Effects of local and landscape conditions on insect pollinator in forest–agricultural landscape of West Java, Indonesia
Effects of local and landscape conditions on insect pollinator in forest–agricultural landscape of West Java, Indonesiawca2014-1624 Dendi Muhamad 1,*Satoru Okubo 1Pampang Parikesit 2Kazuhiko Takeuchi 1 3 1Ecosystem studies, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan, 2Biology, Universitas Padjadjaran, Bandung, Indonesia, 3Integrated Research System of Sustainability Science, The University of Tokyo, Tokyo, Japan
In relation to issue of pollination crisis and importance of crop pollinations to ensure enough food in tropical developing countries, it is crucial to understand roles and effects of human-modified landscapes with fragmented forest remnants in maintaining pollinator diversity while fulfilling the demands of local residences and reducing poverty. To implement appropriate landscape management for maintaining pollination service, sufficient information is essential about parameters of habitat suitability among various human-modified habitats with a range of distances to forests and vegetation characteristics, but such information is scarce. We investigated differences in insect pollinator communities between a remnant forest, two types of mature plantations, two types of agroforests, upland crop fields, rice paddy fields, and human settlements in a forest–agricultural landscape of West Java, and we analyzed the effects of both local and landscape factors on various types of species richness in this landscape. Results of non-metric multidimensional scaling revealed almost no strong difference of insect pollinator species composition among habitat types, although the results also indicated that abundance of crop pollinators (bees and wasps) declined and their replacement with others (beetles, moths, butterflies, and flies) along a gradient of human disturbance. Generalized linear modeling results revealed that insect pollinators were more sensitive to vegetation cover rather than to distance to remnant forest, however crop pollinators were more sensitive to different habitat types: species richness of bees was highest in the remnant forest. Mixed-tree agroforests were colonized by 93 % of crop pollinators found in remnant forest, and maintained the highest richness of insect pollinators together with the remnant forest. We concluded that protection of remnant forests as a source of crop pollinator diversity particularly bees has to be prioritized. However, as different environmental factors affected the richness values of different groups of insect pollinators, appropriate landscape design and habitat management could improve functional diversity in forest–agricultural landscapes in the tropics.