Bird diversity benefits from large and diverse tree islands but not mechanical weeding within an oil palm landscape in Sumatra
The loss, degradation and fragmentation of habitats are the main threats to tropical biodiversity. Oil palm plantations are drivers of habitat alteration and profitable production systems for local smallholders, but these monocultures drive important losses of biodiversity and ecosystem functions. The aim of the Oil Palm Management Experiment at PTPNVI is to evaluate whether alternatives to current nutrient and weed management practices can reduce the negative impacts on ecological services and biodiversity while maintaining current production levels. Within this experiment, the subproject B09 studies insect pollinators, arthropods and flying vertebrates, and integrates plant data from subproject B06 to investigate cascading effects of the experimental treatments on insectivorous flying vertebrates like birds. I will test the hypothesis that plots with less abundant plant cover and diversity will harbor less arthropod food resources, leading to a reduction in bird activity and diversity. This information will be important for proposing management schemes in oil plantations.
Birds´ activity was already recorded using sound recorders in 2017 in the full-factorial management experiment in PTPN6, in the province of Jambi, Sumatra, Indonesia. It comprises 4 sites with 4 plots each (16 plots). Within these plots all combinations of conventional and reduced fertilization with mechanical weeding or herbicide application are represented. The response variables will be species richness, species composition and local abundance of insectivorous birds.