Interstitial spaces provide refuge and foraging/reproductive space for species across various habitats (e.g., terrestrial, coastal to marine ecosystems). Abundance and characteristics of those spaces can also affect local interactions with intra/inter-specifics, leading to a likely strong role in species composition. Ecologists have attempted to quantify those spaces as part of measuring habitat complexity or traits that can explain various species diversity across habitats. However, previous studies have approached this idea using proxy measurements using 2D or fractal (non-dimension) analyses, which provides only a partial understanding of the role of interstitial space shapes and species diversity. Here, we test the prediction that 3D interstitial space shape characteristics are a good predictor of species habitat preferences. We identified spaces used by 1,370 invertebrates of 11 species on 54 oyster clusters from the northern Gulf of Mexico. We then used a Computed -Tomography scanner to characterize those spaces in 3D, using 21 different metrics. Later MANOVA was used to test if there is a significant difference in refuge shape (n=101) occupied by 11 macroinvertebrate species.
Results/Conclusions
Preliminary results from MANOVA analysis indicate that shapes used were separable both by species and by higher taxa (crustaceans, bivalves, polychaetes, and decapods) (Wilks test, p<0.01). This separation is probably because of species-specific morphometric differences, and vulnerabilities to different predators. The separation we found minimizes the chances of sharing spaces with inter/intra-specifics and may determine vulnerability to predators.
We plan to further identify what the distinctive characteristics are that explain the variance of the 3D refuge shapes associated with each species. These indices will be used to predict the number of available refuges for each species within oyster clusters. We will use this to examine the relationship between refuge shape diversity (a combination of abundance and shape characteristics of refugia) and species composition. To our knowledge, this is the first attempt to incorporate 3D morphological data to test the relationship between IS attributes and species composition.