Road induced edge effects on a forest bird community in tropical Asia

Background: Edge effects cause changes in bird community richness, abundance, and/or distribution within a landscape, but the avian guilds most influenced can vary among regions. Although Southeast Asia has the highest rates of deforestation and projected species loss, and is currently undergoing an explosive growth in road infrastructure, there have been few studies of the effects of forest edges on avian communities in this region.Methods: We examined avian community structure in a dry evergreen forest in northeastern Thailand adjacent to a five-lane highway. We evaluated the richness and abundance of birds in 11 guilds at 24 survey points on three parallel transects perpendicular to the edge. At each point, 10-min surveys were conducted during February-August 2014 and March-August 2015. Vegetation measurements were conducted at 16 of the bird survey points and ambient noise was measured at all 24 survey points.Results: We found a strongly negative response to the forest edge for bark-gleaning, sallying, terrestrial, and understory insectivores and a weakly negative response for arboreal frugivore-insectivores, foliage gleaning insectivores, and raptors. Densities of trees and the percentage canopy cover were higher in the interior, and the ambient noise was lower. In contrast, arboreal nectarivore-insectivores responded positively to the forest edge, where there was a higher vegetation cover in the ground layer, a lower tree density, and a higher level of ambient noise.Conclusion: Planners should avoid road development in forests of high conservation value to reduce impacts on biodiversity. Where avoidance is impossible, a number of potential mitigation methods are available, but more detailed assessments of these are needed before they are applied in this region.

Spatial distribution of display sites of Grey Peacock-pheasant in relation to micro-habitat and predators during the breeding season

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 May 2013.× 1200 m at the Huai Kha Khaeng Wildlife Sanctuary, Thailand, between January andResults: 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.Conclusions: Particular microhabitats are required for Grey Peacock-pheasant display. They avoid predators at these places by being active when predators are not.

Roost selection of the endangered Spotted Greenshank(Tringa guttifer) in critical habitat in the Inner Gulf of Thailand

Background: Roost-site quality can significantly affect the individual fitness of shorebirds, but roost sites remain poorly described for many threatened species on the East Asian–Australasian Flyway. We studied roost-site selection of the globally endangered Spotted Greenshank (Tringa guttifer) in the Inner Gulf of Thailand, an area which supports approximately 24% of their global wintering population, during two non-breeding seasons (October 2014–May 2015 and December 2015–February 2016). Methods: We measured nine variables associated with roost site characteristics including water depth, indicators of disturbance/predation risk, and associations with other shorebird species. We predicted that roost ponds with shallow water in proximity to foraging sites would receive higher usage than those further away. Results: A total of 94 sites were measured of which 46 were used for roosts with 23 used repeatedly. All used sites were human-modified ponds, of which 44 were used for salt farming and two used for aquaculture. Roosts were on average 1.10 ± 0.78 (SE) km from foraging sites and 5.8 ± 2.4 cm deep. The most supported model indicated that roost sites were negatively associated with distance to foraging sites and positively associated with the presence of Grey Plover (Pluvialis squatarola) and water depth. Conclusions: Traditional saltpans and other artificial wetlands near (< 1 km) mudflats serve as the primary high-tide roost habitat in the Inner Gulf of Thailand for this Spotted Greenshank population and perhaps seven other globally threatened or near-threatened species. Critically, all observed roost sites are on private land with no formal protection and thus will require creative public–private partnerships to manage sustainably.

Plant-frugivore interactions in an intact tropical forest in north-east Thailand

Fleshy-fruited plants in tropical forests largely rely on vertebrate frugivores to disperse their seeds.Although this plant-animal interaction is typically considered a diffuse mutualism,it is fundamental as it provides the template on which tropical forest communities are structured.We applied a mutualistic network approach to investigate the relationship between small-fruited fleshy plant species and the fruit-eating bird community in an intact evergreen forest in north-east Thailand.A minimum of 53 bird species consumed fruits of 136 plant species.Plant-avian frugivore networks were highly asymmetrical,with observed networks filling 30%of all potential links.Whereas some of the missing links in the present study might be due to undersampling,forbidden links can be attributed to size constraints,accessibility and phenological uncoupling,and although the majority of missing links were unknown(58.2%),many were probably due to a given bird species being either rare or only a very occasional fruit eater.The most common frugivores were bulbuls,barbets and fairy-bluebirds,which were responsible for the majority of fruit removal from small fleshy fruited species in our system.Migratory birds seemed to be a minor component of the plant-frugivore networks,accounting for only 3%of feeding visits to fruiting trees;they filled 2%of the overall potential networks.The majority of interactions were generalized unspecific;however,Saurauia roxburghii Wall.appeared to be dependent on flowerpeckers for dispersal,while Thick-billed Pigeons were only seen to eat figs.

Comparative sensitivity to environmental variation and human disturbance of Asian tapirs (Tapirus indicus) and other wild ungulates in Thailand

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 km2)pro-tected 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 for-est(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.Howev-er,tapirs may not avoid edges but instead prefer wetter evergreen forest,a habitat type that tended to occur fur-ther 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 expect-ed to be less sensitive to disturbance because they are not targets for hunting and trade,and are almost entire-ly 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 un-gulates,and continued legal status for tapirs in the highest category of protection.

Second-growth and small forest clearings have little effect on the temporal activity patterns of Amazonian phyllostomid bats

Secondary forests and human-made forest gaps are conspicuous features of tropical landscapes.Yet,behavioral responses to these aspects of anthropogenically modified forests remain poorly investigated.Here,we analyze the effects of small human-made clearings and secondary forests on tropical bats by examining the guild-and species-level activity patterns of phyllostomids sampled in the Central Amazon,Brazil.Specifically,we contrast the temporal activity patterns and degree of temporal overlap of 6 frugivorous and 4 gleaning animalivorous species in old-growth forest and second-growth forest and of 4 frugivores in old-growth forest and forest clearings.The activity patterns of frugivores and gleaning animalivores did not change between old-growth forest and second-growth,nor did the activity patterns of frugivores between old-growth forest and clearings.However,at the species level,we detected significant differences for Artibeus obscurus(old-growth forest vs.second-growth)and A.concolor(old-growth forest vs.clearings).The degree of temporal overlap was greater than random in all sampled habitats.However,for frugivorous species,the degree of temporal overlap was similar between old-growth forest and second-growth;whereas for gleaning animalivores,it was lower in second-growth than in old-growth forest.On the contrary,forest clearings were characterized by increased temporal overlap between frugivores.Changes in activity patterns and temporal overlap may result from differential foraging opportunities and dissimilar predation risks.Yet,our analyses suggest that activity patterns of bats in second-growth and small forest clearings,2 of the most prominent habitats in humanized tropical landscapes,varies little from the activity patterns in old-growth forest.