Hanlon, Roger

Ecological components such as availability of resources, physical make-up of the
environment, and biotic interactions amongst and between species are factors that determine
habitat selection and coexistence of organisms within a community. A stable coexistence of
species within a community is possible if the limited resources are partitioned to be speciesspecific.
However, sympatric species are expected to exploit similar resources. Two species of
octopus Octopus vulargis and Macrotritopus defilippi with similar ecological requirements
coexist at an intra-coastal habitat. The ecological phenomena of coexistence of species can be
quantified by measuring the ecological components of the niche. The objective of this study is to
identify the components that facilitate coexistence. The ecological components being examined
include: general habitat location, habitat heterogeneity, foraging and feeding times and locations,
and biotic interactions. Global Positioning System will be used to determine the general location
of the octopus species den. The importance of habitat heterogeneity will be addressed by looking
at substrate make-up of the different species dens. Foraging and feeding times and locations will
be recorded to determine any temporal or spatial influence on species coexistence. Field
observations and laboratory habitat selection experiments will be conducted to determine what
habitat each species selects in the presence and absence of the other species. Our studies will
allow identifying ecological components that facilitate coexistence of sympatric species, provide
insight to cephalopod ecology, and conservation at a heterogeneous environment, which is of
importance to maintain marine biodiversity and ecotourism in south Florida.