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Ridley's leaf-nosed bat; Ridley's round-leafed bat (Hipposideros ridleyi)

Mohamed bin Zayed Species project number 11253049

Mohamed bin Zayed Species Conservation (Project No. 11253049) - Ridley's leaf-nosed bat; Ridley's round-leafed bat - Awarded $10,000 on February 15, 2012

Across the tropics forests are increasingly threatened by logging and conversion to exotic tree plantations, but there are also opportunities to mitigate, or offset, biodiversity losses via responsible landscape management. This research, based in a major oil palm producing region of Southeast Asia, aims to provide practical recommendations to land managers to promote the conservation of vulnerable species in oil palm estates.

Among the many species threatened by the expansion of agriculture in Southeast Asia are a suit of 45 forest-dependent insectivorous bats. We are using one of these species, Ridley's leaf-nosed bat (Hipposideros ridleyi), as a flagship to reflect the threats facing bats and other animal groups in agricultural areas across the tropics. Ridley's leaf-nosed bat is classified as Vulnerable by the IUCN, roosts in large fallen hollow trees, and is only reported from scattered undisturbed forest areas on the Malay peninsula, Sumatra and Borneo. Following recent reports of this species in logged-over forest patches, our overall goal is to determine whether Ridley's leaf-nosed bat, and other bats with it, can ultimately persist in forests degraded by logging and isolated by agriculture. We ask whether the persistence of H. ridleyi in logged forests means that it is less threatened than currently recognized, or that its presence in disturbed habitats is only temporary due to roosts being more abundant following logging activities.

We base our assessment in a modified landscape at the Stability of Altered Forest Ecosystems project  in Kalabakan, Sabah, Malaysian Borneo. The plantation company has agreed to set aside forest conservation areas of various sizes throughout the plantation estate. Crucially, the sizes of these set-asides are representative of those legally required by oil palm companies elsewhere in the species' range (e.g. Indonesia, Thailand), and also in other tropical countries (e.g. PNG, Brazil) where oil palm agriculture is expanding.

Our first objective is to undertake harp trap and acoustic surveys to determine the extent to which bats use forested riparian corridors and hilltop patches of various sizes in the oil palm landscape. This will allow us to identify the optimum size of these landscape features that should be prioritized for conservation set-asides within plantations. Secondly, we will quantify the number of bat roosts available for bats in these areas over the long-term. Finally we will provide recommendations to plantation managers (linked to the requirements for certification under the Roundtable for Sustainable Palm Oil) to promote the persistence of H. ridleyi and other bat species in oil palm estates.

Project documents