Movement patterns and habitat selection of the giant day gecko (Phelsuma madagascariensis grandis) in the Masoala rainforest exhibit, Zurich Zoo

Abstract

In 2003, Zurich Zoo opened the Masoala exhibit to help preserving the endemic flora and fauna of Madagascar and to raise public awareness of the threats to this biodiversity hotspot. The enclosure houses more than 45 animal taxa and over 35000 individual plants on almost 11000 m2. After three years of establishment of food webs and demographic changes in the community, there is an urgent demand for animal population monitoring. Therefore, this paper aims (i) to determine how increasing gecko density affects gecko movement patterns in the exhibit and (ii) to assess habitat selection in 12 heterogeneous areas within the exhibit, differing in various environmental parameters (e.g., plant species, sun hours, and food sources). In contrast to an earlier study on this gecko population, our results on gecko movement patterns show that moved distances are evenly distributed amongst distances between 0 to 70 m. Moreover, geckos showed strong habitat preferences for certain areas; plants like Ravenala madagascariensis and Pandanus spp. as well as ventilation tubes and cages were most frequently used as perch sites. When discussed in the framework of the ideal free distribution theory, our results suggest that gecko movement patterns are strongly affected by increasing gecko density.