Arraial do Cabo is located at a tropical region with respect to the terrestrial realm, but due to influence of intense NE winds coming from
the sea, the coastal vegetation is characteristic of arid habitats (Arraial aerial view). Moreover, because of major current patterns and
coastal morphology a local upwelling makes the marine system subtropical (Valentin, 1984), with average water temperature around
22ºC.The subtropical rocky reefs are in fact prevalent along all the southeastern and most of the south coast of Brazil (Floeter et al., 2001).
However, because of the local strong upwelling, water can drop below the 18ºC in Arraial do Cabo, and therefore peculiar temperate-driven
patterns of habitat use are observed for most of the local marine biota (Guimarães & Coutinho,1996). Local embayment habitats with typical
tropical and subtropical fauna and flora are contrasting with exposed, warm-temperate habitats, establishing a gradient within just a few
kilometers. Such unique, intense natural local gradient is worth testing with regards to ecological hypotheses.