Occurrence of blood‐feeding terrestrial leeches (Haemadipsidae) in a degraded forest ecosystem and their potential as ecological indicators. (30th July 2019)

• Record Type: Journal Article
• Authors: Drinkwater, Rosie; Williamson, Joseph; Swinfield, Tom; Deere, Nicolas J.; Struebig, Matthew J.; Clare, Elizabeth L.; Coomes, David; Rossiter, Stephen J.
• Other Names: Dahlsjö Cecilia guestEditor.; Kitching Roger guestEditor.
• Is Part Of: Biotropica. Volume 52:Number 2(2020)
• Page Start: 302
• Page End: 312
• Publication Date: 2019-07-30
• Subjects: Borneo -- Haemadipsidae -- human‐modified forest -- indicators -- occupancy modeling -- thermal tolerance; Biotic communities -- Tropics -- Periodicals; Applied ecology -- Tropics -- Periodicals; Biology -- Tropics -- Periodicals; 577.80913
• DOI: 10.1111/btp.12686
• Languages: English
• ISSNs: 0006-3606

Abstract

Abstract: Blood‐feeding invertebrates are emerging model taxa in biodiversity assessments, both as indicators of mammal abundance and also as sources of mammal DNA for identification. Among these, terrestrial leeches arguably offer the greatest promise; they are abundant and widespread in the humid tropics, and their blood meals can be easily assayed to establish diet. Unfortunately, terrestrial leeches are understudied, with little known about their ecology and behavior. Such information is needed to evaluate their utility as ecological indicators and to account for potential sampling biases that might arise from habitat preferences. By combining occupancy modeling and thermal tolerance assays, we determined the factors affecting species occurrence in the related terrestrial brown ( Haemadipsa sumatrana ) and tiger leech ( Haemadipsa picta ), both of which are widespread in tropical forests in Southeast Asia. We sampled both species across a degraded forest landscape in Sabah, Borneo, in wet and dry seasons, associating occurrence with habitat‐level metrics. We found that, for both species, detection probability increased with canopy height regardless of season. Additionally, increased vegetation heterogeneity had a strong negative influence on brown leech occurrence in the dry season, implying an interaction between vegetation structure and climate. However, we found no difference in physiological thermal tolerance (CTMAX ) between the two species. Finally, using a reduced dataset, we found a small improvement in brown leech model fit when including mammal abundance. Our results suggest that the presence of terrestrial leeches may act as useful ecological indicators of habitat quality and potentially mammalian abundance. Abstract in Indonesia is available with online material. Abstrak: Invertebrata penghisap darah semakin kerap dijadikan taksa model untuk menilai biodiversiti, terutamanya sebagai petunjuk kelimpahan mamalia, dan sumber DNA untuk identifikasi mamalia. Antara haiwan‐haiwan ini, pacat boleh dikatakan paling sesuai untuk kajian sebegini; taburan pacat berlimpah dan meluas di kawasan tropika yang lembap, dan darah yang dihisap dapat dikaji dengan mudah bagi menetapkan sumber makanan pacat tersebut. Malangnya, haiwan ini kurang dikaji, hanya sedikit ditahui mengenai ekologi dan tingkah laku pacat. Maklumat tersebut diperlukan untuk menilai utiliti pacat sebagai petunjuk ekologi dan mengambil kira potensi kecenderungan pensampelan yang mungkin timbul dari pilihan habitat. Kami menggunakan model penghunian dan ujian toleransi suhu untuk menentukan faktor‐faktor yang mempengaruhi taburan species pacat coklat ( Haemadipsa sumatrana ) dan pacat harimau ( H. picta ), yang kedua‐duanya bertaburan luas di dalam hutan tropika Asia Tenggara. Kami mengutip kedua‐dua spesies merentasi landskap hutan terdegradasi di Sabah, Borneo Malaysia pada musim hujan dan musim kemarau, sambil mengaitkan taburan ini dengan metrik habitat. Hasil kajian kami telah menunjukkan bahawa kebarangkalian pengesanan meningkat bersama ketinggian kanopi tanpa mengira musim bagi kedua‐dua spesies.Tambahan pula, kami juga mendapati bahawa heterogeniti tumbuh‐tumbuhan yang tinggi mempunyai kesan negatif yang kuat terhadap kehadiran pacat coklat pada musim kemarau, menguatkan bukti kewujudan interaksi antara struktur hutan dan iklim.Walau bagaimanpun, ujian toleransi termal tidak menunjukkan perbezaan toleransi suhu fisiologi (CTMAX ) antara kedua‐dua spesis pacat. Akhir sekali, dengan menggunakan dataset yang dikurangkan khas untuk mamalia yang dipadankan secara spasial, model yang lebih sesuai telah dihasilkan untuk lintah coklat jika kelimpahan mamalia dimasukkan. Hasil kajian kami mencadangkan bahawa pacat boleh menjadi petunjuk ekologi yang berguna untuk kualiti habitat dan kelimpahan mamalia di hutan yang utuh.