Habitat Preferences of the Critically Endangered Greater Bamboo Lemur (Prolemur simus) and Densities of One of Its Primary Food Sources, Madagascar Giant Bamboo (Cathariostachys madagascariensis), in Sites with Different Degrees of Anthropogenic and Natural Disturbance

Understanding the habitat preferences of a species is critical to the management and conservation of its population. The Critically Endangered greater bamboo lemur, Prolemur simus, is patchily distributed across its geographic range, using a very limited fraction of its total area of occurrence. The ecological basis for this patchy distribution remains largely unexplained. We analyzed the local habitat factors affecting the habitat use of Prolemur simus and densities of one of its primary food sources Madagascar giant bamboo, Cathariostachys madagascariensis. We sampled vegetation and site characteristics along belt transects in mid-altitude rain forest areas of the Ankeniheny–Zahamena rain forest corridor in eastern Madagascar, with (N?=?10) and without (N?=?16) evidence of habitat use by Prolemur simus. In our study site the preferred habitat type of Prolemur simus appears to be primary forest stands with moderate to low levels of human disturbance, greater natural disturbance, high densities of large diameter bamboo, and high structural diversity in tree heights. Cathariostachys madagascariensis appears to exploit canopy gaps created by natural disturbances, and similarly often exploits areas of anthropogenic disturbance. We found the highest densities of bamboo to occur in areas of moderate anthropogenic disturbance, whereas larger diameter culms were associated with lower levels of disturbance and smaller culms with areas of high anthropogenic disturbance. Human use of the forest and protection of the habitat of Prolemur simus are not necessarily incompatible, but our data indicate that the severity and frequency of use should probably be relatively low. Our results suggest that in our study site management strategies that minimize human disturbances, promote structural diversity in tree heights, and maintain relatively high densities of large-culmed bamboo may benefit populations of Prolemur simus.     

New distributional records and conservation implications for the critically endangered greater bamboo lemur Prolemur simus

To improve our knowledge of the distribution of the critically endangered greater bamboo lemur Prolemur simus, we surveyed 6 sites in eastern Madagascar. We found its characteristic feeding signs at 5 sites and made a direct sighting at one of these. One site represents a northern extension of 45 km of the known extant range of the species. Two sites are located in a forest corridor approximately halfway between the previously known southern and northern populations, therefore suggesting a broadly continuous distribution of the species within its range rather than the previously suspected distribution of two distinct populations separated by a distance of over 200 km. Our results illustrate the benefit of species-focussed surveys in determining the true distribution of endangered species, a realistic measure which is necessary in order to assess their current status and to prioritise long-term conservation interventions.     

Conserving Europe’s most endangered butterfly: the Macedonian Grayling (Pseudochazara cingovskii)

The Macedonian Grayling is listed as critically endangered in the recent IUCN Red List of European butterflies because of its extreme rarity and habitat loss due to quarrying. This categorisation was, however, based on rather limited knowledge on its actual distribution, population size and habitat requirements. In 2012, we conducted field surveys to acquire more information. We found the species at six new sites extending its known range of suitable habitat to just under 10 km². The daily population size was estimated using capture-mark-recapture method in the most densely populated part of the Pletvar pass site at more than 650 individuals. Adults proved to be extremely sedentary, not moving far even within the continuous habitat on the same slope. Oviposition was observed on dry plant material and in a rock crevice close to the potential larval host plant Festuca sp. Quarrying is confirmed to be the main threat to the habitat of the Macedonian Grayling with five out of seven populated sites containing active marble quarries. Due to the enlargement of the known area of occupancy, its threat status would now be estimated at endangered. Despite the restricted knowledge about its distribution and trends in the population size, the IUCN criteria proved to be applicable to determine the threat status of a rare and localized butterfly such as Pseudochazara cingovskii. Its original assessment of being called the most threatened butterfly in Europe resulted in immediate research project and subsequent actions that will undoubtedly help to conserve it in the future.     

How limited is dispersal in the rare beetle, Cryptocephalus decemmaculatus (Chrysomelidae, Cryptocephalinae)?

As suitable habitat becomes increasingly fragmented the ability of a species to reach new areas may often dictate whether populations persist or perish. An understanding of dispersal ability is a prerequisite for informed management decisions. This is particularly true for species that have become restricted to one or a small number of sites, as is the case for several species of Cryptocephalus beetle in the UK. Using mark–release–recapture, host-plant marking and direct observations we investigated population size, movement through suitable habitat and the flight behaviour of Cryptocephalus decemmaculatus. In the UK this species is known from only two sites and it is listed as a priority species on the UK Biodiversity Action Plan. At the time of the study, the one known English site for this species supported a population of ~500 individuals. The adult beetles move through their habitat using suitable host-plants as ‘stepping stones’. There appears to be no interchange of adults between sub-populations that are separated by small areas of unsuitable habitat (e.g. small tracts of woodland or areas devoid of scrub), a result reinforced by studies of genetic differentiation between sub-populations. The small population size of this beetle and its association with, mid-successional habitats makes it vulnerable to local extinction. Furthermore, its limited dispersal ability means that other habitat patches are unlikely ever to be colonised naturally.     

Relatedness and other finescale population genetic analyses in the threatened eastern box turtle (Terrapene c. carolina) suggest unexpectedly high vagility with important conservation implications

Genetic analyses of populations are essential to the conservation of threatened and cryptic taxa such as Chelonians. Turtles and tortoises are among the most imperiled vertebrate taxa worldwide, yet many of the natural history traits remain unknown leaving management decisions ill- or improperly informed. The eastern box turtle Terrapene c. carolina is no exception, with many gaps in our knowledge about traits such as juvenile dispersal and patterns of relatedness across the landscape, especially as it is a species not particularly tied to water and vulnerable to human disturbance. In addition, all long-term studies of this species have documented demographic population declines, even in protected habitats. In this study we explore finescale population structuring, gene flow, dispersal, and relatedness at four sites across the species range. These sites vary in habitat fragmentation and surrounding habitat quality. Many radiotelemtery and mark-recapture studies suggest that Terrapene spp. have a sedentary natural history, with small and temporally conserved home ranges and little propensity for dispersal. Based on these data we predicted that populations would be highly structured at fine geographic scales, closely related individuals (1st- and 2nd-degree relatives) would coexist in close proximity, and individuals exhibiting transient behavior would be true transients. All sites had low levels of population structuring, mean pairwise relatedness values were statistically zero, over 90 % of pairs of individuals were unrelated, 4.4–8.7 % were half-siblings, and fewer than 1.0 % were full siblings or parent-offspring pairs. These patterns were consistent across all four sites, regardless of habitat fragmentation. Furthermore, while some related pairs were found within a few meters of each other, others ranged up to 33 km apart. We found that one of two individuals with transient behavior was indeed a true genetic transient. These findings suggest that box turtles may be much more vagile than current management practices recognize. As most turtle species are strongly affected by anthropogenic disturbance, many may require much larger contiguous blocks of intact habitat for species persistence as the box turtle likely does. Management plans may therefore need to be updated to allow for safe and effective long-distance dispersal at the appropriate spatial scales in order to maintain genetic health of these species.     

The NATURA 2000 database as a tool in the analysis of habitat selection at large scales: factors affecting the occurrence of pine and stone martens in Southern Europe

Most studies on habitat selection among animals are conducted at local scales, whereas reliable determination of species requirements at larger spatial scales can be problematic. We used data available for NATURA 2000 sites to determine the habitat requirements of two relatively widespread and common species—pine marten Martes martes and stone marten Martes foina—in Southern Europe. Using presence-absence data, we applied statistical models at two spatial scales. At the local scale (within the dispersal distances of the species), sites occupied by martens were compared with unoccupied sites using buffers of different sizes, whereas at the regional scale, unoccupied sites were selected randomly. To adjust for spatial autocorrelation of data, penalised quasi-likelihood approximations were used. Both species of martens demonstrated preferences for areas with higher proportions of forest cover and steeper terrain. At the local, but not at the regional, scale, pine martens occurred at lower elevations, whilst stone martens occurred at higher elevations. We found that climatic variables (mean temperature, precipitation) had no significant effect on the presence of the martens. The results of our analyses generally confirmed findings of previous studies on habitat selection of both marten species in Southern Europe. This demonstrates the utility of data collected for NATURA 2000 sites for use in various analyses such as conservation planning and evaluating the impact of climate change on the distribution of animal species.     

A Potential Distribution Model and Conservation Plan for the Critically Endangered Ecuadorian Capuchin, Cebus albifrons aequatorialis

Conservation actions that effectively and efficiently target single, highly threatened species require current data on the species’ geographic distribution and environmental associations. The Ecuadorian capuchin (Cebus albifrons aequatorialis) is a critically endangered primate found only in the fragmented forests of western Ecuador and northern Peru, which are among the world’s most severely threatened ecosystems. We use the MAXENT species distribution modeling method to model the potential distribution and environmental associations of Cebus albifrons aequatorialis, using all known presence localities recorded within the last 2 decades as well as 13 climate, topography, vegetation, and land-use data sets covering the entire geographic range of the subspecies. The environmental conditions that our model predicted to be ideal for supporting Cebus albifrons aequatorialis included ≥20% tree cover, mild temperature seasonality, annual precipitation <2000 mm, and low human population density. Our model identified 5028 km² of suitable habitat remaining, although many of these forest fragments are unprotected and are unlikely to support extant populations. Using the median population density across all sites for which data are available, we estimate the total carrying capacity of the remaining habitat to be 12,500 total individuals. The true number of remaining individuals is likely to be considerably lower due to anthropogenic factors. We highlight four critical regions of high predicted suitability in western Ecuador and northern Peru on which immediate conservation actions should focus, and we lay out clear priorities to guide conservation actions for ensuring the long-term survival of this gravely threatened and little known primate.     

Current conservation status of Germain’s langur (<Emphasis Type="Italic">Trachypithecus germaini</Emphasis>) in Vietnam

Following the split of the silvered langurs of Indochina into two species based on molecular and phenotypic data, there is a need to reevaluate their distribution and update their conservation status. Here, we report the distribution and assess the population size of Germain’s langur (Trachypithecus germaini) within its known range across Vietnam. We confirmed this species at six of seven survey sites in different habitats within three provinces in the Mekong Delta Region, including semi-evergreen forest at the Seven Mountains of An Giang Province, mangrove forest in Ngoc Hien and Nam Can Districts and Melaleuca forest in U Minh Ha National Park of Ca Mau Province, and limestone forest at Kien Luong Karst Area and semi-evergreen and evergreen forests at Phu Quoc National Park of Kien Giang Province. We found no evidence of this species in Mui Ca Mau National Park, Ca Mau Province where it was previously reported. We conservatively estimate that the total population of Germain’s langurs in Vietnam consists of 362–406 individuals, with the largest population found in the Kien Luong Karst Area. Hunting and habitat loss are severely impacting Germain’s langur, resulting in the extirpation of the population in Mui Ca Mau National Park and small, isolated populations in the Seven Mountains and Ngoc Hien and Nam Can Districts. However, the ability of this species to inhabit a wide range of forest types, and its increasing population sizes in Phu Quoc National Park and Kien Luong Karst Area, provide signs of hope that continued conservation actions may help in its long-term survival.     

Identifying habitat linkages to maintain connectivity for corridor dwellers in a fragmented landscape

Anthropogenic habitat fragmentation typically precedes conservation planning; maintaining remaining linkages among core habitat areas can thus become a key conservation objective. Identifying linkages for dispersal and ensuring those linkages have long-term protection and management are challenging tasks for wildlife managers. These tasks can be especially daunting for smaller species with low mobility, termed corridor dwellers, which must maintain sustainable populations within corridors. Between May 2007 and June 2009, we collected occurrence locations for a corridor dweller, the Palm Springs pocket mouse (Perognathus longimembris bangsii), from museums, previous research, and our own field sampling. We used those data to model their suitable niche space and then identify suitable linkages between proposed conservation areas. We used a partitioned Mahalanobis D² statistic to create a spatially explicit niche model describing the distribution of a suitable niche space, and we validated the model statistically, with live trapping and with burrowing owl (Athene cunnicularia) diets. Our model identified soil characteristics, topographic ruggedness, and vegetation as variables delimiting Palm Springs pocket mouse habitat; sand content of the soils was an especially important characteristic. Our historic distribution model identified 120,000–90,000 ha as historically potential Palm Springs pocket mouse habitat; roughly 39% of that has been lost to more recent development. Most of the remaining suitable habitat occurred in the northwestern portion of the valley. We modeled habitat within core reserves as well as within proposed linkages between those reserves as having high similarity to known occupied habitats. Live trapping in areas with high (≥0.95) Habitat Suitability Index (HSI) values resulted in captures at 66% of those locations and, along with burrowing owl diets, refined a qualitative model as to what constituted a suitable Palm Springs pocket mouse corridor. While most corridor analyses have focused on mobile species which may traverse corridors in hours, days, or weeks, linkages for corridor dwellers must include habitat for sustaining multi-generational populations. This requires evaluating whether continuous suitable habitat exists within proposed corridors. Our research demonstrates how niche modeling can provide a landscape-scale view of the distribution of suitable habitat to evaluate conservation objectives for connectivity. © 2011 The Wildlife Society.     

A Meta-Analysis of Local Adaptation in Plants

Local adaptation is of fundamental importance in evolutionary, population, conservation, and global-change biology. The generality of local adaptation in plants and whether and how it is influenced by specific species, population and habitat characteristics have, however, not been quantitatively reviewed. Therefore, we examined published data on the outcomes of reciprocal transplant experiments using two approaches. We conducted a meta-analysis to compare the performance of local and foreign plants at all transplant sites. In addition, we analysed frequencies of pairs of plant origin to examine whether local plants perform better than foreign plants at both compared transplant sites. In both approaches, we also examined the effects of population size, and of the habitat and species characteristics that are predicted to affect local adaptation. We show that, overall, local plants performed significantly better than foreign plants at their site of origin: this was found to be the case in 71.0% of the studied sites. However, local plants performed better than foreign plants at both sites of a pair-wise comparison (strict definition of local adaption) only in 45.3% of the 1032 compared population pairs. Furthermore, we found local adaptation much more common for large plant populations (>1000 flowering individuals) than for small populations (<1000 flowering individuals) for which local adaptation was very rare. The degree of local adaptation was independent of plant life history, spatial or temporal habitat heterogeneity, and geographic scale. Our results suggest that local adaptation is less common in plant populations than generally assumed. Moreover, our findings reinforce the fundamental importance of population size for evolutionary theory. The clear role of population size for the ability to evolve local adaptation raises considerable doubt on the ability of small plant populations to cope with changing environments.     

Comparative Population Dynamics of Two Closely Related Species Differing in Ploidy Level

Background

Many studies compare the population dynamics of single species within multiple habitat types, while much less is known about the differences in population dynamics in closely related species in the same habitat. Additionally, comparisons of the effect of habitat types and species are largely missing.

Methodology and Principal Findings

We estimated the importance of the habitat type and species for population dynamics of plants. Specifically, we compared the dynamics of two closely related species, the allotetraploid species Anthericum liliago and the diploid species Anthericum ramosum, occurring in the same habitat type. We also compared the dynamics of A. ramosum in two contrasting habitats. We examined three populations per species and habitat type. The results showed that single life history traits as well as the mean population dynamics of A. liliago and A. ramosum from the same habitat type were more similar than the population dynamics of A. ramosum from the two contrasting habitats.

Conclusions

Our findings suggest that when transferring knowledge regarding population dynamics between populations, we need to take habitat conditions into account, as these conditions appear to be more important than the species involved (ploidy level). However, the two species differ significantly in their overall population growth rates, indicating that the ploidy level has an effect on species performance. In contrast to what has been suggested by previous studies, we observed a higher population growth rate in the diploid species. This is in agreement with the wider range of habitats occupied by the diploid species.     

Life history strategy influences parasite responses to habitat fragmentation

Anthropogenic habitat use is a major threat to biodiversity and is known to increase the abundance of generalist host species such as rodents, which are regarded as potential disease carriers. Parasites have an intimate relationship with their host and the surrounding environment and it is expected that habitat fragmentation will affect parasite infestation levels. We investigated the effect of habitat fragmentation on the ecto- and endoparasitic burdens of a broad niche small mammal, Rhabdomys pumilio, in the Western Cape Province, South Africa. Our aim was to look at the effects of fragmentation on different parasite species with diverse life history characteristics and to determine whether general patterns can be found. Sampling took place within pristine lowland (Fynbos/Renosterveld) areas and at fragmented sites surrounded and isolated by agricultural activities. All arthropod ectoparasites and available gastrointestinal endoparasites were identified. We used conditional autoregressive models to investigate the effects of habitat fragmentation on parasite species richness and abundance of all recovered parasites. Host density and body size were larger in the fragments. Combined ecto- as well as combined endoparasite taxa showed higher parasite species richness in fragmented sites. Parasite abundance was generally higher in the case of R. pumilio individuals in fragmented habitats but it appears that parasites that are more permanently associated with the host’s body and those that are host-specific show the opposite trend. Parasite life history is an important factor that needs to be considered when predicting the effects of habitat fragmentation on parasite and pathogen transmission.     

Matrix Intensification Affects Body and Physiological Condition of Tropical Forest-Dependent Passerines

Matrix land-use intensification is a relatively recent and novel landscape change that can have important influences on the biota within adjacent habitat patches. While there are immediate local changes that it brings about, the influences on individual animals occupying adjacent habitats may be less evident initially. High-intensity land use could induce chronic stress in individuals in nearby remnants, leading ultimately to population declines. We investigated how physiological indicators and body condition measures of tropical forest-dependent birds differ between forest adjacent to surface mining sites and that near farmlands at two distances from remnant edge in southwest Ghana. We used mixed effects models of several condition indices including residual body mass and heterophil to lymphocyte (H/L) ratios (an indicator of elevated chronic stress) to explore the effect of matrix intensity on forest-dependent passerines classed as either sedentary area-sensitive habitat specialists or nomadic generalists. Individual birds occupying tropical forest remnants near surface mining sites were in poorer condition, as indicated by lower residual body mass and elevated chronic stress, compared to those in remnants near agricultural lands. The condition of the sedentary forest habitat specialists white-tailed alethe, Alethe diademata and western olive sunbird, Cyanomitra obscura was most negatively affected by high-intensity surface mining land-use adjacent to remnants, whereas generalist species were not affected. Land use intensification may set in train a new trajectory of faunal relaxation beyond that expected based on habitat loss alone. Patterns of individual condition may be useful in identifying habitats where species population declines may occur before faunal relaxation has concluded.     

Sleeping and Ranging Behavior of the Sambirano Mouse Lemur, <Emphasis Type="Italic">Microcebus sambiranensis</Emphasis>

Primates require secure sleeping sites for periods of rest, but despite their importance, the characteristics of desired sleeping sites are poorly known. Here we investigated the sleeping ecology of a radio-collared population of the Sambirano mouse lemur, Microcebus sambiranensis, during the nonreproductive season in the Anabohazo forest, northwestern Madagascar. We also investigated their ranging behavior and examined the spatial distribution of sleeping sites within the home ranges of the collared individuals. We took measurements of the sleeping tree’s physical characteristics and recorded the number of collared individuals using each sleeping site. We found that M. sambiranensis generally use foliage sleeping sites more frequently than tree holes and individuals slept more frequently in densely foliated trees than in sparsely foliated trees, often alone. We observed no significant differences in home range size or nightly travel distance between males and females; however, home ranges were smaller than those described for other mouse lemur species. Finally, we found that M. sambiranensis sleep peripherally and forage centrally within their home ranges, a behavior not previously described for mouse lemurs. Our results indicate profound differences in the social organization between M. sambiranensis and other mouse lemur species described in the literature, suggesting species-specificity in mouse lemur ecology. Understanding the sleeping ecology and ranging behavior of mouse lemurs is of great importance to their conservation, as these data facilitate the planning of long-term reforestation, habitat management, and population assessment.     

A graph theoretic approach for modelling tiger corridor network in Central India-Eastern Ghats landscape complex,India

Wildlife habitat corridors are components of landscapes, which facilitate the movement of organisms and processes between areas of intact habitat, and thus provide landscape corridor as well as serve as an ideal component to study and understand physiological ecology. Corridors are thus regions within a given landscape that generally comprise native vegetation, and connect otherwise fragmented, disconnected, non-contiguous wildlife habitat patches in the landscape. The purpose of designing corridors as a conservation strategy is primarily to counter, and to the extent possible, mitigate the impacts of habitat fragmentation and loss on the biodiversity of the landscape, as well as support continuance of land use for essential local and global economic activities in the region of reference.In this paper, we use game theory and graph theory to model and design a wildlife corridor in the Central India – Eastern Ghats landscape complex, with tiger (Panthera tigris tigris) as the focal species. We construct a graph using the habitat patches supporting wild tiger populations in the landscape complex as vertices and the possible paths between these vertices as edges. A cost matrix is constructed to indicate the cost incurred by the tiger for passage between the habitat patches in the landscape (based on Shelford's Law of Tolerance), by modelling a two-person Prisoner's Dilemma game. A minimum spanning tree is then obtained by employing Kruskal's algorithm, which would suggest a feasible tiger corridor network for the tiger population within the landscape complex. Additionally, analysis of the graph is done using various centrality measures, in order to identify and focus on potentially important habitat patches, and their potential community structure. Correlation analysis is performed on the centrality indices to draw out interesting trends in the network.     

广西恩城保护区黑叶猴种群数量和保护现状

黑叶猴是栖息于喀斯特石山地区的珍稀濒危灵长类动物,由于非法捕杀和栖息地丧失,种群数量急剧减少。2017年10-12月,我们采用样方法调查恩城国家级自然保护区及其周边地区黑叶猴的种群分布、数量及保护现状,分析其致危因素,为制定有效管理行动计划提供理论依据。本次调查共记录到黑叶猴夜宿地89处,其中有43处夜宿地下方有新鲜排泄物。结合本次调查和访问,确定黑叶猴的种群数量为18群100~105只,包括1只全白化黑叶猴成年雌性个体;其中11群分布在保护区内,7群分布在保护区外。猴群由3~12只个体组成。栖息地破碎化和退化是威胁恩城保护区黑叶猴种群生存的主要因素。     

Information thresholds,habitat loss and population persistence in breeding birds

The combination of spatial structure and non‐linear population dynamics can promote the persistence of coupled populations, even when the average population growth rate of the patches seen in isolation would predict otherwise. This phenomenon has generally been conceptualized and investigated through the movement of individuals among patches that each holds many individuals, as in metapopulation models. However, population persistence can likewise increase as the result of individuals moving among sites (e.g. breeding territories) within in a single patch. Here I examine the latter: individuals making small‐scale informed decisions with respect to where to breed can promote population persistence in poor environments. Based on a simple algebraic model, I demonstrate information thresholds, and predict that greater information use is required for population persistence under lower spatial heterogeneity in habitat quality, all else equal. Second, I implement an individual‐based model to explore prior experience and prospecting on conspecific success within a more complex, and spatially heterogeneous environment. Uniquely, I jointly examine the effects of simulated habitat loss, spatial heterogeneity prior to habitat, and variation in information gathering on population persistence. I find that habitat loss accelerates population quasi‐extinction risk; however, information use reduces extinction probabilities in proportion to the level of information gathering. Per capita reproductive success declines with number of breeding sites, suggesting that information‐mediated Allee effects may contribute to extinction risk. In conclusion, my study suggests that populations in a changing world may be increasingly vulnerable to extinction where patch size and spatial heterogeneity constrain the effectiveness of information‐use strategies.     

Rhinanthus minor population genetic structure and subspecies: Potential seed sources of a keystone species in grassland restoration projects

In the last few decades unimproved semi-natural grasslands have been affected by intensification of land use and habitat fragmentation. Because of their biodiversity these species-rich grasslands are of high conservation importance and efforts are under way to restore such habitats. Detailed knowledge of within species diversity will aid deciding on the optimal seed source for such restoration projects, e.g. local genotypes or ecotypes. Rhinanthus minor is a species that is typically found in semi-natural grasslands and is commonly used in grassland restoration projects. This is because R. minor is a hemiparasitic plant that takes minerals and nutrients from its host, which in turn decreases the host's biomass and leads to opportunities for less competitive species in the vegetation. Here, we investigate genetic diversity within and between R. minor populations. This allowed us to test whether the six different subspecies of R. minor that have been described in the UK, based on their morphology, flowering time, and habitat, can be differentiated using molecular markers. We identified moderate levels of genetic differentiation between R. minor populations within the UK. In addition, R. minor individuals from the UK appear to be distinct from R. minor and Rhinanthus angustifolius individuals from other European countries based on microsatellite genotyping and DNA sequencing of cpDNA and rDNA ITS. The molecular markers used in the current study did not separate populations of R. minor based on either their subspecies or habitat. The implication for the use of R. minor in grassland restoration projects seems to be that it is not necessary to use local seeds or seeds from the same subspecies.     

Better up,worse down: bidirectional consequences of three decades of climate change on a relict population of Erebia cassioides

Orophilous species are often unable to escape the consequences of climate change because mountains are surrounded by unsuitable habitats. Among them, several endemic species belonging to the genus Erebia Dalman (Lepidoptera, Nymphalidae, Satyrinae) can be considered as key species to assess the risk of biodiversity loss of mountain habitats. The aim of this paper is to measure changes that have occurred in the altitudinal distribution of Erebia cassioides on the Pollino Massif (Southern Italy) during the last 37 years. Sixteen sites sampled in 1975 have been resampled after about three decades (2004, 2012). In 1975 56 % of the sampled population inhabited sites above and 44 % sites below the treeline, while in 2004 and 2012 99 % of the population were observed above the treeline. Furthermore, we observed an uphill shift of 180 m in the barycentre altitude of the species distribution and an unexpected increased density of the population above the treeline which led to a range reduction coupled to population increase of E. cassioides. This pattern contrasts with the usually observed one that couples habitat reduction to population decreasing. The reason for the observed pattern is unclear, but the implication for conservation strategies could be important if confirmed for other species. In fact, during coming decades local extinctions as a consequence of climate change might be fewer and more delayed than expected, and relict populations of cold adapted species could be preserved for a longer time span within optimal habitat refugia.     

Limited Pollen Dispersal Contributes to Population Genetic Structure but Not Local Adaptation in Quercus oleoides Forests of Costa Rica

Background

Quercus oleoides Cham. and Schlect., tropical live oak, is a species of conservation importance in its southern range limit of northwestern Costa Rica. It occurs in high-density stands across a fragmented landscape spanning a contrasting elevation and precipitation gradient. We examined genetic diversity and spatial genetic structure in this geographically isolated and genetically distinct population. We characterized population genetic diversity at 11 nuclear microsatellite loci in 260 individuals from 13 sites. We monitored flowering time at 10 sites, and characterized the local environment in order to compare observed spatial genetic structure to hypotheses of isolation-by-distance and isolation-by-environment. Finally, we quantified pollen dispersal distances and tested for local adaptation through a reciprocal transplant experiment in order to experimentally address these hypotheses.

Results

High genetic diversity is maintained in the population and the genetic variation is significantly structured among sampled sites. We identified 5 distinct genetic clusters and average pollen dispersal predominately occurred over short distances. Differences among sites in flowering phenology and environmental factors, however, were not strictly associated with genetic differentiation. Growth and survival of upland and lowland progeny in their native and foreign environments was expected to exhibit evidence of local adaptation due to the more extreme dry season in the lowlands. Seedlings planted in the lowland garden experienced much higher mortality than seedlings in the upland garden, but we did not identify evidence for local adaptation.

Conclusion

Overall, this study indicates that the Costa Rican Q. oleoides population has a rich population genetic history. Despite environmental heterogeneity and habitat fragmentation, isolation-by-distance and isolation-by-environment alone do not explain spatial genetic structure. These results add to studies of genetic structure by examining a common, tropical tree over multiple habitats and provide information for managers of a successional forest in a protected area.