Effectiveness of the common gecko (Hoplodactylus maculatus) as a seed disperser on Mana Island, New Zealand

Abstract

A number of recent studies have documented frugivory by lizards and the effect on seed viability. However, few studies of seed dispersal by lizards have investigated the quantitative and qualitative components of disperser effectiveness. I investigated the role of Hoplodactylus maculatus (common gecko) in frugivory and seed dispersal by measuring levels of fruit removal, dispersal distances, and the effects of gut passage and seed deposition patterns on germination success. Common geckos appeared to be the major frugivore of Coprosma propinqua, removing large quantities of fruit. Forty percent of gecko droppings collected contained seeds, over 95% of which were from C. propinqua. Common geckos dispersed C. propinqua seeds up to at least 9.3 m. Ingestion of C. propinqua seeds by common geckos had no effect on germination success, with 72% of seeds germinating. Geckos tend to deposit seeds beneath rocks; these microhabitats appear to be suitable for germination of C. propinqua, with high levels of mean seed germination (73%). These results provide strong evidence that fruit is an important component of the diet of Hoplodactylus maculatus, and that common geckos provide effective seed dispersal for C. propinqua.