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9,882 results for “Scale”
Data from: Large-scale phylogeny of chameleons suggests African origins and Eocene diversification
Oceanic dispersal has emerged as an important factor contributing to biogeographic patterns in numerous taxa. Chameleons are a clear example of this, as they are primarily found in Africa and Madagascar, but the age of the family is post-Gondwanan break-up. A Malagasy origin for the family has been suggested, yet this hypothesis has not been tested using modern biogeographic methods with a dated phylogeny. To examine competing hypotheses of African and Malagasy origins, we generated a dated phylogeny using between six and 13 genetic markers, for up to 174 taxa representing greater than 90 per cent of all named species. Using three different ancestral-state reconstruction methods (Bayesian and likelihood approaches), we show that the family most probably originated in Africa, with two separate oceanic dispersals to Madagascar during the Palaeocene and the Oligocene, when prevailing oceanic currents would have favoured eastward dispersal. Diversification of genus-level clades took place in the Eocene, and species-level diversification occurred primarily in the Oligocene. Plio-Pleistocene speciation is rare, resulting in a phylogeny dominated by palaeo-endemic species. We suggest that contraction and fragmentation of the Pan-African forest coupled to an increase in open habitats (savannah, grassland, heathland), since the Oligocene played a key role in diversification of this group through vicariance.
Data from: DNA metabarcoding unveils multi‐scale trophic variation in a widespread coastal opportunist
A thorough understanding of ecological networks relies on comprehensive information on trophic relationships among species. Since unpicking the diet of many organisms is unattainable using traditional morphology‐based approaches, the application of high‐throughput sequencing methods represents a rapid and powerful way forward. Here, we assessed the application of DNA‐metabarcoding with nearly universal primers for the mitochondrial marker cytochrome c oxidase I (COI) in defining the trophic ecology of adult brown shrimp, Crangon crangon, in six European estuaries. The exact trophic role of this abundant and widespread coastal benthic species is somewhat controversial, while information on geographical variation remains scant. Results revealed a highly opportunistic behaviour. Shrimp stomach contents contained hundreds of taxa (>1000 molecular operational taxonomic units), of which 291 were identified as distinct species, belonging to 35 phyla. Only twenty ascertained species had a mean relative abundance of more than 0.5%. Predominant species included other abundant coastal and estuarine taxa, including the shore crab Carcinus maenas and the amphipod Corophium volutator. Jacobs' selectivity index estimates based on DNA extracted from both shrimp stomachs and sediment samples were used to assess the shrimp's trophic niche indicating a generalist diet, dominated by crustaceans, polychaetes and fish. Spatial variation in diet composition, at regional and local scales, confirmed the highly flexible nature of this trophic opportunist. Furthermore, the detection of a prevalent, possibly endoparasitic fungus (Purpureocillium lilacinum) in the shrimp's stomach demonstrates the wide range of questions that can be addressed using metabarcoding, towards a more robust reconstruction of ecological networks.
Data from: Three-month modified Rankin Scale as a determinant of five-year cumulative costs after ischemic stroke: an analysis of 11,136 patients in Korea
Objective: Stroke is a devastating and costly disease; however, there is a paucity of information on long-term costs and on how they differ according to 3-month modified Rankin scale (mRS), which is a primary outcome variable in acute stroke intervention trials. Methods: We analyzed a prospective multicenter stroke registry (Clinical Research Collaboration for Stroke in Korea) database through linkage with claims data from the National Health Insurance Service with follow up to December 2016. Healthcare expenditures were converted into daily cost individually, and annual and cumulative costs up to 5 years were estimated and compared according to the 3-month mRS. Results: Between January 2011 and November 2013, 11,136 patients were enrolled in the study. The mean age was 68 years, and 58% were men. The median follow-up period was 3.9 years (range 0–5 years). Mean cumulative cost over 5 years was $117,576 US dollar (USD); the cost in the first year after stroke was the highest ($38,152 USD), which increased markedly from the cost a year before stroke ($8,718 USD). The mean 5-year cumulative costs differed significantly according to the 3-month mRS (P<.001); the costs for a 3-month mRS score of 0 or 5 were $53,578 USD and $257,486 USD, respectively. Three-month mRS was an independent determinant of long-term costs after stroke. Conclusions: We shows that 3-month mRS plays an important role in the prediction of long-term costs after stroke. Such estimates relating to 3-month mRS categories may be valuable when undertaking health economic evaluations related to stroke care.
Data from: Fine-scale environmental control of hybridization in oaks
Natural hybridization is attracting much interest in modern speciation and conservation biology studies, but the underlying mechanisms remain poorly understood. In particular, it is unclear why environmental changes often increase hybridization rates. To study this question, we surveyed mating events in a mixed oak stand and developed a spatially-explicit individual-based hybridization model. This model, where hybridization is frequency dependent, pollen is non-limiting and which allows immigrant pollen to compete with local pollen, takes into account species-specific pollen dispersal and sexual barriers to hybridization. The consequences of pollen limitation on hybridization were studied using another simple model. The results indicate that environmental changes could increase hybridization rates through two distinct mechanisms. First, by disrupting the spatial organisation of communities, they should decrease the proportion of conspecific pollen available for mating, thus increasing hybridization rates. Second, by decreasing the density of conspecifics, they should increase pollen limitation and thus hybridization rates, as a consequence of chance pollination predominating over deterministic pollen competition. Altogether, our results point to a need for considering hybridization events at the appropriate level of organisation and provide new insights into why hybridization rates generally increase in disturbed environments.
Data from: On the spatial scale of dispersal in coral reef fishes
Marine biologists have gone through a paradigm shift, from the assumption that marine populations are largely 'open' due to extensive larval dispersal to the realization that marine dispersal is 'more restricted than previously thought'. Yet, population genetic studies often reveal low levels of genetic structure across large geographic areas. On the other side, more direct approaches such as mark-recapture provide evidence of localized dispersal. To what extent can direct and indirect studies of marine dispersal be reconciled? One approach consists in applying genetic methods that have been validated with direct estimates of dispersal. Here, we use such an approach - genetic isolation-by-distance between individuals in continuous populations - to estimate the spatial scale of dispersal in five species of coral reef fish presenting low levels of genetic structure across the Caribbean. Individuals were sampled continuously along a 220 km transect following the Mesoamerican Barrier Reef, population densities were estimated from surveys covering 17 200 m2 of reef, and samples were genotyped at a total of 58 microsatellite loci. A small but positive isolation-by-distance slope was observed in the five species, providing mean parent-offspring dispersal estimates ranging between 7 and 42 km (CI 1-113 km), and suggesting that there might be a correlation between minimum/maximum PLD and dispersal in coral reef fishes. Coalescent-based simulations indicate that these results are robust to a variety of dispersal distributions and sampling designs. We conclude that low levels of genetic structure across large geographic areas are not necessarily indicative of extensive dispersal at ecological timescales.
Data from: Ecology of ontogenetic body-mass scaling of gill surface area in a freshwater crustacean
Several studies have documented ecological effects on intra- and interspecific body-size scaling of metabolic rate. However, little is known about how various ecological factors may affect the scaling of respiratory structures supporting oxygen uptake for metabolism. Our study is apparently the first to provide evidence for ecological effects on the scaling of a respiratory structure among conspecific populations of any animal. We compared the body-mass scaling of gill surface area (SA) among eight spring-dwelling populations of the amphipod crustacean Gammarus minus. Although gill SA scaling was not related to water temperature, conductivity or G. minus population density, it was significantly related to predation regime (and secondarily to pH). Body-mass scaling slopes for gill SA were significantly lower in four populations inhabiting springs with fish predators than for those in four springs without fish (based on comparing means of the population slopes, or slopes calculated from pooled raw data for each comparison group). As a result, gill SA was proportionately smaller in adult amphipods from fish vs. fishless springs. This scaling difference paralleled similar differences in the scaling exponents for the rates of growth and resting metabolic rate. We hypothesized that gill SA scaling is shallower in fish vs. fishless spring populations of G. minus because of effects of size-selective predation on size-specific growth and activity that in turn affect the scaling of oxygen demand and concomitantly the gill capacity (SA) for oxygen uptake. Although influential theory claims that metabolic scaling is constrained by internal body design, our study builds on previous work to show that the scaling of both metabolism and the respiratory structures supporting it may be ecologically sensitive and evolutionarily malleable.
Data from: Deployment of organic farming at a landscape scale maintains low pest infestation and high crop productivity in vineyards
Organic farming is a promising way to reduce pesticide use but increasing the area under organic farming at the landscape scale could increase pest infestations and reduce crop productivity. Examining the effects of organic farming at multiple spatial scales and in different landscape contexts on pest communities and crop productivity is a major step in the ecological intensification of agricultural systems. We quantified the infestation levels of two pathogens and five arthropod pests, the intensity of pesticide use and crop productivity in 42 vineyards. Using a multi-scale hierarchical design, we unravelled the relative effects of organic farming at both field and landscape scales from the effects of semi-natural habitats in the landscape. At the field scale, pest communities did not differ between organic and conventional farming systems. At the landscape scale, increasing the area under organic farming did not increase pest infestation levels. Three out of seven pest taxa were affected both by local farming systems and the proportion of semi-natural habitats in the landscape. Our findings revealed that the proportion of semi-natural habitats reduced pest infestation for two out of seven pest taxa. Organic vineyards had much lower treatment intensities, very similar levels of pest control and equal crop productivity levels. Synthesis and Applications. Our results clearly indicate that policies promoting the development of organic farming in conventional vineyard landscapes will not lead to greater pest and disease infestations but will reduce the pesticide treatment intensity and maintain crop productivity. Moreover, the interactions between semi-natural habitats in landscape and local farming practices suggest that the deployment of organic farming should be adapted to landscape contexts.
Data from: The dynamics of men's cooperation and social status in a small-scale society
We propose that networks of cooperation and allocation of social status co-emerge in human groups. We substantiate this hypothesis with one of the first longitudinal studies of cooperation in a preindustrial society, spanning eight years. Using longitudinal social network analysis of cooperation among men, we find large effects of kinship, reciprocity, and transitivity in nomination of cooperation partners over time. Independent of these effects, we show that (i) higher status individuals gain more cooperation partners, and (ii) individuals gain status by cooperating with individuals of higher status than themselves. We posit that human hierarchies are more egalitarian relative to other primates species, due in part to greater interdependence between cooperation and status hierarchy.
Data from: Network-scale effects of invasive species on spatially-structured amphibian populations
<p>Understanding the factors affecting the dynamics of spatially-structured populations (SSP) is a central topic of conservation and landscape ecology. Invasive alien species are increasingly important drivers of the dynamics of native species. However, the impacts of invasives are often assessed at the patch scale, while their effects on SSP dynamics are rarely considered. We used long-term abundance data to test whether the impact of invasive crayfish on subpopulations can also affect the whole SSP dynamics, through their influence on source populations. From 2010 to 2018, we surveyed a network of 58 ponds and recorded the abundance of Italian agile frog clutches, the occurrence of an invasive crayfish, and environmental features. Using Bayesian hierarchical models, we assessed relationships between frog abundance in ponds and a) environmental features; b) connectivity within the SSP; c) occurrence of invasive species at both the patch- and the SSP-levels. If spatial relationships between ponds were overlooked, we did not detect effects of crayfish presence on frog abundance or trends. When we jointly considered habitat, subpopulation, and SSP features, processes acting at all these levels affected frog abundance. At the subpopulation scale, frog abundance in a year was related to habitat features, but was unrelated to crayfish occurrence at that site during the previous year. However, when we considered the SSP level, we found a strong negative relationship between frog abundance in a given site and crayfish frequency in surrounding wetlands during the previous year. Hence, SSP-level analyses can identify effects that would remain unnoticed when focussing on single patches. Invasive species can affect population dynamics even in not invaded patches, through the degradation of subpopulation networks. Patch-scale assessments of the impact of invasive species can thus be insufficient: predicting the long-term interplay between invasive and native populations requires landscape-level approaches accounting for the complexity of spatial interactions.</p>
Data from: Spatiotemporal patterns of duck nest density and predation risk: a multi-scale analysis of 18 years and more than 10 000 nests
Many avian species are behaviorally-plastic in selecting nest sites, and may shift to new locations or habitats following an unsuccessful breeding attempt. If there is predictable spatial variation in predation risk, the process of many individuals using prior experience to adaptively change nest sites may scale up to create shifting patterns of nest density at a population level. We used 18 years of waterfowl nesting data to assess whether there were areas of consistently high or low predation risk, and whether low-risk areas increased, and high-risk areas decreased in nest density the following year. We created kernel density maps of successful and unsuccessful nests in consecutive years and found no correlation in predation risk and no evidence for adaptive shifts, although nest density was correlated between years. We also examined between-year correlations in nest density and nest success at three smaller spatial scales: individual nesting fields (10–28 ha), 16-ha grid cells and 4-ha grid cells. Here, results were similar across all scales: we found no evidence for year-to-year correlation in nest success but found strong evidence that nest density was correlated between years, and areas of high nest success increased in nest density the following year. Prior research in this system has demonstrated that areas of high nest density have higher nest success, and taken together, our results suggest that ducks may adaptively select nest sites based on the local density of conspecifics, rather than the physical location of last year's nest. In unpredictable environments, current cues, such as the presence of active conspecific nests, may be especially useful in selecting nest sites. The cues birds use to select breeding locations and successfully avoid predators deserve continued attention, especially in systems of conservation concern.
Data from: Wildflower strips enhance pollination in adjacent strawberry crops at the small scale
Wildflower strips (WFS) are increasingly used to counteract the negative consequences of agricultural intensification. To date, it is poorly understood how WFS promote flower visitation and pollination services in nearby insect-pollinated crops. We therefore ask whether WFS enhance pollination service in adjacent strawberry crops, and how such an effect depends on the distance from WFS. Over two years we examined the effects of experimentally sown WFS compared to grassy strips on pollination services in adjacent strawberry (Fragaria ananassa) crops across a total of 19 study sites. Moreover, we examined flower visitation, species richness and community composition of the most important insect pollinator taxa at different within-field locations varying in distance to WFS. We found increased pollination services at the edge of WFS compared to locally reduced pollination services at the centre, which resulted in no significant difference in seed set between WFS and control fields. Total flower visits and species richness of pollinators were higher in WFS than in adjacent strawberry fields. Moreover, wild bee visitation was enhanced in adjacent strawberry crops near WFS compared to field centres, and intermediate at field edges near grassy strips. Our study demonstrates that diverse WFS can increase wild bee visitation and pollination services in the field edges of adjacent strawberry crops, but that overall visitation and pollination services do not increase. Moreover, our findings show that major pollinator taxa exhibit distinct responses, resulting in a shift of pollinator community composition as a function of distance to WFS with direct effects on crop pollination. Our results that WFS enhance rather than reduce crop pollination services near WFS should distract possible concerns by farmers that WFS may locally absorb rather than export crop pollinators. Considering the spatial restricted enhancement of wild bees and associated pollination services we suggest to establish WFS in the centre of crop fields.
Data from: Multi-scale effects of habitat structure and landscape context on a vertebrate with limited dispersal ability (the brown-throated sloth, Bradypus variegatus)
As human population, food consumption, and demand for forest products continue to rise over the next century, the pressures of land use change on biodiversity are projected to intensify. In tropical regions, countryside habitats that retain abundant tree cover and structurally complex canopies may complement protected areas by providing suitable habitats and landscape connectivity for a significant portion of the native biota. Species with low dispersal capabilities are among the most at risk of extinction as a consequence of land use change. We assessed how the spatial distribution of the brown-throated sloth (Bradypus variegatus), a model species for a vertebrate with limited dispersal ability, is shaped by differences in habitat structure and landscape patterns of countryside habitats in north-central Costa Rica using a multi-scale framework. We quantified the influence of local habitat characteristics and landscape context on sloth occurrence using mixed-effects logistic regression models. We recorded 27 sloths within countryside habitats and found that both local and landscape factors significantly influenced their spatial distribution. Locally, sloths favored structurally complex habitats, with greater canopy cover and variation in tree height and basal area. At the landscape scale, sloths demonstrated a preference for habitats with high proportions of forest and nearly large tracts of forest. Although mixed-use areas and tree plantations are not substitutes for protected forests, our results suggest they provide important supplemental habitats for sloths. To promote the conservation and long-term viability of sloth populations in the tropical countryside, we recommend for land managers to retain structurally complex vegetation and large patches of native habitat.
Data from: Scale-dependent genetic structure of the Idaho giant salamander (Dicamptodon aterrimus) in stream networks
The network architecture of streams and rivers constrains evolutionary, demographic, and ecological processes of freshwater organisms. This consistent architecture also makes stream networks useful for testing general models of population genetic structure and the scaling of gene flow. We examined genetic structure and gene flow in the facultatively paedomorphic Idaho giant salamander, Dicamptodon aterrimus, in stream networks of Idaho and Montana, USA. We used microsatellite data to test population structure models by (1) examining hierarchical partitioning of genetic variation in stream networks and (2) testing for genetic isolation by distance along stream corridors versus overland pathways. Replicated sampling of streams within catchments within three river basins revealed that hierarchical scale had strong effects on genetic structure and gene flow. AMOVA identified significant structure at all hierarchical scales (among streams, among catchments, among basins), but divergence among catchments had the greatest structural influence. Isolation by distance was detected within catchments, and in-stream distance was a strong predictor of genetic divergence. Patterns of genetic divergence suggest that differentiation among streams within catchments was driven by limited migration, consistent with a stream hierarchy model of population structure. However, there was no evidence of migration among catchments within basins, or among basins, indicating that gene flow only counters the effects of genetic drift at smaller scales (within rather than among catchments). These results show the strong influence of stream networks on population structure and genetic divergence of a salamander, with contrasting effects at different hierarchical scales.
Data from: Scaling of processes shaping the clonal dynamics and genetic mosaic of seagrasses through temporal genetic monitoring
Theoretically, the dynamics of clonal and genetic diversities of clonal plant populations are strongly influenced by the competition among clones and rate of seedling recruitment, but little empirical assessment has been made of such dynamics through temporal genetic surveys. We aimed to quantify 3 years of evolution in the clonal and genetic composition of Zostera marina meadows, comparing parameters describing clonal architecture and genetic diversity at nine microsatellite markers. Variations in clonal structure revealed a decrease in the evenness of ramet distribution among genets. This illustrates the increasing dominance of some clonal lineages (multilocus lineages, MLLs) in populations. Despite the persistence of these MLLs over time, genetic differentiation was much stronger in time than in space, at the local scale. Contrastingly with the short-term evolution of clonal architecture, the patterns of genetic structure and genetic diversity sensu stricto (that is, heterozygosity and allelic richness) were stable in time. These results suggest the coexistence of (i) a fine grained (at the scale of a 20 × 30 m quadrat) stable core of persistent genets originating from an initial seedling recruitment and developing spatial dominance through clonal elongation; and (ii) a local (at the scale of the meadow) pool of transient genets subjected to annual turnover. This simultaneous occurrence of initial and repeated recruitment strategies highlights the different spatial scales at which distinct evolutionary drivers and mating systems (clonal competition, clonal growth, propagule dispersal and so on) operate to shape the dynamics of populations and the evolution of polymorphism in space and time.
Data from: Continental-scale biogeographic variation: provinces versus gradients in the Upper Ordovician of Laurentia
Although provinces are widely used to delimit large-scale variations in biotic composition, it is unknown to what extent such variations simply reflect large-scale gradients, much as has been shown at smaller scales for communities. We examine here whether four previously described Middle and Late Ordovician provinces on Laurentia are best described as distinct provinces or as biotic gradients through a combination of the Paleobiology Database and new field data. Both data sets indicate considerable overlap in faunal composition, with spatial patterns in Jaccard similarity, quantified Jaccard similarity, and nonmetric multidimensional scaling ordination structure that correspond to variations in substrate type, specifically from carbonate-dominated strata in western Laurentia to mixed carbonate–siliciclastic strata in the midcontinent to siliciclastic-dominated rocks in easternmost Laurentia. Because sampling was limited to shallow-subtidal settings, this gradient cannot be attributed to variations in water depth. Likewise, geographic distance accounts for only a quarter of the variation in faunal composition. This cross-continent faunal gradient increases in strength into the early Late Ordovician, and appears to represent increased siliciclastic influx into eastern Laurentia during the Taconic orogeny. These results raise the question of whether biogeographic provinces may be in general better interpreted and analyzed as biotic gradients rather than as discrete entities.
Data from: Drivers of the spatial scale that best predict primate responses to landscape structure
Understanding the effect of landscape structure on biodiversity is critically needed to improve management strategies. To accurately evaluate such effect, landscape metrics need to be assessed at the correct scale, i.e. considering the spatial extent at which species‐landscape relationship is strongest (scale of effect, SE). Although SE is highly variable, its drivers are poorly known, but of key relevance to understand the way species use the landscape. In this study, we evaluate whether and how species traits, biological responses, landscape variables and the regional context of the study drive SE in Mexican primates. We estimated the relative abundance and immature‐to‐female ratio (a proxy of reproductive success) of howler monkeys (Alouatta palliata and A. pigra) and spider monkeys (Ateles geoffroyi) in 48 forest patches from four rainforest regions (12 patches per region) with different land‐use intensity. We then assessed the composition (forest cover, matrix functionality) and configuration (forest patch density, connectors' density, forest edge density) of local landscapes considering 13 scales (100 to 1300‐m radius) to identify the spatial extent at which each landscape variable best predict each response variable in each species and region. We found that SE did not differ significantly among the drivers evaluated. However, it tended to be lower for connectors' density than for forest patch density and forest edge density, probably because connectors' density is associated with local‐scale processes such as supplementary dynamics. Surprisingly, SE also tended to be higher in the more disturbed region than in the rest of the regions, probably because primates in the more disturbed region used larger areas of the landscape. Our findings therefore suggest that SE depends more strongly on landscape variables and regional context than on species traits and biological responses, and hence, especial caution should be taken when attempting to generalize SE to different explanatory variables and regions.
Data from: Demographic and spatiotemporal patterns of avian influenza infection at the continental scale, and in relation to annual life cycle of a migratory host
Since the spread of highly pathogenic avian influenza (HPAI) H5N1 in the eastern hemisphere, numerous surveillance programs and studies have been undertaken to detect the occurrence, distribution, or spread of avian influenza viruses (AIV) in wild bird populations worldwide. To identify demographic determinants and spatiotemporal patterns of AIV infection in long distance migratory waterfowl in North America, we fitted generalized linear models with binominal distribution to analyze results from 13,574 blue-winged teal (Anas discors, BWTE) sampled in 2007 to 2010 year round during AIV surveillance programs in Canada and the United States. Our analyses revealed that during late summer staging (July-August) and fall migration (September-October), hatch year (HY) birds were more likely to be infected than after hatch year (AHY) birds, however there was no difference between age categories for the remainder of the year (winter, spring migration, and breeding period), likely due to maturing immune systems and newly acquired immunity of HY birds. Probability of infection increased non-linearly with latitude, and was highest in late summer prior to fall migration when densities of birds and the proportion of susceptible HY birds in the population are highest. Birds in the Central and Mississippi flyways were more likely to be infected compared to those in the Atlantic flyway. Seasonal cycles and spatial variation of AIV infection were largely driven by the dynamics of AIV infection in HY birds, which had more prominent cycles and spatial variation in infection compared to AHY birds. Our results demonstrate demographic as well as seasonal, latitudinal and flyway trends across Canada and the US, while illustrating the importance of migratory host life cycle and age in driving cyclical patterns of prevalence.
Data from: A local evaluation of the individual state-space to scale up Bayesian spatial capture recapture
1. Spatial capture-recapture models (SCR) are used to estimate animal density and to investigate a range of problems in spatial ecology that cannot be addressed with traditional non-spatial methods. Bayesian approaches in particular offer tremendous flexibility for SCR modelling. Increasingly, SCR data are being collected over very large spatial extents making analysis computational intensive, sometimes prohibitively so. 2. To mitigate the computational burden of large-scale SCR models, we developed an improved formulation of the Bayesian SCR model that uses local evaluation of the individual state-space (LESS). Based on prior knowledge about a species' home range size, we created square evaluation windows that restrict the spatial domain in which an individual's detection probability (detector window) and activity center location (AC window) are estimated. We used simulations and empirical data analyses to assess the performance and bias of SCR with LESS. 3. LESS produced unbiased estimates of SCR parameters when the AC window width was ≥5σ (σ: the scale parameter of the half-normal detection function), and when the detector window extended beyond the edge of the AC window by 2σ. Importantly, LESS considerably decreased the computation time needed for fitting SCR models. In our simulations, LESS increased the computation speed of SCR models up to 57 fold. We demonstrate the power of this new approach by mapping the density of an elusive large carnivore – the wolverine (Gulo gulo) – with an unprecedented resolution and across the species' entire range in Norway (more than 200 000 km2). 4. Our approach helps overcome a major computational obstacle to population and landscape-level SCR analyses. The LESS implementation in a Bayesian framework makes the customization and fitting of SCR accessible for practitioners that are working at scales that are relevant for conservation and management.
Forest cover at landscape scales increases male and female gametic diversity of palm seedlings
<p>Genetic diversity shapes the evolutionary potential of plant populations. For outcrossing plants, genetic diversity is influenced by effective population size and by dispersal, first of paternal gametes through pollen, and then of paternal and maternal gametes through seeds. Forest loss often reduces genetic diversity, but the degree to which it differentially impacts the paternal and maternal contributions to genetic diversity and the spatial scale at which these impacts are most pronounced are poorly understood. To address these questions, we genotyped 504 seedlings of the animal-dispersed palm <i>Oenocarpus bataua </i>collected from 29 widely distributed sites across Ecuador and decomposed the contribution of paternal and maternal gametes to overall genetic diversity. The amount of forest cover at a landscape scale (> 10 km radius) had an equally significant positive association with both male and female gametic diversity. In addition, there was a significant positive association between forest cover and effective population size. Stronger fine-scale spatial genetic structure for female versus male gametes was observed at sites with low forest cover, but this did not scale up to differences in male vs female gametic diversity. These findings show that reductions in forest cover at spatial scales much larger than those typically evaluated in ecological studies lead to significant, and equivalent, decreases of diversity in both male and female gametes, and that this association between landscape level forest loss and genetic diversity may be driven directly by reductions in effective population size of <i>O. bataua</i>, rather than by indirect disruptions to local dispersal processes. </p>
Data from: Differential divergence in autosomes and sex chromosomes is associated with intra-island diversification at a very small spatial scale in a songbird lineage
<p>Recently diverged taxa showing marked phenotypic and ecological diversity are optimal systems to understand the genetic processes underlying speciation. We used genome-wide markers to investigate the diversification of the Reunion grey white eye (<i>Zosterops borbonicus</i>) on the small volcanic island of Reunion (Mascarene archipelago), where this species complex exhibits four geographic forms that are parapatrically distributed across the island and differ strikingly in plumage colour. One form restricted to the highlands is separated by a steep ecological gradient from three distinct lowland forms which meet at narrow hybrid zones that are not associated with environmental variables. Analyses of genomic variation based on SNP data from genotyping-by-sequencing and pooled RADseq approaches, reveal that signatures of selection associated with elevation can be found at multiple regions across the genome, whereas most loci associated with the lowland forms are located on the Z sex chromosome. We identified <i>TYRP1</i>, a Z-linked colour gene, as a likely candidate locus underlying colour variation among lowland forms. Tests of demographic models revealed that highland and lowland forms diverged in the presence of gene flow, and divergence has progressed as gene flow was restricted by selection at loci across the genome. This system is promising to investigate how natural selection and reproductive isolation shape the genomic landscape of divergence at multiple stages of the speciation process.</p>
ScienceDex guides
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These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.