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opencc-zeroDec 2017View details →

Data from: Survival analysis and classification methods for forest fire size

Factors affecting wildland-fire size distribution include weather, fuels, and fire suppression activities. We present a novel application of survival analysis to quantify the effects of these factors on a sample of sizes of lightning-caused fires from Alberta, Canada. Two events were observed for each fire: the size at initial assessment (by the first fire fighters to arrive at the scene) and the size at "being held" (a state when no further increase in size is expected). We developed a statistical classifier to try to predict cases where there will be a growth in fire size (i.e., the size at "being held" exceeds the size at initial assessment). Logistic regression was preferred over two alternative classifiers, with covariates consistent with similar past analyses. We conducted survival analysis on the group of fires exhibiting a size increase. A screening process selected three covariates: an index of fire weather at the day the fire started, the fuel type burning at initial assessment, and a factor for the type and capabilities of the method of initial attack. The Cox proportional hazards model performed better than three accelerated failure time alternatives. Both fire weather and fuel type were highly significant, with effects consistent with known fire behaviour. The effects of initial attack method were not statistically significant, but did suggest a reverse causality that could arise if fire management agencies were to dispatch resources based on a-priori assessment of fire growth potentials. We discuss how a more sophisticated analysis of larger data sets could produce unbiased estimates of fire suppression effect under such circumstances.

opencc-zeroDec 2017View details →

Data from: Grow where you thrive, or where only you can survive? An analysis of performance curve evolution in a clade with diverse habitat affinities

Performance curves are valuable tools for quantifying the fundamental niches of organisms and testing hypotheses about evolution, life history trade-offs, and the drivers of variation in species' distribution patterns. Here, we present a novel Bayesian method for characterizing performance curves that facilitates comparisons among species. We then use this model to quantify and compare the hydrological performance curves of 14 different taxa in the genus Lasthenia, an ecologically diverse clade of plants that collectively occupy a variety of habitats with unique hydrological features, including seasonally flooded wetlands called vernal pools. We conducted a growth chamber experiment to measure each taxon's fitness across five hydrological treatments that ranged from severe drought to extended flooding, and identified differences in hydrological performance curves that explain their associations with vernal pool and terrestrial habitats. Our analysis revealed that the distribution of vernal pool taxa in the field do not reflect their optimal hydrological environments: all taxa, regardless of habitat affinity, have highest fitness under similar hydrological conditions of saturated soil without submergence. We also found that a taxon's relative position across flood gradients within vernal pools is best predicted by the height of its performance curve. These results demonstrate the utility of our approach for generating insights into when and how performance curves evolve among taxa as they diversify into distinct environments. To facilitate its use, the modeling framework has been developed into an R package (https://github.com/silastittes/performr).

Data from: Body condition indices predict reproductive success but not survival in a sedentary, tropical bird

Body condition may predict individual fitness because those in better condition have more resources to allocate towards improving their fitness. However, the hypothesis that condition indices are meaningful proxies for fitness has been questioned. Here, we ask if intraspecific variation in condition indices predicts annual reproductive success and survival. We monitored a population of Neochmia phaeton (crimson finch), a sedentary, tropical passerine, for reproductive success and survival over four breeding seasons, and sampled them for commonly used condition indices: mass adjusted for body size, muscle and fat scores, packed cell volume, hemoglobin concentration, total plasma protein, and heterophil to lymphocyte ratio. Our study population is well suited for this research because individuals forage in common areas and do not hold territories such that variation in condition between individuals is not confounded by differences in habitat quality. Furthermore, we controlled for factors that are known to impact condition indices in our study population (e.g., breeding stage) such that we assessed individual condition relative to others in the same context. Condition indices that reflect energy reserves predicted both the probability of an individual fledging young and the number of young produced that survived to independence, but only during some years. Those that were relatively heavy for their body size produced about three times more independent young compared to light individuals. That energy reserves are a meaningful predictor of reproductive success in a sedentary passerine supports the idea that energy reserves are at least sometimes predictors of fitness. However, hematological indices failed to predict reproductive success and none of the indices predicted survival. Therefore, some but not all condition indices may be informative, but because we found that most indices did not predict any component of fitness, we question the ubiquitous interpretation of condition indices as surrogates for individual quality and fitness.

Data from: Early-life disease exposure and associations with adult survival, cause of death, and reproductive success in preindustrial humans

A leading hypothesis proposes that increased human life span since 1850 has resulted from decreased exposure to childhood infections, which has reduced chronic inflammation and later-life mortality rates, particularly from cardiovascular disease, stroke, and cancer. Early-life cohort mortality rate often predicts later-life survival in humans, but such associations could arise from factors other than disease exposure. Additionally, the impact of early-life disease exposure on reproduction remains unknown, and thus previous work ignores a major component of fitness through which selection acts upon life-history strategy. We collected data from seven 18th- and 19th-century Finnish populations experiencing naturally varying mortality and fertility levels. We quantified early-life disease exposure as the detrended child mortality rate from infectious diseases during an individual's first 5 y, controlling for important social factors. We found no support for an association between early-life disease exposure and all-cause mortality risk after age 15 or 50. We also found no link between early-life disease exposure and probability of death specifically from cardiovascular disease, stroke, or cancer. Independent of survival, there was no evidence to support associations between early-life disease exposure and any of several aspects of reproductive performance, including lifetime reproductive success and age at first birth, in either males or females. Our results do not support the prevailing assertion that exposure to infectious diseases in early life has long-lasting associations with later-life all-cause mortality risk or mortality putatively linked to chronic inflammation. Variation in adulthood conditions could therefore be the most likely source of recent increases in adult life span.

Data from: Metabolic programming mediated by an essential fatty acid alters body composition and survival skills of a marine fish

Metabolic programming occurs when variations in nutrition during a specific developmental window result in long-term metabolic effects. It has been studied almost exclusively in humans and other mammals but never in an ecological context. Here, we report metabolic programming and its functional consequences in a marine fish, red drum. We demonstrate that maternal provisioning of eggs with an essential fatty acid, docosahexaenoic acid (DHA), varies with DHA content of the maternal diet. When offspring are reared on a DHA-replete diet, whole-body DHA content of offspring depends upon the amount of DHA that was in the egg. We further demonstrate that whole-body DHA content is correlated with traits related to offspring fitness (escape responses, routine swimming, growth, and survival). DHA content of red drum eggs produced in nature is in the range where the effects of metabolic programming are most pronounced. Our findings indicate that during a brief developmental window DHA plays a role in establishing the pathways for its own uptake or storage, with protracted and possibly permanent effects on ecologically important survival skills of individuals and important implications for dynamics of populations and food webs.

opencc-zeroDec 2013View details →

Data from: Survival relative to new and ancestral host plants, phytoplasma infection and genetic constitution in host races of a polyphagous insect disease vector

Dissemination of vectorborne diseases depends strongly on the vector's host range and the pathogen's reservoir range. Because vectors interact with pathogens, the direction and strength of a vector's host shift is vital for understanding epidemiology and is embedded in the framework of ecological specialization. This study investigates survival in host-race evolution of a polyphagous insect disease vector, Hyalesthes obsoletus, whether survival is related to the direction of the host shift (from field bindweed to stinging nettle), the interaction with plant-specific strains of obligate vectored pathogens/symbionts (stolbur phytoplasma), and whether survival is related to genetic differentiation between the host races. We used a twice repeated, identical nested experimental design to study survival of the vector on alternative hosts and relative to infection status. Survival was tested with Kaplan–Meier analyses, while genetic differentiation between vector populations was quantified with microsatellite allele frequencies. We found significant direct effects of host plant (reduced survival on wrong hosts) and sex (males survive longer than females) in both host races and relative effects of host (nettle animals more affected than bindweed animals) and sex (males more affected than females). Survival of bindweed animals was significantly higher on symptomatic than nonsymptomatic field bindweed, but in the second experiment only. Infection potentially had a positive effect on survival in nettle animals but due to low infection rates the results remain suggestive. Genetic differentiation was not related to survival. Greater negative plant-transfer effect but no negative effect of stolbur in the derived host race suggests preadaptation to the new pathogen/symbiont strain before strong diversifying selection during the specialization process. Physiological maladaptation or failure to accept the ancestral plant will have similar consequences, namely positive assortative mating within host races and a reduction in the likelihood of oviposition on the alternative plant and thus the acquisition of alternative stolbur strains.

opencc-zeroOct 2019View details →

Data from: Intergenerational effects of early adversity on survival in wild baboons

Early life adversity can affect an individual's health, survival, and fertility for many years after the adverse experience. Whether early life adversity also imposes intergenerational effects on the exposed individual's offspring is not well understood. We fill this gap by leveraging prospective, longitudinal data on a wild, long-lived primate. We find that juveniles whose mothers experienced early life adversity exhibit high mortality before age 4, independent of the juvenile's own experience of early adversity. These juveniles often preceded their mothers in death by 1 to 2 years, indicating that high adversity females decline in their ability to raise offspring near the end of life. While we cannot exclude direct effects of a parent's environment on offspring quality (e.g., inherited epigenetic changes), our results are completely consistent with a classic parental effect, in which the environment experienced by a parent affects its future phenotype and therefor e its offspring's phenotype.

opencc-zeroDec 2013View details →

Data from: Density-dependent intraspecific aggression regulates survival in northern Yellowstone wolves (Canis lupus)

1. Understanding the population dynamics of top predators is essential to assess their impact on ecosystems and to guide their management. Key to this understanding is identifying the mechanisms regulating vital rates. 2. Determining the influence of density on survival is necessary to understand the extent to which human-caused mortality is compensatory or additive. In wolves (Canis lupus), empirical evidence for density-dependent survival is lacking. Dispersal is considered the principal way in which wolves adjust their numbers to prey supply or compensate for human exploitation. However, studies to date have primarily focused on exploited wolf populations, in which density-dependent mechanisms are likely weak due to artificially low wolf densities. 3. Using 13 years of data on 280 collared wolves in Yellowstone National Park, we assessed the effect of wolf density, prey abundance and population structure, as well as winter severity, on age-specific survival in two areas (prey-rich vs. prey-poor) of the national park. We further analysed cause-specific mortality and explored the factors driving intraspecific aggression in the prey-rich northern area of the park. 4. Overall, survival rates decreased during the study. In northern Yellowstone, density-dependence regulated adult survival through an increase in intraspecific aggression, independent of prey availability. In the interior of the park, adult survival was less variable and density-independent, despite reduced prey availability. There was no effect of prey population structure in northern Yellowstone, nor of winter severity in either area. Survival was similar among yearlings and adults, but lower for adults older than 6 years. 5. Our results indicate that density-dependent intraspecific aggression is a major driver of adult wolf survival in northern Yellowstone, suggesting intrinsic density-dependent mechanisms have the potential to regulate wolf populations at high ungulate densities. When low prey availability or high removal rates maintain wolves at lower densities, limited inter-pack interactions may prevent density-dependent survival, consistent with our findings in the interior of the park.

opencc-zeroDec 2016View details →

Data from: Nest survival modeling using a multi-species approach in forests managed for timber and biofuel feedstock

1. Switchgrass (Panicum virgatum) intercropping is a novel forest management practice for biomass production intended to generate cellulosic feedstocks within intensively managed loblolly pine-dominated landscapes. These pine plantations are important for early-successional bird species, as short rotation times continually maintain early successional habitat. We tested the efficacy of using community models compared to individual surrogate species models in understanding influences on nest survival. We analysed nest data to test for differences in habitat use for 14 bird species in plots managed for switchgrass intercropping and controls within loblolly pine (Pinus taeda) plantations in Mississippi, USA. 2. We adapted hierarchical models using hyper-parameters to incorporate information from both common and rare species to understand community-level nest survival. This approach incorporates rare species that are often discarded due to low sample sizes, but can inform community-level demographic parameter estimates. We illustrate use of this approach in generating both species-level and community-wide estimates of daily survival rates for songbird nests. We were able to include rare species with low sample size (minimum n = 5) to inform a hyper-prior, allowing us to estimate effects of covariates on daily survival at the community level, then compare this with a single-species approach using surrogate species. Using single species models, we were unable to generate estimates below a sample size of 21 nests per species. 3. Community model species-level survival and parameter estimates were similar to those generated by five single species models, with improved precision in community model parameters. 4. Covariates of nest placement indicated that switchgrass at the nest site (< 4 m) reduced daily nest survival, although intercropping at the forest stand level increased daily nest survival. 5. Synthesis and applications. Community models represent a viable method for estimating community nest survival rates and effects of covariates while incorporating limited data for rarely detected species. Intercropping switchgrass in loblolly pine plantations slightly increased daily nest survival at the research plot scale (0.1 km2), although at a local scale (50 m2) switchgrass negatively influenced nest survival. A likely explanation supported by previous research is intercropping shifted community composition, favouring species with greater disturbance tolerance.

Data from: Density-dependent effects of a widespread invasive herbivore on tree survival and biomass during reforestation

Reforestation has been widely adopted as a solution to multiple global change issues. However, the role of herbivory by invasive species in the restoration of grassland to forest has received little attention. We conducted a field experiment to investigate the impacts of a widespread invasive mammalian herbivore, the European rabbit (Oryctolagus cuniculus), on trees planted in a landscape-scale reforestation program in south-eastern Australia. Three native tree species were planted inside and outside rabbit-proof exclosures within 10 experimental units, and a random half of the units were subjected to intensive and sustained rabbit control for the remainder of the experiment. Quarterly survival of trees, and total aboveground biomass at the conclusion of the experiment, were estimated using hierarchical Bayesian models. Control substantially reduced rabbit densities on the five treatment units relative to the five non-treatment units. Survival of trees planted outside exclosures was highest at lowest rabbit density and declined non-linearly with increasing rabbit density for all three tree species, but even very low rabbit densities had strong negative effects on the survival of trees outside exclosures. There was a three-way interaction between tree height, being outside an exclosure, and rabbit density. Smaller trees planted outside exclosures always had substantially lower overall survival than trees of the same height planted inside exclosures, and the magnitude of the difference increased with increasing rabbit density. Increasing rabbit densities reduced the overall survival of increasingly taller trees of all three species planted outside exclosures. The aboveground biomass of trees surviving outside exclosures was significantly greater in treatment units compared with non-treatment units for all three species. The combined effects of differential survival and accumulation of aboveground biomass led to higher biomasses inside exclosures relative to outside exclosures just 21 months after planting. The aboveground biomass of trees planted outside exclosures declined with increasing rabbit density, and was effectively zero when rabbit densities exceeded 100 active warren entrances/ha. These results demonstrate that invasive herbivores can rapidly arrest the conversion of grassland to forest. Invasive herbivores such as the European rabbit may need to be completely excluded in order to maximize the benefits of reforestation.

Data from: Climate drives adaptive genetic responses associated with survival in big sagebrush (Artemisia tridentata)

A genecological approach was used to explore genetic variation for survival in Artemisia tridentata (big sagebrush). Artemisia tridentata is a widespread and foundational shrub species in western North America. This species has become extremely fragmented, to the detriment of dependent wildlife, and efforts to restore it are now a land management priority. Common garden experiments were established at three sites with seedlings from 55 source-populations. Populations included each of the three predominant subspecies, and cytotype variations. Survival was monitored for five-years to assess differences in survival between gardens and populations. We found evidence of adaptive genetic variation for survival. Survival within gardens differed by source-population and a substantial proportion of this variation was explained by seed climate-of-origin. Plants from areas with the coldest winters had the highest levels of survival, while populations from warmer and drier sites had the lowest levels of survival. Survival was lowest, 36%, in the garden that was prone to the lowest minimum temperatures. These results suggest the importance of climatic driven genetic differences and their effect on survival. Understanding how genetic variation is arrayed across the landscape and its association with climate can greatly enhance the success of restoration and conservation.

opencc-zeroAug 2019View details →

Data from: Disentangling the effects of environmental conditions on wintering and breeding grounds on age-specific survival rates in a trans-Saharan migratory raptor

Migratory species are subject to environmental variability occurring on breeding and wintering grounds. Estimating the relative contribution of environmental factors experienced sequentially during breeding and wintering, and their potential interaction, to the variation of survival is crucial to predict population viability of migratory species. Here we investigated this issue for the Montagu's harrier Circus pygargus, a trans-Saharan migrant. We analysed capture-recapture data from a 29-yr long monitoring of wing-tagged offspring and adults at two study sites in France (Rochefort-RO & Maine-et-Loire-ML). The study period covers a climatic shift occurring in the Sahel with increasing rainfall following a period of droughts (Sahel greening). We found that harriers' adult survival in RO (between 1988 and 2005) varied over time and was sensitive to the interaction between the amount of rainfall in the Sahel and the annual mean breeding success, two proxies of prey availability. The occurrence of adverse conditions on breeding and wintering grounds in the same year decreased survival from 0.70-0.77 to 0.48 ± 0.05. Juvenile survival in RO was slightly more sensitive to conditions in Europe than in the Sahel. Unexpectedly, lower survival rates were found in years with higher mean breeding success, suggesting compensatory density feedbacks may operate. By contrast, adult survival in ML, monitored between 1999 and 2017, was higher compared to RO (0.76 ± 0.03 vs. 0.66 ± 0.02), remained constant and unaffected by any proxy of prey availability. This difference seems consistent with the fact that harriers in ML experienced better and especially less variable environmental conditions during breeding and wintering seasons compared to RO. Overall, we showed that survival of a migratory bird is sensitive to the level of variability in environmental conditions and that adverse conditions on wintering grounds can amplify the negative effects of conditions during the previous breeding season on birds' survival.

Data from: Better-surviving barn swallow mothers produce more and better-surviving sons

Sex allocation theory predicts that parents are selected to bias their progeny sex ratio (SR) towards the sex that will benefit the most from parental quality. Because parental quality may differentially affect survival of sons and daughters, a pivotal test of the adaptive value of SR adjustment is whether parents overproduce offspring of the sex that accrue larger fitness advantages from high parental quality. However, this crucial test of the long-term fitness consequences of sex allocation decisions has seldom been performed. In this study of the barn swallow (Hirundo rustica), we showed a positive correlation between the proportion of sons and maternal annual survival. We then experimentally demonstrated that this association did not depend on the differential costs of rearing offspring of either sex. Finally, we showed that maternal lifespan positively predicted lifespan of sons but not of daughters. Because in barn swallows lifespan is a strong determinant of lifetime reproductive success, the results suggest that mothers overproduce offspring of the sex that benefits the most from maternal quality. Hence, irrespective of mechanisms causing the SR bias and mother-son covariation in lifespan, we provide strong evidence that sex allocation decisions of mothers can highly impact on their lifetime fitness.

opencc-zeroDec 2013View details →

Data from: Female mating preferences and offspring survival: testing hypotheses on the genetic basis of mate choice in a wild lekking bird

Indirect benefits of mate choice result from increased offspring genetic quality and may be important drivers of female behaviour. 'Good-genes-for-viability' models predict that females prefer mates of high additive genetic value, such that offspring survival should correlate with male attractiveness. Mate choice may also vary with genetic diversity (e.g. heterozygosity) or compatibility (e.g. relatedness), where the female's genotype influences choice. The relative importance of these nonexclusive hypotheses remains unclear. Leks offer an excellent opportunity to test their predictions, because lekking males provide no material benefits and choice is relatively unconstrained by social limitations. Using 12 years of data on lekking lance-tailed manakins, Chiroxiphia lanceolata, we tested whether offspring survival correlated with patterns of mate choice. Offspring recruitment weakly increased with father attractiveness (measured as reproductive success, RS), suggesting attractive males provide, if anything, only minor benefits via offspring viability. Both male RS and offspring survival until fledging increased with male heterozygosity. However, despite parent–offspring correlation in heterozygosity, offspring survival was unrelated to its own or maternal heterozygosity or to parental relatedness, suggesting survival was not enhanced by heterozygosity per se. Instead, offspring survival benefits may reflect inheritance of specific alleles or nongenetic effects. Although inbreeding depression in male RS should select for inbreeding avoidance, mates were not less related than expected under random mating. Although mate heterozygosity and relatedness were correlated, selection on mate choice for heterozygosity appeared stronger than that for relatedness and may be the primary mechanism maintaining genetic variation in this system despite directional sexual selection.

Data from: Relative costs of offspring sex and offspring survival in a polygynous mammal

Costs of reproduction are expected to be ubiquitous in wild animal populations and understanding the drivers of variation in these costs is an important aspect of life-history evolution theory. We use a 43 year dataset from a wild population of red deer to examine the relative importance of two factors that influence the costs of reproduction to mothers, and to test whether these costs vary with changing ecological conditions. Like previous studies, our analyses indicate fitness costs of lactation: mothers whose calves survived the summer subsequently showed lower survival and fecundity than those whose calves died soon after birth, accounting for 5% and 14% of the variation in mothers' survival and fecundity, respectively. The production of a male calf depressed maternal survival and fecundity more than production of a female, but accounted for less than 1% of the variation in either fitness component. There was no evidence for any change in the effect of calf survival or sex with increasing population density.

opencc-zeroDec 2016View details →

Data from: Male-mimicking females increase male-male interactions, and decrease male survival and condition in a female-polymorphic damselfly

Biologists are still discovering diverse and powerful ways sexual conflicts shape biodiversity. The present study examines how the proportion of females in a population that exhibit male mimicry, a mating resistance trait, influences conspecific males' behavior, condition and survival. Like most female-polymorphic damselflies, Ischnura ramburii harbors both "andromorph" females, which closely resemble males, and sexually dimorphic "gynomorph" counterparts. There is evidence that male mimicry helps andromorphs evade detection and harassment, but males can also learn to target locally prevalent morph(s) via prior mate encounters. I hypothesized that the presence of male mimics could therefore predispose males to mate recognition errors, and thereby increase rates of costly male-male interactions. Consistent with this hypothesis, male-male interaction rates were highest in mesocosms containing more andromorph (vs. gynomorph) females. Males in andromorph-biased mesocosms also had lower final body mass and higher mortality than males assigned to gynomorph-majority treatments. Male survival and body mass were each negatively affect by mesocosm density, and mortality data revealed a marginally significant interaction between andromorph frequency and population density. These findings suggest that, under sufficiently crowded conditions, female mating resistance traits such as male mimicry could have pronounced indirect effects on male behavior, condition, and survival.

Data from: Biodiversity as insurance for sapling survival in experimental tree plantations

Biodiversity can insure ecosystems against declines in their functioning by increasing the mean level of ecosystem processes and decreasing the spatial or temporal variance of these processes. On this basis, mixing tree species is expected to be an effective management strategy to reduce the risk of planting failure in young plantations. We examined the effects of biodiversity insurance on sapling survival in three tree diversity experiments across Belgium. Based on the survival scoring of 89 254 saplings, planted in 126 plots with up to four-species mixtures, we tested two hypotheses: (i) variability in plot-level survival is lower for mixtures compared to monocultures due to compensation among the species (i.e. buffering effect) and (ii) mean survival is higher due to facilitation (i.e. performance-enhancing effect). Variation in plot-level survival decreased strongly with diversity, indicating a buffering effect. The risk of severe planting failure was reduced in mixtures because species exhibit different survival rates; therefore, mixing ensures that not all trees in the plantation are equally susceptible to environmental stressors. In contrast, the mean plot-level survival did not increase with diversity, and thus, an overall performance-enhancing effect was lacking. However, species-level analyses did show performance-enhancing effects, where some species profited from mixing while others did not. Synthesis and applications. We conclude that biodiversity through mixing tree species insures young experimental plantations against planting failure and is therefore highly recommended as a planting management strategy. The risk of large mortality gaps is reduced if tree plantation saplings are mixed at the scale of individual trees or small cells of trees.

opencc-zeroAug 2019View details →

Data from: Anti-parasite treatment results in decreased estimated survival with increasing Pb levels in the common eider Somateria mollissima

Field experiments where parasites are removed through treatment and contaminant levels in host tissues are recorded can provide insight into the combined effects of parasitism and contaminants in wild populations. In 2013 and 2014, we treated northern common eider ducks (Somateria mollissima) arriving at a breeding colony with either a broad-spectrum antihelminthic (PANACUR®) or distilled water, and measured their blood Pb levels. Breeding propensity and clutch sizes were inversely related to Pb in both treatment groups. In comparison, a negative effect of Pb on resight probability the following year was observed only in the anti-parasitic treatment (APT) group. These contrasting patterns suggest a long-term benefit to survival of intestinal parasitism in eiders experiencing Pb exposure. Arrival date of hens explained some, but not all, of the effects of Pb. We weigh the merits of different hypotheses in explaining our results, including protective bioaccumulation of Pb by parasites, condition-linked thresholds to costly reproduction, and the direct effects of APT on eider health. We conclude that variation in helminth parasitism influences survival in this migratory bird in counterintuitive ways.

opencc-zeroDec 2012View details →

Data from: Home loving boreal hare mitochondria survived several invasions in Iberia: the relative roles of recurrent hybridisation and allele surfing

Genetic introgression from a resident species into an invading close relative can result from repeated hybridisation along the invasion front and/or allele surfing on the expansion wave. Cases where the phenomenon is massive and systematic, such as for hares (genus Lepus) in Iberia, would be best explained by recurrent hybridisation but this is difficult to prove since the donor populations are generally extinct. In the Pyrenean foothills, Lepus europaeus presumably replaced Lepus granatensis recently and the present species border is parallel to the direction of invasion, so that populations of L. granatensis in the contact zone represent proxies of existing variation before the invasion. Among three pairs of populations sampled across this border, we find less differentiation of mtDNA across than along it, as predicted under recurrent hybridisation at the invasion front. Using autosomal microsatellite loci and X and Y-linked diagnostic loci, we show that admixture across the border is quasi-absent, making it unlikely that lack of interspecific mtDNA differentiation result from ongoing gene flow. Furthermore, we find that the local species ranges are climatically contrasted, making it also unlikely that ongoing ecology-driven movement of the contact account for mtDNA introgression. The lack of mtDNA differentiation across the boundary is mostly due to sharing of mtDNA from a boreal species currently extinct in Iberia (Lepus timidus) whose mitochondria have thus remained in place since the last deglaciation despite successive invasions by two other species. Home loving mitochondria thus witness past species distribution rather than ongoing exchanges across stabilised contact zones.

Data from: Conservation implications of ameliorating survival of little brown bats with White-Nose Syndrome

Management of wildlife populations impacted by novel threats is often challenged by a lack of data on temporal changes in demographic response. Populations may suffer rapid declines from the introduction of new stressors, but how demography changes over time is critical to determining long-term outcomes for populations. White-nose syndrome (WNS), an infectious disease of hibernating bats, has caused massive and rapid population declines in several hibernating species of bats in North America since the disease was first observed on the continent in 2006. Estimating annual survival rates and demographic trends among remnant colonies of hibernating bats that experienced mass mortality from WNS is needed to determine long-term population viability of species impacted by this disease. Using mark–recapture data on infected little brown bats (Myotis lucifugus), we estimated the first apparent annual survival rates for four years following WNS detection at a site. We found strong support for an increasing trend in annual survival, which improved from 0.68 (95% CI = 0.44–0.85) to 0.75 (95% CI = 0.51–0.89) for males and 0.65 (95% CI = 0.44–0.81) to 0.70 (95% CI = 0.50–0.84) for females. These results suggest that stabilization at remnant colonies after mass mortality from WNS may be due to improved survival and not from immigration from other areas. Despite ameliorating survival, our stochastic matrix projection model predicts continued declines for little brown bat populations (λ = 0.95), raising concern for the regional persistence of this species. We conducted a vital rate sensitivity analysis and determined that adult and juvenile survival, as opposed to fecundity, are the demographic parameters most important to target to maximize recovery potential of little brown bat populations in areas impacted by WNS.