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5,538 results for “Population data”
Data from: Variation in growth and defence traits among plant populations at different elevations: implications for adaptation to climate change
Alpine plants occurring at high elevation are vulnerable to ongoing climate change, yet relatively little is known about the potential for high‐elevation species to adapt to changing environmental conditions. In particular, the extent to which high‐elevation plants will be able to resist predicted increases in the intensity of biotic interactions, such as herbivory, remains unclear. Species distributed across broad elevational ranges provide an opportunity to investigate evolutionary mechanisms and traits involved in adaptation to varying abiotic and biotic environments. This study focused on the perennial alpine plant Arabis alpina and combined field surveys and climate‐chamber experiments to test for intraspecific genetic divergence in traits related to growth and defence against herbivores. We screened multiple populations from low, intermediate and high elevations across a broad geographic area, characterising differences in growth form, leaf structural traits, palatability for herbivores and defensive chemistry. We then quantified the proportion of variation explained by elevation and population‐level effects. Our results document within‐species genetic divergence in multiple traits relevant for adaptation to the different abiotic and biotic pressures experienced at low and high elevations. Rates of herbivore damage declined with increasing elevation in the field, but plants from high‐ and intermediate‐elevation populations were generally more palatable for specialist herbivores than those from low‐elevation populations in feeding assays. Elevational clines were also observed in several glucosinolate defence compounds, and leaf herbivory more strongly induced glucosinolates in plants from high‐elevation populations than in those from low‐elevation populations. Leaf trichome density and growth form also diverged among populations contributing to growth‐defence phenotypes associated with different elevations. However, populations from similar elevations often differed significantly in both growth and defence‐related traits, with trait variation often better explained by population‐level effects than by elevation alone. Synthesis: Arabis alpina exhibits patterns of genetic variation in growth and defence traits consistent with adaptation to different elevations. However, populations from similar elevations also diverged in many of these ecologically relevant traits. Together, the extent of the observed trait variation suggests that this alpine species has considerable potential to adapt to a changing biotic environment.
Data from: Life-history characteristics and landscape attributes as drivers of genetic variation, gene flow and fine-scale population structure in Northern Dolly Varden (Salvelinus malma malma) in Canada
The Northern Dolly Varden (Salvelinus malma malma) displays variable life-history types and occupies freshwater habitats with varying levels of connectivity. Here, we assayed microsatellite DNA variation in Northern Dolly Varden from the western Canadian Arctic to resolve landscape and life history variables driving variation in genetic diversity and population structure. Overall, genetic variation was highest in anadromous populations and lowest in those isolated above waterfalls with stream-resident forms intermediate between the two. Anadromous and isolated populations were genetically divergent from each other while no genetic differentiation was detectable between sympatric anadromous and stream-resident forms. Population structure was stable over 25 years, hierarchically organized and conformed to an isolation-by-distance pattern, but stream-isolated forms often deviated from these patterns. Gene flow occurred primarily among Yukon North Slope populations and between sympatric anadromous and resident forms. These results were sex-dependent to some extent, but were influenced more by reproductive status and life history. Our study provides novel insights into the life history, population demographic and habitat variables that shape the distribution of genetic variation and population structure in Arctic fluvial habitats while providing a spatial context for management and conservation.
Data from: Bucking the trend: genetic analysis reveals high diversity, large population size and low differentiation in a deep ocean cetacean
Understanding the genetic structure of a population is essential to its conservation and management. We report the level of genetic diversity and determine the population structure of a cryptic deep ocean cetacean, the Gray's beaked whale (Mesoplodon grayi). We analysed 530 bp of mitochondrial control region and 12 microsatellite loci from 94 individuals stranded around New Zealand and Australia. The samples cover a large area of the species distribution (~6000 km) and were collected over a 22-year period. We show high genetic diversity (h=0.933–0.987, π=0.763–0.996% and Rs=4.22–4.37, He=0.624–0.675), and, in contrast to other cetaceans, we found a complete lack of genetic structure in both maternally and biparentally inherited markers. The oceanic habitats around New Zealand are diverse with extremely deep waters, seamounts and submarine canyons that are suitable for Gray's beaked whales and their prey. We propose that the abundance of this rich habitat has promoted genetic homogeneity in this species. Furthermore, it has been suggested that the lack of beaked whale sightings is the result of their low abundance, but this is in contrast to our estimates of female effective population size based on mitochondrial data. In conclusion, the high diversity and lack of genetic structure can be explained by a historically large population size, in combination with no known exploitation, few apparent behavioural barriers and abundant habitat.
Data from: Female polyandry and size-assortative mating in isolated local populations of the Japanese common toad Bufo japonicus
In anurans, female polyandry under male harassment is distributed across taxa because of external aquatic fertilisation. According to the sexual selection theory, male–male competition for access to females is affected by the operational sex ratio (OSR) and population density. The Japanese common toad, Bufo japonicus, is widespread in mainland Japan, and like the European common toad, B. bufo, it engages in explosive breeding. We observed the breeding behaviour of B. japonicus in isolated local populations for three years in two breeding ponds with different population sizes and densities: large-low (L-pond) and small-high (S-pond). We analysed the relative polyandry ratio in egg clutches laid by females and estimated the size-assortative mating pattern to be an indicator of male–male competition in the two ponds. Both ponds tended to exhibit a size-assortative mating pattern; however, the frequency of polyandry was different in the two ponds (L-pond = 20% and S-pond = 90%). We also found that polyandry could occur without multiple amplexus with a high population density, i.e. eggs were often fertilised by free-swimming sperm in the small shallow pond. We propose that high female polyandry ratios without continuous male harassment are generated because of a male-biased OSR and a high population density in the small pond.
Data from: Possible causes of divergent population trends in sympatric African herbivores
Sympatric herbivores experience similar environmental conditions but can vary in their population trends. Identifying factors causing these differences could assist conservation efforts aimed at maintaining fully functional ecosystems. From 1996 – 2013, tsessebe and wildebeest populations in the Okavango Delta, Botswana, declined by 73% and 90%, respectively, whereas zebra populations remained stable. These sympatric, medium sized herbivores are exposed to similar natural and anthropogenic pressures, but apparently differ in their responses to those pressures. To identify factors that could cause these differences, we fitted GPS-enabled collars to six zebra, eight tsessebe and seven wildebeest in the Moremi Game Reserve, Botswana. We calculated utilisation distributions (UDs) from GPS data, and used 95% isopleths to compare seasonal home range size between species. We calculated utilisation intensity (UI) from the UDs and generated spatial layers representing resources and disturbances, and then used model averaging to identify factors affecting UI for each species. We calculated second and third order habitat selection ratios to determine whether species were habitat specialists or generalists. Zebra occupied larger home ranges than tsessebe and wildebeest, showed weaker responses to spatial variables and displayed no third order habitat selection; zebra social systems are also more fluid, allowing for information exchange between stable harems. Herbivore species that are sedentary, occupy small home ranges, are habitat specialists and exist in relatively isolated groups are likely to be less resistant and resilient to the rapid pace of environmental change forecast by climate change scenarios. Resources contained within existing protected areas are unlikely to maintain populations of such species at sufficiently high levels, potentially leading to functional extinction. Special precautions may be needed to ensure that such species can persist in the wild, such as buffer zones around existing protected areas, which would allow greater potential for adaptive movement should current environmental conditions change.
Data from: Population structure of two rabies hosts relative to the known distribution of rabies virus variants in Alaska
For pathogens that infect multiple species the distinction between reservoir hosts and spillover hosts is often difficult. In Alaska, three variants of the arctic rabies virus exist with distinct spatial distributions. We test the hypothesis that rabies virus variant distribution corresponds to the population structure of the primary rabies hosts in Alaska, arctic foxes (Vulpes lagopus) and red foxes (V. vulpes) in order to possibly distinguish reservoir and spill over hosts. We used mitochondrial DNA (mtDNA) sequence and nine microsatellites to assess population structure in those two species. mtDNA structure did not correspond to rabies virus variant structure in either species. Microsatellite analyses gave varying results. Bayesian clustering found 2 groups of arctic foxes in the coastal tundra region, but for red foxes it identified tundra and boreal types. Spatial Bayesian clustering and spatial principal components analysis identified 3 and 4 groups of arctic foxes, respectively, closely matching the distribution of rabies virus variants in the state. Red foxes, conversely, showed eight clusters comprising 2 regions (boreal and tundra) with much admixture. These results run contrary to previous beliefs that arctic fox show no fine-scale spatial population structure. While we cannot rule out that the red fox is part of the maintenance host community for rabies in Alaska, the distribution of virus variants appears to be driven primarily by the artic fox Therefore we show that host population genetics can be utilized to distinguish between maintenance and spillover hosts when used in conjunction with other approaches.
Data from: Population structure of a widespread bat (Tadarida brasiliensis) in an island system
Dispersal is a driving factor in the creation and maintenance of biodiversity, yet little is known about the effects of habitat variation and geography on dispersal and population connectivity in most mammalian groups. Bats of the family Molossidae are fast-flying mammals thought to have potentially high dispersal ability, and recent studies have indicated gene flow across hundreds of kilometers in continental North American populations of the Brazilian free-tailed bat, Tadarida brasiliensis. We examined the population genetics, phylogeography, and morphology of this species in Florida and across islands of The Bahamas, which are part of an island archipelago in the West Indies. Previous studies indicate that bats in the family Phyllostomidae, which are possibly less mobile than members of the family Molossidae, exhibit population structuring across The Bahamas. We hypothesized that T. brasiliensis would show high population connectivity throughout the islands and that T. brasiliensis would show higher connectivity than two species of phyllostomid bats that have been previously examined in The Bahamas. Contrary to our predictions, T. brasiliensis shows high population structure between two groups of islands in The Bahamas, similar to the structure exhibited by one species of phyllostomid bat. Phylogenetic and morphological analyses suggest that this structure may be the result of ancient divergence between two populations of T. brasiliensis that subsequently came into contact in The Bahamas. Our findings additionally suggest that there may be cryptic species within T. brasiliensis in The Bahamas and the West Indies more broadly.
Data from: Are shy individuals less behaviorally variable? Insights from a captive population of mouse lemurs
Increasingly, individual variation in personality has become a focus of behavioral research in animal systems. Boldness and shyness, often quantified as the tendency to explore novel situations, are seen as personality traits important to the fitness landscape of individuals. Here we tested for individual differences within and across contexts in behavioral responses of captive mouse lemurs (Microcebus murinus) to novel objects, novel foods, and handling. We report consistent differences in behavioral responses for objects and handling. We also found that the responses to handling and novel objects were correlated and repeatable. Lastly, we show that shyer individuals may show less variability in their behavioral responses. This study provides new information on the potential for behavioral syndromes in this species and highlights differences in the degree to which behavioral types (e.g., shy/bold) vary in their behavioral responses.
Data from: Sex change and effective population size: implications for population genetic studies in marine fish
Large variance in reproductive success is the primary factor that reduces effective population size (Ne) in natural populations. In sequentially hermaphroditic (sex-changing) fish, the sex ratio is typically skewed and biased towards the 'first' sex, while reproductive success increases considerably after sex change. Therefore, sex-changing fish populations are theoretically expected to have lower Ne than gonochorists (separate sexes), assuming all other parameters are essentially equal. In this study, we estimate Ne from genetic data collected from two ecologically similar species living along the eastern coast of South Africa: one gonochoristic, the 'santer' sea bream Cheimerius nufar, and one protogynous (female-first) sex changer, the 'slinger' sea bream Chrysoblephus puniceus. For both species, no evidence of genetic structuring, nor significant variation in genetic diversity, was found in the study area. Estimates of contemporary Ne were significantly lower in the protogynous species, but the same pattern was not apparent over historical timescales. Overall, our results show that sequential hermaphroditism may affect Ne differently over varying time frames, and that demographic signatures inferred from genetic markers with different inheritance modes also need to be interpreted cautiously, in relation to sex-changing life histories.
Data from: Phenotypic differentiation is associated with divergent sexual selection among closely related barn swallow populations
Sexual selection plays a key role in the diversification of numerous animal clades and may accelerate trait divergence during speciation. However, much of our understanding of this process comes from phylogenetic comparative studies, which rely on surrogate measures such as dimorphism that may not represent selection in wild populations. In this study, we assess sexual selection pressures for multiple male visual signals across four barn swallow (Hirundo rustica) populations. Our sample encompassed 2400 linear km and two described subspecies: European H. r. rustica (in the Czech Republic and Romania) and Eastern Mediterranean H. r. transitiva (in Israel), as well as a potential area of contact (in Turkey). We demonstrate significant phenotypic differentiation in four sexual signaling axes, despite very low-level genomic divergence and no comparable divergence in an ecological trait. Moreover, the direction of phenotypic divergence is consistent with differences in sexual selection pressures among subspecies. Thus, H. r. transitiva, which have the darkest ventral plumage of any population, experience directional selection for darker plumage. Similarly, H. r. rustica, which have the longest tail feathers of any population, experience directional selection for elongated tail feathers and disruptive selection for ventral plumage saturation. These results suggest that sexual selection is the primary driver of phenotypic differentiation in this species. Our findings add to growing evidence of phenotypic divergence with gene flow. However, to our knowledge, this is the first study to relate direct measures of the strength and targets of sexual selection to phenotypic divergence among closely-related wild populations.
Data from: Supportive breeding boosts natural population abundance with minimal negative impacts on fitness of a wild population of Chinook salmon
While supportive breeding programs strive to minimize negative genetic impacts to populations, case studies have found evidence for reduced fitness of artificially produced individuals when they reproduce in the wild. Pedigrees of two complete generations were tracked with molecular markers to investigate differences in reproductive success (RS) of wild and hatchery-reared Chinook salmon spawning in the natural environment to address questions regarding the demographic and genetic impacts of supplementation to a natural population. Results show a demographic boost to the population from supplementation. On average, fish taken into the hatchery produced 4.7 times more adult offspring, and 1.3 times more adult grand-offspring than naturally reproducing fish. Of the wild and hatchery fish that successfully reproduced, we found no significant differences in RS between any comparisons but hatchery-reared males typically had lower RS values than wild males. Mean relative reproductive success (RRS) for hatchery F1 females and males was 1.11 (p = 0.84) and 0.89 (p = 0.56), respectively. RRS of hatchery-reared fish (H) that mated in the wild with either hatchery or wild origin (W) fish were generally equivalent to WxW matings. Mean RRS of HxW and HxH matings was 1.07 (p = 0.92) and 0.94 (p = 0.95), respectively. We conclude that fish chosen for hatchery rearing did not have a detectable negative impact on the fitness of wild fish by mating with them for a single generation. Results suggest that supplementation following similar management practices (e.g., 100% local, wild-origin brood stock) can successfully boost population size with minimal impacts on the fitness of salmon in the wild.
Data from: Spatially varying selection shapes life history clines among populations of Drosophila melanogaster from sub-Saharan Africa
Clines in life history traits, presumably driven by spatially varying selection, are widespread. Major latitudinal clines have been observed, for example, in Drosophila melanogaster, an ancestrally tropical insect from Africa that has colonized temperate habitats on multiple continents. Yet, how geographic factors other than latitude, such as altitude or longitude, affect life history in this species remains poorly understood. Moreover, most previous work has been performed on derived European, American and Australian populations, but whether life history also varies predictably with geography in the ancestral Afro-tropical range has not been investigated systematically. Here, we have examined life history variation among populations of D. melanogaster from sub-Saharan Africa. Viability and reproductive diapause did not vary with geography, but body size increased with altitude, latitude and longitude. Early fecundity covaried positively with altitude and latitude, whereas lifespan showed the opposite trend. Examination of genetic variance–covariance matrices revealed geographic differentiation also in trade-off structure, and QST-FST analysis showed that life history differentiation among populations is likely shaped by selection. Together, our results suggest that geographic and/or climatic factors drive adaptive phenotypic differentiation among ancestral African populations and confirm the widely held notion that latitude and altitude represent parallel gradients.
Data from: Optimizing the trade-off between spatial and genetic sampling efforts in patchy populations: towards a better assessment of functional connectivity using an individual-based sampling scheme
Genetic data are increasingly used in landscape ecology for the indirect assessment of functional connectivity, i.e. the permeability of landscape to movements of organisms. Among available tools, matrix correlation analyses (e.g. Mantel tests or mixed models) are commonly used to test for the relationship between pairwise genetic distances and movement costs incurred by dispersing individuals. When organisms are spatially clustered, a population-based sampling scheme (PSS) is usually performed, so that a large number of genotypes can be used to compute pairwise genetic distances on the basis of allelic frequencies. Because of financial constraints, this kind of sampling scheme implies a drastic reduction in the number of sampled aggregates, thereby reducing sampling coverage at the landscape level. We used matrix correlation analyses on simulated and empirical genetic datasets to investigate the efficiency of an individual-based sampling scheme (ISS) in detecting isolation-by-distance and isolation-by-barrier patterns. Provided that pseudo-replication issues are taken into account (e.g. through restricted permutations in Mantel tests), we showed that the use of inter-individual measures of genotypic dissimilarity may efficiently replace inter-population measures of genetic differentiation: the sampling of only three or four individuals per aggregate may be sufficient to efficiently detect specific genetic patterns in most situations. The ISS proved to be a promising methodological alternative to the more conventional PSS, offering much flexibility in the spatial design of sampling schemes and ensuring an optimal representativeness of landscape heterogeneity in data, with few aggregates left unsampled. Each strategy offering specific advantages, a combined use of both sampling schemes is discussed.
Data from: Gene flow from an adaptively divergent source causes rescue through genetic and demographic factors in two wild populations of Trinidadian guppies
Genetic rescue, an increase in population growth owing to the infusion of new alleles, can aid the persistence of small populations, but its use as a management tool is limited by a lack of empirical data geared towards predicting effects of gene flow on local adaptation and demography. Experimental translocations provide an ideal opportunity to monitor the demographic consequences of gene flow. In this study we take advantage of two experimental introductions of Trinidadian guppies to test the effects of gene flow on downstream native populations. We individually marked guppies from the native populations to monitor population dynamics for 3 months before and 26 months after gene flow. We genotyped all individuals caught during the first 17 months at microsatellite loci to classify individuals by their genetic ancestry: native, immigrant, F1 hybrid, F2 hybrid, or backcross. Our study documents a combination of demographic and genetic rescue over multiple generations under fully natural conditions. Within both recipient populations, we found substantial and long-term increases in population size that could be attributed to high survival and recruitment caused by immigration and gene flow from the introduction sites. Our results suggest that low levels of gene flow, even from a divergent ecotype, can provide a substantial demographic boost to small populations, which may allow them to withstand environmental stochasticity.
Data from: Spatial and ecological population genetic structures within two island-endemic Aeonium species of different niche width
The Crassulacean genus Aeonium is a well-known example for plant species radiation on oceanic archipelagos. However, while allopatric speciation among islands is documented for this genus, the role of intra-island speciation due to population divergence by topographical isolation or ecological heterogeneity has not yet been addressed. The aim of this study was to investigate intraspecific genetic structures and to identify spatial and ecological drivers of genetic population differentiation on the island scale. We analyzed inter simple sequence repeat variation within two island-endemic Aeonium species of La Palma: one widespread generalist that covers a large variety of different habitat types (Ae. davidbramwellii) and one narrow ecological specialist (Ae. nobile), in order to assess evolutionary potentials on this island. Gene pool differentiation and genetic diversity patterns were associated with major landscape structures in both species, with phylogeographic implications. However, overall levels of genetic differentiation were low. For the generalist species, outlier loci detection and loci–environment correlation approaches indicated moderate signatures of divergent selection pressures linked to temperature and precipitation variables, while the specialist species missed such patterns. Our data point to incipient differentiation among populations, emphasizing that ecological heterogeneity and topographical structuring within the small scales of an island can foster evolutionary processes. Very likely, such processes have contributed to the radiation of Aeonium on the Canary Islands. There is also support for different evolutionary mechanisms between generalist and specialist species.
Data from: Counteracting effects of a non-native prey on demography of a native predator culminate in positive population growth
Identifying impacts of non-native species on native populations is central to conservation and ecology. While effects of non-native predators on native prey populations have recently received much attention, impacts of introduced prey on native predator populations are less understood. Non-native prey can influence predator behavior and demography through direct and indirect pathways, yet quantitative assessments of the relative impacts of multiple, potentially counteracting, effects on native predator population growth remain scarce. Using ≈20 years of range-wide monitoring data, we tested for effects of a recently-introduced, rapidly-spreading non-native prey species (Pomacea maculata) on the behavior and demography of the endangered snail kite (Rostrhamus sociabilis). Previous studies found that food-handling difficulties caused by the large size of P. maculata (relative to the native P. paludosa) can lead to energetic deficiencies in juvenile kites, suggesting the potential for evolutionary traps to occur. However, high densities of P. maculata populations could facilitate kites by providing supplemental food resources. Contrary to prior hypotheses, we found that juvenile apparent survival increased ≈50% in wetlands invaded by non-native snails. Breeding rates and number of young fledged/successful nest were also positively associated with non-native snail presence, suggesting direct trophic benefits to kites. We found no direct effects of the invasive snail on adult survival or daily nest survival rates. Kite movements and breeding distribution closely tracked the spread of non-native snail populations. Since 2005, kites have been heavily concentrated in northern regions where non-native snails have established. This geographic shift has had hidden costs, as use of northern regions is associated with lower adult survival. Despite negative impacts to this key vital rate, matrix population modeling indicated that the multifarious effects of the non-native snail invasion on kites culminated in increased population growth rates, likely lowering short-term extinction risks. Results suggest that considering only particular components of behavior or demography may be inadequate to infer the population-dynamic importance of non-native prey on native predators, including their role in creating potential evolutionary traps. Our findings provide information pertinent to Everglades restoration, highlighting potential management trade-offs for non-native species that may aid imperiled species recovery yet disrupt other native communities.
Data from: Long-term genetic monitoring reveals contrasting changes in the genetic composition of newly established populations of the intertidal snail Bembicium vittatum
Newly established populations are susceptible to founder events that reduce genetic variation. This may be counterbalanced by gene flow after populations become established or founders coming from genetically different populations. However, initial gains in genetic diversity may be short-lived if there is limited mixing between lineages and subsequent inbreeding or if one lineage sweeps to fixation through selection or genetic drift. Here, we report on the genetic changes taking place within two newly established populations of intertidal snail over a 15-year period (~ 10 generations). Each translocation was set up using multiple, genetically distinct source populations. Our data show that higher levels of variation in the translocated populations compared to the source populations were maintained over time for both nuclear (microsatellite) and mitochondrial genes. Small changes in allele and haplotype frequencies were observed in the source populations and in one of the translocated populations, but marked changes were evident in the other, where there was a dramatic shift towards the genetic make-up of one of the source populations. These genetic changes occurred despite relatively large numbers of founders (200- 374 adults) and no evidence of the population experiencing a severe reduction in effective population size. Our study shows that the genetic composition of newly established populations can vary greatly over time and that genetic outcomes can be highly variable, and significantly different to expectations, even when they are established using high numbers of individuals and involve source populations from the same geographic regions.
Data from: Small population size and low genomic diversity have no effect on fitness in experimental translocations of a wild fish
<p>Little empirical work in nature has quantified how wild populations with varying effective population sizes and genetic diversity perform when exposed to a gradient of ecologically important environmental conditions. To achieve this, juvenile brook trout from 12 isolated populations or closed metapopulations that differ substantially in population size and genetic diversity were transplanted to previously fishless ponds spanning a wide gradient of ecologically important variables. We evaluated the effect of genome-wide variation, effective population size (Ne), pond habitat, and initial body size on two fitness correlates (survival and growth). Genetic variables had little effect on either fitness correlate, which were determined primarily by habitat (pond temperature, depth, and pH) and initial body size. These results suggest that some vertebrate populations with low genomic diversity, low Ne and long-term isolation can represent important sources of variation and be capable of maintaining fitness in, and ultimately persisting and adapting to, changing environments. Our results also reinforce the paramount importance of improving available habitat and slowing habitat degradation for species conservation.</p>
Data from: Breakdown of a geographic cline explains high performance of introduced populations of a weedy invader
1. What drives the evolution of increased growth and fecundity in plants introduced to a novel range is not well understood. 2. We investigate between-range differences in performance for Verbascum thapsus, a weedy invader known to grow larger in its introduced than native range. Specifically, we question whether adaptation to herbivory or climate best explains increased performance of introduced populations. 3. We grew 14 native and 22 introduced populations of V. thapsus in two common garden locations: near Prague, Czech Republic (native range) and in Colorado, USA (introduced range). By removing herbivores from half of the plants within each garden we tested the prediction of the Evolution of Increased Competitive Ability (EICA) hypothesis: increased performance is driven by an evolutionary shift of resources away from defence against herbivory towards growth and reproduction. We then investigated whether genetically based clines in performance are expressed along climate gradients within both the native and introduced ranges. 4. On average, seeds produce larger rosettes when collected from the introduced versus native range. While this evolution of increased growth in introduced populations in part matches the prediction of EICA, climate, not herbivory, best explains this between-range difference. Specifically, seeds collected from the native range produce smaller rosettes as the climate of origin becomes cooler and drier, while there is no cline in performance in rosettes grown from seed collected from the introduced range, which are large regardless of climate of origin. Thus, a climate-based cline within the native range best explains lower average performance of native compared to introduced populations. SYNTHESIS: The breakdown in a potentially adaptive cline emphasizes the need to more closely investigate the evolutionary processes that shape geographic structuring (or its absence) within the introduced range. In addition, EICA is not universally applicable to all invasion scenarios, and our findings underscore the importance of testing underlying assumptions alongside the predictions of this hypothesis.
Data from: Reliability of macrofossils in woodrat (Neotoma) middens for detecting low-density tree populations
Macrofossils from woodrat (Neotoma) middens serve as an important proxy for reconstructing past vegetation in arid and semiarid regions of North America. The presence/absence of plant macrofossils in middens can provide valuable information on temporal and spatial patterns of plant migration and range boundaries. The primary aim of this study was to determine how local plant abundance, distance of plant populations from midden sites, and species population density on the landscape affect the probability of occurrence of macrofossils in middens. The study was designed with the primary intent of determining the reliability of middens in detecting scattered populations of Pinus ponderosa. We analyzed macrofossil assemblages from 42 modern woodrat middens from West Carrizo Canyon in southeastern Colorado, near the current eastern range margin of Pinus ponderosa. We compared midden contents with composition of the surrounding vegetation, measuring distance from the midden to the nearest individual of selected plant species, and the percent cover of each species within 30 m of the midden. We used this information to model the probability of species presence in a midden across a range of population densities on the landscape. Macrofossils of Juniperus spp., Quercus gambelii, and Opuntia spp. were consistently found in middens regardless of their local abundance in vegetation, although populations occurred within 30 m of all middens. Pinus edulis and P. ponderosa occurred in nearly all middens within 20-30 m of individual trees. P. ponderosa was rare in middens >20-30 m away from individual trees. Results of a simple simulation model suggest that middens become absolutely reliable indicators of P. ponderosa presence on the landscape only when average tree density exceeds 50 stems ha-1. Woodrats reliably collected macrofossils of Pinus edulis, P. ponderosa, Juniperus spp., Quercus gambelii, and Opuntia spp. when populations of these taxa occur within 20-30 m of a midden site. Woodrats did not collect P. ponderosa when the nearest individuals were more than 30 m away. Low-density populations of these and other species may be difficult to detect in fossil woodrat-midden series owing to reduced probability that individuals grow within foraging distance of the middens. Data from this and similar studies can be used to construct and parameterize a forward model of macrofossil representation in woodrat middens.
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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.