Distance Sampling

The population of the Daraina sportive lemur (Lepilemur milanoii) is believed to be mostly confined to the Loky-Manambato region . Very little is known about L. milanoii and it is classified as "Data Deficient" by the IUCN . Despite the management of the area by the NGO Fanamby since 2005, no study had been conducted to determine the presence and the abundance of L. milanoii in the main forest fragments of the region. During the 2011 dry season we surveyed the ten main forest fragments of the Loky-Manambato region and estimated L. milanoii densities and population sizes using line transect distance sampling and the DISTANCE software . The results suggest that sportive lemur densities are reasonably high in the region, but with important discrepancies between forest fragments, with densities ranging from 49.8 ind./km² in Antsaharaingy to 590.5 ind./km² in Ampondrabe. For the region Loky-Manambato we were able to estimate a population size of ~52,000 individuals. This is the first estimate for the total population size and we argue that similar studies should be repeated to monitor environmental changes and anthropogenic pressures (hunting, deforestation, mining, etc.).

Under veterinary and wildlife morphometrics, body condition scoring is one of several techniques for assessing the health of ungulate species. It helps assess and judge the animals' physical appearance condition by visually examining the degree of protuberance of bony processes on the body surface and the condition of the skin. This study is being conducted at Muthangha Wildlife Sanctuary to evaluate the health of three ungulate species using a body condition evaluation technique while keeping a safe distance and causing minimal disturbance to the animals. Then, using a point system based on how their bodies look, Ungulates are rated as having good (0-5), average (6-8), or bad (9-12) body condition. The body condition of all 57 ungulates is assessed, and the results show that the majority (49.12%) are in average condition, followed by good (38.59%) and bad (12.28%). A decrease in body condition appearance may result from the greater quantity of ungulate species in that area, as well as from a shortage of species that provide fodder within the sanctuary. Planting of fodder species inside the sanctuary can help in improving the body appearance of the ungulates and also can minimize the human wildlife conflicts.

4 Resumo: Os primatas da infraordem Platyrrhini são divididos em quatro famílias, dentre elas a Pitheciidae. Um gênero bastante representativo nesta família é Callicebus, com 29 espécies reconhecidas, sendo que 22 ocorrem no Brasil e apenas uma destas, Callicebus pallescens, ocorre na região do Pantanal. Esta espécie, conhecida popularmente na região como boca-d'água, é encontrada nas regiões não inundáveis da borda oeste do Pantanal, especialmente no Maciço do Urucum, Morrarias do Castelo e de Santa Teresa, além da Serra do Amolar. Dados existentes para Callicebus no Pantanal foram coletados utilizando métodos limitados. Este trabalho buscou estimar a densidade e o tamanho dos grupos de Callicebus cf pallescens, na fazenda Santa Teresa, localizada na Morraria de Santa Teresa e baía Vermelha, Corumbá, MS. Para estimar a densidade dos grupos foram utilizados sete transectos lineares percorridos de duas a cinco vezes em dias diferentes. Foi empregado o método de amostragem de dist...

The palm squirrel is one of the common small mammals in Sri Lanka and India, the Indian Palm Squirrel (Funambulus palmarum) is the commonest of all being distributed throughout the island. All palm squirrels are essentially herbivores, however diet varies depending on the species. Funambulus palmarum has a broad, opportunistic diet, consuming a range of foods that vary depending on season. Its diet includes nuts, a range of seeds, fruits, flowers, young shoots, barks, lichens and it occasionally eats insects such as termites and beetles. Heat dumping behavior has also been recorded. Here we report the status of Indian palm squirrels in Barkatullah university campus.

Roadside point counts are often used to estimate trends of bird populations. The use of aural counts of birds without adjustment for detection probability, however, can lead to incorrect population trend estimates. We compared precision of estimates of density and detectability of whistling northern bobwhites (Colinus virginianus) using distance sampling, independent double-observer, and removal methods from roadside surveys. Two observers independently recorded each whistling bird heard, distance from the observer, and time of first detection at 362 call-count stops in Ohio. We examined models that included covariates for year and observer effects for each method and distance from observer effects for the doubleobserver and removal methods using Akaike's Information Criterion (AIC). The best model of detectability from distance sampling included observer and year effects. The best models from the removal and doubleobserver techniques included observer and distance effects. All 3 methods provided precise estimates of detection probability (CV ¼ 2.4-4.4%) with a range of detectability of 0.44-0.95 for a 6-min survey. Density estimates from double-observer surveys had the lowest coefficient of variation (2005 ¼ 3.2%, 2006 ¼ 1.7%), but the removal method also provided precise estimates of density (2005 CV ¼ 3.4%, 2006 CV ¼ 4.8%), and density estimates from distance sampling were less precise (2005 CV ¼ 9.6%, 2006 CV ¼ 7.9%). Assumptions of distance sampling were violated in our study because probability of detecting bobwhites near the observer was <1 or the roadside survey points were not randomly distributed with respect to the birds. Distances also were not consistently recorded by individual members of observer pairs. Although doubleobserver surveys provided more precise estimates, we recommend using the removal method to estimate detectability and abundance of bobwhites. The removal method provided precise estimates of density and detection probability and requires half the personnel time as double-observer surveys. Furthermore, the likelihood of meeting model assumptions is higher for the removal survey than with independent doubleobservers.

Malagasy chameleons are threatened by the relentless pace of habitat destruction. Their great popularity amongst herpetoculturalists has also resulted in collection for international animal markets. Most previous fieldwork has focused on the compilation of much needed species inventories, but little attention has been given to estimating chameleon population densities. This lack of information prevents a reliable assessment of the effects of habitat loss and direct exploitation on wild populations. A simple and repeatable methodology for the monitoring of chameleon populations is therefore urgently required. The present study developed survey techniques based on distance sampling within an area of relatively undisturbed rain forest at Ranomafana National Park. In total 394 individuals from six species were recorded and population densities (+ SE) of 27.2 + 5.4/ha Brookesia spp. and 21.4±4.0/ha Calumma spp. were estimated using the computer program DISTANCE. The authors propose that monitoring of chameleons in areas subject to different threats should begin immediately using the methods outlined in this paper.

Coping with unobservable and mis-classified states in capture-recapture studies.-Multistate markrecapture methods provide an excellent conceptual framework for considering estimation in studies of marked animals. Traditional methods include the assumptions that (1) each state an animal occupies is observable, and (2) state is assigned correctly at each point in time. Failure of either of these assumptions can lead to biased estimates of demographic parameters. I review design and analysis options for minimizing or eliminating these biases. Unobservable states can be adjusted for by including them in the state space of the statistical model, with zero capture probability, and incorporating the robust design, or observing animals in the unobservable state through telemetry, tag recoveries, or incidental observations. Mis-classification can be adjusted for by auxiliary data or incorporating the robust design, in order to estimate the probability of detecting the state an animal occupies. For both unobservable and mis-classified states, the key feature of the robust design is the assumption that the state of the animal is static for at least two sampling occasions.

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Landscape-scale disturbance events, including ecological restoration and fuel reduction activities, can modify habitat and affect relationships between species and their environment. To reduce the risk of uncharacteristic stand-replacing fires in the southwestern United States, land managers are implementing restoration and fuels treatments (e.g., mechanical thinning, prescribed fire) in progressively larger stands of dry, lower elevation ponderosa pine (Pinus ponderosa) forest. We used a Before-After/Control-Impact experimental design to quantify the multi-scale response of avifauna to large (;250-400 ha) prescribed fire treatments on four sites in Arizona and New Mexico dominated by ponderosa pine. Using distance sampling and an information-theoretic approach, we estimated changes in density for 14 bird species detected before (May-June 2002 and after (May-June 2004-2005) prescribed fire treatments. We observed few site-level differences in pre-and posttreatment density, and no species responded strongly to treatment on all four sites. Pointlevel spatial models of individual species response to treatment, habitat variables, and fire severity revealed ecological relationships that were more easily interpreted. At this scale, pretreatment forest structure and patch characteristics were important predictors of posttreatment differences in bird species density. Five species (Pygmy Nuthatch [Sitta pygmaea], Western Bluebird [Sialia mexicana], Steller's Jay [Cyanocitta stelleri ], American Robin [Turdus migratorius], and Hairy Woodpecker [Picoides villosus]) exhibited a strong treatment response, and two of these species (American Robin and Hairy Woodpecker) could be associated with meaningful fire severity response functions. The avifaunal response patterns that we observed were not always consistent with those reported by more common studies of wildland fire events. Our results suggest that, in the short term, the distribution and abundance of common members of the breeding bird community in Southwestern ponderosa pine forests appear to be tolerant of low-to moderate-intensity prescribed fire treatments at multiple spatial scales and across multiple geographic locations.

It is a brief ppt before engineering students about how tiger conservation has been successful in India, traditionally and from 1972 through the present.. However, increase in human-tiger interface creates chances of unusual behaviour of tiger and their possibilities of developing SIB (Self Injurious Behaviour) and IDD (Intellectual Developmental Disability). I also wish that I am proven wrong and the tiger continues to survive as the 'majestic gentle giant of the forests'.

An important metric for many aspects of species conservation planning and risk assessment is an estimate of total population size. For landbirds breeding in North America, Partners in Flight (PIF) generates global, continental, and regional population size estimates. These estimates are an important component of the PIF species assessment process, but have also been used by others for a range of applications. The PIF population size estimates are primarily calculated using a formula designed to extrapolate bird counts recorded by the North American Breeding Bird Survey (BBS) to regional population estimates. The extrapolation formula includes multiple assumptions and sources of uncertainty, but there were previously no attempts to quantify this uncertainty in the published population size estimates aside from a categorical data quality score. Using a Monte Carlo approach, we propagated the main sources of uncertainty arising from individual components of the model through to the final estimation of landbird population sizes. This approach results in distributions of population size estimates rather than point estimates. We found the width of uncertainty of population size estimates to be generally narrower than the order-of-magnitude distances between the population size score categories PIF uses in the species assessment process, suggesting confidence in the categorical ranking used by PIF. Our approach provides a means to identify species whose uncertainty bounds span more than one categorical rank, which was not previously possible with the data quality scores. Although there is still room for additional improvements to the estimation of avian population sizes and uncertainty, particularly with respect to replacing categorical model components with empirical estimates, our estimates of population size distributions have broader utility to a range of conservation planning and risk assessment activities relying on avian population size estimates.

A double kernel method as an alternative to the classical kernel method is proposed to estimate the population abundance by using line transect sampling. The proposed method produces an estimator that is essentially a kernel type of estimator use the kernel estimator twice to improve the performances of the classical kernel estimator. The feasibility of using bootstrap techniques to estimate the bias and variance of the proposed estimator is also addressed. Some numerical examples based on simulated and real data are presented. The results show that the proposed estimator outperforms existingclassical kernel estimator in most considered cases.

We describe a new method for estimating population density of vocally responsive animals, which is based on playback calls coupled with auditory point transect sampling. The method yielded, for red titi monkeys (Callicebus discolor), better estimates than traditional line transect surveys. We propose it as an effective alternative for sampling certain cryptic, but vocally responsive animal species.

The Slender Loris in India includes two subspecies, the Mysore Slender Loris and the Malabar Slender Loris, with unidentified populations at overlapping ranges of the subspecies. Prior to 1996, the knowledge on Indian lorises was mostly limited to laboratory studies, or some anecdotes from the wild. Since late 1990, several intensive field studies have been carried out which informed about the status, ecology, behaviour, conservation issues, and management of the Slender Loris in India. Here, we review all these studies, discuss the major findings and identify directions for future research. 

An updated list confirms the presence of 134 species of wild mammals in the Western Ghats, India. The superimposed distribution range of all, and threatened species of mammals depicts the potential mammalian key diversity areas for the Western Ghats, which can be prioritized for long-term conservation. These mammalian key diversity areas are confined to the central and the southern Western Ghats. The most crucial key diversity areas for both threatened and all mammalian species occur in Pushpagiri-Talakaveri, the Nilgiri Biosphere, the Anamalai Hills, the Periyar landscape and the Agastyamalai Hills.

Grey Peacock Pheasant (Polyplectron bicalcaratum) is identified as ecological indicator of forest ecosystem in tropical rain forest. Study on density and abundance was carried out by line transect method in Lengteng wildlife sanctuary, Mizoram, northeast India for 27 months. Transects are walked four times a month in early morning hours. In 108 transect sampling, 134 individuals were recorded with the encounter rate 0.51±0.06/km and density of 0.14/kmP P. The altitudinal distribution range is 1621m – 1783m above sea level, within this range they confined foraging in an area of about 5 kmP P. Largest group observed was comprised of 5 members and the average group size was 0.23 individuals. Male – female sex ratio was 1.89. The low population density of grey peacock pheasant in the present study may be attributed to the skulking behaviour of the bird and the steep terrain with thick undergrowth. The results and its possible reasons are discussed in detail.

Galliformes, commonly referred to as ‘gallinaceous birds’ or ‘game birds’, is a large and diverse group of birds that comprises of 70 genera and 284 species, while 45 species of galliformes are known from India. Meanwhile proper record of Galliformes is not available in the state of Mizoram. Therefore a preliminary survey on galliformes was conducted from September 2012 - December 2013 in Mizoram with the aim to provide reliable information on their diversity, distribution range and their conservation issues in the tropical hilly state. The state of Mizoram, located in northeast India, is sandwiched by two international borders, viz. Bangladesh from the west and Myanmar from the east and south. It lies in the Indo-Myanmar Biodiversity Hotspot Area. In order to know the species composition and distribution, information was collected by field survey at important protected areas and secondary information from 245 villages covering all the eight districts. Analysis of secondary informat...

Reconnaissance on spatial distribution of pheasants in eight districts of Mizoram was done during September 2012 to March 2013. The study shows that six species inhabit the study areas. Red Jun-glefowl (Gallus gallus) and Kalij Pheasants (Lophura Leucomelanos lathami) are most versatile in distribution and are present in all sites (n=235). Grey Peacock Pheasant (Polyplectron bicalcara-tum) is recorded in 103 sites and is more abundant in middle and eastern parts of the state. Mrs. Hume’s Pheasant (Syrmaticus humiae) is recorded at 10 sites and Blyth’s Tragopan (Tragopan blythii) at 4 sites, both in eastern higher elevation ranges. A lone record of Green Peafowl (Pavo muticus) is from Tarpho village, Lunglei district, near Myanmar boundary. Comparison of the present data with previous records and possible sites for endangered pheasants has been dis-cussed.

The line transect distance sampling method provides unbiased estimates of abundance when organisms are distributed randomly or line transects are laid out randomly, sample sizes are large and other assumptions of the method are met; such, however, is rarely the case in real life. We conducted a simulation study to investigate how spatial distribution and density of objects, and total length, layout and number of transects influence bias, precision, and accuracy of estimates of abundance obtained by distance sampling along line transects. Overall, density estimated using the distance sampling method was within 4.9% of the true density, but it varied substantially depending upon spatial distribution of objects. Of the three spatial distribution patterns considered, estimates of density were least biased, and most precise and accurate when objects were distributed randomly; they were most biased, and least precise and accurate when objects followed a clumped distribution. The estimated bias (% difference between true density and estimated density) for clumped, random and uniform distribution was 13.1%, -0.4%, and 2.1%, respectively; precision (% coefficient of variation, CV( D )) was 13.7%, 9.1%, and 9.2%; and accuracy (root mean-squared error, RMSE) was 27.9%, 7.4%, and 11.7% for clumped, random, and uniform distribution, respectively. Increasing total transect length and using several short transects (as opposed to few long transects) generally reduced bias, and increased accuracy and precision of estimates of abundance. A systematic layout of transects worked as well as, or better than, random layout, except when objects were distributed uniformly in space. This study advances the utility of the line transect method by providing information both on how study design affects accuracy and precision of abundance estimates, and how it can be improved when assumptions of the method are not strictly met based on a priori knowledge of the spatial distribution and presumed density of the target organism through appropriate changes in the study design.

1. Population surveys are often used to estimate the density, abundance, or distribution of natural populations. Recently, model-based approaches to analyzing survey data have become popular because one can more readily accommodate departures from pre-planned survey routes and construct more detailed maps than one can with design-based procedures. 2. Spatial models for population distributions (SMPDs) often make the implicit assumption that locations chosen for sampling and animal abundance at those locations are conditionally independent given modelled covariates. However, this assumption may be violated when survey effort is non-randomized, leading to preferential sampling. 3. We develop a hierarchical statistical modelling framework for detecting and alleviating the biasing effects of preferential sampling in spatial distribution models fitted to count data. The approach works by specifying a joint model for population density and the locations selected for sampling, and specifying a dependent correlation structure between the two processes. 4. Using simulation, we show that moderate levels of preferential sampling can lead to large (e.g. 40%) bias in estimates of animal density and that our modelling approach can considerably reduce this bias. In contrast, preferential sampling did not appear to bias inferences about parameters informing species-habitat relationships (i.e. slope parameters). 5. We apply our approach to aerial survey counts of bearded seals (Erignathus barbatus) in the eastern Bering Sea. As expected, models with a preferential sampling effect led to lower abundance than those without. However, several lines of reasoning (better predictive performance, higher biological realism) led us to prefer models without a preferential sampling effect for this dataset. 6. When population surveys break from traditional scientific survey design principles, ecologists should recognize the potentially biasing effects of preferential sampling when estimating population density or occurrence. Joint models, such as those described in this paper, can be used to test and correct for such biases. However, such models can be unstable; ultimately the best way to avoid preferential sampling bias is to incorporate design-based principles such as randomization and/or systematic sampling into survey design.

Conserving large populations with unique adaptations is essential for minimizing extinction risks. Sundarban mangroves (&gt;10,000 km2) are the only mangrove inhabited by tigers. Baseline information about this tiger population is lacking due to its man‐eating reputation and logistic difficulties of sampling. Herein, we adapt photographic capture‐mark‐recapture (CMR) and distance sampling to estimate tiger and prey densities. We placed baited camera stations in a typical mangrove in 2010 and 2012. We used telemetry based tiger home‐range radius (5.73 km, SE 0.72 km) to estimate effective trapping area (ETA). An effort of 407 and 1073 trap nights were exerted to photocapture 10 and 22 unique tigers in 2010 and 2012. We accounted for use of bait by modelling behaviour and heterogeneity effects in program MARK and secr package in program R. Using traditional CMR, tiger number was estimated at 11 (SE 2) and density at 4.07 (SE range 3.09–5.17) in 2010 while in 2012, tiger number was 24 ...

Summary1. Indices of abundance offer cost effective and rapid methods for estimating abundance of endangered species across large landscapes, yet their wide usage is controversial due to their potential of being biased. Here, we assess the utility of indices for the daunting task of estimating the abundance of the endangered tiger at landscape scales.2. We use double sampling to estimate two indices of tiger abundance (encounters of pugmarks and scats per km searched) and calibrate those indices against contemporaneous estimates of tiger densities obtained using camera‐trap mark–recapture (CTMR) at 21 sites (5185 km2) in Central and North India. We use simple and multiple weighted regressions to evaluate relationships between tiger density and indices. A model for estimating tiger density from indices was validated by Jackknife analysis and precision was assessed by correlating predicted tiger density with CTMR density. We conduct power analysis to estimate the ability of CTMR and o...

The Plain Pigeon {Columha inornata) was listed as endangered in Puerto Rico in 1970. During ^986-1992 and 1997-2001, we collected point transect survey data to estimate density, population size, and rate of change. Density and population size estimates increased between 1986-1992 and 1997-2001. With a mean density of 0.25 ± 0.06 SE individuals/ha and a mean population size in the area of the surveys of 3,746 ± 892 SE individuals during 1997-2001, we believe that the status of the Plain Pigeon is not as precarious as it was during 1986-1992, when mean density was 0.02 ± 0.003 SE individuals/ha and mean population size in the area of the surveys was 218 ± 42 SE individuals. However, Plain Pigeons are not widely distributed and the loss and fragmentation of second growth forests combined with the effects of hurricanes and other factors may cause their extinction. Because Plain Pigeons have a spatially clumped distribution, we recommend sampling at least 1,195 points during peak nesting activity (March through June) throughout the island, with at least 526 points covering areas of abundance in eastcentral Puerto Rico, to monitor population changes and evaluate the effectiveness of management actions.

The Plain Pigeon {Columha inornata) was listed as endangered in Puerto Rico in 1970. During ^986-1992 and 1997-2001, we collected point transect survey data to estimate density, population size, and rate of change. Density and population size estimates increased between 1986-1992 and 1997-2001. With a mean density of 0.25 ± 0.06 SE individuals/ha and a mean population size in the area of the surveys of 3,746 ± 892 SE individuals during 1997-2001, we believe that the status of the Plain Pigeon is not as precarious as it was during 1986-1992, when mean density was 0.02 ± 0.003 SE individuals/ha and mean population size in the area of the surveys was 218 ± 42 SE individuals. However, Plain Pigeons are not widely distributed and the loss and fragmentation of second growth forests combined with the effects of hurricanes and other factors may cause their extinction. Because Plain Pigeons have a spatially clumped distribution, we recommend sampling at least 1,195 points during peak nesting activity (March through June) throughout the island, with at least 526 points covering areas of abundance in eastcentral Puerto Rico, to monitor population changes and evaluate the effectiveness of management actions.

Ideally, a statistical population is the same as, or accurately represents its corresponding biological population. However, in practice, they rarely align in space and time, which can lead to variable exposure to sampling and biased inference. We often view a population mismatch as a temporary emigration process and resolve it with replicate and/or repeat sampling, though this approach is not feasible for all species and habitats. We developed a hierarchical Bayesian integrated model to estimate abundance of a biological population of the Kittlitz's murrelet (Brachyramphus brevirostris), a highly mobile, non-territorial, ice-associated seabird of conservation concern in Alaska and eastern Russia. Our model combines datasets from boat and telemetry surveys to account for all components of detection probability, specifically using telemetry locations to estimate probability of presence (pp) and line transect distance sampling to estimate probability of detection (pd). By estimating pp directly, we were able to account for temporary emigration from the sampled area, which changed with shifting icefloes between sampling occasions. Between 2007 and 2012, annual pp was highly variable, ranging from 0.33 to 0.75 (median=0.50, SE=0.02), but was not predictable using five environmental covariates. In years when two boat surveys were conducted, our model reduced the coefficient of variation (CV) of abundance estimates by 13-35%, yet in the year with only one boat survey (2009), the CV skyrocketed about 10-fold, emphasizing the importance of a second survey if pp varies. Although we increased the precision of annual abundance estimates by accounting for pp, we did not see the same improvement in the estimate of mean r, or trend, indicating that while we reduced within-year variance, we failed to account for a source(s) of variation across years, which we suspect is related to the propensity for murrelets to skip breeding in some years. Our integrated model to resolve a population mismatch is simple, flexible, and scalable for generating unbiased and precise abundance estimates of highly mobile species that occupy dynamic habitats where other open population models are not feasible. Importantly, it improves inference of the biological population, which is the true population of interest. We urge ecologists to think critically about the population in which they want to draw inference, especially as tracking technology improves and model complexity increases.

AяѠѡџюѐѡ.-Point counts are the method most commonly used to estimate abundance of birds, but they oĞ en fail to account properly for incomplete and variable detection probabilities. We developed a technique that combines distance and double-observer sampling to estimate detection probabilities and eff ective area surveyed. We applied this paired-observer, variable circular-plot (POVCP) technique to point-count surveys (n = 753) conducted in closed-canopy forests of southeast Alaska. Distance data were analyzed for each species to model a detection probability for each observer and calculate an estimate of density. We then multiplied each observer's density estimates by a correction factor to adjust for detection probabilities <1 at plot center. We compared analytical results from four survey methods: single-observer fi xed-radius (50-m) plot; single-observer, variable circular-plot (SOVCP); double-observer fi xed-radius (50-m) plot; and POVCP. We examined diff erences in detection probabilities at plot center, eff ective area surveyed, and densities for fi ve bird species: Pacifi c-slope Flycatcher (Empidonax diffi cilis), Winter Wren (Troglodytes troglodytes), Golden-crowned Kinglet (Regulus satrapa), Hermit Thrush (Catharus guĴ atus), and Townsend's Warbler (Dendroica townsendi). Average detection probabilities for paired observers increased ~8% (SE = 2.9) for all species once estimates were corrected for birds missed at plot center. Density estimators of fi xed-radius survey methods were likely negatively biased, because the key assumption of perfect detection was not met. Density estimates generated using SOVCP and POVCP were similar, but standard errors were much lower for the POVCP survey method. We recommend using POVCP when study objectives require precise estimates of density. Failure to account for diff erences in detection probabilities and eff ective area surveyed results in biased population estimators and, therefore, faulty inferences about the population in question.

The Plain Pigeon {Columha inornata) was listed as endangered in Puerto Rico in 1970. During ^986-1992 and 1997-2001, we collected point transect survey data to estimate density, population size, and rate of change. Density and population size estimates increased between 1986-1992 and 1997-2001. With a mean density of 0.25 ± 0.06 SE individuals/ha and a mean population size in the area of the surveys of 3,746 ± 892 SE individuals during 1997-2001, we believe that the status of the Plain Pigeon is not as precarious as it was during 1986-1992, when mean density was 0.02 ± 0.003 SE individuals/ha and mean population size in the area of the surveys was 218 ± 42 SE individuals. However, Plain Pigeons are not widely distributed and the loss and fragmentation of second growth forests combined with the effects of hurricanes and other factors may cause their extinction. Because Plain Pigeons have a spatially clumped distribution, we recommend sampling at least 1,195 points during peak nesting activity (March through June) throughout the island, with at least 526 points covering areas of abundance in eastcentral Puerto Rico, to monitor population changes and evaluate the effectiveness of management actions.

An out of habitat (OOH) marine mammal is an individual found outside of their natural range, e.g., an Atlantic walrus (Odobenus rosmarus rosmarus) along the coastline of mainland Europe, or an individual within their natural range in habitat that is not optimal for their health or survival due to a lack of suitable conditions and/or because of potential conflict with humans. As the number of OOH marine mammals appears to be increasing, and following on from two international workshops, here we define what constitutes an OOH marine mammal and provide a detailed assessment of potential drivers. Climate change, habitat loss and/or degradation, disturbance, changes in prey distribution, and morbidity may all be reasons for a marine mammal being OOH. Appropriate management of OOH marine mammals is considered. This may simply involve monitoring to better understand the situation, to protect the welfare of the animal(s) and to ensure that members of the public are kept safe. However, on occasion, further intervention may be required, such as providing safe areas for the OOH marine mammal(s), encouraging the animal(s) to move, capture and translocation, or euthanasia. Regardless of the action taken, educating and communicating with the public are key elements of OOH marine mammal management. Lessons can be learned from human-wildlife conflict and rewilding scenarios. The potential for OOH marine mammals to be pioneers seeking new habitat, contributing to species resilience in the face of rapidly changing environments, and how to include them in conservation legislation and management planning are considered.

A realização desta dissertação durante este ano foi para mim uma árú;r-tarefa apenas concretizável devido à ajuda de algumas pessoas a quem não posso deixar de agradecer. Em primeiro lugar quero agtadecer ao meu orientador, Professor Doutor Russell Alpizar-Jara, pela enoÍTne compreensão que sempre demonstrou, especialmente nos momentos em que me senti um pouco desanimada. Quero também agradecer-lhe por se mostrar sempre disponível e pelas suas explicações e sugestões dadas ao longo do ano. Agradeço também ao Mestre José Saias, por me ter dado uma grande ajuda na programação com o MS-DOS e com o Cygwin, essencial para a realização das simulações. Agradeço ainda ao Mestre João Filipe Monteiro, por me ter facultado alguma bibliografia importante para o trabalho. Agradeço aos elementos do Júri as sugestões dadas durante a discussão da dissertação e que ajudaram a melhorar alguns aspectos do texto. Por flrm quero agradecer aos meus pais, Brígida e António, por se mostrarem sempre compreensivos pela minha "quase ausência" no seio familiar, durante o ano. A todos o meu profundo MUITO OBRIGADA. No decurso desta investigaçáo, foi apresentada no XXIVth International Biometric Conference, que decorreu em Dublin de 13 a 18 Julho de 2008, uma comunicação (poster) intitulada "Model selection in distance sampling,,. Foi também apresentada no XW Congresso SPE, que decorreu em Vila Real de I a 4 de Outubro de 2008, uma comunicação oral com o título "Selecção de modelos em amostragem por distâncias". , SUMARIO A selecção do modelo que se ajuste adequadamente a um conjunto de dados é uma parte fulcral no processo da inferência estatística. O critério mais comum para seleccionar uma função de detectabilidade, que se ajuste a um conjunto de dados de distâncias, baseado na informação K-L, denomina-se criterio de informação de Akaike (AIC). Para avaliar a performance da rotina da selecção de modelos implementada no programa DISTANCE, realizaram-se simulações Monte Carlo para gerar dados de duas funções densidade de probabilidade frequentemente usadas. Aplicando esta metodologia, observou-se um enviesamento substancial na selecção do modelo, sendo os estimadores dos parâmetros baseados no modelo seleccionado frequentemente enviesados. Utilizaram-se duas abordagens na estimação dos parâmetros: selecção de modelos tradicional e ponderação de modelos. Para ilustrar a metodologia da selecção de modelos usaram-se dados provenientes de um estudo controlado. Palavras-chave: Amostragem por distâncias, critério de informação de Akaike, ponderação de modelos, selecção de modelos.

Knowledge about distribution of primate species and their densities is crucial for conservation and management. However, such information is often lacking or anecdotal, even for seemingly abundant species. Long‐tailed macaques (Macaca fascicularis) are distributed across southeast Asia and recognized by the International Union for Conservation of Nature Species Survival Commission Primate Specialist Group (IUCN SSC PSG) as both widespread and rapidly declining. Precise local density and abundance data are scarce across their range. To provide density and abundance estimates for a long‐tailed macaque population we conducted line transect distance sampling throughout Baluran National Park (250 km2), East Java, Indonesia covering all habitats. Long‐tailed macaque density was 41.4 ind/km2 (95% confidence interval, CI: 23.04–74.39), with an estimated abundance of 10,350 individuals (95% CI: 5,760–18,598). A density of 41.4 ind/km2 is lower than previous estimates for other sites in Java....

Eastern Himalayan biodiversity hotspot is rich in pheasant diversity, as eleven of the seventeen pheasant species in India occur here. Despite the richness, these pheasants have been least studied in their natural habitats and their current population status, ecology and behavioural patterns are unknown. We estimated abundance, habitat use and activity pattern of three pheasants, i.e. Red Jungle Fowl Gallus gallus (RJF), Kalij Pheasant Lophura leucomelanos (KP) and Grey Peacock Pheasant Polyplectron bicalcaratum (GPP) in Pakke Wildlife Sanctuary and Tiger Reserve, Arunachal Pradesh. Data collected from line transects and camera traps were used for estimating abundance, habitat use and activity patterns. Program Oriana 4.2 was used to determine the activity pattern of three species. Questionnaire survey was conducted around the protected area to determine the conservation threats for these species. Red jungle fowl had the highest density of 12.9 individuals/km 2 and a photographic rate of 3.19/100 trap nights among all the pheasants. Shrub cover, litter cover and grass cover were positively associated (p<0.001) with pheasant detections, where as disturbance (p<0.001) was negatively correlated. 60% of habitat overlap was observed between KP and RJF. Dillenia indica dominated habitats were significantly correlated with pheasants detections (R=0.34, p<.0001). The mean activity of GPP, RJF and KP were 6.30 hrs ± 3.37 hrs, 7.49 hrs ± 0.14 hrs and 8.29 hrs ± 0.18 hrs respectively. Additional studies on current status of these species and management plans are critical for pheasant conservation in this critical biodiversity hotspot.

SummarySix out of seven vulture species whose global ranges lie largely or wholly within Africa are listed as globally threatened. Since their current distributions individually span up to 39 range states there is a pressing need to develop robust, standardised methods that provide a clear measure of range-wide changes in abundance. Yet, survey methods currently used tend to yield either of two measures: estimates of breeding density, derived mainly from nest counts; or linear encounter rates, derived from road surveys. Here, we present the results of a six-year survey of six vulture species in Uganda, in which we used road counts, in combination with Distance sampling, to determine both encounter rates and densities within protected areas (PAs), and in predominantly pastoral and agricultural areas. In combination, five scavenging species were detected 4–6 times more frequently in PAs than elsewhere, and two species, White-backed Vulture Gyps africanus and Lappet-faced Vulture Torgu...

The designation of "climate refuge areas" should be an important part of a more integrated, ecosystem-based approach to protect endangered species. Identifying "climate refugia" areas should be a priority as resource managers begin to develop adaptive policies. This article describes policy innovation in California that includes important strategic elements and goals that can support the identification and protection of climate refugia for special status species, and offers a case study of the Gaviota coast in southern California. The essay concludes with general recommendations for planning and policy development to support better protection of endangered species, and emphasizes the importance of better local land-use planning.

Over the last decades roe deer (Capreolus capreolus) populations have increased in number and distribution throughout Europe. Such increases have profound impacts on ecosystems, both positive and negative. Therefore monitoring roe deer populations is essential for the appropriate management of this species, in order to achieve a balance between conservation and mitigation of the negative impacts. Despite being required for an effective management plan, the study of roe deer ecology in Portugal is at an early stage, and hence there is still a complete lack of knowledge of roe deer density within its known range. Distance sampling of pellet groups coupled with production and decay rates for pellet groups provided density estimates for roe deer in northeastern Portugal (Lombada National Hunting Area--LNHA, Serra de Montesinho--SM and Serra da Nogueira--SN; LNHA and SM located in Montesinho Natural Park). The estimated roe deer density using a stratified detection function was 1.23/100 ...

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In this study I estimate population densities and biomass of the major prey species of tiger Panthera tigris, leopard Panthera pardus and dhole Cuon alpinus in Bhutan's temperate ecosystem and recommend measures for reducing crop damage whilst simultaneously protecting ungulate populations. Thirty-two transects totalling 849 km were walked to estimate densities and biomass of ungulates and primates in Bhutan's Jigme Singye Wangchuck National Park during 2005-2006. Adequate detections (. 40 sightings) for analysis using Distance were obtained for wild pig Sus scrofa (n 5 54), muntjac Munticus muntjac (n 5 102) and sambar Cervus unicolor (n 5 48). Because of similarity in morphology and habitat use, density of serow Capricornis sumatraensis was estimated using the detection probability for sambar. Detections for langur Trachypithecus geei and macaque Macca mulatta were combined (n 5 39) to estimate primate density. Mean estimated densities were 3.68 wild pig, 2.17 muntjac, 1.19 sambar, 2.37 primates and 0.36 serow km -2 . The three primary prey species of large predators, wild pig, sambar and muntjac, provided a biomass of 379 kg km -2 , which could support up to 1.2 tigers per 100 km 2 . However, the presence of other sympatric carnivores competing for prey in the same area suggests that the actual number of tigers that could be supported is lower. Livestock (density, 6.0 km -2 ; biomass, 615 kg km -2 ) apparently supplement prey availability. Ungulate density in the study area is generally low compared to other areas in the Indian sub-continent, and this may be due to conflicts with farmers, excessive grazing of livestock in the forest and the rugged terrain.

Counting techniques are widely used to study and monitor terrestrial birds. To assess current applications of counting techniques, we reviewed landbird studies published 1989-1998 in nine major journals and one symposium. Commonly used techniques fell into two groups: procedures that used counts of bird detections as an index to abundance (index counts), and procedures that used empirical models of detectability to estimate density. Index counts rely upon assumptions concerning detectability that are difficult or impossible to meet in most field studies, but nonetheless remain the technique of choice among ornithologists; 95% of studies we reviewed relied upon point counts, strip transects, or other index procedures. Detectability-based density estimates were rarely used and deserve wider application in landbird studies. Distance sampling is a comprehensive extension of earlier detectability-based procedures (variable-width transects, variable circular plots) and a viable alternative to index counts. We provide a conceptual overview of distance sampling, specific recommendations for applying this technique to studies of landbirds, and an introduction to analysis of distance sampling data using the program DISTANCE.

Over the last decades roe deer (Capreolus capreolus) populations have increased in number and distribution throughout Europe. Such increases have profound impacts on ecosystems, both positive and negative. Therefore monitoring roe deer populations is essential for the appropriate management of this species, in order to achieve a balance between conservation and mitigation of the negative impacts. Despite being required for an effective management plan, the study of roe deer ecology in Portugal is at an early stage, and hence there is still a complete lack of knowledge of roe deer density within its known range. Distance sampling of pellet groups coupled with production and decay rates for pellet groups provided density estimates for roe deer in northeastern Portugal (Lombada National Hunting Area--LNHA, Serra de Montesinho--SM and Serra da Nogueira--SN; LNHA and SM located in Montesinho Natural Park). The estimated roe deer density using a stratified detection function was 1.23/100 ...

Global positioning system (GPS) technology has greatly improved the ability to investigate animal ecology at fine spatial and temporal scales but many GPS telemetry-based investigations may be underutilizing the technical capabilities of modern transmitters. We estimated eastern timber wolf (Canis lycaon) movement distance and territory size using variable GPS transmitter sampling frequencies to evaluate the effect of programming details on estimated movement patterns, territory size, and transmitter performance. Estimated movement distance decreased exponentially as sampling frequency was reduced from 1 location every 5 minutes to 1 location every 24 hours, implying that intense sampling frequencies were required for accurate measurement of finescale wolf movements. Wolf territory size estimates using 95% minimum convex polygons declined with decreasing sampling frequency, whereas estimates using adaptive kernel methods were comparable across a range of sampling intensities. Estimated transmitter battery longevity increased as the interval between fixes was lengthened but transmitter efficiency, defined as the number of successful fixes obtained during battery lifespan of the transmitter, was highest with fix intervals of intermediate length. Although GPS transmitters are effective for documenting fine-scale movements of animals, we argue their performance is strongly dependent upon transmitter programming and scale of analysis. Effective use of GPS transmitters will require study-specific assessment of the trade-offs between sampling needs versus transmitter efficiency and longevity.

The aim of this paper is to determine diet composition of threatened pheasant species i.e. Satyr Tragopan Tragopan satyra, Himalayan Monal Lophophorus impejanus, Kaleej Lophura leucomelana and Koklass Pucrasia macrolopha in their native forest which was never studied earlier. A study was conducted in the Kumaon region of western Himalaya for two years by collecting dropping material. Faeces were identified through direct sighting of defecating species. The diet items of each pheasant species mainly comprised plant materials followed by invertebrates and grit. A significant difference was observed in consuming food items by all pheasant species. Monal emerged as a specialist feeder on plants which were not eaten by other species. The Satyr and Koklass were more similar in terms of diet composition in both seasons while Kaleej and Monal were least similar, only invertebrates and grit were common in the diet of these species. No significant difference was observed in diet composition in different seasons of all pheasant species. The results expected to provide valuable information for the management of these pheasants in Himalayas.

AimTree crowns determine light interception, carbon and water exchange. Thus, understanding the factors causing tree crown allometry to vary at the tree and stand level matters greatly for the development of future vegetation modelling and for the calibration of remote sensing products. Nevertheless, we know little about large‐scale variation and determinants in tropical tree crown allometry. In this study, we explored the continental variation in scaling exponents of site‐specific crown allometry and assessed their relationships with environmental and stand‐level variables in the tropics.LocationGlobal tropics.Time periodEarly 21st century.Major taxa studiedWoody plants.MethodsUsing a dataset of 87,737 trees distributed among 245 forest and savanna sites across the tropics, we fitted site‐specific allometric relationships between crown dimensions (crown depth, diameter and volume) and stem diameter using power‐law models. Stand‐level and environmental drivers of crown allometric re...

Over the last decades roe deer (Capreolus capreolus) populations have increased in number and distribution throughout Europe. Such increases have profound impacts on ecosystems, both positive and negative. Therefore monitoring roe deer populations is essential for the appropriate management of this species, in order to achieve a balance between conservation and mitigation of the negative impacts. Despite being required for an effective management plan, the study of roe deer ecology in Portugal is at an early stage, and hence there is still a complete lack of knowledge of roe deer density within its known range. Distance sampling of pellet groups coupled with production and decay rates for pellet groups provided density estimates for roe deer in northeastern Portugal (Lombada National Hunting Area--LNHA, Serra de Montesinho--SM and Serra da Nogueira--SN; LNHA and SM located in Montesinho Natural Park). The estimated roe deer density using a stratified detection function was 1.23/100 ...

Ethiopian wolves (EWs), Canis simensis, are the rarest canids in the world and Africa's most endangered carnivore, found in only six isolated habitat fragments in the highlands of Ethiopia. Previous reports on the prevalence of parasites in the EW in Bale Mountains National Park (BMNP) are limited, with little information on their helminth fauna. This study seeks to understand the prevalence of helminth parasites in the EW in BMNP, Ethiopia. In this study, fecal samples were collected from 43 EWs in Web Valley (WV), BMNP, from June to October 2020, and the presence of helminth eggs was assessed using fecal sedimentation and centrifugal floatation methods with microscopy. Forty-two out of 43 fecal samples from wolves (98%) contained eggs from two taxonomic groups of helminths. Eggs from Capillaria spp. and Trichuris vulpis were found most frequently, followed by Toxocara canis, Diphyllobothrium spp., Toxascaris leonina, and Capillaria aerophila. One EW (2%) was recorded for harboring the cestode Moniezia expansa. About 9 of the 43 EWs (21%) presented monospecific infection: 9 EWs (21%) harbored 2 parasite species, 9 EWs (21%) hosted 3 parasite species, 11 EWs (26%) had infection involving 4 parasite species, 2 EWs (5%) were infected with 5 parasite species, 1 EW (2%) presented 6 parasite species, 1 EW (2%) harbored 7 parasite species, and 1 EW (2%) was diagnosed without parasite species. Concurrent helminth infection was highly associated with female EW. Megeti 3 was associated with a low level of concurrent helminth infection. The prevalence of helminth parasites found in wolves in the study area suggests that the environment is highly contaminated with intestinal parasites. Regular control of parasite transmission in EW, domestic dogs, and humans in and around BMNP, public education, and further parasite epidemiological studies must be conducted.

A survey of White-Throated Monkey (Cercopithecus erythrogaster) in Afi Mountain Wildlife Sanctuary (AMWS), Cross River State, Nigeria, was conducted to determine its status, ecology and population density. Line transect method of wildlife population determination was used. Ten transects were randomly selected for the study. Transect length of 2.0km and widths of 0.02km were systematically established, 1.0km from each other. Each transect was covered by an observer and census was done simultaneously in all the ten selected transects. The census started simultaneously at an agreed time, dates and places, this lasted for six weeks with data collected weekly. During the census, each observer was equipped with a binocular for easy observation and field notebook to record the information. Direct method of animal sighting was used. Mean population density of White-Throated Monkeys in Afi Mountain Wildlife Sanctuary was 0/km 2 , implying that the species was not sighted during the survey even though fecal matter and footprints suspected to be that of White-throated monkey were observed. The vegetation assessment revealed the study area to be composed of tropical rainforest plants species. Dominant species include: Pycnantus angolensis, Bailonella toxisperma, Tetrapleura tetraptera, Clapacca standtii and Cola spp. Observation also revealed that serious anthropogenic activities were on-going. Therefore, it is recommended that more population surveys of white-throated monkey be carried out in AMWS possibly using methods other than direct sighting. There is also need to carry out research on the ecological requirement and biology of the numerous species, especially the endangered Cross River Gorilla and the Drill Monkey in the study area.