Comparing density analyses and carnivore ecology in Madagascar's southeastern rainforest
Gerber, Brian Daniel
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Madagascar is renowned for its biodiversity, but also for forest loss, fragmentation, and degradation, making it a global conservation priority. With few studies dedicated to Madagascarâ s carnivores, little is known about their ecology. My objectives were to 1) compare density estimation techniques applicable to enumerating rare and/or elusive carnivores, 2) investigate Malagasy carnivore distributions, abundance and density, and occupancy/use across four sites that vary in forest disturbance, and 3) explore temporal activity patterns of rainforest carnivores. I found the spatially-explicit-capture-recapture models were empirically superior, as they are flexible and account for spatial variation in detection probability and area estimation. I found both endemic and exotic carnivore composition varied among four rainforest sites: Primary, Selectively-logged, Fragments <2.5 km and Fragments >15 km from contiguous-primary rainforest. All endemic carnivores were present in the Primary and Selectively-logged rainforest, while endemic carnivore species richness decreased and exotic carnivore species richness increased in the fragmented forests. Malagasy civet (Fossa fossana) density Â± SE was significantly less in the Selectively-logged compared to the Primary rainforest (1.38 Â± 0.22, 3.19 Â± 0.55 civets/km2, respectively); they were absent from both fragmented forests. Fossa (Cryptoprocta ferox) density Â± SE was not different between the Primary and Selectively-logged rainforests (0.12 Â± 0.05, 0.09 Â± 0.04 adults/km2, respectively); a single animal was detected in the Fragments <2.5 km, while none were detected in the Fragments >15 km. Malagasy carnivores had varied temporal activity overlap (5.8-88.8%). C. ferox preferred crepuscular activity, but overall exhibited a cathemeral activity pattern.
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