Habitat degradation is pervasive across the tropics and is particularly acute in Southeast Asia, with major implications for biodiversity. Much research has addressed the impact of degradation on species diversity; however, little is known about how ecological interactions are altered, including those that constitute important ecosystem functions such as consumption of herbivores. To examine how rainforest degradation alters trophic interaction networks, we applied DNA metabarcoding to construct interaction networks linking forest‐dwelling insectivorous bat species and their prey, comparing old‐growth forest and forest degraded by logging in Sabah, Borneo. Individual bats in logged rainforest consumed a lower richness of prey than those in old‐growth forest. As a result, interaction networks in logged forests had a less nested structure. These network structures were associated with reduced network redundancy and thus increased vulnerability to perturbations in logged forests. Our results show how ecological interactions change between old‐growth and logged forests, with potentially negative implications for ecosystem function and network stability.

Data Accessibility Statement:Data are currently archived at the Centre for Ecology and 20 Hydrology Environmental Information Data Centre 21 (https://doi.org/10.5285/8b106445-d8e0-482c-b517-5a372a09dc91) and will be released from 22 embargo following publication. Specific analysis scripts are available on GitHub with links 23 given in the manuscript and will be archived on Zenodo prior to publication. 24 25 Statement of authorship: SR, EC, DHB, MS and OTL conceived the project, DHB, VK and JB 26 undertook field collections and laboratory work, DHB analysed the data with input from EC, 27 and DHB wrote the manuscript with input from all authors. 28 3 Abstract 29 1. Habitat degradation is pervasive across the tropics and is particularly acute in Southeast 30 Asia, with major implications for biodiversity. Much research has addressed the impact 31 of degradation on species diversity; however, little is known about how ecological 32 interactions are altered, including those that constitute important ecosystem functions 33 such as pest consumption.34 2. We examined how rainforest degradation alters trophic interaction networks linking 35 insectivorous bats and their prey. We used DNA metabarcoding to study the diets of 36 forest-dwelling insectivorous bat species, and compared bat-prey interaction networks 37 between old growth forest and forest degraded by logging in Sabah, Borneo.38 3. We predicted that rainforest degradation would cause measurable reductions in the 39 numbers of prey consumed by individual bats, and that this degradation would yield 40 networks in logged forest with lower functional complementarity, modularity and 41 nestedness than those in old growth forest.42 4. Compared to bats in old growth rainforest, bats in logged sites consumed a lower 43 diversity of prey. Their interaction networks were less nested and had a more modular 44 structure in which bat species had lower closeness centrality scores than in old growth 45 forest. These network structures were associated with reduced network redundancy and 46 thus increased vulnerability to perturbations in logged forests.47 5. Our results show how ecological interactions change between old growth and logged 48 forests, with potentially negative implications for ecosystem function and network 49 stability. We also highlight the potential importance of insectivorous bats in consuming 50 invertebrate pests.51 4 Malay abstract 52 1. Degradasi habitat merupakan suatu fenomena yang berleluasa dikawasan tropika, 53 terutamanya di Asia Tenggara dengan implikasi yang besar ke atas biodiversiti. Banyak 54 kajian telahpun meneliti impak degradasi habitat atas kepelbagaian spesis. Walau 55 bagaimanapun, dari segi mana interaksi ekologi diubah suai kurang diselidik, termasuk 56 interaksi yang membentuk fungsi ekosistem yang penting seperti pemakanan binatang 57 perosak.58 2. Kami telah memeriksa bagaimana degradasi hutan hujan tropika dapat mengubah suai 59 interaksi antara tahap trofik yang menghubungkan kelawar yang memakan serangga 60 dan mangsa mereka. Ka...

Logging activities degrade forest habitats across large areas of the tropics, but the impacts on trophic interactions that underpin forest ecosystems are poorly understood. DNA metabarcoding provides an invaluable tool to investigate such interactions, allowing analysis at a far greater scale and resolution than has previously been possible. We analysed the diet of the insectivorous fawn leaf-nosed bat Hipposideros cervinus across a forest disturbance gradient in Borneo, using a dataset of ecological interactions from an unprecedented number of bat-derived faecal samples. Bats predominantly consumed insects from the orders Lepidoptera, Blattodea, Diptera and Coleoptera, and the taxonomic composition of their diet remained relatively consistent across sites regardless of logging disturbance. There was little difference in the richness of prey consumed in each logging treatment, indicating potential resilience of this species to habitat degradation. In fact, bats consumed a high richness of prey items, and intensive sampling is needed to reliably compare feeding ecology over multiple sites regardless of the bioinformatic procedures used.

Logging activities degrade forest habitats across large areas of the tropics, but the impacts on trophic interactions that underpin forest ecosystems are poorly understood. DNA metabarcoding provides an invaluable tool to investigate such interactions, allowing analysis at a far greater scale and resolution than has previously been possible. We analysed the diet of the insectivorous fawn leaf-nosed bat Hipposideros cervinus across a forest disturbance gradient in Borneo, using a dataset of ecological interactions from an unprecedented number of bat-derived faecal samples. Bats predominantly consumed insects from the orders Lepidoptera, Diptera, Blattodea, and Coleoptera, and the taxonomic composition of their diet remained relatively consistent across sites regardless of logging disturbance. There was little difference in the richness of prey consumed per-bat in each logging treatment, indicating potential resilience of this species to habitat degradation. In fact, bats consumed a high richness of prey items, and intensive sampling is needed to reliably compare feeding ecology over multiple sites. Multiple bioinformatic parameters were used, to assess how they altered our perception of sampling completeness. While parameter choice altered estimates of completeness, a very high sampling effort was always required to detect the entire prey community.