Showing papers in "Animal Conservation in 2017"

Seasonality and human disturbance alter brown bear activity patterns: implications for circumpolar carnivore conservation?

Abstract: Wildlife may adapt activity patterns to daily and seasonal variations in environmental factors and human activity. At the daily scale, diurnal or nocturnal activity can be a response to variations in food availability and/or human avoidance. At the seasonal scale, variation in prey vulnerability underlies the influence of predators on prey population dynamics, which is of management concern when predation affects domestic species. We analyzed the movement patterns of 133 GPS-collared brown bears in three study areas in Sweden in spring, when bears prey on the calves of domestic reindeer and moose, and in summer–early fall, when bears rely mostly on berries, in three areas with a gradient of human disturbance. In spring, the bears' daily movement patterns and time of predation on ungulates overlapped. In summer–early fall, when bears are hyperphagic to store fat for hibernation and reproduction, variation in the degree of nocturnal behavior among study areas likely reflected behavioral adjustments to reduce the risk of encountering people. Flexibility in daily movement patterns by large carnivores may help them survive in human-dominated landscapes, but behavioral changes may also reflect environmental degradation, for example human disturbance influencing foraging opportunities. Diurnal human activity disturbs the carnivores, but that does not hinder depredation on reindeer, because it occurs mostly at night. Thus, ideally carnivores and reindeer should be separated spatially to reduce depredations. A zoning system prioritizing carnivore conservation and reindeer herding in different areas might help reduce a long-lasting conflict.

Defaunation and biomass collapse of mammals in the largest Atlantic forest remnant

Abstract: Large continuous rainforests are the main hope for sustaining the population of large-bodied vertebrates that cannot cope with fragmentation or unsustainable hunting. The Brazilian Atlantic forest is considered a biodiversity hotspot and although highly fragmented, it still contains large forest patches that may be important for the conservation of mammals that require large areas. Here, we estimated species richness, density and biomass of medium- and large-sized mammals along the largest remnant of the Atlantic rainforest, Brazil (the Serra do Mar bioregion), an estimated area of 8000 km2. We recorded 44 species based on 4090 km of diurnal line transects and camera traps, animal tracks and interviews in 11 continental regions and two large land-bridge islands. We found high levels of similarity in mammalian composition between pairs of sites in the continental forest sites (0.84–1), but much lower similarity between pairs from the continental forest sites and the two large land-bridge islands (0.29–0.74) indicating potential local extinctions or poor dispersal of continental mammals to these islands. In addition, we found that the density and biomass varied 16- and 70-fold among sites, respectively. Mammalian biomass declined by up to 98% in intensively hunted sites and was 53-fold lower than in other Neotropical non-fragmented forests. Although this large forest remnant is able to maintain a high diversity of medium- and large-bodied mammal species, their low density and biomass may affect the long-term persistence of these populations and the ecosystem services they provide.

Ecotourism marketing alternative to charismatic megafauna can also support biodiversity conservation

Abstract: Charismatic species are the main attractor of ecotourists to protected areas, but this narrow interest leads to under-appreciation of other biodiversity as well as cultural values of protected areas. Many protected areas with high conservation value, but little funding, lack charismatic species. Exploring tourists' preferences alternative to charismatic species may help identify ecotourism markets that are more likely to support such areas. We used a choice experiment and latent class model to explore tourists' heterogeneous preference for biodiversity and biodiversity-related activities in South African national parks. We found that tourists' preferences were not restricted to charismatic species, but extended to less charismatic biodiversity, as well as to landscapes. In addition, biodiversity-related activities, such as camping and game drives, the sense of wilderness attached to the place tourists were visiting and accessibility of protected areas, also affected tourists' preferences. Particularly, domestic tourists, as well as more experienced international tourists, were more likely to support initiatives that promote a broader biodiversity experience than charismatic species alone, and were prepared to travel longer distances to do so. Our results reveal new opportunities to promote and support biodiversity conservation at sites where only less charismatic biodiversity is present. In addition, our results may help inform land-use planning based on public preferences for biodiversity conservation, incorporating sense of place.

Adverse effects of artificial illumination on bat drinking activity

Abstract: Artificial illumination at night (ALAN) alters many aspects of animal behaviour. Commuting and foraging bats have been found to be affected by ALAN, but no study has yet addressed the impact of lighting on drinking activity, despite its critical importance for bats. We experimentally illuminated cattle troughs used by drinking bats at four forest sites in Italy, and compared drinking activity and foraging activity under lit and dark conditions. We predicted that (1) the number of bat species and drinking events will be lower under illumination and (2) forest bat species will be more affected than edge specialists. We recorded 2549 drinking events from 12 species or species groups, most of which decreased drinking activity under illumination. The effects of ALAN on drinking were stronger than on foraging. Forest species never drank when the light was on. Edge-foraging species reduced drinking activity while also increasing foraging under lit conditions. We highlight a previously overlooked negative effect of ALAN on bats, whose implications may be locally catastrophic. Given the importance of water sites for both bat foraging and drinking, their illumination should be forbidden, appropriately mitigated or, if necessary, compensated for with the creation of alternative drinking sites.

All roads lead to Iran: Predicting landscape connectivity of the last stronghold for the critically endangered Asiatic cheetah

Abstract: Effective conservation solutions for small and isolated wildlife populations depend on identifying and preserving critical biological corridors and dispersal routes. With a worldwide population of ≤70 individuals, the critically endangered Asiatic cheetah Acinonyx jubatus venaticus persists in several fragmented nuclei in Iran. Connectivity between nuclei is crucial for the survival of this subspecies, but detailed information to guide conservation actions is lacking. We developed a resistance surface that predicted cost of cheetah movement as functions of topographical complexity, human development, surface water and landscape protection level. We predicted alternative models for the landscape connectivity of Asiatic cheetahs, considering the combination of relative landscape resistance and different dispersal ability scenarios. We predicted that core connected habitat patches are concentrated in three sub-regions, and within these sub-regions, populations were predicted to be broken up into two to eight isolated patches, depending on the dispersal ability scenario. Despite the achievements of recent conservation initiatives, long-term survival of the Asiatic cheetah in Iran is threatened by the combination of its small population size and fragmented distribution. We propose that conservation of the Asiatic cheetah urgently requires integrated landscape-level management to reduce mortality risk, protect core areas and corridors, and ultimately establish stepping-stone populations to integrate this fragmented population.

Landscape connectivity losses due to sea level rise and land use change

Abstract: A fundamental problem in landscape ecology is understanding the isolating effects of different patterns of habitat loss and fragmentation on species and ecosystems. In the 21st century, urban development and sea level rise (SLR) are predicted to affect large areas of the United States, further exacerbating already fragmented and densely populated landscapes. Increasing or restoring habitat connectivity may ameliorate these effects, but the broad-reaching efforts required to assess current and future changes to connectivity, especially in low-lying areas vulnerable to SLR, are still under development. To address these issues, we strategically identified a small group of regionally significant species that represent a range of characteristics and ecological requirements useful for examining landscape connectivity. We used expert opinion to parameterize divergent species responses (i.e. resistance) to landscape features and to assess permeability of the landscape. From this, we estimated contemporary and future low-resistance habitat cores in the year 2100. We modeled six species for habitat connectivity using a multiscaled circuit theory-based approach and analysed them collectively to indicate landscape connectivity across the Southeastern United States. Using this approach, we were able to forecast changing connectivity patterns based on predicted urbanization and SLR. Our results suggest that there will be a 41% reduction in the number of low-resistance cores and a 35% decrease in mean area of remaining cores. In addition, current areas of high landscape connectivity will become more fragmented as future connectivity values indicate a more homogenized landscape structure. In the future landscape, pathways for connectivity are likely to move inland and northward as sea level and urbanization pressures increase. Our results may inform more comprehensive planning initiatives regionally or nationally, while simultaneously providing a multiscaled context for localized planning efforts.

Noise from a phantom road experiment alters the age structure of a community of migrating birds

Abstract: Several past studies have demonstrated the effects of anthropogenic noise on populations of animals. Yet, differing effects of noise by age and subsequent changes in the age structure of populations are poorly understood. We experimentally tested the effects of traffic noise alone on the age structure of a community of migrating birds at a fall stopover site in south-western Idaho using an array of speakers – creating a phantom road – that replicated the sound of a roadway without other confounding aspects of roads. Both hatch-year and adult birds were negatively affected by noise – having lower capture rates, lower body condition and lower stopover efficiency along the phantom road when the noise was on compared to control conditions. However, hatch-year birds responded more strongly which lead to a significant shift in the ratio of hatch-year to adult birds under noisy conditions. Our previous work using the phantom road demonstrated that traffic noise can degrade the quality of a stopover site by affecting the ability of migrating birds to gain body condition. Here, we demonstrate differences between age classes such that although noise degrades habitat for both hatch-year and adult migrants, there are still differences in responses to noise between age groups. Despite alternative explanations of our results such as changes in behavior affecting capture likelihood, evidence suggests that younger birds avoided the phantom road more than adult birds perhaps because of different tradeoffs between foraging and predation risk and differing strategies of site selection during migration.

Testing the demographic effects of divergent immigrants on small populations of Trinidadian guppies

Abstract: Augmenting small and isolated populations with immigrants from elsewhere is a potentially powerful, yet controversial management tool. The goal of this approach was to increase population sizes via demographic and/or genetic rescue, but augmentation can also have the unintended consequence of breaking down local adaptation and reducing population fitness through outbreeding depression. In theory, outbreeding depression is more likely the more divergent immigrants are from the recipient population. Managers should therefore choose immigrant populations that are as adaptively and genetically similar as possible. However, for species of conservation concern, divergent source populations are often the only option. A crucial question that remains in applied conservation is whether the positive effects of augmentation with divergent immigrants will outweigh the potential risks of outbreeding depression. Here, we evaluate the demographic effects of augmenting small, inbred laboratory populations of Trinidadian guppies with two different types of immigrants: (1) adaptively divergent but genetically similar or (2) adaptively similar but genetically divergent, and compare them against the demography of control populations with no immigration. After 1–2 generations, we found that adult abundance remained constant or slightly declined over the duration of the experiment in the control populations. In contrast, adult recruitment and total abundance increased in augmented populations. Furthermore, treatments that received immigrants from the adaptively similar but genetically divergent population attained overall larger population sizes than those that received immigrants from the adaptively divergent but genetically similar population. Although our experimental design could not parse out the effects of demographic and genetic rescue, our results do suggest that augmentation can be better than no action, even in situations where only divergent immigrant sources are available.

Global correlates of extinction risk in freshwater crayfish

Abstract: Global trait-based analyses can shed light on the factors predisposing species to high extinction risk, and can help bridge knowledge gaps in speciose and poorly known taxa. In this paper, I conduct the first global comparative study of crayfish extinction risk. I collated data on intrinsic (biology and ecology) and extrinsic (environment and threats) factors for 450 crayfish species assessed on the IUCN Red List. Phylogenetic multiple regression models were used to identify correlates of risk in all species; in centres of diversity (American cambarids and Australian parastacids); and among threat types (agriculture, water management, pollution). I assessed the relative ability of threat maps quantifying specific threats (e.g. river fragmentation, mercury deposition) or a generic threat (human population density) to predict crayfish extinction risk. I also quantified the effects of range size on extinction risk with variation partitioning and multiplicative bivariate regressions. Crayfish with small range size, small body size, habitat dependency on caves, and with ranges in areas of low precipitation, high altitude and high human population density were at higher risk of extinction. Correlates of risk varied between American cambarids and Australian parastacids, suggesting that centres of diversity shape patterns of extinction risk in crayfish. The explanatory power of models ranged between 31 and 65%, with low explanatory power for models based on threat types. Few specific threat measures were significantly related to extinction risk, suggesting that large-scale threat mapping may not be informative for freshwater invertebrates. In the absence of population data for most freshwater invertebrates, trait-based models are powerful and cost-effective tools for understanding and mitigating drivers of extinction risk.

The vacant planting: limited influence of habitat restoration on patch colonization patterns by arboreal marsupials in south-eastern Australia

Abstract: Many key questions remain unresolved about how biodiversity responds to temporal increases in native vegetation cover resulting from extensive restoration efforts We quantified occupancy and colonization probability of old growth, regrowth and planted woodland patches by arboreal marsupials within Australian agricultural landscapes subject to woodland restoration over an 11-year period Our analyses focused on the common brushtail possum Trichosurus vulpecula and common ringtail possum Pseudocheirus peregrinus We found strong evidence of a gradient in occupancy levels ranging from highest in old growth woodland, approaching zero in plantings, with regrowth woodland intermediate between these two broad types of vegetation structure Plantings were not occupied by either species at the outset of our investigation and were rarely colonized throughout the subsequent 10 years We hypothesize that a lack of shelter sites in large old hollow-bearing trees is one of the key factors limiting the occurrence of plantings by cavity-dependent arboreal marsupials, suggesting a lag between planting establishment and the time required for plantings to become suitable habitat We found the probability of colonization was positively related to the amount of vegetation cover in the surrounding landscape Unexpectedly, colonization probability was not influenced by a temporal increase in woody vegetation cover surrounding a patch A paucity of relationships between patch colonization and the temporal change in vegetation cover may be explained by the fact that most of the increased vegetation cover in our study landscapes over the past decade has resulted from establishment of plantings which are generally not suitable nesting habitat for arboreal marsupials Our findings have key management implications such as emphasizing the value of old growth woodland for arboreal marsupials and of targeting restoration efforts around old growth and regrowth woodland patches, and the flawed notion of biodiversity offsets that allow replantings to compensate for clearing old growth woodland

To protect everything, please click here: does a revolution in data collection guarantee one in conservation?

Abstract: An editorial published in Nature (2007) states that “… it can sometimes comes as a surprise for outsiders to learn how far removed the conservation biologist often is from actual efforts to save species”. For conservation biologists who are involved in practical conservation work particularly in countries where the national capacity and infrastructure for conservation is limited, it is clear that it will take more than technology to save the world. We observe an increasing emphasis on technology in the literature and among the research community and ask: How can a revolution in data collection best lead to one in conservation?

High mortality and small population size prevent population recovery of a reintroduced mesopredator

Abstract: Northern Australia's native mammal fauna has undergone a severe decline in recent decades. Putative factors include altered fire regimes, cat predation, poisoning by cane toads and disease. Populations of northern quolls, Dasyurus hallucatus severely declined following cane toad invasion and have not recovered. We monitored a population of northern quolls in Kakadu National Park that was supplemented with ‘toad-smart’ individuals, to determine whether cane toad poisoning or predation was preventing population recovery. The population increased after supplementation, but crashed in March 2012, coincident with a high level of trap disturbance by canids. Canid predation was the major source of mortality for radio-tagged quolls. We used population viability analyses (PVA) to explore how changes in mortality influenced the likelihood of extinction. With no management, the quoll population has a 48% chance of extinction over the next 20 years. Sensitivity analyses highlighted small population size and high mortality as the main reasons for the population failing to recover. We then explored whether population supplementation or reducing mortality could increase the likelihood of persistence. One year of supplementation increased the probability of population survival over 20 years from 51.6% to 81.7%. Continuing supplementation for 3 or 5 years increased the probability of population survival to 96.5% and 98.1% respectively. Similarly, a 2.5% reduction in the rate of mortality for juveniles and adult females increased the probability of population persistence over 20 years to 83.6%. Further reductions in mortality of 5% and 10% increased the probability of survival to 92.2% and 99.4% respectively. The results of the PVA suggest that small interventions could have a significant positive effect on population survival. We hypothesize that predation from food-subsidized canids is preventing the recovery of quoll populations. Future management actions to reduce mortality, via improved fire management, or through population supplementation, are necessary to ensure the persistence of the northern quoll.

Adaptive space use by baboons (Papio ursinus) in response to management interventions in a human-changed landscape

Abstract: Growing human populations are increasingly competing with wildlife for limited resources and this can result in chronic human–wildlife conflict. In the Cape Peninsula, South Africa, chacma baboons Papio ursinus are habitual raiders of urban and rural areas, foraging on a variety of human-derived foods. Raiding behaviour is considered a threat to human health and safety, may result in damage to property, and has adverse welfare and conservation impacts on baboons. To mitigate this conflict, Cape Town municipality employs field rangers with paintball markers that ‘herd’ baboons away from the urban edge. While this strategy is successful in reducing the time baboons spend in urban spaces, baboons still raid successfully. Here, we use direct observation and GPS data to investigate how one troop uses the peri-urban space and exploits human-derived foods in urban areas and on farmland. We contrast this behaviour with the individual management strategies adopted by field rangers which we assessed in individual interviews. We find that baboons utilize space (1) where inter-individual variation in field ranger management strategy is highest, (2) that is close to refuges in forested habitat and (3) that is close to the urban edge. Overall, this suggests adaptive space use by the baboons, whereby they minimize distances to refuges and potential food rewards, while exploiting uncertainty in risk variability that arises due to inter-individual differences in ranger management strategy. Together these results highlight the need for ranger consensus to reinforce management efficiency when dealing with a highly adaptive primate.

Estimates of avian collision with power lines and carcass disappearance across differing environments

Abstract: Data on collisions of birds with high-voltage electric power lines are scarce and are often gathered without protocols for the correction of carcass disappearance. There is actually growing awareness that it is important to accomplish carcass removal trials in order to develop correction factors for producing adjusted estimates of mortality due to collisions. In this study, we provided for the first time raw counts and estimates of bird collisions across seven Italian areas that largely differ in their habitats. We also carried out carcass removal trials to compute the rate of carcass disappearance and produce better estimates of collision events and of optimal time intervals of carcass searches. Results of 1-year monitoring showed a general low frequency of birds collided with the power lines. Carcass removal trials showed effects of carcass size and season on the carcass disappearance, which varied largely among the study areas. In four areas, both small and large carcasses had more than 50% probability to be removed within 3–5 days from their distribution. Given the high variation among study areas, we suggest that estimates of carcass persistence and optimal time intervals should be conducted concurrently for each new study site.

The impact of lions on the demography and ecology of endangered African wild dogs

Abstract: It has long been recognized that superior carnivores can impact on the demography and ecology of smaller members of the guild, although exact mechanisms remain unclear. Here we use original data from a unique natural experiment to study some of the mechanisms by which African lions Panthera leo impact on African wild dogs Lycaon pictus. Using a study site where wild dogs outnumbered lions for several years prior to lion population recovery, we aimed to investigate whether or not, and by which means, wild dog populations are regulated and influenced by lions. We used 38 pack-years of demographic and behavioural data across two 4-year periods where lion density differed 20-fold (pre-lion era: 1996–1999 and lion era: 2010–2013) to assess how lions may affect wild dog pack size and age structure, litter size and pup survival (n = 329 pups), as well as den site selection (n = 46 dens). Pack size was significantly greater during the pre-lion era. The pup to adult ratio was lower during the lion era and the change in pack composition was directly attributable to significantly greater lion-induced pup mortality. We also demonstrate a behavioural shift, with locations selected for the vulnerable denning period being in more rugged terrain and in areas with lower prey densities during the lion era, as compared with the pre-lion era. Lower adult recruitment into a population of an obligate cooperative breeder like the African wild dog can have complex consequences, including on feeding and defence of young, and mate finding.

Mismatch between goals and the scale of actions constrains adaptive carnivore management: the case of the wolverine in Sweden

Abstract: Efficient conservation of wide-ranging carnivores requires that adaptive management consider the varying ecological and societal conditions within the entire range of a population. In northern Europe, large carnivore management has to balance carnivore conservation and maintaining the indigenous reindeer-herding culture. Wolverine Gulo gulo monitoring and management in Sweden is currently focused on alpine reindeer husbandry areas where wolverine abundance and associated depredation conflicts have been highest. However, this focus ignores a potential southwards population expansion because current monitoring relies on snow-based tracking methods that are not applicable outside northern alpine areas. Thus, in this study we: (1) used available monitoring data from 1996 to 2014 in Sweden to assess wolverine distribution trends in relation to national management goals, and (2) evaluate the current monitoring protocol against the use of camera stations as an alternative, snow-independent, method for detecting wolverine presence at the southern periphery of its distribution. We show that the wolverine population in Sweden has expanded considerably into the boreal forest landscape, and colonized areas without reindeer husbandry and persistent spring snow cover. The latter indicates a less strict relationship between wolverine distribution and snow cover than previously hypothesized. Current management continues to use a monitoring protocol that is only adapted to high-conflict alpine areas, and is not adapting to changing conditions in the population range, which creates a problematic scale mismatch. Consequently, national management decisions are currently based on incomplete population information, as roughly a third of wolverine's range is not included in official population estimates, which could have detrimental consequences for conflict mitigation and conservation efforts. This illustrates that an important key to successful carnivore conservation is flexible management that considers the entire range of conditions at the appropriate regional and temporal scales under which carnivores, environment and people interact.

Predicting landscape connectivity for the Asian elephant in its largest remaining subpopulation

Abstract: Landscape connectivity between protected areas is crucial for the conservation of megafauna. But often, corridor identification relies on expert knowledge that is subjective and not spatially synoptic. Landscape analysis allows generalization of expert knowledge when satellite tracking or genetic data are not available. The Nilgiri Biosphere Reserve in southern India supports the largest wild populations of the endangered Asian elephant Elephas maximus. Current understanding of connectivity in this region is based on corridors identified by experts, which are not empirically validated and incongruent with each other. To more rigorously assess population connectivity for the Asian elephant, we evaluated a combination of three resistance layers and three dispersal abilities. The resistance models were based on the combined contributions of land cover, topographical slope, elevation, roads and buildings. A spatially explicit connectivity modeling tool predicted optimal movement corridors as a function of factorial least-cost routes across the resistance maps. A resistant kernel approach produced maps of the expected frequency of elephant movement through each cell to define core areas. We conducted a sensitivity analysis to determine the influence of resistance and dispersal. We selected the resistance surface and dispersal ability that produced the highest correlation with observed elephant densities. We evaluated the optimality of expert corridors by using a path randomization method. Eleven out of 24 expert corridors had connectivity values significantly higher than expected by chance, while only two corridors were spatially congruent between expert teams. Areas with the highest connectivity corresponded well with priority areas identified by conservationists and elephant density predicted by the resistant kernel connectivity model correlated significantly with surveys (Spearman's ρ = 0.85, n = 500, P ≪ 0.001). The results provide the first rigorous, spatially synoptic and empirically validated evaluation of the connectivity of the elephant population across the reserve.

Modeling landscape connectivity for bobcats using expert-opinion and empirically derived models: how well do they work?

Abstract: Efforts to retain ecological connectivity have become a conservation priority to permit animal movements within home ranges, allow dispersal between populations and provide opportunities for animals to respond to climate change. We used expert-opinion and empirically derived models to investigate landscape connectivity at two spatial scales among bobcats Lynx rufus in New Hampshire, USA. Paths of marked bobcats were compared to random movements in the context of program CircuitScape. At the local scale (within home ranges), the empirical model (based on observations and telemetry locations) performed better than the expert-opinion model. At the regional scale (state of New Hampshire), both models identified urban development as a potential barrier; however, the models differed in predicting how specific natural features (e.g. mountains and large water bodies) and some roads affected bobcat movements. When compared with bobcat population structure based on genetic information, the expert-opinion model overestimated the influence of roads. Alternatively, the empirical model overestimated the influence of snow. Our findings indicate that the empirically based resistance model was better at describing landscape-scale effects, whereas the expert-opinion model provided a good understanding of gene flow at a regional scale. As such, both models may be considered complementary. Bobcats were sensitive to disruptions imposed by habitat fragmentation and thus may be a suitable focal species for evaluating the consequences of land-use changes on the regional suite of mesocarnivores.

‘The early bird catches the nest’: possible competition between scops owls and ring-necked parakeets

Abstract: Competition for critical resources is one of the key mechanisms through which invasive species impact on native communities. Among birds, the widely introduced ring-necked parakeet Psittacula krameri locally affects cavity-nesting communities through competition for suitable tree cavities, although it remains unclear to what extent such competition translates into population declines of native species. Here, we studied the potential for nest site competition between ring-necked parakeets and the native scops owl Otus scops, a small nocturnal migratory raptor, by comparing the spatial distribution of the nest site locations of the raptor before (2002) and after (2015) the parakeet invasion. Pre-invasion nesting sites of scops owls (2002) strongly coincided with those selected by ring-necked parakeets, but although both parakeet and scops owl populations increased during the study period, this was no longer true for 2015. Ring-necked parakeets took over several cavities formerly occupied by scops owls, and land-use data suggest that because of the higher overall breeding densities in 2015, scops owls were forced to occupy suboptimal breeding habitats to minimize nest site competition with invasive parakeets. Ring-necked parakeets start breeding early in the season, a behaviour enabling them to secure the best nest sites first, before the owls return from their wintering grounds. Our study highlights that locally observed competition not necessarily impacts on population dynamics of competing species and thus warns against uncritical extrapolation of smaller scale studies for assessing invasive species risks at larger spatial scales. Nonetheless, given the increasing number of studies demonstrating its competitive capacities, monitoring of ring-necked parakeet populations is prudent and mitigation measures (such as mounting of man-made nest-boxes, which are used by scops owls, but not by parakeets) may be justified when the parakeets are likely to invade areas harbouring cavity-nesters of conservation concern.

Fishers' knowledge as an information source to investigate bycatch of marine mammals in the South China Sea

Abstract: Bycatch mortality is a significant driver of marine mammal population declines. However, there is little information available on patterns or magnitude of bycatch mortality in many heavily fished Asian marine systems such as the South China Sea (SCS). To address this limited knowledge base, we conducted interviews with fishers to gather local ecological knowledge on marine mammal bycatch around Hainan Island, China. Gillnets were the primary fishing gear used in local fisheries, and were also responsible for the majority of reported marine mammal bycatch events in recent decades. Bycatch events were reported from all seasons but were most frequent in spring (38.4%), which might relate to seasonal variation in fishing activities. The spatial pattern of relative bycatch densities for Indo-Pacific humpback dolphins, Indo-Pacific finless porpoises and unidentified small dolphins varied around Hainan and neighbouring waters. A substantial proportion of informants (36.1 and 9.2% respectively) reported that they have eaten or sold marine mammal meat, demonstrating the continued existence of cultural practices of consuming marine mammals on Hainan. Responses of fishers to bycatch events were dependent both on their existing attitudes and perceptions towards marine mammals and on other sociocultural factors. Almost half of informants agreed that marine mammal populations in the SCS have decreased. Declines were thought by informants to have been caused by overfishing, water pollution and vessel collisions, with bycatch responsible for further declines in dolphins.

Grain spilled from moving trains create a substantial wildlife attractant in protected areas

Abstract: Transportation corridors can attract threatened wildlife via habitat enhancement and foraging opportunities, leading to collisions with vehicles. But wildlife may also be attracted to energy-dense food products that are spilled or discarded from moving vehicles, which is rarely studied. Therefore, we quantified train-spilled attractants in Banff and Yoho National Parks, Canada, where agricultural products (hereafter, grain) are transported along 134 km of railway and may contribute to wildlife mortality. We measured grain deposition from 2012 to 2015 at 19 sites and assessed the performance of three structures developed to measure spilled grain. We then modeled grain deposition with respect to four types of spatial and temporal variables: those related to grain shipment, physical habitat characteristic, train-related characteristics and variables specific to the study site. Grain was spilled at a mean rate of 1.64 g m−2 day−1 (sd = 3.60) from April to October (n = 3 years) and 1.52 (sd = 2.37) from November to March (n = 1 year). Extrapolating annual deposition across the study area yielded enough grain (110 tons) to provide 4.77 × 108 kcal of gross energy, which is equivalent to the average annual caloric needs of 42–54 grizzly bears Ursus arctos horribilis; the regional population is estimated at 50–73 animals. Much of this energy will not be accessible or available to bears; however, their attraction to it could contribute to rising and unsustainable rates of mortality. Models explained 9–31% of the variance in deposition for each grain type, primarily via coarse temporal variables of shipping rates and month. The absence of more specific predictive variables suggests that mitigation should target broader policies, such as prompt reporting and repair of leaky hopper cars, and limits to train stoppage in protected areas. We encourage more global assessment of the under-studied issue of food attractants spilled by vehicles along transportation corridors.

Divergent forecasts for two salt marsh specialists in response to sea level rise

Abstract: Ecosystem specialists are predicted to be more vulnerable to global change than generalists, but whether specialists within an ecosystem will respond similarly to those changes is often largely unknown. Will specialists track changes in their habitats as a group, or are their distributions governed by landscape gradients that will make some species more sensitive to habitat changes? In this study, we forecasted the effects of sea level rise (SLR) on two salt marsh specialist bird species: clapper rails Rallus crepitans and seaside sparrows Ammodramus maritimus. We sampled the abundance of these two species in salt marshes throughout the Georgia, USA, coast in 2013–2014, and analyzed count data using a Bayesian N-mixture model. Model predictions were applied to an SLR land cover model to determine distribution shifts over 100 years. Both species distributions were most sensitive to the relative elevation gradient, with clapper rails using lower elevation marshes and seaside sparrows using higher elevation marshes. These disparities in habitat use, along with other differences according to marsh salinity and distance to forested areas, led to divergent responses to SLR. Clapper rail habitat is predicted to increase with SLR by 52%, but seaside sparrow habitat will contract by 81% by the year 2100. Seaside sparrow habitat is not predicted to decline until sometime between 2025 and 2050, at which point the decline will rapidly accelerate, indicating the importance of careful monitoring in future decades. Diverging responses to a global perturbation create a conservation planning dilemma: if specialists have opposing responses to SLR, it may be difficult to manage conservation areas that accommodate many species.

Toll-like receptor variation in the bottlenecked population of the endangered Seychelles warbler

Abstract: In small populations, drift results in a loss of genetic variation, which reduces adaptive evolutionary potential. Furthermore, the probability of consanguineous mating increases which may result in inbreeding depression. Under certain circumstances, balancing selection can counteract drift and maintain variation at key loci. Identifying such loci is important from a conservation perspective and may provide insight into how different evolutionary forces interact in small populations. Toll-like receptor (TLR) genes play a pivotal role in vertebrate innate immune defence by recognizing invading pathogens. We characterize TLR variation in the Seychelles warbler (SW) Acrocephalus sechellensis, an endangered passerine that recently suffered a population bottleneck. Five of seven TLR loci were polymorphic, with one locus (TLR15) containing four functional variants and showing an excess of heterozygotes. Haplotype-level tests failed to detect selection at these loci, but site-specific tests detected signatures of positive selection within TLR3 and TLR15. After characterizing variation (excluding TLR15) in 5–6 other Acrocephalus species, we found that TLR variation was positively correlated with population size across species and followed the pattern observed at neutral microsatellite loci. The depauperate TLR variation observed suggests that even at important immunity-related loci, balancing selection may only attenuate the overriding effects of drift. However, in the SW, TLR15 appears to be an outlier and warrants further investigation. The low levels of TLR variation may be disadvantageous for the long-term viability of the SW and conservation measures that maximize the retention of the variation should be considered.

Local factors mediate the response of biodiversity to land use on two African mountains

Abstract: Land-use change is the single biggest driver of biodiversity loss in the tropics. Biodiversity models can be useful tools to inform policymakers and conservationists of the likely response of species to anthropogenic pressures, including land-use change. However, such models generalize biodiversity responses across wide areas and many taxa, potentially missing important characteristics of particular sites or clades. Comparisons of biodiversity models with independently collected field data can help us understand the local factors that mediate broad-scale responses. We collected independent bird occurrence and abundance data along two elevational transects in Mount Kilimanjaro, Tanzania and the Taita Hills, Kenya. We estimated the local response to land use and compared our estimates with modelled local responses based on a large database of many different taxa across Africa. To identify the local factors mediating responses to land use, we compared environmental and species assemblage information between sites in the independent and African-wide datasets. Bird species richness and abundance responses to land use in the independent data followed similar trends as suggested by the African-wide biodiversity model, however the land-use classification was too coarse to capture fully the variability introduced by local agricultural management practices. A comparison of assemblage characteristics showed that the sites on Kilimanjaro and the Taita Hills had higher proportions of forest specialists in croplands compared to the Africa-wide average. Local human population density, forest cover and vegetation greenness also differed significantly between the independent and Africa-wide datasets. Biodiversity models including those variables performed better, particularly in croplands, but still could not accurately predict the magnitude of local species responses to most land uses, probably because local features of the land management are still missed. Overall, our study demonstrates that local factors mediate biodiversity responses to land use and cautions against applying biodiversity models to local contexts without prior knowledge of which factors are locally relevant.

Cutaneous bacteria, but not peptides, are associated with chytridiomycosis resistance in Peruvian marsupial frogs

Abstract: Amphibians are a highly threatened vertebrate group, and populations of these animals have declined drastically An important global threat to amphibians is the pathogenic fungus Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis However, not all species develop chytridiomycosis when exposed to Bd We compared susceptibility to disease in two species of marsupial frogs and found that Gastrotheca nebulanastes is susceptible, whereas its congeneric G excubitor is resistant Since Bd is a skin pathogen, it is possible that cutaneous defenses like symbiotic bacteria and antimicrobial peptides protect the resistant species We tested this hypothesis by comparing the anti-Bd abilities of cutaneous defenses between the two Gastrotheca species Cultivable bacteria and peptides were isolated from the skin and tested for their abilities to inhibit Bd with in vitro co-culture assays Twenty-six bacteria were identified by sequencing their 16S rRNA gene and 19 peptides were profiled by MALDI TOF mass spectrometry We found that bacteria, but not peptides, differed between the two species in their ability to inhibit Bd growth The resistant G excubitor harbored more isolates of cultivable anti-Bd bacteria both in number and proportion (6/15 vs 1/11) Also, the one anti-Bd isolate from G nebulanastes demonstrated the weakest ability to inhibit Bd growth Our results highlight the importance of anti-Bd skin bacteria in providing frog species with protection from Bd and can inform mitigation strategies for other wildlife diseases

Rabbits killing hares: an invasive mammal modifies native predator–prey dynamics

Abstract: Invasive species management requires practical evidence of the impacts of introduced species over ecosystem structure and functioning. Theoretical ecology and empirical data support the potential of introduced mammals to drive native species to extinction, indeed the majority of practical evidence comes from insular environments, where conditions may differ from the mainland. We analyzed the effects of an introduced lagomorph, the eastern cottontail Sylvilagus floridanus on two native mammals, the European hare Lepus europaeus and the red fox Vulpes vulpes. We used relative abundances collected over 8 years at 30 protected areas in Italy. A generalized linear mixed model was fit to test various hypotheses about the relationships between cottontails, foxes and climatic conditions over the abundance of native hares. In our model, hare and cottontail abundances did not show a negative relationship and we believe that no direct competition occurs between the two species. However, the relationship between fox and hare abundances, positive when cottontails were scarce, became more and more negative as cottontails increased: this supports the hypothesis that indirect dynamics like apparent competition exists between the two lagomorphs. Climatic conditions, expressed through the North Atlantic Oscillation, did not affect the relationship between cottontail and hare abundances. As the impact of parasites on mammal populations is generally climate dependent, we believe that cottontails do not play a direct role in the cycle of parasites affecting hares. Our results provide a clue that an invasive mammal, the eastern cottontail, is modifying the predator–prey relationship between two native species in a non-insular environment. The existence of such dynamics should lead wildlife managers to account for the effect of introduced species in their decision making, directing control activities on cottontails and not on native foxes.

Identification of candidate pelagic marine protected areas through a seabird seasonal-, multispecific- and extinction risk-based approach

Abstract: With increasing pressure on the oceans from environmental change, there has been a global call for improved protection of marine ecosystems through the implementation of marine protected areas (MPAs). Here, we used species distribution modelling (SDM) of tracking data from 14 seabird species to identify key marine areas in the southwest Atlantic Ocean, valuing areas based on seabird species occurrence, seasonality and extinction risk. We also compared overlaps between the outputs generated by the SDM and layers representing important human threats (fishing intensity, ship density, plastic and oil pollution, ocean acidification), and calculated loss in conservation value using fishing and ship density as cost layers. The key marine areas were located on the southern Patagonian Shelf, overlapping extensively with areas of high fishing activity, and did not change seasonally, while seasonal areas were located off south and southeast Brazil and overlapped with areas of high plastic pollution and ocean acidification. Non-seasonal key areas were located off northeast Brazil on an area of high biodiversity, and with relatively low human impacts. We found support for the use of seasonal areas depending on the seabird assemblage used, because there was a loss in conservation value for the seasonal compared to the non-seasonal approach when using ‘cost’ layers. Our approach, accounting for seasonal changes in seabird assemblages and their risk of extinction, identified additional candidate areas for incorporation in the network of pelagic MPAs.

Interactions between domestic and wild carnivores around the greater Serengeti ecosystem

Abstract: The domestic and wild carnivore interface is complex, yet understudied. Interactions between carnivore species have important implications for direct interference competition, cross-species transmission of shared pathogens and conservation threats to wild carnivores. However, carnivore intraguild interactions are hard to quantify. In this study, we asked 512 villagers residing around a conservation area in the Serengeti Ecosystem, Tanzania, to report on the presence of wild carnivores in their village, the number of domestic dogs Canis familiaris and cats Felis catus in their household and interactions between domestic and wild carnivores. Wild carnivores are abundant near households surrounding the Serengeti National Park, villagers have many free-ranging domestic dogs (and would like to have more) and direct and indirect contacts between wild and domestic carnivores are common. Large carnivores, such as spotted hyenas and leopards, often killed or wounded domestic dogs. Small carnivores, such as mongoose, bat-eared fox, serval and wildcat, are locally abundant and frequently interact with domestic dogs. We demonstrate that interspecific carnivore behavior, human culture and local and regional geography play a complex role in domestic and wild carnivore interaction risk around conservation areas. Through the use of household surveys, we were able to efficiently obtain data on a wide scope of carnivore interactions over a large area, which may provide a direction for future targeted and in-depth research to reduce interspecific conflict. Improving the health and husbandry of domestic animals and reducing the unintentional feeding of wild carnivores could reduce dog–wildlife interactions and the potential for pathogen transmission at the domestic–wild animal interface.

Challenges of using behavior to monitor anthropogenic impacts on wildlife: a case study on illegal killing of African elephants

Abstract: Monitoring anthropogenic impacts on wildlife can be challenging, particularly when human activities affecting wildlife are cryptic. Using anti-predator behaviors as proxies for perceived pressure is appealing because of the relative ease with which they can be recorded and the presumed relationship between the threat of interest and a predator stimulus. However, behaviors are plastic and affected by factors unrelated to human activity. Consequently, it is critical to assess the relationship between behavioral indicators and their context before interpretation. In this study we used a combination of behavior, movement and demography from a threatened population of African elephants in northern Kenya to determine whether reaction to research vehicles was indicative of poaching pressure. We used mixed-effects models predicting reaction of elephants to observer vehicle approaches in which we treated individuals as random effects and included ecological, anthropogenic, spatial, social and demographic predictor variables. Contrary to our hypothesis, recorded levels of reactive behavior did not increase with poaching levels in either a population-level dataset or a data subset of individuals whose spatial behavior was precisely known via radio-tracking. Rather, primary productivity positively predicted reactive behavior in both datasets. This relationship was heightened by the presence of musth males in the radio-collar dataset. Reactivity was not related to the time since entering the protected areas, but increased among groups that spent less time in the protected areas. Inter-individual differences were apparent, suggesting the importance of inherent differences (e.g. personality) across groups. In our study, elephants plagued by a severe human threat did not react defensively to humans in another context, suggesting nuanced discrimination of threats. Our study demonstrates the caution that should be taken in designing studies that use behavioral indices to represent threat and contributes to a growing body of literature employing behavioral indicators to monitor wildlife populations of conservation concern.