Investigating ecotourism impacts on mammal activity in a Costa Rican protected area

Costa Rica belongs to one of the 36 world biodiversity hotspots, representing one of the most important ecotourism destinations in the world and providing huge socio-economic and environmental benefits. However, tourism may have an impact on biodiversity which should be investigated thoroughly, giving priority to poorly studied areas. The Karen Mogensen Wildlife Refuge (KMWR) is part of the Biological Corridor of the Nicoya peninsula (NW Costa Rica), among the least studied regions of the country in terms of mammalian fauna. In the past, this area underwent significant human-alterations, but most habitats were restored thanks to the establishment in 1996 of a private protected area, owned by ASEPALECO association. Inside the KMWR, ecotourism and the establishment of an eco-lodge represent a fundamental income for the economic sustainability of the protected area. Through a camera trapping survey, we investigated the mammal community of the KMWR and we assessed the influence of tourists on their diel activity patterns. The survey was carried out from mid-January to mid-April 2019 using six camera traps placed close to the paths and sources of water, with the aim to improve animal detectability. A species accumulation curve was built to assess if our survey effort was sufficient to describe the community. To assess if mammal community was disturbed by human presence, we tested if the presence of tourists changed the diel activity patterns of i) the most common species (>50 detections), ii) the entire community, iii) nocturnal vs. diurnal species, and iv) strictly terrestrial vs. predominantly or semi-arboreal species. We described the diel patterns with a probability density function (Kernel Density Estimate), and we calculated the coefficient of overlap ∆i to compare the activity variation in relation to tourists’ presence/absence; we tested the statistical significance of the difference through the Watson’s two-sample test. Tourist presence/absence data were provided by ASEPALECO, which records all the entrances in the protected area. In 537 trap-days we recorded 467 independent detections of 12 mammals: Odocoileus virginianus, Dicotyles tajacu, Puma concolor, Leopardus pardalis, Conepatus semistriatus, Eira barbara, Nasua narica, Didelphis marsupialis, Tamandua mexicana, Cebus imitator, Cuniculus paca, Dasyprocta punctata. The accumulation curve indicated that we reached a plateau after 219 trap-days, i.e., no new mammals recorded after this period. During the sampling, tourists were present for 52 days, and absent for 50 days, with little difference in the number of camera-trap detections (239 and 228, respectively). The presence/absence of tourists did not produce any significant change (e.g., ∆i>0.77) in the temporal activity patterns all species and groups considered. Our results showed that the number of large mammals in the KMWR is comparable to that recorded in other protected area of Costa Rica, including some rare and elusive species; this suggests that habitat restoration was effective for mammal conservation. Interestingly, during our survey, we documented the first reproductive event of the top-predator Puma concolor in the area, an encouraging indication of the recovery of the food-web, after years of protection. There is a large literature documenting the impact of tourism on wildlife activity patterns, showing an increase of nocturnality. However, our results showed little effects of tourists on the activity patterns of species and groups. This suggests that present tourism management in the KMWR is compatible with mammal conservation and provides a nice example of sustainable touristic exploitation.