The role of fruit bats in plant community changes in an urban forest in Indonesia

Urban forests are important for alleviating the impact of environmental stress in intensely developed cities and play a role in maintaining natural interactions in urban ecosystems. Two of the most densely populated cities in Southeast Asia: Jakarta and Depok, Indonesia, have seen a dramatic decrease in green spaces, despite the importance of such spaces in making these cities more liveable and sustainable. One of the few remaining green spaces in the greater Jakarta area is the urban forest at Universitas Indonesia, yet little is known about its native biota, especially its bats. A host plant association study was conducted to determine the role of fruit bats in the urban forest ecosystem, which are suspected to be seed dispersers and pollinators. Eight fruit bat species (Cynopterus brachyotis, C. horsfieldii, C. minutus, C. sphinx, C. titthaecheilus, Macroglossus minimus,M. sobrinus, and Rousettus amplexicaudatus) consumed plant products from 26 plant species. Bat-plant species pairs were significantly associated (Cramer's V = 0.51, p < 0.05). Ficus species comprised the highest percentage of plants consumed (25%), yet they were never deliberately planted, suggesting that fruit bats introduced them from other areas. Additionally, introduced plants were found outside the introduction area. By acting as seed dispersers and pollinators, fruit bats potentially contribute to the current plant diversity in the urban forest and connect distant plant populations. Fruit bats facilitated seed dispersal of species important to forest regeneration, an important insight for future plans to increase green spaces to mitigate the negative effects of anthropogenic change in urban environments.