Wed, Aug 04, 2021:On Demand
Background/Question/Methods
Urban development and habitat encroachment are a global threat to biodiversity. Studies of wildlife thriving in urban environments are important to evaluate the impact of these anthropogenic changes to species. In the Caribbean region, West Indian boas (Chilabothrus sp) are island endemics that tend to be at the top of their trophic level within their respective home ranges, play essential roles in their ecosystem, and some are of international concern. Research of population structure, spatial ecology, and habitat selection of snakes in urban fragmented landscapes is required. The Puerto Rican boa (Chilabothrus inornatus), a federally protected species endemic to Puerto Rico, has a wide distribution on the island and inhabits highly modified landscapes with fragmented forest remnants. Here, I conducted a mark-recapture and radiotelemetry study from 2013-2019 to examine the population structure, home range and habitat use of the Puerto Rican boa in an urban fragmented landscape inside a military installation. Captured boas were identified with a subcutaneous microchip, and demographic characteristics (age class, sex, length) were recorded. Ten boas were radio-tracked for home range analysis and for habitat preference on two different spatial scales: landscape and home range level.
Results/Conclusions Fifty-six boas were captured and twelve were radio-tracked. Abundance of boas was low and encounter rate was 0.04 boas / person-hours. Radio-tracked boas spent more than 80% of their time inside forest fragments and home range averaged 3.61 ha which was lower than counterparts at rural, non-fragmented habitats. Five boas were recaptured and were encountered on the same forest fragment after 1-4 years of first encounter. Boas selected non-random locations both at the landscape and home range level. At home range level, boas selected habitats with more canopy cover, litter depth and woody material. It is possible that boas in different forest fragments use habitat differently depending on structure of forest, habitat type, period of succession and prey availability. At the landscape level, boas preferred forest landcover with larger, taller trees over urban or grassland landcover which might indicate why boas’ home ranges and movements were confined most of the time to forest fragments. Urban forests can be biodiversity reservoirs for species dwelling in urban environments. Since urban environments and habitat fragmentation frequency are expected to increase, the conservation and adequate management of these habitats are important for boa conservation efforts.
Results/Conclusions Fifty-six boas were captured and twelve were radio-tracked. Abundance of boas was low and encounter rate was 0.04 boas / person-hours. Radio-tracked boas spent more than 80% of their time inside forest fragments and home range averaged 3.61 ha which was lower than counterparts at rural, non-fragmented habitats. Five boas were recaptured and were encountered on the same forest fragment after 1-4 years of first encounter. Boas selected non-random locations both at the landscape and home range level. At home range level, boas selected habitats with more canopy cover, litter depth and woody material. It is possible that boas in different forest fragments use habitat differently depending on structure of forest, habitat type, period of succession and prey availability. At the landscape level, boas preferred forest landcover with larger, taller trees over urban or grassland landcover which might indicate why boas’ home ranges and movements were confined most of the time to forest fragments. Urban forests can be biodiversity reservoirs for species dwelling in urban environments. Since urban environments and habitat fragmentation frequency are expected to increase, the conservation and adequate management of these habitats are important for boa conservation efforts.