fawn usage areas decreased fawn mortality risk within the first 20 days of life, but elevated mortality risk thereafter. All fawns with any amount of early successional land cover in their usage areas died of predation (n = 13) at various time intervals, suggesting limited areas of potential fawning cover may be targeted by predators. However, fawn predation risk seemed to be high regardless of landscape covariates due to the limited number of surviving fawns. Coyote-caused mortality occurred over a longer period at a consistently higher magnitude than all other forms of mortality, indicating possible delayed prey-switching behavior and coyote predation as an important factor of fawn survival. The low recruitment of fawns influenced by high predation rates and homogenous habitat conditions is likely the cause of deer population declines in the region.

Silvicultural canopy gaps improve health and growth of eastern hemlocks infested with Adelges tsugae in the southern Appalachian Mountains

The hemlock woolly adelgid (HWA, Adelges tsugae Annand) is an invasive forest insect threatening the sustainability of eastern hemlock (Tsuga canadensis (L.) Carrière) in eastern North America. In this study, cutting small gaps in the forest canopy above understory eastern hemlocks was evaluated as a potential tool for use in the integrated pest management of HWA. Two gap sizes and two gap creation methods (felling vs. girdling trees) were assessed for effects on HWA density, hemlock crown health, hemlock growth, and regeneration of competing tree species, at three different latitude groups in the southern Appalachian Mountains. In all three latitude groups, the treatment that removed the most canopy competition (Large Fell) increased the production of new hemlock shoots, reduced the percentage of dead shoots, and increased basal area increment of target hemlocks relative to unreleased trees. Smaller gaps and those that removed fewer competing live trees (Girdle treatments) also improved hemlock health in the southernmost latitude group. Positive effects of canopy gaps on hemlock crown condition and growth occurred despite similar or higher HWA densities on gap-released vs. unreleased trees. In regression analysis, more than half the variability in crown transparency change and basal area growth post-treatment was explained by the competition index of live trees remaining, average HWA density index, and tree size (dominant tree height and hemlock dbh). In the southernmost latitude group, the regeneration density of deciduous species increased significantly in the three years following gap creation and were highest in the Large Fell treatment. Results support the hypothesis that the increased availability of sunlight (and possibly other limited resources) resulting from canopy gaps (radius approximately ¼ to ½ dominant tree height) improves the physiological tolerance of eastern hemlock to HWA infestation and could complement biological control by providing a more stable source of new shoots with adelgid prey for predatory insects.

The Variscan belts of North-West Africa: An African legacy to the Wilson Cycle concept

The concept of cyclic closure and opening of oceans along the same crustal scar was introduced by J.T. Wilson (1966) based on the example of the Atlantic Ocean and its continental borders. At that time, the only Variscan orogen cited south of Europe along the Atlantic coast of Africa was the Mauritanides of Mauritania. Here we report on the recent achievements in the Mauritanides from Mauritania to Morocco, and on the Moroccan Meseta orogen, which also records the Variscan orogeny. The Southern and Central Mauritanides are a poly-orogenic, Pan-African and Variscan orogen characterized by a thin-skinned tectonic style that mirrors the structure of the southern Appalachians, but with a different tectonic history. The Northern Mauritanides crops out in the Moroccan Oulad Dlim massif, northwest of the Reguibat Rise. This part of the belt compares with the southern part, but additionally exhibits in the west a Silurian-Devonian sector that shows possible affinities with Gondwana-derived Appalachian terranes. The Western Meseta is only affected by Variscan events, which were mild in the westernmost Meseta Coastal Block, while the Eastern Meseta was also affected by Eo-Variscan events. The along-strike change from the Mauritanides to the Meseta orogen is interpreted as a transition from a head-on collision south of the South Meseta transform fault (SMF, precursor of the South Atlas Fault, SAF) to a dextral, transpressional collision north of the SMF. South of the SAF, the Anti-Atlas and the Dhlou-Zemmour expose the foreland foldbelts of the Meseta and northernmost Mauritanides. The Coastal Block was likely displaced from the south-westernmost Anti-Atlas during the Early Carboniferous.The Wilson Cycle concept mostly applied in that the Atlantic Ocean opened where the prior Rheic Ocean had closed. Possible exceptions are the Sehoul Block north of Western Meseta and the Silurian-Devonian Sector of the Oulad Dlim massif, which may have separated from NW-Africa and re-amalgamated to it during the Variscan orogeny. Likewise, a NW-African fragment from the Anti-Atlas may have stranded in offshore Massachusetts in eastern North America. An early Ediacaran-Cambrian Wilson cycle nested in the classic cycle introduced by Wilson (1966) occurred along the margin of NW-Africa, where Cadomian terranes rifted off Africa, and some were transferred to Europe and some accreted back to NW-Africa. This early cycle likely controlled the localization of the subsequent Rheic rift, and that of the Atlantic rift along the Mauritanides after the Variscan collision.

Soil Respiration and Related Abiotic and Remotely Sensed Variables in Different Overstories and Understories in a High-Elevation Southern Appalachian Forest

Accurately predicting soil respiration (Rs) has received considerable attention recently due to its importance as a significant carbon flux back to the atmosphere. Even small changes in Rs can have a significant impact on the net ecosystem productivity of forests. Variations in Rs have been related to both spatial and temporal variation due to changes in both abiotic and biotic factors. This study focused on soil temperature and moisture and changes in the species composition of the overstory and understory and how these variables impact Rs. Sample plots consisted of four vegetation types: eastern hemlock (Tsuga canadensis L. Carriere)-dominated overstory, mountain laurel (Kalmia latifolia L.)-dominated understory, hardwood-dominated overstory, and cinnamon fern (Osmundastrum cinnamomeum (L.) C. Presl)-dominated understory, with four replications of each. Remotely sensed data collected for each plot, light detection and ranging, and hyperspectral data, were compiled from the National Ecological Observatory Network (NEON) to determine if they could improve predictions of Rs. Soil temperature and soil moisture explained 82% of the variation in Rs. There were no statistically significant differences between the average annual Rs rates among the vegetation types. However, when looking at monthly Rs, cinnamon fern plots had statistically higher rates in the summer when it was abundant and hemlock had significantly higher rates in the dormant months. At the same soil temperature, the vegetation types’ Rs rates were not statistically different. However, the cinnamon fern plots showed the most sensitivity to soil moisture changes and were the wettest sites. Normalized Difference Lignin Index (NDLI) was the only vegetation index (VI) to vary between the vegetation types. It also correlated with Rs for the months of August and September. Photochemical reflectance index (PRI), normalized difference vegetation index (NDVI), and normalized difference nitrogen index (NDNI) also correlated with September’s Rs. In the future, further research into the accuracy and the spatial scale of VIs could provide us with more information on the capability of VIs to estimate Rs at these fine scales. The differences we found in monthly Rs rates among the vegetation types might have been driven by varying litter quality and quantity, litter decomposition rates, and root respiration rates. Future efforts to understand carbon dynamics on a broader scale should consider the temporal and finer-scale differences we observed.

Comparing passive and active macroinvertebrate sampling gear efficacy during biomonitoring in Southern Appalachian mountain streams

AbstractAquatic invertebrates are important components of any aquatic ecosystem and are frequently monitored to determine the ecological integrity of those systems. Various gear types are used to collect aquatic macroinvertebrates in wadeable streams. We analyzed commonly used active and passive gear types, including kick seines, Hess samplers, drift nets, and Hester–Dendy samplers, across a watershed in the Great Smoky Mountains National Park to determine their efficacy under various habitat conditions in wadeable Southern Appalachian mountain streams. Hester–Dendy samplers were significantly different from other gear types for most univariate and multivariate analyses. Kick and Hess samples were most similar in multivariate comparisons of macroinvertebrate assemblages. Drift samples were similar in most univariate analyses but were distinct from other gear types when analyzed with multivariate techniques. Our results indicate that comprehensive assessments of macroinvertebrate assemblages require multiple gear types, various analytical approaches, and consistent taxonomic resolution. The complexity of the fluvial system in question should be thoroughly assessed prior to formulating a macroinvertebrate biomonitoring protocol to better ensure robust and meaningful results.

Acorn production, climate, and tree-ring growth of five oak species in southern Appalachian forests

Oak (Quercus) are a dominant and important tree genus in the Central Hardwood Region (USA) due to their commercial timber value, and food value of their protein-rich seed – acorns – to wildlife. Acorn production is characteristic of masting, with highly variable crop sizes that are synchronized within populations, but with consideration variation among individual trees. Critical to acorn masting studies are longitudinal datasets, which are often difficult to maintain due to a host of constraints. One possible approach to extending mast datasets involves the use of dendrochronology, where tree-ring-width variability serves as a proxy for annual acorn production. In this study, we addressed the future utility of mast reconstructions by examining relationships between acorn production, climate, and tree-ring data from five common oak species in southern Appalachian hardwood forests (Bent Creek Experimental Forest). We found little evidence to suggest that acorn production influences seasonally resolved tree-ring data, even when we considered early and latewood growth separately, or when we analyzed trees with substantially higher overall investment in acorn production (i.e., super producers). Monthly climate (temperature, precipitation) correlated to acorn production was strongest when lagged, which could indicate weather conditions were more important for phases of flower production and fertilization than acorn maturation. However, relationships were relatively weak, indicating limited potential for the forecasting of acorn crops, or for reconstruction methods that combine observed weather data and tree-ring responses to masting. Overall, our findings provide some support for the role of resource dynamics in regulating masting in oaks, but relationships between radial growth and acorn production are not sufficiently strong, at least in this location, to permit tree-ring based reconstruction of masting in these oak species.

Assessing golden‐winged warbler dispersal habitat in a highly parcelized landscape

AbstractGolden‐winged warblers (Vermivora chrysoptera) are facing population declines in the southern Appalachian Mountains. Breeding habitat loss is considered one of the primary reasons for golden‐winged warbler declines in the region. Expanding breeding habitat availability in a manner that promotes population expansion across an interconnected network of habitat patches is particularly problematic in a landscape dominated by private land ownership. We assessed the connectivity of golden‐winged warbler breeding habitat in a 29,680‐ha landscape with 5,664 ownership parcels between 2 state‐owned game lands in northwestern North Carolina, USA, in fall 2021. We created a connectivity map and provided examples of 3 means of prioritizing parcels for golden‐winged warbler habitat maintenance and management based on dispersal distances of fledglings that could return the following spring with prior familiarity of potential nesting areas. Prioritized parcels can guide land acquisition and conservation easement development as well as active management. Despite being highly parcelized, the area has both well‐connected and disjointed clusters of core habitat patches, but habitat management on privately owned parcels would be needed to connect core habitat patches to enable dispersing golden‐winged warbler fledglings to encounter potential breeding habitat that they could use the following spring.

Hiding in the Arctic and in mountains: a (dis)entangled classification of Claxtonia (Heterotardigrada: Echiniscidae)

Abstract Numerous evolutionary lineages representing an armoured, limno-terrestrial family Echiniscidae are restricted to high mountainous or polar localities, exhibiting clear cold stenothermic preferences. One such group is the genus Claxtonia, with its type species Claxtonia wendti, originally described from Svalbard and later on reported globally. In this paper, we re-describe this taxon by establishing the neotype from Spitsbergen. We sequenced five genetic markers (18S rRNA, 28S rRNA, ITS-1, ITS-2, and COI) for multiple populations of Claxtonia, including C. mauccii, C. molluscorum, C. wendti, and several potentially new species, collected in the Alps, Andes, Carpathians, Scotland, Iceland, Southern Appalachians, Spitsbergen, Scandinavian Peninsula, Borneo, and the West Indies. The relationships between these species are elucidated thanks to the phylogenetic reconstructions based on nuclear loci. Various Claxtonia species frequently co-occur in mosses and lichens, which hampers delineating their probable geographic ranges. All historical records of C. wendti are questioned in the light of our revision. Delineation of new species within the genus is nipped in the bud due to numerous problems with original species descriptions, unknown intraspecific (including ontogenetic) variability, and the lack of DNA barcodes. Finally, it is hypothesized that Claxtonia potentially comprises two lineages: a cold-stenothermic one and a thermophilic subtropical–tropical one.

Pityopsis ruthii: An Updated Review of Conservation Efforts for an Endangered Plant.

Pityopsis ruthii (Small) Small, Ruth's golden aster, is an endangered Asteraceae species that grows in the riparian zone along small sections of two rivers in the Southern Appalachian Mountains of the United States of America (USA). Since 1985, the species has been listed under the Endangered Species Act by the United States Fish and Wildlife Service (USFWS). The mission of the USFWS is to conserve, protect, and enhance fish, wildlife, and plants and their habitats for the continued benefit of the American people. The agency provides national leadership in the recovery and conservation of imperiled plant species by working with the scientific community to protect important habitats, increase species' populations, and identify and reduce threats to species survival with the goal of removal from federal protection. Over the past 35 years, research efforts have focused on studies designed to delineate the range and size of populations, determine habitat requirements, reproductive and propagation potential, and understand the demographic, ecological, and genetic factors that may increase vulnerability to extinction for P. ruthii. Cooperative partnerships have driven the completion of actions called for in the strategy to recover P. ruthii, and in this review, we highlight these efforts within the context of species conservation.