Selection of Fruit by Gibbons (Hylobates muelleri × agilis) in the Rain Forests of Central Borneo

Gibbons (Hylobates spp.) are among the main frugivorous primates in Southeast Asia, yet little is known about the criteria by which they select fruit for consumption. We studied two gibbon groups for 14 mo in the lowland dipterocarp forests of Central Borneo to determine their selectivity for different fruit species and traits. Ideal gibbon fruit were yellow, large, with a juicy-soft pulp, thin skin and available in large crops. Gibbons ultimately sought seedless fruit, but when seeds were present they selected fruit with a single, well-protected seed. Given that few fruit exhibited all the desired traits, we also carried out a multiple regression using the selection ratios of the various fruit species and their associated fruit traits to determine which traits ultimately determined gibbon choice. The analysis was stratified to account for differences in fruit availability. Selection was strongest when fruit were abundant in the forest and was based on seed width (<21 mm), color (yellow-orange), and fruit weight (1–5 g). No selection is apparent when food abundance was intermediate, but when fruit were scarce they preferentially ate larger fruit (6–30 g).     

Dry season habitat use by critically endangered white-shouldered ibis in northern Cambodia

We present the first scientific study of white-shouldered ibis Pseudibis davisoni habitat preferences in dry dipterocarp forest. Foraging sites included seasonal pools, forest understorey grasslands and fallow rice fields, with terrestrial sites used more following rainfall. Habitat and anthropogenic effects in logistic models of foraging site selection were examined by multimodel inference and model averaging. White-shouldered ibis preferred pools with greater cover of short vegetation (<25 cm) and less of the boundary enclosed, and forest sites with greater cover of bare substrate and lower people encounter rate. At forest sites, livestock density was positively related to bare substrate extent and thus may improve suitability for foraging ibis. At pools, livestock removed tall vegetation between the early and late dry season indicating their importance in opening up foraging habitats after wet season growth. However, by the late dry season, pools with greater livestock density had less short vegetation, the habitat favoured by ibis. Conservation strategies for white-shouldered ibis must consider a range of habitats, not just seasonal wetlands, and should incorporate extensive grazing and associated burning practises of local communities. Further understanding of the effects of these practices on vegetation, prey abundance and prey availability are therefore needed for effective conservation of this species. This will also develop our understanding of potentially beneficial anthropogenic influences in tropical environments.     

Pollination biology in a lowland dipterocarp forest inSarawak, Malaysia. I. Characteristics of the plant-pollinator communityin a lowland dipterocarp forest

Flowerings and flower visitors were observed continuously in alowland dipterocarp forest in Sarawak, Malaysia, for 53 mo in1992-1996. Flower visitors of 270 plant species were observed orcollected, and pollinators were assessed by observing body contact tostigmas and anthers. We recognized 12 categories of pollination systems.Among them, plants pollinated by social bees included the largest numberof species (32%) and were followed by beetle-pollinated species(20%). Pollination systems were significantly related with somefloral characters (flowering time of day, reward, and floral shape), butnot with floral color. Based on the relationships between pollinatorsand floral characters, we described pollination syndromes found in alowland dipterocarp forest. The dominance of social bees and beetlesamong pollinators is discussed in relation to the general floweringobserved in dipterocarp forests of West Malesia. In spite of high plantspecies diversity and consequent low population densities of lowlanddipterocarp forests, long-distance-specific pollinators were uncommoncompared with theNeotropics.     

王朗自然保护区大熊猫原始林与次生林的生境利用比较研究

为研究大熊猫对不同森林生境的利用情况,2012年和2013年在四川省王朗国家级自然保护区布设了30条调查线路开展了大熊猫生境调查,对49个大熊猫原始林利用样方和43个次生林利用样方中的16个变量进行了调查和统计分析。研究发现大熊猫可以利用采伐后自然恢复50多年的次生林,但原始林生境和次生林生境仍存在较大差异：与大熊猫所利用的原始林生境相比较,次生林生境的乔木胸径较小,灌木密度和灌木胸径较大,倒木较少。研究发现,加强对次生林的保护对大熊猫生境的保护工作有重要的意义。     

Influence of Forest Seasonality on Gibbon Food Choice in the Rain Forests of Barito Ulu,Central Kalimantan

We describe the diet of two hybrid gibbon groups (Hylobates mulleri x H. agilis) in relation to forest seasonality. We collected data over 12 mo in lowland dipterocarp forest in the Barito Ulu research area, Central Kalimantan, Indonesia. Although non-fig fruit was the main dietary item (52–64% of diet), gibbon diet was most strongly influenced by the availability of flowers. During periods when flowers were most abundant and the gibbons increased consumption of them, they also ate figs or young leaves more often. We suggest that although flowers are nutritionally rich sources of food, providing relatively high levels of protein compared to fruit, they are unlikely to satiate gibbon hunger and they seek dietary bulk from figs or young leaves, because they are easily obtained. Rainfall also influenced food choice, and non-fig fruit availability had a weak influence on fruit selection for one group. The group concentrated feeding on the fruit of a few species when fruit was most abundant and ate a greater diversity of species when fruit was scarce. Gibbon diet appeared not to be influenced by changes in availability of figs, young leaves and diversity of fruiting species.