Behavioral Indicators in Marine Conservation: Lessons from a Pristine Seagrass Ecosystem

Abstract

In light of ongoing changes to marine ecosystems, there is a need for behavioral indicators that can identify critical habitats and assess anthropogenic impacts. Although the application of behavior to conservation has yielded mixed results, habitat selection behavior has promise as such an indicator. Terrestrial studies and a decade of work in Shark Bay's pristine seagrass ecosystem show that habitat selection theory based on the ideal free distribution can be used to assess critical habitats based on food and safety and signal impacts of anthropogenic disturbance. One lesson from our studies of dugongs (Dugong dugon) and other species at risk from tiger sharks (Galeocerdo cuvier) is that physical attributes of habitats may influence the effects of predators, and, by extension, human disturbance. These species generally prefer seagrass bank edges, which facilitate escape from sharks, even though shark density is lower over interior portions of the banks. Thus, habitat selection indicates that a bank's quality is determined largely by its proportion of edge microhabitat rather than its size, and that the presence of predators in neighboring habitats can influence prey space-use decisions where predators are scarce or absent. By extension, efforts to curb the effects of human disturbance, which can mimic those of predation risk, may be unsuccessful if protected areas border those subject to continued disturbance. Future marine studies should assess habitat selection in more disturbed habitats and across a range of physical settings to better elucidate the conservation benefits of using habitat selection as a behavioral indicator.