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Data from: Widespread generalist clones are associated with range and niche expansion in allopolyploids of Pacific Northwest Hawthorns (Crataegus L.)
— 2017-08-16 Range and niche expansion are commonly associated with transitions to asexuality, polyploidy, and hybridity (allopolyploidy) in plants. The ability of asexual polyploids to colonize novel habitats may be due to widespread generalist clones, multiple ecologically specialized clones, or may be a neutral byproduct of multiple, independent origins of asexual polyploids throughout the range. We have quantified niche size and divergence for hawthorns of the Pacific Northwest using data from herbarium vouchers with known cytotypes. We find that all polyploid niches diverge from that of the diploid range, and allopolyploids have the broadest niches. Allotetraploids have the largest niche and the widest geographic distribution. We then assessed the genetic mechanism of range expansion by surveying the ecological and geographic distribution of genotypes within each cytotype from sites in which fine-scale habitat assessments were completed. We find no isolation by either geographic or ecological distance in allopolyploids, suggesting high dispersal and colonization ability. In contrast, autotriploids and diploids show patterns of isolation by geographic distance. We also compared the geographic and ecological distributions of clonal genotypes with those of randomly drawn sites of the most widespread cytotype. We found that most clones are geographically widespread and occur in a variety of habitats. We interpret these findings to suggest that patterns of range and niche expansion in Pacific Northwest Hawthorns may stem from these widespread, ecologically generalist clones of hybrid origin. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Visual ecology of true lemurs suggests a cathemeral origin for the primate cone opsin polymorphism
— 2016-09-15 In contrast to the majority of primates, which exhibit dedicated diurnality or nocturnality, all species of Eulemur are cathemeral. Color vision, in particular, is strongly affected by the spectral composition and intensity of ambient light, and the impact of activity period on the evolution of primate color vision is actively debated. We studied three groups of wild brown lemurs (Eulemur fulvus) in Ankarafantsika National Park, Madagascar over a one-year span. We also used non-invasive fecal DNA collection and analysis to study the opsin genes underlying the color vision of 24 individuals. We quantify the color and brightness of dietary fruits and modeled the chromaticity and discriminability of food objects to different visual phenotypes under daylight, twilight, and moonlight conditions. We found that E. fulvus possesses routine dichromacy, unlike its congener E. flavifrons, for which polymorphic trichromacy has been reported. Our models suggest that dichromacy is well-suited to the foraging ecology of E. fulvus. The performance of modeled dichromats and trichromats is comparable under nocturnal illuminants and the luminance values of most diet items are detectable across light conditions. The trichromatic phenotype demonstrates a modest advantage under daylight conditions only. Our results, taken together with reports of polymorphic trichromacy in E. flavifrons, suggest functional ecological variation in the visual system of the genus Eulemur. Interspecific phenotypic variation in the color vision of a genus is both unexpected and instructive. Ecological differences between species of Eulemur could reveal thresholds for the origins of polymorphic trichromacy, which preceded the evolution of routine trichromatic vision in humans and other primates. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Water availability as an agent of selection in introduced populations of Arabidopsis thaliana: impacts on flowering time evolution
— 2016-03-31 Flowering is one of the most influential events in the life history of a plant and one of the main determinants of reproductive investment and lifetime fitness. It is also a highly complex trait controlled by dozens of genes. Understanding the selective pressures influencing time to flowering, and being able to reliably predict how it will evolve in novel environments, are unsolved challenges for plant evolutionary geneticists. Using the model plant species, Arabidopsis thaliana, we examined the impact of simulated high and low winter precipitation levels on the flowering time of naturalized lines from across the eastern portion of the introduced North American range, and the fitness consequences of early versus late flowering. Flowering time order was significantly correlated across two environments—in a previous common garden experiment and in environmental chambers set to mimic mid-range photoperiod and temperature conditions. Plants in low water flowered earlier, had fewer basal branches and produced fewer fruits. Selection in both treatments favored earlier flowering and more basal branches. Our analyses revealed an interaction between flowering time and water treatment for fitness, where flowering later was more deleterious for fitness in the low water treatment. Our results are consistent with the hypothesis that differences in winter precipitation levels are one of the selective agents underlying a flowering time cline in introduced A. thaliana populations. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Widespread genetic incompatibilities between first-step mutations during parallel adaptation of Saccharomyces cerevisiae to a common environment
— 2017-12-19 Independently evolving populations may adapt to similar selection pressures via different genetic changes. The interactions between such changes, such as in a hybrid individual, can inform us about what course adaptation may follow and allow us to determine whether gene flow would be facilitated or hampered following secondary contact. We used Saccharomyces cerevisiae to measure the genetic interactions between first-step mutations that independently evolved in the same biosynthetic pathway following exposure to the fungicide nystatin. We found that genetic interactions are prevalent and predominantly negative, with the majority of mutations causing lower growth when combined in a double mutant than when alone as a single mutant (sign epistasis). The prevalence of sign epistasis is surprising given the small number of mutations tested and runs counter to expectations for mutations arising in a single biosynthetic pathway in the face of a simple selective pressure. Furthermore, in one third of pairwise interactions, the double mutant grew less well than either single mutant (reciprocal sign epistasis). The observation of reciprocal sign epistasis among these first adaptive mutations arising in the same genetic background indicates that partial postzygotic reproductive isolation could evolve rapidly between populations under similar selective pressures, even with only a single genetic change in each. The nature of the epistatic relationships was sensitive, however, to the level of drug stress in the assay conditions, as many double mutants became fitter than the single mutants at higher concentrations of nystatin. We discuss the implications of these results both for our understanding of epistatic interactions among beneficial mutations in the same biochemical pathway and for speciation. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Why less complexity produces better forecasts: an independent data evaluation of kelp habitat models
— 2018-08-08 Understanding how species are distributed in the environment is increasingly important for natural resource management, particularly for keystone and habitat forming species, and those of conservation concern. Habitat suitability models are fundamental to developing this understanding; however their use in management continues to be limited due to often-vague model objectives and inadequate evaluation methods. Along the Northeast Pacific coast, canopy kelps (Macrocystis pyrifera and Nereocystis luetkeana) provide biogenic habitat and considerable primary production to nearshore ecosystems. We investigated the distribution of these species by examining a series of increasingly complex habitat suitability models ranging from process-based models based on species' ecology to complex Generalised Additive Models applied to purpose-collected survey data. Seeking limits on model complexity, we explored the relationship between model complexity and forecast skill, measured using both cross-validation and independent data evaluation. Our analysis confirmed the importance of predictors used in models of coastal kelp distributions developed elsewhere (i.e., depth, bottom type, bottom slope, and exposure); it also identified additional important factors including salinity, and interactions between exposure and salinity, and slope and tidal energy. Comparative results showed that cross-validation can lead to over-fitting, while independent data evaluation clearly identified the appropriate model complexity for generating habitat forecasts. Our results also illustrate that, depending on the evaluation data, predictions from simpler models can out-perform those from more complex models. Collectively, the insights from evaluating multiple models with multiple data sets contribute to the holistic assessment of model forecast skill. The continued development of methods and metrics for evaluating model forecasts with independent data, and the explicit consideration of model objectives and assumptions, promise to increase the utility of model forecasts to decision makers. https://creativecommons.org/publicdomain/zero/1.0/
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Depot-specific analysis of human adipose cells and their responses to Bisphenol S
— 2020-11-18 <p class="CxSpFirst" style="margin-bottom:14px;">Exposure to endocrine disrupting chemicals (EDCs) is associated with adverse health outcomes including obesity and diabetes.  Obesity, and more specifically visceral obesity, is correlated with metabolic disease.  The adipose tissue is an endocrine organ and a potential target for many environmental pollutants including bisphenols.  The subcutaneous and the omental (visceral) depots are comprised of mature adipocytes and residing progenitors, which may be different between the depots and may be EDCs targets.  Bisphenol A (BPA) is a suspected metabolic disruptor, and is being replaced with structurally similar compounds such as bisphenol S (BPS).  Like BPA, BPS induces adipogenesis in murine and primary human subcutaneous preadipocytes.  However, the effect of BPS on omental preadipocytes is not known.  In this study, we show that human primary progenitors from omental depots have a distinct transcriptomic signature as compared to progenitors derived from donor-matched subcutaneous depots.  Furthermore, we show that BPS increases adipogenesis of both omental and subcutaneous preadipocytes and can mimic the action of glucocorticoids or peroxisome proliferator-activated receptor g (PPARg) agonists.  We also show that BPS treatment, at 0.1 µM and 25 µM, modifies the adipokine profiles of both omental and subcutaneous derived adipocytes, in a depot specific manner.  Taken together our data show distinct gene expression profiles in the omental versus subcutaneous progenitors and similar responses to the BPA analogue, BPS.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Genetic diversity and multiple origins of polyploid Atriplex nummularia Lindl. (Chenopodiaceae).
— 2011-07-27 Few studies have described the genetic diversity within and between populations of polyploid plant species despite the general acceptance of the importance of polyploidy in plant diversification and speciation. The genus Atriplex has a complex evolutionary history in Australia that has included polyploidy and hybridization among perennial forms. The octoploid, dioecious species Atriplex nummularia is proposed to have evolved from an octoploid ancestor in the coastal semi-arid fringe of south-western Australia, and to have spread east and diversified into taxa which occupy edaphically different habitats. Despite interest in the diversification of the genus, and the ecological and economic importance of A. nummularia, there are no descriptions of the genetic structure of the species. Nuclear microsatellite markers and principal coordinate analysis, analysis of molecular variance, Bayesian and phenetic analyses were used to investigate the diversity and taxonomic relationships of two common subspecies of A. nummularia. Genetic diversity was high overall (A = 509, A′ = 42.4, Ho = 0.824, H′ = 2.8), but values were significantly lower in the western subspecies, A. nummularia ssp. spathulata. As in other outbreeding, perennial species, most of the genetic diversity was within populations (FST = 0.125). Clear divergence of subspecies was evident in principal coordinate analysis, neighbor-joining and Bayesian clustering analyses and the differentiation of populations was very low within subspecies (FSC = 0.048). These findings support the taxonomic separation of the two subspecies. Clustering patterns based on Bayesian analyses suggested that the polyploid subspecies of A. nummularia have multiple origins. https://creativecommons.org/publicdomain/zero/1.0/
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Multiscale drivers of phytoplankton communities in north-temperate lakes
— 2020-01-13 <p>Multiple factors operating across different spatial and temporal scales affect beta-diversity—the variation in community composition among sites. Disentangling the relative influence of co-occurring ecological drivers over broad biogeographic gradients and time is critical to developing mechanistic understandings of community responses to natural environmental heterogeneity as well as predicting the effects of anthropogenic change. We partitioned taxonomic beta-diversity in phytoplankton communities across 75 north-temperate lakes and reservoirs in Alberta, Canada, using data-driven, spatially-constrained null models to differentiate between spatially-structured, spatially-independent, and spuriously correlated associations with a suite of biologically relevant environmental variables. Beta-diversity was largely independent of space, indicating spatial processes (e.g. dispersal limitation) likely play a minor role in structuring freshwater phytoplankton communities at the regional scale. Our findings also identified seasonal differences in the importance of environmental factors, suggesting a general shift towards greater relevance of local, in-lake (e.g. nutrients and Secchi depth) over regional, atmospheric and catchment-level (e.g. monthly solar radiation and grassland coverage) drivers as the open-water growing season progressed. Several local and regional variables explained taxonomic variation jointly, reflecting climatic and land-use linkages (e.g. air temperature and water column stability or pastureland and nutrient enrichment) that underscore the importance of understanding how phytoplankton communities integrate—and may serve as sentinels of—broader anthropogenic changes. We also discovered similar community composition in natural and constructed water bodies, demonstrating rapid filtering of regional species to match local environmental conditions in reservoirs comparable to those in natural habitats. Finally, certain factors related to human-footprint (e.g. cropland development) explained the composition of bloom-forming and/or toxic cyanobacteria more than the overall phytoplankton community, suggesting their heightened importance to integrated watershed management.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Grape moth density in Bordeaux vineyards depends on local habitat management despite effects of landscape heterogeneity on their biological control
— 2017-12-12 1. Biological control of crop pests is a major ecosystem service affected by several variables acting at multiple spatial scales. Among these variables, heterogeneity at the habitat and landscape scales are known key drivers of trophic interactions and pest density in agroecosystems. However, studies that try to disentangle their relative effects in perennial cropping systems are scarce and nothing is known about their impacts on insect pest density and pesticide applications. 2. We examined the effect of heterogeneity at these two scales on grape moths, one of the most damaging insect pests in European vineyards, and their biological control in 20 vineyards during three consecutive years. We used local vegetation management and the proportion of semi-natural habitats in the surrounding landscape as proxies of heterogeneity at the habitat and landscape scales. Grape moth density was measured over time, as well as biological control services provided by different groups: birds, invertebrate predators, parasitoids and entomopathogenic fungi. 3. Over the 3 years, grape moth density was mainly determined by local heterogeneity, with significantly fewer larvae of the first generation established in vineyards with full compared to partial grass cover. 4. Despite these effects, biological control of grape moths was not primarily affected by local vegetation management but by landscape heterogeneity, and the direction of this effect varied over time. Notably, predation by birds increased with landscape heterogeneity in spring, depending on local vegetation management, while attacks by pathogenic fungi decreased with landscape heterogeneity during winter. 5. Synthesis and applications. Our results suggest that bottom-up processes related to habitat heterogeneity drive grape moth occurrence much more than top-down processes. These results have important implications for the ecological intensification of vineyard landscapes. We found that maintaining full grass cover within vineyards reduced grape moth density to a level below common intervention thresholds. Landscape heterogeneity in the close vicinity of vineyards contributed to improved biological pest control by birds, but depended on local vegetation management. Moreover, opposing effects of landscape management on biological pest control services over time revealed that strategies based only on manipulating landscape heterogeneity might not be the optimal option to limit grape moth density in vineyards. https://creativecommons.org/publicdomain/zero/1.0/
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Effect of ocrelizumab on vaccine responses in patients with multiple sclerosis: The VELOCE study
— 2020-08-10 <p style="margin-bottom:4px;"><b>Objective</b></p> <p style="margin-bottom:4px;"><span>The phase IIIb VELOCE study (NCT02545868) assessed responses to selected vaccines in ocrelizumab (OCR)-treated patients with relapsing multiple sclerosis.</span></p> <p style="margin-bottom:4px;"><b>Methods</b></p> <p style="margin-bottom:4px;">Patients were randomized 2:1 into Group OCR (n=68; OCR 600mg); or Control (n=34; interferon-β or no disease-modifying therapy). All received tetanus toxoid (TT)-containing vaccine, Pneumovax® (23-PPV) and keyhole limpet hemocyanin (KLH). Group OCR was subdivided into OCR1 (n=33) and OCR2 (n=35) at randomization. OCR1 received Prevnar® (13-PCV) 4 weeks after 23-PPV; OCR2 and Control received influenza vaccine. Vaccinations started 12 weeks after OCR initiation (Group OCR) or on Day 1 (Control).</p> <p style="margin-bottom:4px;"><b>Results</b></p> <p style="margin-bottom:4px;">Positive response rate to TT vaccine at 8 weeks was 23.9% in OCR vs 54.5% in Control. Positive response rate to ≥5 serotypes in 23-PPV at 4 weeks was 71.6% in OCR and 100% in Control. Prevnar® did not enhance response to pneumococcal serotypes in common with Pneumovax®. Humoral response to KLH was decreased in OCR vs Control. Seroprotection rates at 4 weeks against five influenza strains ranged from 55.6–80.0% in OCR2 and 75.0–97.0% in Control.</p> <p style="margin-bottom:4px;"><b>Conclusion</b></p> <p>Peripherally B-cell depleted OCR recipients mounted attenuated humoral responses to clinically relevant vaccines and the neoantigen, KLH, suggesting use of standard non-live vaccines while on OCR treatment remains a consideration. For seasonal influenza vaccines, it is recommended to vaccinate patients on OCR, as a potentially protective humoral response, even if attenuated, can be expected.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Emulating a target trial of statin use and risk of dementia using cohort data
— 2021-06-07 <p style="margin-bottom:11px;"><b>Objective: </b>Observational data can be used to attempt to emulate a target trial of statin use and estimate analogues of intention-to-treat and per-protocol effects on dementia risk.</p> <p style="margin-bottom:11px;"><b>Methods:</b> Using data from a prospective cohort study in the Netherlands, we conceptualized a sequence of “trials” in which eligible individuals ages 55-80 years were classified as statin initiators or non-initiators for every consecutive month between 1993 and 2007 and were followed until diagnosis of dementia, death, loss to follow-up, or the end of follow-up. We estimated two types of effects of statin use on dementia and a combined endpoint of dementia or death: the effect of initiation versus no initiation and the effect of sustained use versus no use. We estimated risk by statin treatment strategy over time via pooled logistic regression. We used inverse-probability weighting to account for treatment-confounder feedback in estimation of per-protocol effects.</p> <p style="margin-bottom:11px;"><b>Results: </b>Of 233,526 eligible person-trials (6,373 individuals), there were 622 initiators and 232,904 non-initiators. Comparing statin initiation with no initiation, the 10-year risk differences (95% CI) were -0.1% (-2.3%, 1.8%) for dementia and 0.3% (-2.7%, 3.3%) for dementia or death. Comparing sustained statin use versus no use, the 10-year risk differences were -2.2% (-5.2%, 1.6%) for dementia and -5.1% (-10.5%, -1.1%) for dementia or death.</p> <p style="margin-bottom:11px;"><b>Conclusions: </b>Individuals with sustained statin use, but not statin initiation alone, had reduced 10-year risks of dementia and dementia or death. Our results should be interpreted with caution due to the small number of initiators and events, and potential for residual confounding.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Hitting the moving target: modelling ontogenetic shifts with stable isotopes reveals the importance of isotopic turnover
— 2017-02-12 Ontogenetic niche shifts are widely prevalent in nature and are important in shaping the structure and dynamics of ecosystems. Stable isotope analysis is a powerful tool to assess these shifts, with δ15N providing a measure of trophic level and δ13C a measure of energy source. Previous applications of stable isotopes to study ontogenetic niche shifts have not considered the appreciable time-lag between diet and consumer tissue associated with isotopic turnover. These time-lags introduce significant complexity into field studies of ontogenetic niche shifts. Juvenile Chinook Salmon (Oncorhynchus tshawytscha) migrate from freshwater to marine ecosystems, and shift their diet from feeding primarily on invertebrates to feeding primarily on fish. This dual ontogenetic habitat and diet shift, in addition to the long time-lag associated with isotopic turnover, suggests that there is potential for a disconnect between the prey sources that juvenile salmon are consuming, and the inferred prey sources from stable isotope analysis. We developed a model that considered ontogenetic niche shifts and time-lags associated with isotopic turnover, and compared this ‘ontogeny’ model to one that considered only isotopic turnover. We used a Bayesian framework to explicitly account for parameter uncertainty. Data showed overwhelming support for the ontogeny model relative to the isotopic turnover model. Estimated variables from best model fits indicate that the ontogeny model predicts a much greater reliance on fish prey than does the stomach content data. Overall, we found that this method of quantifying ontogenetic niche shifts effectively accounted for both isotopic turnover and ontogenetic diet shifts; a finding that could be widely applicable to a variety of systems. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Host specialization involving attraction, avoidance and performance, in two phytophagous moth species
— 2015-10-15 Host specialization plays a key role in the extreme diversification of phytophagous insects. Whereas proximate mechanisms of specialization have been studied extensively, their consequences for species divergence remain unclear. Preference for, and performance on hosts are thought to be a major source of divergence in phytophagous insects. We assessed these major components of specialization in two moth species, the European corn borer (ECB) and the Adzuki bean borer (ABB), by testing their oviposition behaviour in different conditions (choice or no-choice set-ups) and their performances, by reciprocal transplant at the larval stage on the usual host and an alternative host plant. We demonstrated that both ABB and ECB have a strong preference for their host plants for oviposition, but that relative larval performances on the usual host and an alternative host differed according to the experiment and the trait considered (weight or survival). Finally, we show for the first time that the preference for maize in ECB conceals a strong avoidance of mugwort. The differences in performance, attraction and avoidance between ECB and ABB are discussed in the light of the underlying mechanisms and divergence process. https://creativecommons.org/publicdomain/zero/1.0/
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New application of strontium isotopes reveals evidence of limited migratory behaviour in Late Cretaceous hadrosaurs
— 2020-02-11 <p style="text-align:justify;margin-bottom:11px;">Dinosaur migration patterns are very difficult to determine, often relying solely on the geographic distribution of fossils.  Unfortunately, it is generally not possible to determine if a fossil taxon’s geographic distribution is the result of migration or simply a wide distribution.  Whereas some attempts have been made to use isotopic systems to determine migratory patterns in dinosaurs, these methods have yet to achieve wider usage in the study of dinosaur ecology.</p> <p style="text-align:justify;margin-bottom:11px;">Here we have used strontium isotope ratios from fossil enamel to reconstruct the movements of an individual hadrosaur from Dinosaur Provincial Park in Alberta, Canada.  Results from this study are consistent with a range or migratory pattern between Dinosaur Provincial Park and a contemporaneous locality in the South Saskatchewan River area, Alberta Canada.  This represents a minimum distance of approximately 80 km, which is consistent with migrations seen in modern elephants. These results suggest the continent-wide distribution of some hadrosaur species in the Late Cretaceous of North America is not the result of extremely long-range migratory behaviours.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Functional traits explain ecosystem function through opposing mechanisms
— 2018-05-15 The ability to explain why multispecies assemblages produce greater biomass compared to monocultures, has been a central goal in the quest to understand biodiversity effects on ecosystem function. Species contributions to ecosystem function can be driven by two processes: niche complementarity and a selection effect that is influenced by fitness (competitive) differences, and both can be approximated with measures of species’ traits. It has been hypothesised that fitness differences are associated with few, singular traits while complementarity requires multidimensional trait measures. Here, using experimental data from plant assemblages, I show that the selection effect was strongest when trait dissimilarity was low, while complementarity was greatest with high trait dissimilarity. Selection effects were best explained by a single trait, plant height. Complementarity was correlated with dissimilarity across multiple traits, representing above and below ground processes. By identifying the relevant traits linked to ecosystem function, we obtain the ability to predict combinations of species that will maximise ecosystem function. https://creativecommons.org/publicdomain/zero/1.0/
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Density dependence of clutch size and offspring sex ratio in starling colonies
— 2022-05-06 <p><span lang="EN-GB">Optimal life-history theory predicts that individuals should adjust both the number and the sex of their offspring to maximize fitness in response to environmental and social factors such as breeding density. While reductions in optimal clutch size are well-studied in birds, the evidence for sex ratio adjustments is still equivocal and, so far, we lack a thorough understanding of how these strategies interact to maximize fitness. Here, we investigate how breeding density simultaneously affects brood sex ratio and clutch size in a sexually dimorphic and polygynous bird. We tested the prediction that mothers breeding at a higher density lay smaller clutches and overproduce daughters, the sex with less variable fitness returns and that disperses further away from their natal territory. We distributed nest boxes at either a high (HD) or a low density (LD) and monitored clutch sizes and sex ratios during five years in a wild breeding colony of spotless starlings. While mothers breeding in HD nests produced more daughters than those breeding in LD nests, the density dependence of clutch size varied among years, with a tendency to lay smaller clutches in HD nests. Our results suggest that mothers consistently adjust offspring sex ratio in response to breeding density, whereas adjustments in clutch size varied in a more complex way. These results support the role of sex allocation strategies in response to density and show that further theoretical and empirical research is required to understand the interaction between clutch size and sex ratio adjustments in animals.</span></p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: The socially mediated recovery of a fearful fish paired with periodically replaced calm models
— 2018-09-13 Social learning is an important mechanism for acquiring knowledge about environmental risk. However, little work has explored the learning of safety and how such learning outcomes are shaped by the social environment. Here, we exposed minnows, Pimephales promelas, to a high-risk environment to induce behavioral responses associated with fear (e.g., neophobia). We then used the presence of calm conspecific models (low-risk individuals) to weaken these responses. When observers (individuals from the high-risk environment) and models were paired consistently in a one-on-one setting, the observers showed no recovery (i.e., no weakening of the fear responses), and instead the models indirectly acquired those responses (i.e., a socially-transmitted state of fear). However, observers paired with models that were periodically replaced with new calm models showed a significant recovery, and each new model showed diminished socially-transmitted fear. We argue that our understanding of predation-related fear and social information transfer can prove fruitful in understanding problems with fear and stress across animal taxa, including among humans who experience post-traumatic stress and secondary trauma. Our findings indicate that the periodic replacement of models can promote fear recovery in observers and reduce socially-transmitted fear in models. https://creativecommons.org/publicdomain/zero/1.0/
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Extinction dynamics under extreme conservation threat: The flora of St. Helena
— 2022-07-07 <p style="text-align:start;text-indent:0px;"><span><span style="font-style:normal;"><span><span style="font-weight:normal;"><span style="letter-spacing:normal;"><span><span><span style="white-space:normal;"><span><span><span>The flora of the island of St Helena provides an amplified system for the study of extinction by reason of the island’s high endemism, small size, vulnerable biota, length of time of severe disturbance (since 1502) and severity of threats. Endemic plants have been eliminated from 96.5% of St Helena by habitat loss. There are eight recorded extinctions in the vascular flora since 1771 giving an extinction rate of 581 extinctions per million species per year (E/MSY). This is considerably higher than background extinction rates, variously estimated at 1 or 0.1 E/MSY. We have no information for plant extinctions prior to 1771 but applying the same extinction rate to the period 1502 to 1771 suggests that there may be around ten unrecorded historical extinctions. We use census data and population decline estimates to project likely extinction forward in time. The projected overall extinction rate for the next 200 years is somewhat higher at 625 E/MSY. However, our data predict an extinction crunch in the next 50 years with 4 species out of the remaining 48 likely to become extinct during this period. It is interesting that during a period when the native plant areas dropped to 3.5% of the original, the extinction rate appears to have remained shallowly linear with under 30% of the endemic flora becoming extinct.</span></span></span></span></span></span></span></span></span></span></span></p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Loss of genetic integrity in wild lake trout populations following stocking: insights from an exhaustive study of 72 lakes from Québec, Canada
— 2014-03-28 Stocking represents the most important management tool worldwide to increase and sustain commercial and recreational fisheries in a context of overexploitation. Genetic impacts of this practice have been investigated in many studies, which examined population and individual admixture, but few have investigated determinants of these processes. Here, we addressed these questions from the genotyping at 19 microsatellite loci of 3341 adult lake trout (Salvelinus namaycush) from 72 unstocked and stocked lakes. Results showed an increase in genetic diversity and a twofold decrease in the extent of genetic differentiation among stocked populations when compared to unstocked. Stocked populations were characterized by significant admixture at both population and individual levels. Moreover, levels of admixture in stocked populations were strongly correlated with stocking intensity and a threshold value of total homogenization between source and stocked populations was identified. Our results also suggest that under certain scenarios, the genetic impacts of stocking could be of short duration. Overall, our study emphasizes the important alteration of the genetic integrity of stocked populations and the need to better understand determinants of admixture to optimize stocking strategies and to conserve the genetic integrity of wild populations. https://creativecommons.org/publicdomain/zero/1.0/

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