Best beach front real estate: microhabitat segregation of sympatric species of geckos on Mo'orea, French Polynesia

Abstract

Background Understanding how interspecific interactions affect a species and its access to resources is of great importance in a changing environment with limited resources. Investigating the effects of interspecific interactions of sympatric gecko species in Moorea provided insight into gecko community dynamics. The aim of this study is to understand the preference of diurnal shelter as a means of effectively managing available resources in a manner that allows for the coexistence of four sympatric species of nocturnal geckos. Microhabitat preference of four species of nocturnal geckos who coexist within an overlapping niche were examined by addressing the following questions: Will different species of geckos prefer to choose different diurnal shelters when in the presence of heterospecifics? Will shelter choice by the native geckos differ in different biomes? Out of the three most common species of geckos studied, which species will have a higher prevalence of taking refuge in horizontal microhabitats as opposed to vertical microhabitats? Methods To quantify patterns of microhabitat selection of sympatric gekkonids, a field survey categorized into three zones that ranged from high, intermediate, and low human disturbance was conducted. In field study observed shelter preferences was categorized into either ground, plant, or vertical shelters. In addition, interaction experiments with individuals of three gecko species were conducted. Results The results suggested interspecific interactions may in fact have an impact on the preference of diurnal sleeping shelter choice by geckos. Comparing conspecific with heterospecific trials of G. oceanica and H. frenatus, results suggested interspecific interactions playing a significant role in shelter preference. This same comparison for L. lugubris revealed interspecific interactions not playing an important role in their preference for shelter. Results from field survey yielded significant trends of each of the four species preferring certain shelter types from three categories. Shelter preference of vertical shelters by G. oceanica was reflected both in experimental and field studies. This trend of similar shelter preference when both field and experimental studies were compared did not hold true for H. frenatus and L. lugubris. Furthermore, human disturbance did not seem to play a significant role in influencing diurnal shelter preference of gecko species. Discussion Using this investigative approach, gecko shelter preferences was revealed. The results from this study suggested that although in some cases certain species held strong shelter preferences, these preferences change due to interspecific interactions. Understanding more about the severity of these interactions can help bridge the gap of understanding pertaining to the factors that shape the distributions and abundances of different gecko species who live in communities where resources are very limited.