The conservation of endemic reptiles is essential to maintain ecological balance in fragile xeric island ecosystems. Terrestrial geckos within the genus Sphaerodactylus are some of the world’s smallest amniotes. They differ from most geckos in their voiceless and diurnal nature. Detailed descriptions regarding interspecific and intraspecific ecology in Puerto Rico are scarce in literature. Our research aimed to provide novel information regarding Sphaerodactylus nicholsi and Sphaerodactylus roosevelti ecology while in sympatry at The Salt Flats Refuge in Cabo Rojo, Puerto Rico. Our main research question was: Does resource partitioning occur among Sphaerodactylus within The Salt Flats refuge? Using transects during one year, we captured individuals of each species and collected microhabitat data. We classified substrate as one of the following types: Leaf litter (LL), Vegetation (V), Mixed (M), Bare Ground (BG) and Other (O). Over-story cover (%) was measured using a Spherical Densiometer. Capture time was also recorded. We used an electronic digital caliper and Pesola© scale to obtain morphometrical data such as snout-vent length (mm), tail length (mm) and weight (g). We then classified each gecko within the following age categories: Hatchling, Juvenile or Adult. We also sexed adult individuals whenever possible. Egg-bearing females were noted as “gravid”.
Results/Conclusions
Significant differences exist within interspecific substrate type (p=<0.0001, α=0.05). S.nicholsi prefers leaf litter whereas S.roosevelti predominantly selects vegetation. Moreover, over-story cover (%) is significantly higher (p= <0.0001, α=0.05) in S.nicholsi (71.39+/-36.79%) than S.roosevelti (23.10 +/-35.97%). Interspecific differences are also significant in temporal preference (p= <0.0001, a=0.05) with S.roosevelti being more nocturnal than S.nicholsi. Significant differences (p= <0.0001, α=0.05) are also present between S.nicholsi age categories for substrate type, over-story cover (%) and temporal preference. Secondary substrate selected was vegetation for adults, bare ground for hatchlings and mixed for juveniles. Secondary temporal preference was night for adults, and morning for hatchlings and juveniles. Adults selected lower over-story cover (59.64+/-41.26%) than hatchlings (85.25 +/-24.65%) and juveniles (84.64+/-25.01%). Likewise S.roosevelti age categories significantly differed in substrate type (p= 0.0175, α=0.05) and over-story cover (%) (p= 0.0373, α=0.05), but not in temporal preference (p= 0.3296, α=0.05). Adults and juveniles selected primary substrate of vegetation whereas hatchlings chose bare ground. Adults selected higher over-story cover (29.09+/-38.24%) than hatchlings (10.44+/-28.14%) and juveniles (14.53+/-29.83%).Our results demonstrate interspecific and intraspecific spatial and temporal resource partitioning at The Salt Flats Refuge. Our findings are relevant to future conservation efforts concerning worldwide sphaerodactylids threatened by unprecedented climate change effects.