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Co‐occurrence between species may be mediated by ecological differences or competitive interactions, but the nature of these interactions can vary across spatial scales. At coarse scales, species may appear to broadly co‐occur, but at fine scales, particularly for species with small home ranges, species may utilize different aspects of the microhabitat such that co‐occurrence is limited and competitive interactions are reduced or eliminated. We investigated the microhabitat use of two morphologically and ecologically similar woodland salamanders (the Red‐backed Salamander, Plethodon cinereus, and the Northern Ravine Salamander, P. electromorphus) that are distributed throughout the Alleghany Plateau in eastern North America to determine whether they partition habitat at finer scales. We also tested if P. electromorphus is a specialist on habitat types that allow it to exclude P. cinereus, or if P. electromorphus uses lower quality habitat as a refuge to avoid P. cinereus. At a site of microsympatry, we repeatedly sampled plots during two seasons, each within a different area of the landscape, and used occupancy and abundance modeling to assess the extent of co‐occurrence and test whether the species use different microhabitat conditions. Plethodon cinereus greatly outnumbered P. electromorphus and occupied a greater proportion of plots, most plots where we detected P. electromorphus we also detected P. cinereus. In contrast to patterns documented in some montane species pairs, in which a high‐elevation habitat specialist excludes a low‐elevation generalist, we found that P. electromorphus primarily used microhabitat conditions favorable for both species, such as north‐facing slopes, yet did not have a negative effect on the abundances of P. cinereus. In the presence of an abundant competitor, microhabitat use of the less abundant species may narrow toward optimal conditions with sufficient resources to facilitate co‐occurrence. [ABSTRACT FROM AUTHOR]

Areas affected by forest fires are increasing worldwide, making salvage logging (i.e., harvesting fire-affected trees) an increasingly used practice to reduce the economic impacts of fire on forestry. However, salvage logging can have strong ecological impacts, notably on post-fire forest regeneration and biodiversity. Burn severity (i.e., the degree to which fires impact the vegetation and soil) is also a central element that interacts with pre-fire forest characteristics and salvages logging to control post-fire forest dynamics and biodiversity. In an ecosystem-based forest management context, spatial patterns of burn severity should thus be considered when planning salvage logging operations. This study presents a simple and innovative method to generate burn severity maps with Landsat and Sentinel-2 multispectral imageries to support salvage logging operations rapidly after a fire event. We assembled a unique dataset involving 330 plots from 10 burns (from 2010 to 2020) in which burn severity has been estimated on the field using the composite burn index (CBI) approach in eastern North America. CBI values were modelled as a univariate function of changes in spectral indices using the first cloud-free post-fire satellite images taken after the burns. Our results demonstrate that using free satellite images with straightforward methods can produce reliable and ecologically meaningful burn severity maps within the few weeks following a fire event. The method was then applied to a case study with salvage logging that illustrates how our burn severity maps could be a useful tool for guiding post-fire forestry operations in an ecosystem-based management context. We combined burn severity maps with pre-fire forest composition and age maps to assess immediate post-fire forest. We discuss how such an approach helps to guide salvage planning and maintain residual forests that are representative of the initial post-fire spatial variability in burn severity and pre-fire vegetation. We conclude that rapid mapping of burn severity after a forest fire event may offer many other applications for identifying and managing recently burned forests. • Interactions between salvage logging and burn severity control post-fire dynamics. • Unsalvaged residual forests should represent the variability in burn severity. • Free satellite imagery can rapidly produce burn severity maps after a fire event. • Such maps are powerful tool for guiding post-fire salvage logging operations. [ABSTRACT FROM AUTHOR]

Scientific models that guide restoration/management protocols should be reviewed periodically as new data become available. We examine ecological concepts used to guide restoration of pine savannas and woodlands, historically prominent but now rare habitats in the southern North American Coastal Plain. For many decades, pine savanna management has been guided predominantly by a biome-centric succession model. Pine savannas have been considered early-successional communities that, in the absence of fire, transition rapidly toward closed-canopy hardwood forests. Recurrent fires have been viewed as exogenous disturbances that maintain savanna ecosystems as a sub-climax, blocking succession to an equilibrium steady state (closed-canopy forests). Over recent decades, a vegetation-fire feedback model has emerged in which pine savannas are conceptualized as persistent, non-equilibrium communities maintained by endogenous, co-evolutionary vegetation-fire feedbacks. Endemic plant species are resistant to fires and specialized for post-fire conditions generated by frequent lightning fires, primarily within a distinct fire season. These species produce pyrogenic fine fuels that are easily ignited. The resulting fire regimes, entrained by these vegetation-fire feedbacks, are predicted to result in persistent pine savannas. Local variation over space and time in evolutionary feedback mechanisms between pyrogenic vegetation and fire regimes produces heterogeneous landscapes. Disturbances of these feedbacks, such as human fire suppression, are postulated to result in rapid transition to communities lacking feedback elements, such as closed-canopy forest and those without pyrogenic species. Succession-based management focuses on reversing the transition to forest, primarily by removing hardwoods and reintroducing fire as a disturbance. However, we advocate restoration and management approaches that target reinstitution of functional vegetation-fire feedbacks. Such approaches should favor native pyrogenic plant species and reinstitute fire regimes that mimic historical, evolutionarily derived fire regimes. Vegetation-fire feedback concepts should be useful in addressing resistance and resilience of fiery ecosystems worldwide to inherent changes in feedback mechanisms, constituting a framework useful in addressing global management challenges. [ABSTRACT FROM AUTHOR]

Native perennial grasses have potential as lowinput biomass feedstocks. Basin wildrye [Leymus cinereus (Scribn. & Merr.) Á. Löve] is the largest native grass in western North America but is susceptible to defoliation. Creeping wildrye [Leymus triticoides (Buckley) Pilg.] is a shorter less productive grass with durable rhizomes and higher forage quality. Two creeping wildrye pseudo-backcross populations derived from interspecific hybrids were used to identify quantitative trait loci (QTL) controlling plant height, rhizome spreading, flowering, postanthesis biomass yield, cellulosic fiber, lignin, and protein traits using a linkage map comprising 376 expressed sequence tags and 423 other DNA markers. Biomass yields of the F1 hybrids and pseudo-backcross populations were significantly greater than creeping wildrye with some genotypes nearly equal to or greater than basin wildrye. Rhizome spreading and forage quality of the creeping wildrye pseudo-backcross populations were significantly greater than basin wildrye. Six of nine plant height QTL overlap with biomass QTL. Three flowering QTL detected in both populations overlap with fiber QTL. Plant height and flowering QTL were aligned to genes controlling dwarfing, photoperiod response, and vernalization in wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) using the Brachypodium distachyon (L.) P. Beauv. genome reference sequence. Evidence suggests that genetic mechanisms controlling plant height and flowering are conserved among temperate grasses and reveals pathways for improving biomass production and forage quality. [ABSTRACT FROM AUTHOR]

Abstract: Delayed maturation and age-biased dispersal work in concert under past selection to maximize individual fitness and contribute to population viability; however, these life history attributes can become dysfunctional in a dynamic, anthropogenic landscape when important population demographics cannot redistribute in response to novel landscape change. We used long-term monitoring data to estimate age at maturity, potential longevity, survival, and fidelity for the declining eastern diamondback rattlesnake (EDB), Crotalus adamanteus. We used radio telemetry data and known-fate models to examine adult survival, and we combined mark-recapture and radio telemetry data to examine survival and fidelity using a combined recapture/recovery model. Monthly adult survival was higher during the active season (April–November; 99.5%) as compared to the inactive season (December–March; 96.3%), despite a higher probability of detecting human-caused mortalities during the active season. Rattlesnakes matured in 7.1years and potential longevity exceeded 20years. Fidelity estimates indicated mature EDBs had a low probability of dispersing from the study area, while younger, sexually immature individuals were more likely to emigrate. The combination of a slow life history and an ontogenetic shift in emigration suggests EDB life history limits the species’ ability to respond to landscape change, shedding further light on EDB imperilment. Management efforts will benefit from activities that maintain high adult survival. Furthermore, EDB fidelity should be considered in conservation plans, particularly in light of the species’ longevity, as these characteristics suggest that mature EDBs may not readily redistribute at the landscape scale in response to habitat degradation. [Copyright &y& Elsevier]

Basin wildrye [Leymus cinereus (Scribn. and Merr.) Á. Löve] and creeping wildrye [Leymus triticoides (Buckley) Pilg.] are native perennial grasses cultivated for seed used for fire rehabilitation and revegetation in western North America. Although L. cinereus produces large spike inflorescences with many seeds, it is prone to seed shattering. Seed can be harvested before shattering, but often displays poor germination and seedling vigor. Conversely, L. triticoides has fewer seeds per spike, but relatively strong seed retention. Both species are allotetraploid (2n = 4x = 28) and form fertile hybrids used for breeding and genetic research. A dominant, major-effect seed-shattering gene (SH6) from L. cinereus was previously identified in an L. triticoides backcross population. In this study, a DNA marker was used to select the recessive L. triticoides seed-retention allele (sh6) in cycle six (C6) of a L. cinereus × L. triticoides breeding population and evaluate gene × harvest date effects on seed yield and germination characteristics in a full-sib family derived from homozygous (sh6/sh6) and heterozygous (SH6/sh6) C6 parents. Although seed yields of shattering genotypes were 19.4% greater than non-shattering genotypes on the first harvest dates, yields of non-shattering genotypes were 167% greater on the last harvest dates. Seed harvested on the last harvest date reached 50% germination 4.2 days (26.4%) earlier and displayed 20.5% higher upper percentage germination limits than seed harvested on the first harvest date. Results indicate that the sh6 seed-retention gene will improve basin wildrye seed retention and indirectly improve seed germination by enabling later harvest dates. [ABSTRACT FROM AUTHOR]

As competition for water resources in areas of western North America intensify as a result of increasing human populations, the sustainability of turfgrass irrigation with limited water resources is questionable. A potential part of the solution is the use of recycled wastewater for landscape irrigation. However, as a result of high levels of salt, successful irrigation with recycled wastewater will likely need to be coupled with selection for increased salinity tolerance in turfgrass species. Additionally, salinity tolerant turfgrass will allow production on soils with inherently high salt levels. The study described here characterized the relative salinity tolerance of 93 accessions of Poa germplasm from the USDA National Plant Germplasm System (NPGS). Control cultivars of tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire], perennial ryegrass (Lolium perenne L.), and kentucky bluegrass (Poa pratensis L.) were also evaluated for comparison. Kentucky bluegrass accessions exhibited a wide range of LD50 (salinity dosage necessary to kill 50% of plants) values from 811 ECdays (PI 369296 from Russia) to 1922 ECdays (PI 371768 from the United States). Five kentucky bluegrass accessions exhibited salinity tolerance equal to or better than that of the tall fescue (LD50 = 1815 ECdays) and perennial ryegrass (LD50 = 1754 ECdays) checks. Thus, there is sufficient variation within this species to develop bluegrass with substantially higher salinity tolerance. [ABSTRACT FROM AUTHOR]

The incidence of human papillomavirus-positive (HPV+) oropharyngeal cancer (OPC) has increased rapidly in North America. HPV serology has been proposed as a sensitive, scalable, and cost-effective early detection test. HPV seropositivity can precede clinical presentation of OPC by several years, so additional diagnostic and/or surveillance procedures may be necessary to optimize early cancer detection. The potential for HPV circulating tumor DNA (ctDNA) to confirm a diagnosis of OPC in seropositive individuals is poorly understood. Moreover, the concordance of baseline HPV serology and HPV ctDNA and their respective associations with cancer burden in OPC patients are not known. We hypothesized that plasma levels of HPV antibodies and HPV ctDNA are associated with disease burden in a cohort of p16+ OPC patients. We analyzed pre-treatment peripheral blood plasma from 100 patients with non-metastatic p16+ OPC treated with definitive (chemo)radiotherapy. A multiplex ELISA was used for serologic evidence of HPV proteins (L1, E1, E2, E4, E6, E6) from 10 HPV genotypes, quantified by mean fluorescence intensity (MFI). Plasma HPV ctDNA was quantified by whole viral genome sequencing utilizing a custom HPV-targeted capture panel for 38 HPV genotypes (HPV-seq). Gross tumor volume (GTV) was obtained from the sum of all target contours on computed tomography simulation scans. Statistical tests Kruskal-Wallis and Pearson's r were used to compare the assays. Seropositivity and HPV ctDNA positivity were found in 100% of cases. Serological results indicated 10 genotypes, and HPV ctDNA results indicated 9 distinct genotypes; both assays identified HPV16 as the most prevalent genotype (98% for each). Among the 98 patients with detectable HPV16 within ctDNA, HPV16 E6 seropositivity demonstrated high sensitivity (95%), while E1 (50%), E4 (47%), E7 (66%), and L1 (63%) demonstrated considerably lower sensitivities. HPV ctDNA but not HPV16 E6 MFI was positively associated with disease burden as determined by T- and N-category (Table 1), and by GTV (ctDNA vs GTV, r=0.47 p=1.0e-06; E6 MFI vs GTV, r=-0.14 p=0.17). This is the first report to compare HPV serology and HPV ctDNA sequencing in OPC patient plasma. Both tests were highly sensitive and could identify multiple oncogenic HPV genotypes. The level of HPV16 ctDNA but not HPV16 E6 antibodies in plasma was associated with disease burden. These findings have potential implications for early detection and prognostication. [ABSTRACT FROM AUTHOR]

Most models of allopatric speciation predict that the two daughter species will have range sizes different from each other's and potentially from that of their common ancestor. However, I find that this difference is less than that expected under a variety of null models of range evolution. Sister species' range values may therefore become more similar in the time following speciation. Greater-than-expected similarity (symmetry) has also been treated as a form of range size heritability. I therefore compare the results of this symmetry approach to a test for phylogenetic signal, using the range sizes of North American birds. I find that range size is heritable under both tests. I suggest that null models for range size heritability should be informed by an explicit model of evolution. Comparative methods may give erroneous results if they fail to take the unusual form of inheritance of range size into account.