Dry season drinking from terrestrial man-made watering holes in arboreal wild Temminck’s red colobus, The Gambia

Like most arboreal primates, redcolobus monkeys obtain most water from plants in their diet, licking their body or drinking occasionally from standing water in tree holes. Terrestrial drinking is not normally reported for arboreal primates. Here we report observations of terrestrial drinking from man-made watering holes by Temminck’s red colobus (Piliocolobus badius temminckii) in Abuko Nature Reserve and Bijilo Forest Park, The Gambia. Colobus drinking behaviour in Abuko has been reported previously by Starin (1991, 2002), mostly involving juveniles or lactating females; water was most commonly obtained by licking water from the body and leaves or obtained from tree holes. Some juveniles were seen drinking from swampy ground and puddles in the dry season, but otherwise the only terrestrial water body available to colobus during the study by Starin contained crocodiles, a known predator of red colobus at the site. Our observations show that shallow man-made watering holes that have since been created and do not harbour predators were used by different age classes. We discuss some of the implications of this behaviour for this endangered subspecies and report on the trend of increasing temperatures in The Gambia

Applying Knowledge of Species-Typical Scavenging Behavior to the Search and Recovery of Mammalian Skeletal Remains.

Forensic investigations involving animal scavenging of human remains require a physical search of the scene and surrounding areas. However, there is currently no standard procedure in the U.K. for physical searches of scavenged human remains. The Winthrop and grid search methods used by police specialist searchers for scavenged remains were examined through the use of mock red fox (Vulpes vulpes) scatter scenes. Forty-two police specialist searchers from two different regions within the U.K. were divided between those briefed and not briefed with fox-typical scavenging information. Briefing searchers with scavenging information significantly affected the recovery of scattered bones (χ(2) = 11.45, df = 1, p = 0.001). Searchers briefed with scavenging information were 2.05 times more likely to recover bones. Adaptions to search methods used by searchers were evident on a regional level, such that searchers more accustom to a peri-urban to rural region recovered a higher percentage of scattered bones (58.33%, n = 84)

An Investigation of Red Fox (Vulpes vulpes) and Eurasian Badger (Meles meles) Scavenging, Scattering, and Removal of Deer Remains: Forensic Implications and Applications

Within northwest Europe, especially the United Kingdom, the red fox (Vulpes vulpes) and the Eurasian Badger (Meles meles) are the largest wild scavengers capable of modifying a set of remains through scavenging. Knowledge of region-specific and species-typical scavenging behaviors of scavengers within the crime scene area and surroundings can aid in more efficient and accurate interpretations. The scavenging behaviors of captive and wild foxes and badgers were recorded and compared through actualistic methods and direct observation. The scavenging by wild foxes and badgers of surface-deposited baits and whole deer (Cervus nippon; Capreolus capreolus) in a woodland was observed and analyzed. Wild foxes were found to scavenge deer more frequently than badgers. The scavenging of deer remains by foxes was also compared with forensic cases. The scavenging pattern and recovery distances of deer and human remains scavenged by foxes were similar but were potentially affected by the condition and deposition of a body, and the presence of clothing

Sleeping trees and sleep-related behaviours of the siamang (Symphalangus syndactylus) in a tropical lowland rainforest, Sumatra, Indonesia

Sleeping tree selection and related behaviours of a family group and a solitary female siamang (Symphalangus syndactylus) were investigated over a 5-month period in northern Sumatra, Indonesia. We performed all day follows, sleeping tree surveys and forest plot enumerations in the field. We tested whether: (1) physical characteristics of sleeping trees and the surrounding trees, together with siamang behaviours, supported selection based on predation risk and access requirements; (2) the preferences of a solitary siamang were similar to those of a family group; and (3) sleeping site locations within home ranges were indicative of home range defence, scramble competition with other groups or other species, or food requirements. Our data showed that (1) sleeping trees were tall, emergent trees with some, albeit low, connectivity to the neighbouring canopy, and that they were surrounded by other tall trees. Siamangs showed early entry into and departure from sleeping trees, and slept at the ends of branches. These results indicate that the siamangs’ choice of sleeping trees and related behaviours were strongly driven by predator avoidance. The observed regular reuse of sleeping sites, however, did not support anti-predation theory. (2) The solitary female displayed selection criteria for sleeping trees that were similar to those of the family group, but she slept more frequently in smaller trees than the latter. (3) Siamangs selected sleeping trees to avoid neighbouring groups, monopolise resources (competition), and to be near their last feeding tree. Our findings indicate selectivity in the siamangs’ use of sleeping trees, with only a few trees in the study site being used for this purpose. Any reduction in the availability of such trees might make otherwise suitable habitat unsuitable for these highly arboreal small apes

Structural attributes of individual trees for identifying homogeneouspatches in a tropical rainforest

Mapping and monitoring tropical rainforests and quantifying their carbon stocks are important, bothfor devising strategies for their conservation and mitigating the effects of climate change. AirborneLaser Scanning (ALS) has advantages over other remote sensing techniques for describing the three-dimensional structure of forests. This study identifies forest patches using ALS-based structural attributesin a tropical rainforest in Sumatra, Indonesia. A method to group trees with similar attributes into forestpatches based on Thiessen polygons and k-medoids clustering is developed, combining the advantagesof both raster and individual tree–based methods. The structural composition of the patches could be anindicator of habitat type and quality. The patches could also be a basis for developing allometric modelsfor more accurate estimation of carbon stock than is currently possible with generalised models

Scavenging in Northwestern Europe: A Survey of UK Police Specialist Search Officers

Physical search methods used by police specialist searchers are based on counter-terrorism methods and not on the search and recovery of outdoor surface deposited human remains, nevertheless these methods are applied to scenes involving human remains. Additionally, there is limited published forensic literature within Northwestern Europe on the potential taphonomic agents within this region that are capable of modifying human remains through scavenging, scattering and removal. The counter-terrorism basis in physical search methods and the gap in published forensic literature regarding scavenging in this region can potentially impede searchers’ abilities to adapt physical search methods to their full efficiency in the search and recovery of scavenged human remains. This paper analysed through a questionnaire survey of 111 police specialist searchers, within the U.K., the impact of animal scavenging on the search and recovery of human remains.According to questionnaire respondents’ experiences and knowledge, the occurrence of scavenging at scenes in which respondents took part in a physical search for human remains was common (63.46%,n= 66) and happened most frequently with surface deposits (68.25%,n= 43). Scavenging resulted in the recovery of incomplete sets of remains (59.79%, n= 58) and influenced search perimeters (58.33%, n= 35). Scavenging also affected recovery rates at scene searches (80.43%,n= 74) that included the use of cadaver dogs with police handlers. The impact scavengers within this region have on different crime scene scenarios and search methods is not reflected in current published literature or search standards

Measuring and modelling microclimatic air temperature in a historically degraded tropical forest

Climate change is predicted to cause widespread disruptions to global biodiversity. Most climate models are at the macroscale, operating at a ~1 km resolution and predicting future temperatures at 1.5–2 m above ground level, making them unable to predict microclimates at the scale that many organisms experience temperature. We studied the efects of forest structure and vertical position on microclimatic air temperature within forest canopy in a historically degraded tropical forest in Sikundur, Northern Sumatra, Indonesia. We collected temperature measurements in ffteen plots over 20 months, alongside vegetation structure data from the same ffteen 25×25 m plots. We also performed airborne surveys using an unmanned aerial vehicle (UAV) to record canopy structure remotely, both over the plot locations and a wider area. We hypothesised that old-growth forest structure would moderate microclimatic air temperature. Our data showed that Sikundur is a thermally dynamic envi ronment, with simultaneously recorded temperatures at diferent locations within the canopy varying by up to~15 °C. Our models (R2=0.90 to 0.95) showed that temperature diferences between data loggers at diferent sites were largely determined by variation in recording height and the amount of solar radiation reaching the topmost part of the canopy, although strong interactions between these abiotic factors and canopy structure shaped microclimate air temperature variation. The impacts of forest degradation have smaller relative influence on models of microclimatic air temperature than abiotic factors, but the loss of canopy density increases temperature. This may render areas of degraded tropical forests unsuitable for some forest dwelling species with the advent of future climate chang

Forest maturity has a stronger influence on the prevalence of spider monkeys than howler monkeys in an anthropogenically impacted rainforest landscape

[EN] The transformation and depletion of primary forest over the past few decades have placed almost half of the world's primate species under the threat of extinction. Developing any successful conservation program for primates requires distribution and demography data, as well as an understanding of the relationships between these factors and their habitat. Between March and June 2010 and 2011 we collected data on the presence and demographic parameters of howler and spider monkeys by carrying out surveys, and validated our findings using local knowledge. We then examined the relationship between forest type and the presence of these primates at 54 sites in the northern area of the Selva Zoque Corridor, Mexico. We detected 86 spider monkey groups across 31 plots and censused 391 individuals (mean +/- SD = 5.9 +/- 3.0 individuals per sub-group, n = 67 sub-groups). We also detected 69 howler monkey groups across 30 plots and censused 117 individuals (mean +/- SD = 5.3 +/- 2.4 individuals per group, n = 22 groups). Howler monkey presence was not related to any specific vegetation type, while spider monkeys were present in areas with a higher percentage of tall forest (trees > 25 m high). Overall, spider monkeys were more prevalent than howler monkeys in our sampling sites and showed demographic characteristics similar to those in better protected areas, suggesting that the landscape features in the Uxpanapa Valley are suitable for their needs. Conversely, howler monkey presence was found to be more limited than in other regions, possibly due to the extended presence of spider monkeys.We thank the National Council of Science of Technology (CONACyT) and the Veracruz State Government for providing financial support to the project (grant no. 108990). ASG received support from Bournemouth University, the Centro de Investigaciones Tropicales and CONACyT (registration 195409) to conduct all the data analysis as part of her PhD. JCD received funding from the Isaac Newton Trust. We thank C. A. Munoz-Robles for providing the base map of the study site. We are very grateful to the communities of the Uxpanapa Valley for helping us throughout the development of this project. We are grateful to Dr Bicca-Marques and to two anonymous reviewers for their comments, which greatly helped in improving this manuscript. This study complied with the legal requirements of Mexico (SEMARNAT-DGVS/03660/11) and was approved by Universidad Veracruzana

Locating emergent trees in a tropical rainforest using data from an Unmanned Aerial Vehicle (UAV)

Emergent trees, which are taller than surrounding trees with exposed crowns, provide crucial services to several rainforest species especially to endangered primates such as gibbons and siamangs (Hylobatidae). Hylobatids show a preference for emergent trees as sleeping sites and for vocal displays, however, they are under threat from both habitat modifications and the impacts of climate change. Traditional plot-based ground surveys have limitations in detecting and mapping emergent trees across a landscape, especially in dense tropical forests. In this study, a method is developed to detect emergent trees in a tropical rainforest in Sumatra, Indonesia, using a photogrammetric point cloud derived from RGB images collected using an Unmanned Aerial Vehicle (UAV). If a treetop, identified as a local maximum in a Digital Surface Model generated from the point cloud, was higher than the surrounding treetops (Trees_EM), and its crown was exposed above its neighbours (Trees_SL; assessed using slope and circularity measures), it was identified as an emergent tree, which might therefore be selected preferentially as a sleeping tree by hylobatids. A total of 54 out of 63 trees were classified as emergent by the algorithm and in the field. The algorithm is based on relative height rather than canopy height (due to a lack of terrain data in photogrammetric point clouds in a rainforest environment), which makes it equally applicable to photogrammetric and airborne laser scanning point cloud data

Effects of anthropogenic disturbance on group densities of Thomas' langurs (Presbytis thomasi) within a lowland tropical forest, north Sumatra

Ecosystems around the globe are facing irreversible impacts due to climate change, habitat destruction, hunting, and an ever-increasing human population. Estimating densities of species across their geographical range helps us to understand natural variation and anthropogenic effects on species densities and to assess the effectiveness of existing conservation measures. Various methods have been used to produce accurate and precise population density estimates, each with associated limitations. Acoustic surveys for species producing loud calls have become common due to their ease of use, low cost, and reduced timescale. Relative to many other mammal taxa, primate species have been studied extensively, producing a wealth of data on socioecology and behavior, but for most species, density estimates over large geographical ranges are still lacking. We used an acoustic spatial capture–recapture model to estimate group density of unhabituated Thomas' langurs (Presbytis thomasi), a primate endemic to the Indonesian island of Sumatra, over a 60 km2 area of lowland dipterocarp forest. We then assessed if vegetation structure and distance from human habitation affected density estimates. Estimates of group density differed almost threefold between survey locations (from 2.79 to 8.08 groups/km2); there was no clear relationship with forest structure, but there was a significantly positive relationship between group density and distance from human habitation, with an increase of 0.38 groups/km2 for every km of distance. Although large-scale logging within the Sikundur region ceased ~30 years ago, the impacts of logging continue to have detrimental effects on the species within the area