This paper describes changes in bird communities following the conversion of lowland forest to commercial oil palm and rubber plantations. Conversion of forest to plantations resulted in a reduction in species richness of at least 60%, with insectivores and frugivores suffering greater losses than more omnivorous species. Of the 128 species recorded across all habitats, 84% were recorded in forest, and 60% were recorded only in that habitat. Of the 16 Globally Threatened or Near-Threatened species recorded in the study, 15 were recorded only in forest. Species occurring in plantations were significantly more widespread in Thailand than species recorded only in forests and had a tendency towards smaller body size. Species richness in plantations was unaffected by plantation age or distance from nearest forest edge, but was significantly greater where undergrowth was allowed to regenerate beneath the crop trees. Bird communities in oil palm and rubber plantations were extremely similar, and there was a strong positive correlation across species in their relative abundance in each plantation type. The results indicate that a high proportion of species formerly present in the region are unable to adapt to conversion of forest to oil palm and rubber plantations, resulting in large losses of bird species and family richness and the replacement of species with restricted ranges and high conservation status by those with extensive ranges and low conservation status. Initiatives that reduce pressure to clear new land for plantations, for example by increasing productivity in existing plantations and improving protected area networks, are likely to be more effective in conserving threatened forest birds than initiatives to improve conditions within plantations, though both should be encouraged.
Southeast Asia's tropical forests suffer the highest rates of deforestation and disturbance of any on Earth, with poorly understood impacts on native fauna. Asian tapirs (Tapirus indicus) are among the least studied of the large mammals in these forests. Using records from 9 camera trap surveys in 7 of the largest (>1000 km(2) ) protected area complexes, we assessed the influence of environmental variation and human-induced disturbance on tapir occurrence. Tapirs were detected at 13% of locations sampled, significantly associated with evergreen forest (P < 0.001). A multiple logistic regression model predicted tapir presence 87% of the time. According to this model, tapir occurrence was positively influenced by annual rainfall and proximity to the forest edge. However, tapirs may not avoid edges but instead prefer wetter evergreen forest, a habitat type that tended to occur further from the forest edge at higher elevations in our particular study sites (P < 0.001). By comparison, 4 other wild ungulate species that share habitats with tapirs showed a range of differing responses. Tapirs are expected to be less sensitive to disturbance because they are not targets for hunting and trade, and are almost entirely active at night, so avoid peak traffic periods in parks. Tapir populations in Thailand may be more stable than in other parts of their global range because rates of forest loss have decreased >40% over the past 20 years. We recommend surveys to fill gaps in the understanding of the status in lesser-known protected areas, research to better understand the fine-scale environmental influences on behavior and habitats of tapirs, and other forest ungulates, and continued legal status for tapirs in the highest category of protection.
SummaryGurney's Pitta Pitta gurneyi was not seen in the wild for over 30 years before its rediscovery in a small area in southern Thailand in 1986. In 2003, it was found over a much larger area in southern Myanmar (Burma) after an even longer absence of records. This paper reports the results of recent research on both populations. In Myanmar, birds were found in a high proportion of visited sites, including sites up to 40 km further north than any previous records in the country. Occupied forest sites had a higher density of seedlings, saplings, bamboo and rattan than unoccupied forest sites, suggesting a preference for regenerating forest. There was no evidence of a decline in the species's likelihood of occurrence up to at least the highest visited altitude of 230 m. Maximum entropy models suggested a potential range size of between 3,200 and 5,800 km 2 and the predicted range extended just over the border into Thailand, suggesting that birds might persist there. Population estimates for southern Myanmar ranged from 9,300 to 35,000 territories, with a mid-point estimate of 20,000 territories, based upon range sizes modelled from different parameters and a range of territory densities estimated from Thailand. The population in southern Thailand was estimated at between 15 and 20 territories in 2003, 2005 and 2007, and there was a reduction in the historic rate of forest loss in the core range over the same period, suggesting that long-term declines have been at least temporarily contained by recent conservation intervention. However, nesting success in Thailand was very low, due to heavy nest predation by cat snakes Boiga. Nests were usually built close to waterlogged areas and damp gullies, and nestlings were fed almost exclusively on earthworms. Occupied sites in Thailand had a higher density of seedlings, saplings, spiny palms and rattans, but sparser ground cover and a lower density of large trees and bamboo, than forests in Myanmar, indicating their secondary nature. Occupied and unoccupied sites in Myanmar were structurally more similar to each other than either was to occupied sites in Thailand. The results suggest that the species might inhabit a wider range of altitudes, slopes and forest types than previously thought, and so might persist in previously unsurveyed areas and might survive or even benefit from a degree of forest disturbance. However, the species's conservation-dependent status in Thailand and accelerating forest clearance in Myanmar suggest that forest protection measures are urgently needed to secure its long-term future.
Background:The destruction and fragmentation of forest in Southeast Asia is accelerating biodiversity loss, resulting in a range of management and conservation actions. For some species, a detailed understanding of microhabitat selection is critical for this, especially in the breeding season. Methods:To understand the factors that explain how specific habitats are used by the Grey Peacock-pheasant (Polyplectron bicalcaratum) in the breeding season, we used camera trapping and microhabitat sampling to assess the microhabitat selection of males. We also looked at their interaction with predators in an area of 1200 m × 1200 m at the Huai Kha Khaeng Wildlife Sanctuary, Thailand, between January and May 2013. Results:We show that display scrapes are situated on flatter open areas with small saplings and some vines, typified by low horizontal understory density. We hypothesise that this allows a trade-off between courtship display and the avoidance of predators. Our study showed that the position of Grey Peacock-pheasant display scrapes regularly overlapped with predators within the same microhabitat. We hypothesise that the species' behavioural responses to temporal variation in predation risk allows them to avoid most predators.
Summary The suitable habitats of the Endangered Green Peafowl Pavo muticus have declined by 80% over the past century due to extensive anthropogenic degradation. Currently, only six strongholds remain in mainland South-east Asia. While there are estimates of the species’ presence and status in five of these, the sixth one, defined as an “expected stronghold” located in the suitable dry forest along the Salawin River between Thailand and Myanmar, is not well documented. This study assessed the status of the area as a stronghold for the Green Peafowl’s long-term survival by estimating 1) the population density, 2) the current extension of suitable habitats, and 3) the threats to its survival. The area had an estimated density of 0.27 calling males/km2 (CI = 0.07–1.01) inhabiting 9,154 km2 of a mosaic of forest types, including mixed dry pine, mixed deciduous, and dry dipterocarp forests. Higher estimates were reported in other strongholds, including 0.8 birds/km2 in Bago Yoma (Myanmar), 15.8 birds/km2 in north-east Thailand, 1.13–11.34 birds/km2 in HuaiKhaKhaeng Wildlife Sanctuary (Thailand), 0.15–1.7 birds/km2 in northern Cambodia, and 0.15–4.69 birds/km2 in eastern Cambodia / south-central Vietnam. Hunting, habitat disturbance, and the presence of humans posed the greatest danger to the species across the surveyed area. Our results confirm the potential of the area for the species’ long-term survival. However, this “expected stronghold,” which could sustain a population of over 10 calling males/km2 like other high-quality strongholds, is in dire need of a comprehensive management plan to help reduce anthropogenic pressure. Ultimately, transboundary management between Thailand and Myanmar is crucial for the long-term repopulation of this stronghold.
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