No abstract

The social organization of a group-living animal is defined by a balance between group dynamic events such as group formation, group dissolution, and dispersal events and group stability in membership and over time. Understanding these processes, which are relevant for questions ranging from disease transmission patterns to the evolution of polygyny, requires long-term monitoring of multiple social units over time. Because all great ape species are long-lived and elusive, the number of studies on these key aspects of social organization are limited, especially for western lowland gorillas (Gorilla gorilla gorilla). In this study, we used non-invasive genetic samples collected within an approximately 100 km area of Loango National Park, Gabon to reconstruct group compositions and changes in composition over more than a decade. We identified 98 gorillas and 11 mixed sex groups sampled during 2014-2017. Using published data from 85 individuals and 12 groups surveyed between 2005 and 2009 at the same locality, we tracked groups and individuals back in time. The identification of 11 silverbacks via parentage analyses and the genetic tracking of 39 individuals across studies allowed us to infer six group formations, five group dissolutions, and 40 dispersal events within 12 years. We also observed four groups persisting across the sampling periods with a maximum inferred existence of nearly 17 years and exhibiting variation in membership stability. Our results highlight the variation in composition and stability among groups of western lowland gorillas and illustrate the power of non-invasive genetic sampling for long-term monitoring.

The hill forests of Karen State, Myanmar, were previously inaccessible to biologists and conservationists for security and political reasons. We have, however, now been able to conduct six surveys across the area, using camera traps, for a total of 9,511 trap-nights, to ascertain the presence of threatened mammal species. We obtained 4,191 records of at least 31 mammal species, including 17 categorized as Near Threatened, Vulnerable or Endangered on the IUCN Red List. Carnivores were especially diverse, with 19 species recorded, indicating a globally significant community, including the tiger Panthera tigris, leopard Panthera pardus and dhole Cuon alpinus. Our methodology was not appropriate for estimating relative abundance or occupancy but the species richness of the mammal community, the number of records and the number of locations where species were detected suggest the area is important for the conservation of a globally threatened mammal community that is in decline across the majority of its range. Despite long-standing conservation efforts undertaken by the Karen people, their forests are threatened by hunting and habitat loss. These threats are likely to be exacerbated as political change brings rapid development. Urgent action is thus needed to assist the Karen people to protect one of South-east Asia's last intact rich and diverse ecosystems.

SummaryThe Maleo Macrocephalon Maleo is a megapode bird endemic to Sulawesi, Indonesia, that lays large eggs at communal nesting grounds in naturally-heated sands or soils. It is classified as ‘Endangered’ and many populations have been extirpated due to overexploitation of eggs and loss of connectivity between forest and nesting grounds. The distribution and status of nesting grounds across Northern and Central Sulawesi are relatively well-established, but almost nothing is known about potential Maleo populations of South-east Sulawesi. In this study we used previously established methods to formally assess the status of three Maleo nesting grounds in Buton, South-east Sulawesi, and interviewed egg collectors at these three sites to determine the trends of populations and threats over time. All nesting grounds were severely threatened and can be expected to be abandoned in the near future due to extensive harvest of eggs and deforestation. Eggs were collected both for the wildlife trade (intensively harvested and sold as luxury items to people from distant cities) and local use (opportunistically harvested and both eaten and sold locally). All egg collectors remarked on an increase in illegal logging around nesting grounds over the previous decade. Though the Maleo’s current situation is dire, previous case studies show that collaborative grassroots initiatives supported by government and NGOs can protect nesting grounds and reverse population declines.

Abstract:Anthropogenic edge effects, whereby disturbance strength increases in proximity to ecotone boundaries, are known to strongly affect individual species but we lack a general understanding of how they vary by species, disturbance type and regional context. We deployed 46 camera-trap stations for a total of 3545 trap-days at two sites in Sulawesi, Indonesia, obtaining 937 detections of five vertebrate species. Anoa (Bubalus spp.) were more abundant near edges, booted macaque (Macaca ochreata) and red jungle fowl (Gallus gallus) were less abundant near edges, and edges did not impact Sulawesi warty pig (Sus celebensis) or Malay civet (Viverra tangalunga). But the relative importance of habitat disturbance from agriculture, roads and villages differed for each species, and edge-induced disturbances varied not only in magnitude but also in direction between the study areas. In the strongest instance, macaque local abundance was 3.5 times higher near villages than it was 3 km into the forest in one reserve, but 2.8 times higher 3 km into the forest than near villages in the other reserve. Our results suggest that responses to habitat edges among species and edge types are idiosyncratic, and that landscape-level context can strongly alter the influence of local disturbance on biodiversity.

Hunting for bushmeat represents a complex social–ecological system ill‐suited to top‐down management. Community participatory management is an alternative approach with increasing support for both ethical and pragmatic reasons. Key to a community approach is long‐term monitoring: this can both catalyse local ownership of and cohesion around management and is necessary to assess the effects of interventions and make changes as needed through adaptive management. Yet community‐driven methods to monitor hunting remain underdeveloped: they often fail to account for sampling bias and do not incorporate space in a thorough way, and data are not communally analysed to simulate effects of potential management decisions. We created a novel community bushmeat monitoring programme to address these gaps across 20 villages in north‐eastern Gabon. Paraecologists conducted standardised monitoring of bushmeat, and hundreds of hunters conducted GPS self‐follows mapping village hunting catchments. We integrated these data to estimate the proportion of bushmeat sampled and make robust extrapolations of total offtake across space and time, estimating an annual offtake of ~30,000 animals of >56 species across all villages. Here, we present our approach and data—and apply them through a case study of six sympatric duiker species—to inform new directions for social–ecological bushmeat research and management.

Genetic estimation of population sizes has been critical for monitoring cryptic and rare species; however, population estimates do not inherently reveal the permanence or stability of the population under study. Thus, it is important to monitor not only the number of individuals in a population, but also how they are associated in groups and how those groups are distributed across the landscape. Adding to the challenge of obtaining such information with high precision for endangered and elusive species is the need for long-term collection of such data. In this study we compare sampling approaches and genotype non-invasive genetic samples to estimate the number and distribution of wild western lowland gorillas occupying a ~ 100 km 2 area in Loango National Park, Gabon, for the periods 2005-2007 and 2014-2017. Based on the number of genotyped individuals we inferred a minimum of 83 gorillas during the first and 81 gorillas during the second study period. We also obtained similar capture-recapture population size estimates for the two periods despite variance in social dynamics like group formations, group dissolutions and individual dispersal. We furthermore found area fidelity for two groups that were sampled for 10-12 years, despite variation in group membership. Our results revealed how individual movements link groups in a 'network' and show that western lowland gorilla populations can show a high degree of temporal and geographic stability concurrent with substantial social dynamics.

Accurate estimations of animal populations are necessary for management, conservation, and policy decisions. However, methods for surveying animal communities disproportionately represent specific groups or guilds. For example, transect surveys can provide robust data for large arboreal species but underestimate cryptic or small‐bodied terrestrial species, whereas camera traps have the inverse tendency. The integration of information from multiple methodologies would provide the most complete inference on population size or responses to putative covariates, yet a simple, robust framework that allows integration and comparison of multiple data sources has been lacking. We use 27,813 counts of 35 species or species groups derived from concurrent visual transects, dung transects, and camera trap surveys in tropical forests and compare them within a generalized joint attribute modeling framework (GJAM) that both compares and integrates field‐collected dung, visual, and camera trap data to quantify the species‐ and trait‐specific differences in detection for each method. The effectiveness of survey method was strongly dependent on species, as well as animal traits. These differences in effectiveness contributed to meaningful differences in the reported strength of a known important covariate for animal communities (distance to nearest village). Data fusion through GJAM allows clear and unambiguous comparisons of the counts provided from each different methodology, the incorporation of trait information, and fusion of all three data streams to generate a more complete estimate of the effects of an anthropogenic disturbance covariate. Research and conservation resources are extremely limited, which often means that field campaigns attempt to maximize the amount of information gathered especially in remote, hard‐to‐access areas. Advances in these understudied areas will be accelerated by analytical methods that can fully leverage the total body of diverse biodiversity field data, even when they are collected using different methods. We demonstrate that survey methods vary in their effectiveness for counting species based on biological traits, but more importantly that generative models like GJAM can integrate data from multiple sources in one cohesive statistical framework to make improved inference in understudied environments.