Tony King

Assessing Initial Reintroduction Success in Long-Lived Primates by Quantifying Survival, Reproduction, and Dispersal Parameters: Western Lowland Gorillas (Gorilla gorilla gorilla) in Congo and Gabon

Postrelease monitoring is an important aspect of reintroduction projects, one outcome of which is to allow an assessment of the initial success of the reintroduction, often measured by quantifying survival and reproduction rates. In long-lived species, accurate estimations of demographic parameters are difficult to obtain, and therefore assessment of reintroduction success in such species is challenging. To assess the initial success of a reintroduction program for the long-lived, slow-reproducing, and critically endangered western lowland gorilla Gorilla gorilla gorilla, we analyzed postrelease monitoring data from 2 reintroduced populations, in the Batéké Plateau region of the Republics of Congo and Gabon, to quantify several demographic parameters, and compared our results with published data on wild gorilla populations. Annual survival rate of the 51 released gorillas was 97.4%, 9 females gave birth to 11 infants at an annual birth rate of 0.196 births per adult female, and first-year survival of the infants was 81.8%. Annual birth rate within the reintroduced populations is not significantly different from that given for wild western gorilla populations, and other demographic parameters fall within the range of published data for wild gorilla populations. Our analysis illustrates that the reintroduction program has been successful in terms of the initial measures of postrelease survival and reproduction, and our quantitative data should facilitate the development of a population model that can predict the probability of population persistence and therefore provide an indication of longer-term reintroduction success.

New Distributional Records and Conservation Implications for the Critically Endangered Greater Bamboo Lemur Prolemur simus

To improve our knowledge of the distribution of the critically endangered greater bamboo lemur Prolemur simus, we surveyed 6 sites in eastern Madagascar. We found its characteristic feeding signs at 5 sites and made a direct sighting at one of these. One site represents a northern extension of 45 km of the known extant range of the species. Two sites are located in a forest corridor approximately halfway between the previously known southern and northern populations, therefore suggesting a broadly continuous distribution of the species within its range rather than the previously suspected distribution of two distinct populations separated by a distance of over 200 km. Our results illustrate the benefit of species-focussed surveys in determining the true distribution of endangered species, a realistic measure which is necessary in order to assess their current status and to prioritise long-term conservation interventions.

Habitat Preferences of the Critically Endangered Greater Bamboo Lemur (Prolemur simus) and Densities of One of Its Primary Food Sources, Madagascar Giant Bamboo (Cathariostachys madagascariensis), in Sites with Different Degrees of Anthropogenic and Natural Disturbance

Understanding the habitat preferences of a species is critical to the management and conservation of its population. The Critically Endangered greater bamboo lemur, Prolemur simus, is patchily distributed across its geographic range, using a very limited fraction of its total area of occurrence. The ecological basis for this patchy distribution remains largely unexplained. We analyzed the local habitat factors affecting the habitat use of Prolemur simus and densities of one of its primary food sources Madagascar giant bamboo, Cathariostachys madagascariensis. We sampled vegetation and site characteristics along belt transects in mid-altitude rain forest areas of the Ankeniheny–Zahamena rain forest corridor in eastern Madagascar, with (N = 10) and without (N = 16) evidence of habitat use by Prolemur simus. In our study site the preferred habitat type of Prolemur simus appears to be primary forest stands with moderate to low levels of human disturbance, greater natural disturbance, high densities of large diameter bamboo, and high structural diversity in tree heights. Cathariostachys madagascariensis appears to exploit canopy gaps created by natural disturbances, and similarly often exploits areas of anthropogenic disturbance. We found the highest densities of bamboo to occur in areas of moderate anthropogenic disturbance, whereas larger diameter culms were associated with lower levels of disturbance and smaller culms with areas of high anthropogenic disturbance. Human use of the forest and protection of the habitat of Prolemur simus are not necessarily incompatible, but our data indicate that the severity and frequency of use should probably be relatively low. Our results suggest that in our study site management strategies that minimize human disturbances, promote structural diversity in tree heights, and maintain relatively high densities of large-culmed bamboo may benefit populations of Prolemur simus.

Southern Range Extensions for the Critically Endangered Black-and-White Ruffed Lemur Varecia variegata and Greater Bamboo Lemur Prolemur simus

Abstract: The Vondrozo-Midongy rainforest corridor in south-eastern Madagascar is an example of a habitat corridor between otherwise disconnected protected areas, and is therefore considered important for the conservation of the endemic biodiversity of the island. Through several years of collaboration with local communities surrounding this corridor, WWF-Madagascar learned that members of some of these communities claimed the existence there of the black-and-white ruffed lemur (Varecia variegata) and the greater bamboo lemur (Prolemur simus), both regarded as Critically Endangered by the IUCN and not known by the scientific community to be present in the corridor. We therefore surveyed six sites in three communes in May 2010 to confirm this information. We made direct observations of Varecia variegata at two sites, which represent a southern extension to the known range of the species. We also found the characteristic feeding remains of Prolemur simus in the three most southerly sites, observations which also represent a major southern extension of the known range of this species. However, the feeding signs we found were old, at least a year old by our estimations, so we recommend further research to ascertain whether the population still exists there. The corridor is threatened by many anthropogenic pressures, and further reinforcement of the conservation program for the corridor is therefore likely to be necessary to ensure the viability of endangered lemurs in the region, and the role of the corridor in ensuring biological connectivity between the more substantial forests to the south and north.

Large-culmed Bamboos in Madagascar: Distribution and Field Identification of the Primary Food Sources of the Critically Endangered Greater Bamboo Lemur Prolemur simus

Abstract: The greater bamboo lemur Prolemur simus is a Critically Endangered lemur endemic to eastern Madagascar. Wild P. simus populations have diets dominated by bamboo (Poaceae: Bambusoideae), particularly large-culmed species of two endemic genera, Cathariostachys and Valiha, but also of an endemic Arundinaria and the pantropical Bambusa vulgaris. A good understanding of the distribution and biology of large-culmed bamboos would, therefore, be a major help in understanding the factors influencing the distribution and conservation requirements of P. simus. During four years of research within the context of a collaborative programme aimed at conserving P. simus, we undertook surveys at 47 low-, mid- and high-elevation sites in eastern Madagascar between November 2008 and September 2012, covering a distance of over 1000 km from Makira in the north to Midongy in the south. We provide and illustrate characteristics helpful in the field identification, at least to generic level, of the large-culmed woody bamboos we encountered. The most frequently encountered non-endemic large-culmed bamboo was Bambusa vulgaris, with both the green and the yellow forms commonly planted in or near rivers, towns and villages. We made 1,343 georeferenced records of endemic, large-culmed bamboos, recording Cathariostachys from Makira to Midongy, Valiha diffusa from Makira to the southern parts of the COFAV, and Arundinaria from Zahamena to the COFAV. Valiha diffusa was recorded only at low elevations (9–576 m), and Arundinaria only at high elevations (1018–1667 m), while Cathariostachys was distributed across a wide range of elevations, from 53 to 1471 m, although most records were between 600 and 1,260 m. Valiha diffusa had the most variable culm diameters, ranging from 1.7 to 9.5 cm. Cathariostachys had the largest mean culm diameter of the endemic large-culmed bamboos (6.1 cm), and Arundinaria the smallest (4.0 cm). Culm diameters of Bambusa vulgaris were larger than those of the endemic bamboos, with a mean of 9.58. Cathariostachys had thinner mean culms at lowland compared to higher elevation sites. The revised distribution map we provide for Cathariostachys appears to correspond well to the potential current distribution of P. simus based on recent direct sightings, indirect feeding signs and unconfirmed local knowledge. Cathariostachys does not, however, currently occur throughout the historic range of P. simus. Valiha does occur at one P. simus subfossil site outside the current range, and therefore may have been the primary food source for the species there. Further research into the historical distribution of large-culmed bamboos in Madagascar would be very helpful in establishing how eventual changes in bamboo distributions over time may have affected changes in P. simus distribution.

The fruit bats (Chiroptera: Pteropodidae) of the Lesio-Louna Reserve, Bateke Plateau, Republic of Congo

Abstract We present the results of the first survey of the fruit bats of the Lesio-Louna Reserve in the Republic of Congo, an area representative of the larger Bateke Plateau region of the country. Mist-netting was conducted in 2002 during four seasonal sampling periods: late wet season, early dry season, late dry season and early wet season. Five species were recorded. Two were frequently trapped, Micropteropus pusillus (n=102 individuals) and Epomops franqueti (n=57). The remaining three were captured only occasionally, Myonycteris torquata (n=5), Hypsignathus monstrosus (n=2) and Megaloglossus woermanni (n=2). In agreement with studies of other fauna, our results confirm that the Bateke Plateau supports species associated with both forest and savanna habitats. However, species typical of forested habitats were also netted in forest edge and neighbouring savanna, suggesting that these species utilise surrounding habitat within the forest-savanna mosaic characteristic of the study area. We found statistically significant seasonal variation in juvenile body mass and forearm length in E. franqueti and in adult female nipple length in M. pusillus, suggesting breeding seasonality in both these species in the reserve.

Estimation of population density of Eidolon helvum on the island of Príncipe, Gulf of Guinea / Estimation de densité de population de Eidolon helvum sur l'île de Príncipe, Golfe de Guinée

Abstract Eidolon helvum is a widespread African fruit bat. It is migratory and can form colonies of millions of individuals. On Príncipe, in the Gulf of Guinea, there are seemingly large numbers of E. helvum . Here, they have lost their migratory behaviour and rely on the availability of the year-round food resources on the island, which is small (128 km2) but is dominated by both primary rainforest and fruit-tree plantations. We visited the major roost for E. helvum on the island. Exit counts carried out on two consecutive nights showed the roost was used by between 10,539 (SE±67) and 14,160 (SE±324) individuals. Compared to mainland Africa, the colony was small, no doubt constrained by the size of the island. Nonetheless, Príncipe still supports a considerable density of E. helvum of between 82 and 111 bats/km2, which is comparable with densities found on mainland Africa.

Behavioural Ecology and Group Cohesion of Juvenile Western Lowland Gorillas (Gorilla g. gorilla) during Rehabilitation in the Batéké Plateaux National Park, Gabon

Rehabilitation of animals followed by reintroduction into the wild can benefit conservation by supplementing depleted wild populations or reintroducing a species in an area where it has been extirpated or become extinct. The western lowland gorilla (WLG, Gorilla g. gorilla) is persistently poached; infants are often illegally traded and used as pets. Some are confiscated and rehabilitated, then kept in sanctuaries or reintroduced into the wild. Prior to reintroduction, the ability of the orphans to survive independently in their environment needs to be assessed. Here, we performed a multivariate analysis, including diet composition, activity-budget, and pattern of strata using of a group of five juvenile WLG in the process of rehabilitation and distinguished three sub-periods of ecological significance: the high furgivory period, the Dialium fruits consumption period, and the high folivory period. The consequences of these variations on their well-being (play behaviour) and the group cohesion (spatial proximity and social interactions) were examined. Like wild WLGs, diets shifted seasonally from frugivorous to folivorous, while the same staple foods were consumed and large amounts of Dialium fruits were seasonally gathered high in trees. When succulent fruit intake was the highest, thus providing high energy from sugar, juveniles spent less time feeding, more time playing and group cohesion was the highest. Conversely, the cohesion decreased with increasing folivory, individuals spent more time feeding and less time playing together. Nonetheless, the group cohesion also decreased after the death of one highly social, wild-born orphan. This may underscore the importance of skilled individuals in the cohesion and well-being of the entire group and, ultimately, to rehabilitation success. This study evaluates the rehabilitation success with regards to the methods used and highlights the need to consider a set of individual and environmental factors for enhancing rehabilitation while preserving the local biodiversity and individual well-being.

Distributional Limits and Melanism in the South-West of the Range of the Crowned Sifaka (Propithecus coronatus), Madagascar

Abstract: From mid-November to late December 2011, we surveyed 12 sites in nine communes in and around the south-western part of the range of the Endangered crowned sifaka Propithecus coronatus in western Madagascar. We observed sifaka appearing to be P. coronatus at four sites in the Menabe Region; at three of them several of the sifaka were melanistic. Deckens sifaka P. deckenii were recorded at three sites, and Verreauxs sifaka P. verreauxi at one site. We found no evidence of sifakas between the Tsiribihina and Manambolo rivers west of latitude about 45°E, and local people claimed they have never existed there. We therefore recommend that the forests in this area be excluded from the current distribution range of P. coronatus. We found no sifakas resembling P. deckenii in the melanistic P. coronatus groups, which appears to confirm the hypothesis that most previous reports of possible sympatry between these two species can be better explained by melanism in P. deckenii. The typical individuals of P. coronatus we report showed lightly or heavily washed rufous coloration on the forearms and upper back. The melanistic forms we describe can be categorized as either a “very dark” form, characterized by dark brown to blackish coloration on the forearms and upper back, or as an “intermediate” form, showing dull rufous or light brown forearms and upper back. In reality there appeared to be a continuum in chromatic variation from the typically colored individuals, through the intermediate melanistic form, to the very dark form. These melanistic sifakas appear similar to the darker melanistic forms of P. deckenii north of the Manombolo River, rather than to the melanistic forms of P. coronatus reported to the south-east of our survey sites, or to melanistic forms of P. verreauxi south of the Tsiribihina River. Ancient gene-flow between sifaka taxa may be one of the causes of these melanistic tendencies, but we recommend further research to clarify the situation. These newly reported populations are at a high risk of local extinction. Containing melanistic forms not found elsewhere, we propose that they should be considered of considerable conservation importance with regard to preserving unique chromatic variation, and probably also genetic diversity, in P. coronatus.

Modelling Population Viability of Three Independent Javan Gibbon ( Hylobates moloch ) Populations on Java, Indonesia

Population viability analysis is a predictive procedure that uses a combination of different modelling approaches to estimate species vulnerability to extinction. Javan gibbons (Hylobates moloch) are vulnerable to local extinction primarily due to loss of habitat and hunting for the illegal pet trade. Using the modelling software VORTEX, we assessed the status of Javan gibbons in 3 areas (Ujung Kulon National Park, Halimun-Salak National Park, and Dieng Mountains) which hold over half of the remaining estimated number of gibbons on Java. Ujung Kulon and Halimun-Salak are long-time protected areas, whereas Dieng Mountains remain unprotected. For each area, we calculated the probability of extinction over a 100-year time period by testing different area-specific scenarios (e.g., hunting, deforestation, and increase in carrying capacity). Our modelling suggests each of the populations has a high chance of becoming extinct within the next 100 years if hunting and deforestation persist. If these threats are eliminated, the model shows each of the populations are large enough to persist in the long term whilst maintaining high levels of current genetic diversity. We conclude that specific actions should be implemented to develop more inclusive conservation management practices, especially improving awareness regarding the illegal wildlife trade and increased protection of wild populations and their habitats.