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Mesoscale cortex-wide neural dynamics predict self-initiated actions in mice several seconds prior to movement
— 2022-02-11 <p>Volition - the sense of control or agency over one’s voluntary actions - is widely recognized as the basis of both human subjective experience and natural behavior in non-human animals. To date, several human studies have found peaks in neural activity preceding voluntary actions, e.g. the readiness potential (RP), and some have shown upcoming actions could be decoded even before awareness. While these findings may pose a challenge to traditional accounts of human volition, some have proposed that random processes underlie and explain pre-movement neural activity. Here we seek to address part of this controversy by evaluating whether pre-movement neural activity in mice contains structure beyond that present in random neural activity. Implementing a self-initiated water-rewarded lever pull paradigm in mice while recording widefield [Ca++] neural activity we find that cortical activity changes in variance seconds prior to movement and that upcoming lever pulls or spontaneous body movements could be predicted between 1 second to more than 10 seconds prior to movement, similar to but even earlier than in human studies. We show that mice, like humans, are biased towards initiation of voluntary actions during specific phases of neural activity oscillations but that the pre-movement neural code in mice changes over time and is widely distributed as behavior prediction improved when using all vs single cortical areas. These findings support the presence of structured multi-second neural dynamics preceding voluntary action beyond that expected from random processes. Our results also suggest that neural mechanisms underlying self-initiated voluntary action could be preserved between mice and humans.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Panderodus from the Waukesha lagerstätte of Wisconsin, USA: the anatomy of primitive macrophagous vertebrate predators
— 2021-06-29 <p>Conodonts are an extinct group of early vertebrates. Articulated fossils of their feeding apparatus (‘natural assemblages’) are rare, and preserved soft tissues vanishingly so. Here, a primitive conodont with preserved soft tissues is redescribed from the Waukesha Lagerstätte of Wisconsin, USA. Although the feeding apparatus of derived prioniodontid conodonts is well understood, together with the homologies between taxa, the same is not true of more primitive conodonts that have apparatuses composed entirely of coniform elements. The new data provide insight to the long-term problem of determining homology across different types of conodont feeding apparatus. The Waukesha <i>Panderodus</i> preserves an almost complete apparatus and comprises two parallel rows of elements that occluded across the sagittal plane. A pair of M elements lies at the rostral end of the apparatus, with four pairs of S elements located immediately caudal to them. Three pairs of P elements are identified at the caudal end of the apparatus, for the first time in a primitive conodont with coniform elements. A symmetrical S<sub>0</sub> element is located on the midline between the M–S and P suites and provides the key for establishing homology with more derived ramiform–pectiniform apparatuses. The exceptional preservation reveals cartilaginous supports for the elements that inserted into their basal cavities. The trunk of the animal is poorly preserved but was dorso-ventrally flattened in life with transverse myomeres containing muscle fibrils. Overall, the specimen shows that <i>Panderodus</i> was a macrophagous feeder and provides an insight to the functional anatomy of early vertebrate predation.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Testing for parallel allochronic isolation in lake-stream stickleback
— 2015-09-16 The evolution of reproductive isolation (RI) is a critical step shaping progress toward speciation. In the context of ecological speciation, a critical question is the extent to which specific reproductive barriers important to RI evolve rapidly and predictably in response to environmental differences. Only reproductive barriers with these properties (importance, rapidity, predictability) will drive the diversification of species that are cohesively structured by environment type. One candidate barrier that might exhibit such properties is allochrony, whereby populations breed at different times. We studied six independent lake-stream population pairs of threespine stickleback (Gasterosteus aculeatus Linnaeus, 1758) that are known from genetic studies to show RI. However, the specific reproductive barriers driving this RI have proven elusive, leading to a “conundrum of missing reproductive isolation.” We here show that breeding times differ among some of the populations, but not in a consistent manner between lakes and streams. Moreover, the timing differences between lake and stream populations within each pair could account for only a small proportion of total RI measured with neutral genetic markers. Allochrony cannot solve the conundrum of missing reproductive isolation in lake-stream stickleback. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: The effects of ivacaftor on bone density and microarchitecture in children and adults with cystic fibrosis
— 2021-05-07 <p style="margin-bottom:11px;"><b>Context:</b> Cystic fibrosis transmembrane conductance (CFTR) dysfunction may play a role in CF-related bone disease (CFBD). Ivacaftor is a CFTR potentiator effective in improving pulmonary and nutritional outcomes in patients with the G551D-CFTR mutation. The effects of ivacaftor on bone health are unknown.</p> <p style="margin-bottom:11px;"><b>Objective:</b> To determine the impact of ivacaftor on bone density and microarchitecture in children and adults with CF.</p> <p style="margin-bottom:11px;"><b>Design:</b> Prospective observational multiple cohort study.</p> <p style="margin-bottom:11px;"><b>Setting:</b> Outpatient clinical research center within a tertiary academic medical center.</p> <p style="margin-bottom:11px;"><b>Patients or Other Participants</b>: Three cohorts of age-, race-, and gender-matched subjects were enrolled: 26 subjects (15 adults and 11 children) with CF and the G551D-CFTR mutation who were planning to start or had started treatment with ivacaftor within three months (Ivacaftor cohort); 26 subjects with CF were not treated with ivacaftor (CF Control cohort); and 26 healthy volunteers.</p> <p style="margin-bottom:11px;"><b>Interventions:</b> All treatments, including ivacaftor, were managed by the subjects’ pulmonologists.</p> <p style="margin-bottom:11px;"><b>Main Outcome Measures:</b> Bone microarchitecture by high resolution peripheral quantitative computed tomography (HR-pQCT), areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) and bone turnover markers at baseline, 1, and 2 years.</p> <p style="margin-bottom:11px;"><b>Results: </b> Cortical volume, area, and porosity at the radius and tibia increased significantly in adults in the Ivacaftor cohort. No significant differences were observed in changes in aBMD, trabecular microarchitecture, or estimated bone strength in adults or in any outcome measures in children.</p> <p style="margin-bottom:11px;"><b>Conclusions: </b>Treatment with ivacaftor was associated with increases in cortical microarchitecture in adults with CF. Further studies are needed to understand the implications of these findings.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Female mating experience and genetic background independently influence male mating success in fruit flies
— 2020-10-27 <p>When the reproductive interests of males and females conflict, males can evolve traits that are harmful to females, and females can coevolve traits to resist this harm. In the fruit fly, <i>Drosophila melanogaster</i>, there is genetic variation in female resistance traits, which can affect the pre- and post-mating success of males that try to mate with them. However, it is not clear to what extent the expression of these phenotypes can be modified by environmental factors such as sociosexual experience. Here, we tested how the genetic background of a female and her previous mating experience interact to affect the mating success of focal males. In the experience phase, we placed females from 28 distinct genetic backgrounds individually either with a single male (low conflict) or with three males (high conflict) for 48 hours. In the subsequent test phase, we measured the mating and post-mating fertilization success of focal males paired individually with each female. We found that focal males paired with females from the high conflict treatment were less successful at mating, took longer to mate when they were successful, and had a lower proportion of paternity share. Furthermore, we identified significant female genetic variation associated with male mating success. These results indicate that female experience, along with intrinsic genetic factors, can independently influence different fitness components of her subsequent mates and has implications for our understanding of plastic female mating strategies and the evolution of sexually antagonistic traits in males and females.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Linking transcriptomic and genomic variation to growth in brook charr hybrids (Salvelinus fontinalis, Mitchill)
— 2012-12-12 Hybridization can lead to phenotypic differences arising from changes in gene expression patterns or new allele combinations. Variation in gene expression is thought to be controlled by differences in transcription regulation of parental alleles, either through cis or trans regulatory elements. A previous study among brook charr hybrids from different populations (Rupert, Laval, and domestic) showing distinct length at age during early life stages also revealed different patterns in transcription regulation inheritance of transcript abundance. In the present study, transcript abundance by means of RNA-seq and qRT-PCR, SNP genotypes and allelic imbalance were assessed in order to understand the molecular mechanisms underlying the observed transcriptomic and differences in length at age among domestic × Rupert hybrids and Laval × domestic hybrids. We found 198 differentially expressed genes between the two hybrid crosses and allelic imbalance could be analyzed for 69 of them. Among these 69 genes, 36 genes exhibited cis acting regulatory effects in both of the two crosses, thus confirming the prevalent role of cis acting regulatory elements in the regulation of differentially expressed genes among intraspecific hybrids. In addition, we detected a significant association between SNP genotypes of three genes and length at age. Our study is thus one of the few that have highlighted some of the molecular mechanisms potentially involved in the differential phenotypic expression in intraspecific hybrids for non-model species. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Predicting the outcome of competition when fitness inequality is variable
— 2015-07-07 Traditional niche theory predicts that when species compete for one limiting resource in simple ecological settings the more fit competitor should exclude the less fit competitor. Since the advent of neutral theory ecologists have increasingly become interested both in how the magnitude of fitness inequality between competitors and stochasticity may affect this prediction. We used numerical simulations to investigate the outcome of two-species resource competition along gradients of fitness inequality (inequality in R*) and initial population size in the presence of demographic stochasticity. We found that the deterministic prediction of more fit competitors excluding less fit competitors was often unobserved when fitness inequalities were low or stochasticity was strong, and unexpected outcomes such as dominance by the less fit competitor, long-term co-persistence of both competitors or the extinction of both competitors could be common. By examining the interaction between fitness inequality and stochasticity our results mark the range of parameter space in which the predictions of niche theory break down most severely, and suggest that questions about whether competitive dynamics are driven by neutral or niche processes may be locally contingent. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: The effect of deleterious mutations and age on recombination in Drosophila melanogaster
— 2011-08-11 At the population level, recombination mediates the efficiency with which selection can eliminate deleterious mutations. At the individual level, deleterious alleles may influence recombination, which would change the rate at which linkage disequilibrium is eroded and thereby alter the efficiency with which deleterious alleles are purged. Here we test whether the presence of a deleterious allele on one autosome affects recombination on another autosome. We find that deleterious alleles not only alter the rate but also the pattern of recombination. However, there is little support that different deleterious alleles affect recombination in a consistent manner. Because we have detailed information on individual females across their life times, we are able to examine how recombination patterns change with age and find that these patterns are also affected by the presence of deleterious alleles. The differences among genotypes or among age classes is large enough to add substantial noise to genetic mapping experiments that do not consider these sources of variation. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Impacts of deforestation-induced warming on the metabolism, growth, and trophic interactions of an afrotropical stream fish
— 2019-01-18 1. In ectotherms, anthropogenic warming often increases energy requirements for metabolism, which can either impair growth (when resources are limiting) or lead to higher predator feeding rates and possibly stronger top-down trophic interactions. However, the relative importance of these effects in nature remains unclear because: 1) thermal adaptation or acclimation could lower metabolic costs; 2) greater prey production at warmer temperatures could compensate for higher predator feeding rates; and/or 3) temperature effects on trophic interactions via altered biological rates could be small relative to other, temperature-unrelated human impacts on food webs. 2. Here, we examined effects of deforestation-associated warming on the minnow Enteromius neumayeri, occurring in both forested (cool) and deforested (warm) streams located inside or nearby an afrotropical rainforest. Combining approaches from physiological and community ecology, we quantified impacts of anthropogenic warming on the metabolism, growth, and trophic interactions of this tropical ectotherm. We then compared these effects with impacts of land use unrelated to temperature. 3. In a long-term laboratory acclimation experiment quantifying the temperature-dependence of growth and metabolism in E. neumayeri, warming increased metabolic rates and decreased growth (at a limited ration). We found no evidence of local (thermal) adaptation, with warming affecting farm and forest populations similarly. 4. Then, using mark-recapture methods to quantify impacts of warming on performance in situ, we found similar growth rates in fish from deforested and forested streams despite their distinct thermal environments. This suggests higher prey consumption at deforested sites to compensate for greater metabolic costs, which could strengthen fish-invertebrate interactions. 5. Finally, we developed a bioenergetics model to estimate fish-invertebrate interaction strength and quantify temperature-related and unrelated impacts of land use on this interaction. We found that although warming increased fish consumption, it apparently increased invertebrate production even more and thus had a net weakening effect on estimated interaction strength. Most importantly, variation in both fish and invertebrate density not directly related to temperature had a much stronger influence on estimated interaction strength than temperature effects on predator consumption and prey growth. 6. We conclude that ectotherms can sometimes offset the metabolic costs of warming with a small increase in consumption that hardly effects food web interactions compared to non-metabolic impacts of anthropogenic disturbances. Future research should assess whether this is a common feature of heavily-impacted ecosystems facing multiple stressors. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Long-term fitness consequences of early environment in a long-lived ungulate
— 2017-03-20 Cohort effects can be a major source of heterogeneity and play an important role in population dynamics. Silver-spoon effects, when environmental quality at birth improves future performance regardless of the adult environment, can induce strong lagged responses on population growth. Alternatively, the external predictive adaptive response (PAR) hypothesis predicts that organisms will adjust their developmental trajectory and physiology during early life in anticipation of expected adult conditions but has rarely been assessed in wild species. We used over 40 years of detailed individual monitoring of bighorn ewes (Ovis canadensis) to quantify long-term cohort effects on survival and reproduction. We then tested both the silver-spoon and the PAR hypotheses. Cohort effects involved a strong interaction between birth and current environments: reproduction and survival were lowest for ewes that were born and lived at high population densities. This interaction, however, does not support the PAR hypothesis because individuals with matching high-density birth and adult environments had reduced fitness. Instead, individuals born at high density had overall lower lifetime fitness suggesting a silver-spoon effect. Early-life conditions can induce long-term changes in fitness components, and their effects on cohort fitness vary according to adult environment. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: The Collins’ monster, a spinous suspension-feeding lobopodian from the Cambrian Burgess Shale of British Columbia
— 2020-07-15 Lobopodians, a paraphyletic group of Palaeozoic vermiform animals bearing metameric appendages, are key to the origin of extant panarthropods. First discovered in 1983 on Mount Stephen (Yoho National Park, British Columbia), the Cambrian (Wuliuan) Burgess Shale lobopodian nicknamed “Collins’ monster” is formally described as <i>Collinsovermis monstruosus</i> gen. et sp. nov. A formal systematic revision of the poorly known lobopodian <i>Acinocricus stichus</i> from Utah is also provided. The body of <i>Collinsovermis</i> is plump and compact, lacking space between lobopod pairs but shows the diagnostic suspension-feeding characters of luolishaniid lobopodians. The six anterior lobopod pairs are elongate, adorned with long and slightly curved ventral spinules arranged in a chevron-like pattern. The eight posterior lobopod pairs, which attach to a truncated body termination, are stout and smooth, each terminated by a single strong recurved claw. Each somite bears a pair of dorsal spines; somites 4 and posteriad bear an additional median spine. The spines on somites 1–3 are much shorter than the spines on the remaining somites. The head is short, bears a pair of antenniform outgrowths, and is covered by an oblong sclerite. <i>Collinsovermis</i> plus <i>Collinsium</i> and <i>Acinocricus</i> comprise a sub-group of stout luolishaniid lobopodians with remarkably long spinules on the front lobopods, interpreted here as a clade (Teratopodidae). This clade is distinct from both the comparatively slenderer <i>Luolishania</i> and a sub-group composed of <i>Facivermis</i> and <i>Ovatiovermis</i> with posterior lobopods reduced or absent. Luolishaniids were mostly sessile forerunners of arthropods that had coupled efficient suspension-feeding devices and, as in <i>Collinsovermis</i> defensive features. https://creativecommons.org/publicdomain/zero/1.0/
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Favoring recruitment as a conservation strategy to improve the resilience of long-lived reptile populations: insights from a population viability analysis
— 2022-08-03 <p>In long-lived species, although adult survival typically has the highest elasticity, temporal variations in less canalized demographic parameters are the main drivers of population dynamics. Targeting recruitment rates may thus be the most effective strategy to manage these species. We analyzed 1136 capture–recapture histories collected over 9 years in an isolated population of the critically endangered Lesser Antillean iguana, using a robust-design Pradel model to estimate adult survival and recruitment rates. From an adult population size estimated at 928 in 2013, we found a yearly decline of 4% over the 8-year period. As expected under the canalization hypothesis for a long-lived species, adult survival was high and constant, with little possibility for improvement, whereas the recruitment rate varied over time and likely drove the observed population decline. We then used a prospective perturbation analysis to explore whether managing the species’ immature cohorts would at least slow the population decline. The prospective perturbation analysis suggested that a significant and sustained conservation effort would be needed to achieve a recruitment rate high enough to slow the population decline. We posit that the high recruitment rate achieved in 2014 – likely due to the maintenance in 2012 of the main nesting sites used by this population – would be sufficient to slow this population’s decline if it was sustained each year. Based on the results of diverse pilot studies we conducted, we identified the most likely threats targeting the eggs and immature cohorts, stressing the need to improve reproductive success and survival of immature iguanas. The threats we identified are also involved in the decline of several reptile species, and species from other taxa such as ground-nesting birds. These findings on a little-studied taxon provide further evidence that focusing on the immature life stages of long-lived species can be key to their conservation.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Multiple decades of stocking has resulted in limited hatchery introgression in wild brook trout (Salvelinus fontinalis) populations of Nova Scotia
— 2020-01-17 <p>Many populations of freshwater fishes are threatened with losses, and increasingly, the release of hatchery individuals is one strategy being implemented to support wild populations. However, stocking of hatchery individuals may pose long-term threats to wild populations, particularly if genetic interactions occur between wild and hatchery individuals. One highly prized sport fish that has been heavily stocked throughout its range is the brook trout (Salvelinus fontinalis). In Nova Scotia, Canada, hatchery brook trout have been stocked since the early 1900s, and despite continued stocking efforts, populations have suffered declines in recent decades. Before this study, the genetic structure of brook trout populations in the province was unknown; however, given the potential negative consequences associated with hatchery stocking, it is possible that hatchery programs have adversely affected the genetic integrity of wild populations. To assess the influence of hatchery supplementation on wild populations, we genotyped wild brook trout from 12 river systems and hatchery brook trout from two major hatcheries using 100 microsatellite loci. Genetic analyses of wild trout revealed extensive population genetic structure among and within river systems and significant isolation-by-distance. Hatchery stocks were genetically distinct from wild populations, and most populations showed limited to no evidence of hatchery introgression (&lt;5% hatchery ancestry). Only a single location had a substantial number of hatchery-derived trout and was located in the only river where a local strain is used for supplementation. The amount of hatchery stocking within a watershed did not influence the level of hatchery introgression. Neutral genetic structure of wild populations was influenced by geography with some influence of climate and stocking indices. Overall, our study suggests that long-term stocking has not significantly affected the genetic integrity of wild trout populations, highlighting the variable outcomes of stocking and the need to evaluate the consequences on a case-by-case basis</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Nets versus spraying: a spatial modelling approach reveals indoor residual spraying targets Anopheles mosquito habitats better than mosquito nets in Tanzania
— 2018-11-07 The global implementation of malaria interventions has averted hundreds of millions of clinical malaria cases in the last decade. This study assesses predicted Anopheles mosquito distributions across the United Republic of Tanzania before large-scale insecticide-treated net (ITN) rollouts and indoor residual spraying (IRS) initiatives to determine whether mosquito net usage by children under the age of five and IRS are targeted to areas where historical evidence indicates mosquitoes thrive. Demographic and Health Surveys data from 2011-2012 and 2015-2016 include detailed measurements of mosquito net and IRS use across Tanzania. Anopheline data are far less intensively collected, but we constructed a Maxent-built baseline mosquito habitat suitability (MHS) map (AUC=0.872) with Tanzanian Anopheles occurrence records from 1999-2003. This MHS model was tested against independently-observed georeferenced Plasmodium falciparum cases from the Malaria Atlas Project, with ~87% of cases from 1999-2003 (n=107) and ~84% of cases from 1985-2012 (n=919) occurring in areas of high predicted suitability for mosquitoes. We compared the validated MHS with subsequent malaria interventions using mixed effects logistic regression. Specifically, we assessed whether Anopheles habitat suitability related to the frequency that ≥1 child in a household reportedly slept under a mosquito net when that intervention later became widely available, and whether IRS was reportedly applied to dwellings over a one-year period. There was no evidence that mosquito net use the night before the survey related to MHS from 2011-2012 and marginally significant evidence (p<0.05) from 2015-2016 (β=1.466, 95% C.I.=0.848-2.103, marginal R2=0.020, respectively). However, the likelihood of IRS treatments rose relatively strongly in the 12 months prior to both surveys (β=13.466, 95% C.I.=10.488-16.456, marginal R2=0.144, and β=6.817, 95% C.I.=5.439-8.303, marginal R2=0.136, respectively). IRS treatments have therefore been targeted more effectively than mosquito nets toward areas where anopheline habitat suitability was previously found to be high. https://creativecommons.org/publicdomain/zero/1.0/
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Distinct type II opsins in the eye decode light properties for background adaptation and behavioural background preference
— 2021-09-21 <p style="text-align:justify;">Crypsis increases survival by reducing predator detection. <i>Xenopus laevis</i> tadpoles decode light properties from the substrate to induce two responses: A cryptic coloration response where dorsal skin pigmentation is adjusted to the colour of the substrate (background adaptation) and a behavioural crypsis where organisms move to align with a specific colour surface (background preference). Both processes require organisms to detect reflected light from the substrate. We explored the relationship between background adaptation and preference and the light properties able to trigger both responses. We also analysed which retinal photosensor (type II opsin) is involved. Our results showed that these two processes are segregated mechanistically, as there is no correlation between the preference for a specific background with the level of skin pigmentation, and different dorsal retina-localized type II opsins appear to underlie the two crypsis modes. Indeed, inhibition of melanopsin affects background adaptation but not background preference. Instead, we propose pinopsin is the photosensor involved in background preference. <i>pinopsin</i> mRNA is co-expressed with mRNA for the <i>sws1</i> cone photopigment in dorsally-located photoreceptors. Importantly, the developmental onset of pinopsin expression aligns with the emergence of the preference for a white background, but after the background adaptation phenotype appears. Furthermore, white background preference of tadpoles is associated with increased <i>pinopsin</i> expression, a feature that is lost in pre-metamorphic froglets along with a preference for a white background. Thus, our data show a mechanistic dissociation between background adaptation and background preference, and we suggest melanopsin and pinopsin, respectively, initiate the two responses.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Differences in spatial synchrony and interspecific concordance inform guild-level population trends for aerial insectivorous birds
— 2015-09-03 Many animal species exhibit spatiotemporal synchrony in population fluctuations, which may provide crucial information about ecological processes driving population change. We examined spatial synchrony and concordance among population trajectories of five aerial insectivorous bird species: chimney swift Chaetura pelagica, purple martin Progne subis, barn swallow Hirundo rustica, tree swallow Tachycineta bicolor, and northern rough-winged swallow Stelgidopteryx serripennis. Aerial insectivores have undergone severe guild-wide declines that were considered more prevalent in northeastern North America. Here, we addressed four general questions including spatial synchrony within species, spatial concordance among species, frequency of declining trends among species, and geographic location of declining trends. We used dynamic factor analysis to identify large-scale common trends underlying stratum-specific annual indices for each species, representing population trajectories shared by spatially synchronous populations, from 46 yr of North American Breeding Bird Survey data. Indices were derived from Bayesian hierarchical models with continuous autoregressive spatial structures. Stratum-level spatial concordance among species was assessed using cross-correlation analysis. Probability of long-term declining trends was compared among species using Bayesian generalized linear models. Chimney swifts exhibited declining trends throughout North America, with less severe declines through the industrialized Mid-Atlantic and Great Lakes regions. Northern rough-winged swallows exhibited declining trends throughout the west. Spatial concordance among species was limited, the proportion of declining trends varied among species, and contrary to previous reports, declining trends were not more prevalent in the northeast. Purple martins, barn swallows, and tree swallows exhibited synchrony across smaller spatial scales. The extensive within-species synchrony and limited concordance suggest that population trajectories of these aerial insectivores are responding to large-scale but complex and species- and region-specific environmental conditions (e.g. climate, land use). A single driver of trends for aerial insectivores as a guild appears unlikely. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Tropical trees in a wind-exposed island ecosystem: height-diameter allometry and size at onset of maturity
— 2015-12-19 1. Tropical tree species adapted to high wind environments might be expected to differ systematically in terms of stem allometry and life-history patterns, as compared with species found in less windy forests. We quantified height-diameter (H-D) allometries and relative size at onset of maturity (RSOM) for rainforest tree and tree fern species native to Dominica, West Indies, an island that experiences some of the highest average wind speeds pantropically. 2. H-D allometries for 17 Dominican angiosperm tree species were strongly concave on a log-log scale with asymptotic heights ranging from 9-32 m among species, averaging 25 m for canopy trees. H-D allometries for species-pooled data deviated strongly from recorded patterns for other tropical forest trees: asymptotic heights for trees in Dominica were 30-116% lower than those recorded for continental rainforest trees in Australia, South America, Africa, and Southeast Asia. In a subset of canopy trees sampled in steep, sheltered valleys, heights were 12-26% larger at a given diameter, and approached those observed in other tropical regions, suggesting large phenotypic responses of H-D allometries to wind conditions. 3. RSOM (quantified as the ratio of height at onset of reproduction to asymptotic maximum height) for Dominican angiosperm species was highly variable, ranging from 0.23-0.89 (mean 0.54), similar to patterns observed in Malaysia and Panama; very low RSOM values were estimated for two tree fern species. Pooling data from Dominica with published values from other tropical forests, we observed a significant negative correlation between RSOM and wood density. 4. Synthesis: Our data suggest that wind regimes are a critical determinant of height-diameter (H-D) allometries of tropical trees at both the local and global scale. Although we found no evidence for a systematic differences in reproductive onset related to wind regime, RSOM was negatively correlated with species’ wood density, suggesting that more shade-tolerant tree species show a longer period of gradually increasing reproductive allocation through ontogeny. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: The potential for spatial distribution indices to signal thresholds in marine fish biomass
— 2016-02-19 The frequently observed positive relationship between fish population abundance and spatial distribution suggests that changes in distribution can be indicative of trends in abundance. If contractions in spatial distribution precede declines in spawning stock biomass (SSB), spatial distribution reference points could complement the SSB reference points that are commonly used in marine conservation biology and fisheries management. When relevant spatial distribution information is integrated into fisheries management and recovery plans, risks and uncertainties associated with a plan based solely on the SSB criterion would be reduced. To assess the added value of spatial distribution data, we examine the relationship between SSB and four metrics of spatial distribution intended to reflect changes in population range, concentration, and density for 10 demersal populations (9 species) inhabiting the Scotian Shelf, Northwest Atlantic. Our primary purpose is to assess their potential to serve as indices of SSB, using fisheries independent survey data. We find that metrics of density offer the best correlate of spawner biomass. A decline in the frequency of encountering high density areas is associated with, and in a few cases preceded by, rapid declines in SSB in 6 of 10 populations. Density-based indices have considerable potential to serve both as an indicator of SSB and as spatially based reference points in fisheries management. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Induced defences alter the strength and direction of natural selection on reproductive traits in common milkweed
— 2017-01-25 Evolutionary biologists have long sought to understand the ecological processes that generate plant reproductive diversity. Recent evidence indicates that constitutive antiherbivore defences can alter natural selection on reproductive traits, but it is unclear whether induced defences will have the same effect and whether reduced foliar damage in defended plants is the cause of this pattern. In a factorial field experiment using common milkweed, Asclepias syriaca L., we induced plant defences using jasmonic acid (JA) and imposed foliar damage using scissors. We found that JA-induced plants experienced selection for more inflorescences that were smaller in size (fewer flowers), whereas control plants only experienced a trend towards selection for larger inflorescences (more flowers); all effects were independent of foliar damage. Our results demonstrate that induced defences can alter both the strength and direction of selection on reproductive traits, and suggest that antiherbivore defences may promote the evolution of plant reproductive diversity. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Incorporating interspecific competition into species-distribution mapping by upward scaling of small-scale model projections to the landscape
— 2018-01-31 There are a number of overarching questions and debate in the scientific community concerning the importance of biotic interactions in species distribution models at large spatial scales. In this paper, we present a framework for revising the potential distribution of tree species native to the Western Ecoregion of Nova Scotia, Canada, by integrating the long-term effects of interspecific competition into an existing abiotic-factor-based definition of potential species distribution (PSD). The PSD model is developed by combining spatially explicit data of individualistic species’ response to normalized incident photosynthetically active radiation, soil water content, and growing degree days. A revised PSD model adds biomass output simulated over a 100-year timeframe with a robust forest gap model and scaled up to the landscape using a forestland classification technique. To demonstrate the method, we applied the calculation to the natural range of 16 target tree species as found in 1,240 provincial forest-inventory plots. The revised PSD model, with the long-term effects of interspecific competition accounted for, predicted that eastern hemlock (Tsuga canadensis), American beech (Fagus grandifolia), white birch (Betula papyrifera), red oak (Quercus rubra), sugar maple (Acer saccharum), and trembling aspen (Populus tremuloides) would experience a significant decline in their original distribution compared with balsam fir (Abies balsamea), black spruce (Picea mariana), red spruce (Picea rubens), red maple (Acer rubrum L.), and yellow birch (Betula alleghaniensis). True model accuracy improved from 64.2% with original PSD evaluations to 81.7% with revised PSD. Kappa statistics slightly increased from 0.26 (fair) to 0.41 (moderate) for original and revised PSDs, respectively. https://creativecommons.org/publicdomain/zero/1.0/

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2.Move the map to display your area of interest. Holding the shift key and clicking to draw a box allows for zooming in on a specific area. Search results change as the map moves.
3.Access a record by clicking on an item in the search results or by clicking on a location pin and the linked record title.
Note: Clusters are intended to provide a visual preview of data location. Because there is a maximum of 50 records displayed on the map, they may not be a completely accurate reflection of the total number of search results.

(Source Repository: Dryad)

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