Habitat use of the northern striped gecko Toropuku inexpectatus and biases in detection

The northern striped gecko (Toropuku inexpectatus) is an arboreal gecko endemic to Aotearoa | New Zealand, formally described in 2020 and primarily known from one monitored population on the Coromandel Peninsula. Little is known about the northern striped geckos’ use of habitat, which impedes monitoring, and thus limits effective conservation management. We evaluated the geckos’ habitat use via Very High Frequency radio telemetry of 32 individual geckos for three months in the summer of 2024 and compared data to the available habitat. We also investigated potential observer biases during systematic searching (visual searching at night), currently the preferred monitoring method. The geckos used a wide variety of forest habitat, preferring edge habitats and shrub-like vegetation. While inactive during the day, and in close proximity to the forest edge, geckos sheltered under the leaf litter on the forest floor. While away from the forest edge, geckos moved into the forest canopy and did not utilise the forest floor. We uncovered observer biases in systematic search techniques, favouring observation of geckos near forest edges and often on or near the fern kiokio (Parablechnum novae-zelandiae). Systematic searches only captured a portion of gecko habitat use and largely failed to locate geckos in the complex vegetation that was preferred by them. The limitation of systematic searching indicates the potential for undiscovered populations in the remote forests of the Coromandel Peninsula. Overall, our results contribute to a better understanding of the ecology of the northern striped gecko and where to find them, potentially enabling improvements in surveys and monitoring and, ultimately, conservation of one of the most elusive geckos of Aotearoa.