Showing papers in "Animal Conservation in 2012"

Comparison of density estimation methods for mammal populations with camera traps in the Kaa‐Iya del Gran Chaco landscape

Abstract: Sampling animal populations with camera traps has become increasingly popular over the past two decades, particularly for species that are cryptic, elusive, exist at low densities or range over large areas. The results have been widely used to estimate population size and density. We analyzed data from 13 camera trap surveys conducted at five sites across the Kaa-Iya landscape, Bolivian Chaco, for jaguar, puma, ocelot and lowland tapir. We compared two spatially explicit capture–recapture (SCR) software packages: secr, a likelihood-based approach, and SPACECAP, a Bayesian approach, both of which are implemented within the R environment and can be used to estimate animal density from photographic records of individual animals that simultaneously employ spatial information about the capture location relative to the sample location. As a non-spatial analysis, we used the program CAPTURE 2 to estimate abundance from the capture–recapture records of individuals identified through camera trap photos combined with an ad hoc estimation of the effective survey area to estimate density. SCR methods estimated jaguar population densities from 0.31 to 1.82 individuals per 100 km2 across the Kaa-Iya sites; puma from 0.36 to 7.99; ocelot from 1.67 to 51.7; and tapir from 7.38 to 42.9. Density estimates using either secr or SPACECAP were generally lower than the estimates generated using the non-spatial method for all surveys and species; and density estimates using SPACECAP were generally lower than that using secr. We recommend using either secr or SPACECAP because the spatially explicit methods are not biased by an informal estimation of an effective survey area. Although SPACECAP and secr are less sensitive than non-spatial methods to the size of the grid used for sampling, we recommend grid sizes several times larger than the average home range (known or estimated) of the target species.

Agricultural lands as ecological traps for grizzly bears

Abstract: Human–carnivore conflicts on agricultural lands are a global conservation issue affecting carnivore population viability, and human safety and livelihoods. Locations of conflicts are influenced by both human presence and carnivore habitat selection, although these two aspects of conflict rarely have been examined concurrently. Advances in animal tracking have facilitated examination of carnivore habitat selection and movements affording new opportunities to understand spatial patterns of conflict. We reviewed 10 years of data on conflicts between grizzly bears and humans in southwestern Alberta, Canada. We used logistic regression models in a geographic information system to map the probability of bear–human conflict from these data, and the relative probability of grizzly bear habitat selection based on global positioning system radiotelemetry data. We overlaid these maps to identify ecological traps, as well as areas of secure habitat. The majority of the landscape was seldom selected by bears, followed by ecological traps where most conflicts occurred. Only a small portion of the landscape was identified as secure habitat. Such mapping methods can be used to identify areas where conflict reduction strategies have the greatest potential to be effective. Our results highlight the need for comprehensive management to reduce conflicts and to identify areas where those conflicts are most problematic. These methods will be particularly useful for carnivores known to be in conflict with agriculture, such as large carnivores that prey on livestock, or pose a threat to human safety.

Unexpected outcomes of invasive predator control: the importance of evaluating conservation management actions

Abstract: Decisions regarding the implementation of conservation management actions should be based on the effectiveness of past investments However, because of limited evaluation of existing data, actions may be prescribed without evidence of producing a beneficial conservation outcome We analysed empirical data, collected over 23 years across southern Australia, on the impact of fox baiting on malleefowl to determine its effectiveness We employed data from extensive monitoring surveys to evaluate the observed relationships between investment in fox control, fox baiting intensity, fox presence and two alternative measures of the malleefowl's response: the number of breeding pairs and population growth This study is the first to quantify the return on investment from fox control in a conservation context We discovered there is limited quantitative evidence for a benefit of fox baiting on malleefowl, despite it being the main management action implemented for this nationally threatened, well-studied and iconic species We found that fox baiting did not significantly decrease the presence of foxes and fox presence was positively correlated with malleefowl conservation Malleefowl breeding population size increased with investment in baiting, although this relationship depended on the number of years the site had been baited Nonetheless, most sites had a negative relationship between investment and breeding population In contrast, malleefowl population growth did not benefit from baiting, suggesting that fox baiting is generally not a cost-effective management action for the conservation of this species This study provides a powerful example of why management decisions should be based on evidence, rather than ecological intuition Even though the malleefowl is one of the best-monitored species of conservation concern in Australia, we are still uncertain how to cost-effectively manage this species We emphasize the urgent need to assess what data we have and determine which species and what actions are most in need of evaluation

A brighter future for frogs? The influence of carotenoids on the health, development and reproductive success of the red‐eye tree frog

Abstract: Ex situ conservation is an important tool for the prevention of species extinction in amphibians. Currently, there is limited information on the nutritional requirements of amphibians in captivity, and there have been anecdotal reports of skin colour degradation in captive amphibians. Amphibians use carotenoids for skin pigmentation, and because carotenoids are only obtainable through the diet, colour degradation could result from limited carotenoid availability. Studies of other vertebrate taxa have shown that carotenoids contribute to health and reproductive success; however, their importance to amphibians is currently unknown. We assessed the influence of carotenoids on the health and development of red-eye tree frogs (Agalychnis callidryas) during larval and post-metamorphic stages, and looked at effects on skin colour and reproductive success. Carry-over effects of larval exposure to carotenoids were also investigated, and the effects of carotenoids on skin colour development and degradation in adulthood were examined. Carotenoids did not significantly influence larval growth or survival; however, post-metamorphic carotenoid availability significantly increased growth rate in female but not in male frogs. Frogs fed a carotenoid diet post-metamorphosis had significantly redder skin than controls, and larval carotenoid exposure significantly influenced post-metamorphic skin colour. Fecundity was significantly higher in female frogs raised on a carotenoid diet post-metamorphosis compared with controls. Finally, skin colour did not change in adulthood despite changes in dietary carotenoid availability, which suggests that there is a critical period during post-metamorphic growth for deposition of carotenoids in the skin. We have shown that carotenoids influence the development, phenotype and reproductive success of A. callidryas, and these important nutrients should therefore be considered when nutritional recommendations for amphibians are made.

Females first? Past, present and future variability in offspring sex ratio at a temperate sea turtle breeding area

Abstract: The long-term survival of species with temperature-dependant sex determination requires a sufficient range of incubation temperatures to ensure that both males and females are produced. The primary sex ratio of sea turtles is determined by the temperature experienced by eggs during the middle third of incubation. Here, we investigated the variability in the production of male and female offspring by loggerhead sea turtles Caretta caretta at six nesting beaches in the temperate breeding area of Zakynthos, Greece. Hatchling sex ratios were estimated using incubation durations and sand temperatures for 2007–2009, while the empirical relationship between air and sand temperature was used to infer historical (1875–2010) and future (2011–2100) hatchling sex ratios. First, all six beaches produced males; 55% of production was across five beaches, while 45% was focused on one beach (primarily in July). Second, male production varied across the season in different years; there was an initial peak in June, with production (rising, declining or plateauing) later in the season being regulated by August air temperatures. Interestingly, the annual male production rate estimated from the 3-year dataset (23%) was half that estimated from the 135-year reconstruction (50%), with the latter showing broad interannual variation. Finally, modelled predictions of future sex ratios ranged from a conservative 7.6% decline in male production by 2100 versus no production by 2038. This study provides a baseline from which predicted trends in hatchling sex ratio, in parallel to regular field assessments, could be used to provide guidelines for the selection of appropriate nest protection management protocols, to maintain required sex ratios that safeguard the future of this population.

Monitoring in the presence of species misidentification: the case of the Eurasian lynx in the Alps

Abstract: Inferring the distribution and abundance of a species from field records must deal with false-negative and false-positive errors. False-negative errors occur if a species present goes undetected, while false-positive errors are typically a consequence of species misidentification. False-positive observations in studies of rare species may cause an overestimation of the distribution or abundance of the species and distort trend indices. We illustrate this issue with the monitoring of the Eurasian lynx in the Alps. We developed a three-level classification of field records according to their reliability as inferred from whether they were validated or not. The first category (C1) represents ‘hard fact’ data (e.g. dead lynx); the second category (C2) includes confirmed data (e.g. tracks verified by an expert); and the third category (C3) are unconfirmed data (e.g. any kind of direct visual observation). For lynx, which is a comparatively well-known species in the Alps, we use site-occupancy modelling to estimate its distribution and show that the inferred lynx distribution is highly sensitive to presence sign category: it is larger if based on C3 records compared with the more reliable C1 and C2 records. We believe that the reason for this is a fairly high frequency of false-positive errors among C3 records. This suggests that distribution records for many lesser-known species may be similarly unreliable, because they are mostly or exclusively based on unconfirmed and thus soft data. Nevertheless, such soft data form a considerable part of species assessments as presented, for example in the International Union for Conservation of Nature Red List. However, C3 records can often not be discarded because they may be the only information available. When inferring the distribution of rare carnivores, especially for species with an expanding or shrinking range, we recommend a rigorous discrimination between fully reliable and un- or only partly reliable data, in order to identify possible methodological problems in the distribution maps related to false-positive records.

Rarity, trophy hunting and ungulates

Abstract: The size and shape of a trophy constitute major determinants of its value. We postulate that the rarity of a species, whatever its causes, also plays a major role in determining its value among hunters. We investigated a role for an Anthropogenic Allee effect in trophy hunting, where human attraction to rarity could lead to an over-exploitative chain reaction that could eventually drive the targeted species to extinction. We performed an inter-specific analysis of trophy prices of 202 ungulate taxa and quantified to what extent morphological characteristics and their rarity accounted for the observed variation in their price. We found that once location and body mass were accounted for, trophies of rare species attain higher prices than those of more common species. By driving trophy price increase, this rarity effect may encourage the exploitation of rare species regardless of their availability, with potentially profound consequences for populations.

Survival on the ark: life history trends in captive parrots.

Abstract: Members of the order Psittaciformes (parrots and cockatoos) are among the most long-lived and endangered avian species. Comprehensive data on lifespan and breeding are critical to setting conservation priorities, parameterizing population viability models, and managing captive and wild populations. To meet these needs, we analyzed 83, 212 life history records of captive birds from the International Species Information System and calculated lifespan and breeding parameters for 260 species of parrots (71% of extant species). Species varied widely in lifespan, with larger species generally living longer than smaller ones. The highest maximum lifespan recorded was 92 years in Cacatua moluccensis, but only 11 other species had a maximum lifespan over 50 years. Our data indicate that while some captive individuals are capable of reaching extraordinary ages, median lifespans are generally shorter than widely assumed, albeit with some increase seen in birds presently held in zoos. Species that lived longer and bred later in life tended to be more threatened according to IUCN classifications. We documented several individuals of multiple species that were able to breed for more than two decades, but the majority of clades examined had much shorter active reproduction periods. Post-breeding periods were surprisingly long and in many cases surpassed the duration of active breeding. Our results demonstrate the value of the ISIS database to estimate life history data for an at-risk taxon that is difficult to study in the wild, and provide life history data that is crucial for predictive modeling of future species endangerment and proactively managing captive populations of parrots.

Factors affecting mortality of shearwaters stranded by light pollution

Abstract: Every year and across the world, thousands of fledglings of different petrel species crash into human structures because they are disorientated by artificial lights during their first flights. As this phenomenon is rather predictable, rescue campaigns are organized to help birds to reach the ocean, but unfortunately, a low proportion gets hurt or dies. Despite the huge number of affected individuals, and the fact that the problem was detected a long time ago, little is known on this source of mortality. We have studied the factors (i.e. body condition, plumage development, fledging date and sex) influencing the mortality of Cory's Shearwater Calonectris diomedea fledglings stranded inland due to light pollution in Tenerife (Canary Islands) during two consecutive breeding seasons (2009 and 2010). Late fledglings showed lower values of a body condition index than early ones. No sex biases were detected, neither considering stranded birds overall, nor for recovery dates or in the body condition of rescued fledglings. Our results indicate that late birds stranded by lights showing abundant down are more susceptible to fatal collisions and that the lights do not selectively kill birds with lower body condition indices. An enhancement of veterinary care should be done during the last part of the fledging period when more fatal collisions occur, especially focused on fledglings with abundant down. More research to determine why some individuals end up disoriented around artificial lights and others do not is urgently needed to minimize or prevent fallouts.

Abundance and exploitation of loggerhead turtles nesting in Boa Vista island, Cape Verde: The only substantial rookery in the eastern Atlantic

Abstract: The main nesting area for loggerhead turtles in the eastern Atlantic is in the Cape Verde Islands, largely restricted to the island of Boa Vista. Extensive monitoring demonstrated a globally significant population for the species despite a sustained high level of anthropogenic take of nesting females for local consumption. Through an extensive stratified monitoring program across the island in the seasons 2007–2009, we estimated a total of 13 955, 12 028 and 19 950 clutches in the 3 years, respectively. These values indicate that the mean number of nesting females averaged 3700. Considering that a female breed, on average, every 2.4 years, we estimate that the overall number of adult females in the population during these three seasons was 8900. These levels are much higher than those suggested in previous studies which were more constrained in spatial coverage. Our findings indicate that Cape Verde hosts the third largest nesting aggregation for this species in the world after the south-eastern US and Oman, with some sites having a particularly high density of nests, facilitating targeted monitoring and conservation. Consumption of sea turtle meat is a traditional practice in Cape Verde that continues despite national sea turtle protection laws. We estimated that 36, 18 and 5% of nesting females were harvested in the 3 years of the study, respectively. Increasing beach protection and monitoring, ongoing educational programs and cooperative projects with local communities are urgently needed to further safeguard the only major loggerhead nesting aggregation in the eastern Atlantic.

The social side of human-wildlife interaction: wildlife can learn harmful behaviours from each other

Abstract: Although harmful human–wildlife interactions involving anthropogenic food sources are a significant issue for wildlife conservation, few studies have addressed whether social learning may influence how animals learn to use anthropogenic foods We examined a long-term (1993–2003) human–wildlife interaction involving the illegal feeding of bottlenose dolphins (Tursiops aduncus) by recreational fishers in south-western Australia We developed predictor variables for whether dolphins learned to accept food handouts from human provisioners, based on biological (age-class, sex) and behavioural (ranging and association patterns) data for a population of 74 dolphins Two variables provided clear predictors for whether dolphins became conditioned to food handouts: the use of areas with high densities of recreational boats (BOAT) and the average coefficient of association with previously conditioned dolphins (ASSOC) An individual was more likely to become conditioned when it spent more time in high boat density areas and when it spent more time with other conditioned dolphins When considering all the models available, there was strong weight of evidence for the effects of ASSOC and BOAT on the response variable We were unable to detect any effects of age-class and sex with the available statistical power These findings suggest that social learning can facilitate the acquisition of undesirable and maladaptive behaviours in wildlife, and indicate the value of long-term individual-specific data for the conservation management of wildlife engaging in undesirable interactions with humans

Natural mixing of species: novel plant–animal communities on Caribbean Islands

Abstract: Global anthropogenic activities are responsible for the modification of landscapes, creation of novel environments and movement of species across biogeographic regions. A consequence of this activity is the mixing of native and introduced species and the formation of novel biotic communities. We review the ecological consequences of the mixing of native and introduced species in the Caribbean Islands especially in Puerto Rico and the US Virgin Islands. Here we found documented examples indicating that novel communities of native and naturalized organisms are ubiquitous. The coexistence of species originating from different biogeographical regions raises research questions that demand attention for their ecological and conservation importance. For example: Is animal abundance in novel communities a measure of habitat quality? To what degree are populations in novel communities self-sustaining? What are the consequences of species eradication? How does an introduced animal’s trophic position affect its effects on novel and native communities? We suggest that novel communities that emerge in the Caribbean after deforestation and land abandonment could be harbingers of how the biota might respond elsewhere to rapidly changing environmental conditions, including global and climate change.

Bird functional diversity and wildfires in the Amazon: the role of forest structure

Abstract: Fire is becoming a common phenomenon in Amazonian forest, modifying the structure and composition of natural assemblages. In particular, fire is known to affect patterns of bird diversity in tropical forests, but we have little understanding of the consequences of this for the functional diversity of bird assemblages. For example, frequent fires could act as an environmental filter selecting species with similar traits and, thus, producing a functional clustering pattern. Here, we used body mass, and dietary and foraging traits to calculate the functional structure of understorey bird assemblages in Amazonian forests analysed 3 years after they had passed under three disturbance levels within the 19971998 El-Nino period: unburned, burned once and burned twice. First, we tested whether observed levels of functional diversity were different among these forests and also from what one would expect by chance. Then, we investigated if habitat structure was able to predict changes in the functional structure of the studied bird assemblages. In general, there was no evidence of fire reducing functional diversity nor selecting species functionally more similar than expected by chance. Therefore, bird functional diversity was not different from random in unburned and burned forests. This provides some evidence in favour of high functional redundancy of bird species in the tropics, but also indicates that neutral theories of biodiversity, where processes such as dispersal and survival are more important than biological traits to community assembly, may apply to the assemblages studied. Also, we showed that bird assemblages from forests disturbed by wildfires have the tendency to be functionally overdispersed whereas assemblages from pristine forests tend to be functionally clustered. Thus, environmental structure, in part driven by forest responses to fire, is more important than simple categorical definitions of burn frequency for explaining trait-based assembly rules of understorey birds in the Amazon forest.

The influence of unburnt patches and distance from refuges on post-fire bird communities

Abstract: Predicting the response of faunal communities to fire presents a challenge for land managers worldwide because the post-fire responses of species may vary between locations and fire events. Post-fire recovery can occur via nucleated recovery from in situ surviving populations or by colonization from ex situ populations. Fine-scale spatial patterns in the patchiness of fires and the proximity of burnt sites to source populations may contribute to both the variability in post-fire responses and the processes by which populations recover. We examined the avifauna at recently burnt sites within extensive semi-arid shrublands of south-eastern Australia, including 72 sites 27 years since fire) and varied in the presence or absence of small (25–900 m2) unburnt patches of vegetation. For sites < 5 years since fire, species richness was higher at sites closer to unburnt vegetation and at sites containing unburnt patches. These patterns were no longer evident at sites of 10 years since fire. The probability of occurrence of three of seven bird species modelled decreased with increasing distance to unburnt vegetation, but this pattern was evident only at sites burnt uniformly. One species was found almost exclusively at patchily burnt sites. These results are consistent with the hypothesis that proximity to unburnt vegetation enhances post-fire occupancy, and that colonization from ex situ populations is an important process for post-fire recovery of avifauna. Additionally, small unburnt patches enhance the rapid recovery of assemblages post-fire. These patterns are important for understanding the dynamics of post-fire population recovery. We recommend that management of fire for ecological purposes should explicitly consider the role that the spatial attributes of fires play in determining the post-fire community.

Invasive woody plants affect the composition of native lizard and small mammal communities in riparian woodlands

Abstract: Nonnative Tamarix spp. (saltcedar) is among the most invasive and common trees along riparian habitats in the western U S, impacting native plant communities and habitat quality. Tamarix dominance causes a reduction in habitat physiognomic heterogeneity in riparian habitats. Animal abundance, diversity and habitat associations in monotypic stands of saltcedar remain largely unexplored for non-avian communities. We sampled small vertebrate and ground arthropod communities in monotypic Tamarix stands and in mixed stands of Tamarix and native (Populus, Salix, and Prosopis spp.) trees in riparian habitats along the Virgin River in the Mojave Desert. Our survey of faunal communities suggests that many species of arthropods, reptiles and small mammals utilize both Tamarix-dominated and mixed habitats along the Virgin River. Small mammal and lizard communities were dominated by generalist species. Mixed stands had greater arthropod abundance, lizard abundance and small mammal diversity; whereas, monotypic and mixed stands had similar lizard diversity. The habitat of mixed sites was characterized by ‘nativeness’ (areas with native riparian trees) and less ‘shady exotic thickets’ (areas with Tamarix and high overstory cover) compared to Tamarix-dominated stands. There were species-specific responses to habitat physiognomy. Peromyscus maniculatus (deer mouse) was associated with shady exotic thickets. Sceloporus magister (desert spiny lizard) and Neotoma lepida (desert woodrat) were associated with native trees and woody debris. Seven rodent and lizard species’ abundances were explained by habitat physiognomy variables. Rare and specialist species were more impacted by nonnative vegetation. These results contribute to the body of research on animal utilization of nonnative habitats and relation to habitat physiognomy. Management of nonnative plants should consider how control activities could impact habitat physiognomy and native animal communities in riparian habitat.

Factors influencing degradation of DNA and hormones in maned wolf scat

Abstract: The ability to noninvasively detect the presence of species and assess physiological health by DNA and hormone analysis makes scat a valuable tool for ecology and conservation. We assessed factors associated with DNA and hormone degradation in a four-season study that employed detection dogs to collect scats from maned wolf (Chrysocyon brachyurus) in the Brazilian Cerrado, a tropical savanna landscape mosaic. Fecal DNA sample viability was assessed by attempting polymerase chain reaction amplification of a mitochondrial DNA (mtDNA) locus (~ 246 bp) and a nuclear DNA zinc finger protein gene (~ 195 bp). We assessed how extraction method, environmental exposure, and amount of odor, moisture and diet items in the sample influenced DNA amplification and allelic dropout rates. Samples that amplified mtDNA were assayed for glucocorticoids and thyroid hormone. Amount of odor and moisture (indicating freshness) predicted mtDNA amplification success, as well as mean hormone levels. While factors related to sample condition were negatively correlated with lower mean hormone levels, samples comprised mainly of fruit had higher levels of glucocorticoids and lower levels of thyroid hormone, and we thus interpret this result as biologically meaningful. In summary, DNA and hormone degradation are predicted by measures of sample freshness, making the assessment of sample quality an important criterion for sample collection as well to manage measurement error in analyses of hormone concentration associated with environmental disturbance.

Does translocation influence physiological stress in the desert tortoise

Abstract: Wildlife translocation is increasingly used to mitigate disturbances to animals or habitat due to human activities, yet little is known about the extent to which translocating animals causes stress. To understand the relationship between physiological stress and translocation, we conducted a multiyear study (2007–2009) using a population of desert tortoises (Gopherus agassizii) near Fort Irwin, California. Blood samples were collected from adult tortoises in three treatment groups (resident, translocated and control) for 1 year prior to and 2 years after translocation. Samples were analyzed by radioimmunoassay for plasma total corticosterone (CORT), a glucocorticoid hormone commonly associated with stress responses in reptiles. CORT values were analyzed in relation to potential covariates (animal sex, date, behavior, treatment, handling time, air temperature, home-range size, precipitation and annual plant production) among seasons and years. CORT values in males were higher than in females, and values for both varied monthly throughout the activity season and among years. Year and sex were strong predictors of CORT, and translocation explained little in terms of CORT. Based on these results, we conclude that translocation does not elicit a physiological stress response in desert tortoises.

Variation in terrestrial mammal abundance on pastoral and conservation land tenures in north-eastern Australian tropical savannas

Abstract: The introduction of domestic cattle into systems that have had little historical grazing by large herbivores, such as the case in Australia, can lead to both direct and indirect changes in native flora and fauna. In this study, we investigate the differences in native mammal abundance between pastoral land managed for cattle production and conservation land in Australian tropical savannas. We systematically sampled 68 sites for mammals in north-eastern Queensland representing the two land tenures, which represent land with introduced stock and native herbivores present, and land where only native herbivores occur. We recorded 17 species of mammals representing five families and two functional groups (small mammals and macropods). Generalized linear mixed effects models identified that there was a significant positive relationship between increasing total ground cover and small mammal abundance and also the abundance of two species, Pseudomys desertor and P. gracilicaudatus. We recorded a reduction in abundance on pastoral land for macropods and small mammals, and four species, M. robustus, M. rufus, Leggadina lakedownensis, P. gracilicaudatus. Total ground cover and perennial grass cover was lower on pastoral land. Small mammal abundance on pastoral land was less even with increasing ground cover. Our results suggest that on pastoral land, native mammal abundance is affected and this has some relationship to ground cover changes. We recognize that there are other confounding management differences between pastoral and conservation lands such fire use, dingo baiting, and the manner of weed invasion and control that could influence mammal pattern. We conclude that conservation strategies for mammals in Australia’s tropical savannas need to include a variety of land management schemes and tenures including land free from grazing by domestic livestock.

Monitoring sea ice habitat fragmentation for polar bear conservation

Abstract: Polar bears are a sea ice-dependent carnivore, sensitive to sea ice habitat loss. Climate change has negatively affected sea ice habitat through much of this species' range. We applied landscape fragmentation analysis to quantify polar bear sea ice habitat loss and fragmentation trends (1979–2008) in Foxe Basin, Hudson Strait and Hudson Bay, Canada. Microwave satellite derived monthly mean sea ice concentration maps were classified into four habitat quality categories, and the trends in fragmentation metrics were analyzed. In all regions where preferred habitat declined, sea ice season length decreased and habitat fragmentation increased. The observed trends may affect polar bear movement patterns, energetics and ultimately population trends. Monitoring of sea ice habitat condition in combination with harvest data can provide a dynamic approach to population management and conservation.

Distribution and spatial genetic structure of European wildcat in France

Abstract: Given the problem of hybridization with domestic cats, there is a growing need to identify populations of the European wildcat Felis silvestris silvestris in order to protect the genetic integrity of this subspecies. In this paper, we use known locations of observations of wildcats or recovered carcasses to reassess the distribution of the wildcat in France and, in cases where carcasses were collected, we use both phenotypic and molecular genetic analyses to distinguish wildcats from hybrids with domestic cats. Spatially explicit multivariate analysis of wildcat' genotypes was then performed to define genetic units. Our study confirms the presence of wildcats in a large area of c. 155 000 km2, suggestive of a range of expansion, and divided into two clearly distinct and unconnected areas – the Pyrenees and the north-eastern part of France. However, European wildcat populations may be decreasing in the French Pyrenees, whereas the north-eastern part represents the main area (MA) of wildcat presence. This extension does not appear to be primarily due to hybrids, as both wildcats and hybrids were located throughout the MA. In addition, we found that genetic diversity of wildcats in the MA is remarkably high, suggesting that French populations are not threatened by a lack of genetic diversity. Furthermore, wildcats of the MA are structured into two genetically distinct populations that are contiguous and probably extend into Germany to form the largest area of wildcat presence in Europe and an area of major interest for their conservation. Our study calls for localized examination of the feasibility and usefulness of wildlife corridors to enhance connectivity between the different populations, thereby allowing sufficient levels of immigration and gene flow within the regional meta-population to ensure the long-term viability of these populations.

Host limitation of the thick-shelled river mussel: identifying the threats to declining affiliate species

Abstract: The conservation of endangered affiliate species, which are critically dependent on the presence of another species, is often hindered by a poor understanding of the relationships between the interacting partners. The parasitic stage of endangered unionid bivalves constitutes a tight host–affiliate linkage between the mussels and their host fishes. However, the threats resulting from potential shortages of the host species are rarely sufficiently quantified and incorporated into conservation strategies. In this paper, we integrated both host quality and availability analyses to assess the potential threats to the endangered thick-shelled river mussel Unio crassus that result from the impairment of its host resources in Central Europe. The experimental determination of the compatibility of U. crassus parasitic larvae (glochidia) with its potential host fishes revealed an intermediate level of host specificity. At least, some glochidia successfully developed on 14 of the 27 potential hosts that were evaluated. Nevertheless, only three fish species (Scardinius erythrophthalmus, Phoxinus phoxinus and Cottus gobio) enabled the majority of the attached glochidia to transform successfully. Subsequently, our analysis of host availability at sites inhabited by living or extirpated populations of U. crassus showed that the local extirpations of U. crassus are likely associated with an impaired status of the fish assemblage and with the absence of the primary host fishes. These results indicate that the availability of host fish resources may have played at least an additive role in the present pan-European decline of U. crassus and that the evaluation of host limitation without precise data on the host compatibility or host abundance may be ineffective for identifying the threats to particular species. It demonstrates a strong need for more thorough incorporation of host limitation issues into conservation strategies for U. crassus and probably also for other species of freshwater mussels that were previously considered safe from host limitation.

Effects of matrix composition and configuration on forest bird movements in a fragmented Afromontane biodiversity hot spot

Abstract: Persistence of forest-dependent species in fragmented landscapes strongly relies on sufficient dispersal between patches, making it important to understand how animal movements are affected by the intervening matrix. Movements can be influenced through selection or avoidance of land cover based on their perceived suitability for foraging or providing cover. The composition and configuration of the matrix will, therefore, most likely be an important factor to consider when estimating connectivity between patches. To address this, we performed translocation experiments to understand how forest birds used different land cover types in a fine-grained matrix of a fragmented Afromontane biodiversity hotspot (Taita Hills, Kenya). Our results revealed that use of land cover types for both the forest specialist Cabanis’s greenbul Phyllastrephus cabanisi and for the forest generalist white-starred robin Pogonocichla stellata was disproportional to their availability. However, this effect was influenced by matrix configuration; in patchy matrices, land cover selection was more pronounced compared with more uniform matrices, especially for the forest specialist. At the scale of movement steps, risk avoidance seemed to be a strong factor in the route decisions for both species. Observed steps contained on average lower proportions of open land cover and did less frequently intersect built-up areas than expected. P. stellata did not differentiate between the alternative land cover types, whereas P. cabanisi preferred steps that contained more indigenous forest. The observed negative relationship between degree of forest dependency and matrix permeability implies that for members of the Taita bird community, which are even more dependent on intact forest habitat (i.e. the critically endangered Taita thrush Turdus helleri), current permeability of the matrix may be even lower. Matrix restoration to improve connectivity may, therefore, be a crucial instrument for the long-term survival of forest-dependent species in these fragmented Afromontane landscapes.

Estimating tropical forest ungulate densities from sign surveys using abundance models of occupancy

Abstract: Large ungulates critically influence forest structure and functioning besides being seriously threatened by anthropogenic pressures. For assessing their populations, surveys of ungulate sign encounters are widely used because of their practicality. However, these yield unreliable results because of their failure to address the problem of imperfect detection. Here, we present an innovative application to address this key weakness in traditional ungulate sign surveys. We describe the ecological process of ungulate sign deposition as well as the observation process of sign detection in our modelling. We simulate 183 ecological and sampling-related parameter values to first evaluate model performance. Simulation results demonstrate that we can achieve good estimates of animal density when the radius of the animal daily movement range is accounted for during survey design. We design and conduct a field survey of ungulate signs to estimate ungulate densities using both occupancy and distance sampling approaches. For five species of ungulates, the densities estimated from our sign survey (number of ungulate clusters km -2 ) were 1.46(0.68) chital Axis axis, 1.42(0.67) sambar Rusa unicolor, 1.01(0.44) gaur Bos gaurus, 0.74(0.39) wild pig Sus scrofa and 1.42(1.59) muntjac Muntiacus muntjak, and were similar to those generated from line transect sampling 2.16(0.76) chital, 2.47(0.56) sambar, 0.94(0.3) gaur, 1.09(0.37) wild pig and 4.03(0.83) muntjac), except for muntjac. The potential utility of this approach extends beyond sign surveys of forest ungulates to a wider range of animal monitoring contexts, including those based on scent-station surveys and camera trap surveys of elusive mammals.

Combining information in hierarchical models improves inferences in population ecology and demographic population analyses

Abstract: Statistical models that include random effects are becoming more common in population ecology all the time. Random effects are two or more effects of some grouping factor that belong together, in the sense that we can imagine they were generated by a common stochastic process. Thus, they are similar, but not identical, and therefore assumed to be exchangeable. Models with random effects contain as a description of this common stochastic process so-called prior distributions, with estimable hyperparameters, for instance the mean and the variance for normally distributed random effects. Models with random effects have intrinsically more than one level; therefore, they are often called hierarchical models (Royle & Dorazio, 2008) or multilevel models (Gelman & Hill, 2007). Interest in hierarchical models often focuses on the hyperparameters, but the realizations from the process described by the prior distributions, that is, the random effects, can also be estimated. The main difference to treating a set of effects as fixed is that in a random effects model, the parameters of a grouping factor are no longer estimated independently. Rather, the assumption that they come from a common prior distribution induces a dependence, which means that the estimate of each is somewhat influenced by the estimate of all other effects comprising that factor. This is often called borrowing strength from the ensemble. One consequence of treating a factor as random is that its effect estimates are pulled in towards the overall mean, which is called shrinkage in the literature. If the assumption of a common stochastic process is reasonable, borrowing strength and shrinkage typically leads to better estimates compared with their fixed effects counterparts (Gelman, 2005; chapter 4 in Kery & Schaub, 2012). Hierarchical models are not at all intrinsically Bayesian; rather, they can be analysed using likelihood or Bayesian methods (Royle & Dorazio, 2008), though Bayesian analysis is often easier, especially for ecologists using MCMC engines like WinBUGS (Lunn et al., 2000) or JAGS (Plummer, 2003). One particularly interesting use of hierarchical model is as a formal way of combining information, for instance, coming from different studies. A good example is the feature paper by Halstead et al. (2012), where estimates of survival probabilities of a snake species from radio-tracking data at multiple study sites in the same region are combined in a hierarchical model that is fitted using the WinBUGS software. Sample size at each site was fairly low. Hence, Halstead and colleagues treated each study site as a replicate and estimated the hyperparameters of the distribution that collects together the sitespecific parameters, which were treated as random effects. Hierarchical modelling thus provides a formal way of combining this information, where study sites with more information (e.g. more snakes or with more precise estimates) get more weight in contributing to the estimates of the overall mean and the among-site variability (the mean and the variance hyperparameters). Site-specific estimates are shrunken towards the mean, where the degree of shrinkage depends on the precision of the site-specific estimates. This is a desirable property, as it avoids possible overinterpretation of patterns that may be due to some idiosyncrasy of a small sample. Borrowing strength typically also helps against boundary estimates that are frequent in survival analysis with small sample size. Thus, not only were Halstead and colleagues able to obtain a formal estimate of the regional mean of the interesting parameters, but arguably they also obtained better site-specific estimates owing to the sharing of information among all sites. In a sense, what they did is a meta-analysis. A further advantage of combining data from several studies is increased precision of the site-specific estimates, because they borrow strength from the entire dataset. Increased precision means to have more power to detect an effect, which is especially advantageous when dealing with rare species, where sample size is typically small to very small. A similar approach was chosen by Papadatou et al. (2012) who estimated survival probabilities of several bat species (i.e. where species was bs_bs_banner

Is there a future for Amur tigers in a restored tiger conservation landscape in Northeast China

Abstract: The future of wild tigers is dire, and the Global Tiger Initiative’s (GTI) goal of doubling tiger population size by the next year of the tiger in 2022 will be challenging. The GTI has identified 20 tiger conservation landscapes (TCL) within which recovery actions will be needed to achieve these goals. The Amur tiger conservation landscape offers the best hope for tiger recovery in China where all other subspecies have most likely become extirpated. To prioritize recovery planning within this TCL, we used tiger occurrence data from adjacent areas of the Russian Far East to develop two empirical models of potential habitat that were then averaged with an expert-based habitat suitability model to identify potential tiger habitat in the Changbaishan ecosystem in Northeast China. We assessed the connectivity of tiger habitat patches using least-cost path analysis calibrated against known tiger movements in the Russian Far East to identify priority tiger conservation areas (TCAs). Using a habitat-based population estimation approach, we predicted that a potential of 98 (83–112) adult tigers could occupy all TCAs in the Changbaishan ecosystem. By combining information about habitat quality, connectivity and potential population size, we identified the three best TCAs totaling over 25 000 km 2 of potential habitat that could hold 79 (63–82) adult tigers. Strong recovery actions are needed to restore potential tiger habitat to promote recovery of Amur tigers in China, including restoring ungulate populations, increasing tiger survival through improved anti-poaching activities, landuse planning that reduces human access and agricultural lands in and adjacent to key TCAs, and maintaining connectivity both within and across international boundaries. Our approach will be useful in other TCLs to prioritize recovery actions to restore worldwide tiger populations.

Evaluating indices of conservation success: a comparative analysis of outcome- and output-based indices

Abstract: Conservation funders require methods by which to evaluate the relative success of projects within their portfolios. One approach is to develop robust indices of success that are consistent between projects and evaluators. We used three contrasting indices to evaluate factors contributing to success of projects funded by the UK Government's Darwin Initiative. The indices were: Darwin Outputs (related to the Darwin Initiative's own method of evaluating the success of the projects it supports), Impact Assessment (based on the method developed by Mace etal. for evaluating the success of projects supported by zoos) and a Ranked Outcomes (a qualitatively ranked outcome index). We evaluated the internal consistency of the indices by comparing the assessments of multiple independent scorers. We assessed their robustness by checking for differences between indices and assessors in the success level assigned to a given project. We then used mixed effects models to analyse the factors contributing to project success, as expressed by each index, and compared the factors highlighted as important by each index. Although there were systematic differences between scorers, relative rankings between scorers were consistent. The indices were in fair agreement as to project success ranks, although the success ranks assigned by subjective ranked outcome- and output-based indices were more consistent between assessors than the impact assessment index. Higher levels of funding led to projects receiving consistently higher success scores. Other variables varied in their importance between indices, although metrics of education were consistently important. This study shows that it is possible to develop robust outcome-based indices of conservation success for comparison of projects within a funder's portfolio, although the nuances picked up by different indices suggest a need for multiple indices to capture different facets of success. We also highlight the need for thorough testing of the robustness of success indices before widespread adoption. © 2012 The Authors. Animal Conservation © 2012 The Zoological Society of London.

Does supplemental feeding affect the viability of translocated populations? The example of the hihi

Abstract: Translocations are commonly used conservation actions that aim at establishing new, self-sustaining populations of threatened species. However, many translocated populations are not self-sustaining but managed through supplemental feeding from the onset. Often, the decision to start managing is ad hoc, but managers will eventually have to make decisions for the future, for example, stop intervening, continue as it is or change the quantity of food provided. Such a decision requires managers to quantify the importance of supplemental feeding in determining the performance and population dynamics of translocated populations, information that is rarely available in the published literature. Using the hihi as a case study, we examined the importance of supplemental feeding for the viability of a translocated population in New Zealand. We found that supplemental feeding positively affected the survival and abundance of translocated adult hihi but also found evidence of negative density dependence on recruitment. We present two stochastic population models that project the hihi population under different management scenarios, quantitatively assessing the impact supplemental feeding has had on the population. Our results illustrate how important long-term targeted monitoring is for robust decision making about adaptive management.

Urinary cortisol levels of gray-cheeked mangabeys are higher in disturbed compared to undisturbed forest areas in Kibale National Park, Uganda

Abstract: Habitat disturbance due to anthropogenic activities is a source of acute and chronic energetic stress in wild animals, including primates. Physiological responses to stress can compromise growth and reproduction, increase susceptibility to infection and lead to deleterious effects on health and conservation efforts. However, physiological measures of energetic stress in association with habitat disturbance are uncommon, especially for wild primate species. Here, we report differences in the stress hormone cortisol in two subpopulations of wild gray-cheeked mangabeys (Lophocebus albigena) inhabiting disturbed and undisturbed forest areas of Kibale National Park, Uganda. Cortisol levels were assessed via opportunistically and noninvasively collected urine samples using previously validated methods. We hypothesized that mangabeys in disturbed forest (DF) areas would experience greater stress and therefore exhibit higher average cortisol levels than conspecifics in nearby relatively undisturbed forest areas (UF). As predicted, mangabeys in the disturbed area had significantly higher cortisol levels (unpaired t-test of log transformed data, t = 4.88, d.f. = 108, P < 0.0001). Mangabeys in undisturbed forest exhibited expected diurnal patterns of cortisol excretion while those in disturbed areas did not, suggesting alteration of the circadian pattern of hypothalamic-pituitary-adrenal function (DF, r = 0.12, P = 0.43; UF, r = 0.35, P = 0.005). Reasons for differences are unclear, but could include altered food availability and distribution, human contact or other anthropogenic effects. Noninvasive measurements of urinary hormones are useful for quantifying animal energetic stress in the wild and assessing the effects of conservation efforts to attenuate anthropogenic stress in wild populations.

Cryptic hybridization and introgression between invasive Cyprinid species Cyprinus carpio and Carassius auratus in Australia: implications for invasive species management

Abstract: Interspecies hybridization is of concern for the management of invasive species, as it can allow the exchange of advantageous alleles between introduced species and undermine control efforts. In this study, hybridization between populations of introduced common carp and goldfish in Australia is investigated. Common carp and goldfish were sampled extensively from the Murray-Darling Basin, the largest river basin in Australia. Fish identified in the field as hybrids, on the basis of having truncated or missing pairs of barbels around their mouths, were also sampled. All fish were genotyped for five microsatellite loci that could be amplified through polymerase chain reaction in both species, and the mitochondrial DNA control region was sequenced in the field-identified hybrids and a subset of the goldfish and common carp. Bayesian clustering analyses, factorial correspondence analysis and direct inspection of the microsatellite profiles confirmed that all fish identified as hybrids in the field had ancestry from both species. A number of cryptic hybrids were also identified. While most hybrids were inferred to be F1-generation, some F2-generation and backcrossed individuals were detected, indicating that gene flow is ongoing between carp and goldfish in Australia. Gene flow was biased in favor of male carp mating with female goldfish, as 19 of the 20 F1-generation hybrids had goldfish maternal ancestry. This ongoing gene flow could allow advantageous alleles (e.g. resistance to koi herpes virus) to move between species. This study illustrates that invasive species control programs should not only target the species considered most destructive, but should also consider the risks posed by introgression with related species.

Predation of Atlantic Petrel chicks by house mice on Gough Island

Abstract: The impacts of predation by invasive mammals on island fauna are a major driver of insular biodiversity loss. Devastating, hitherto unsuspected impacts of predatory house mice on breeding seabirds have been described recently. We studied the fate of 178 Atlantic Petrel Pterodroma incerta nests at Gough Island, over four seasons, from October 2003 to January 2008. Introduced house mice Mus musculus were found in all study burrows checked for mouse visits. From October 2003 to September 2004, we video-recorded attacks by mice on six (of 13) live, healthy Atlantic Petrel chicks and on one (of three) great shearwater Puffinus gravis chicks. In all years, chicks died from mouse attacks. Stage-specific daily nest survival rates were modelled, from which estimates of breeding success were derived that accounted for the variable exposure periods studied among years. Average daily survival rate of eggs was 0.998, and hatching success through the entire incubation period (55.5 days) was 0.924 [95% confidence interval (CI) 0.903–0.940]. Daily chick survival rates were 0.990, which gave a modelled fledging success of 0.247 (CI 0.165–0.338) over the 138-day chick period, and average annual breeding success (chicks fledged per breeding attempt) of 0.228 (CI 0.150–0.318), which is low compared with congeners. Productivity estimates were used as a parameter in a population simulation model, which predicted a population multiplication rate (λ) of 0.993 (CI = 0.966–1.021). However, in the one season studied from laying to fledging (2007), from 58 nests, only one chick fledged (1.7%). This suggests the wide errors on the model results may obscure a more severe reality. More than 60% of model simulations resulted in an International Union for Conservation of Nature classification of Endangered. Our results add support to calls to eradicate mice from Gough Island. More generally, mice cannot be ignored as a potential threat to island fauna, and island restoration and management plans should routinely include eradication of introduced mice.