Trophically transmitted parasites as “cross-taxon surrogates” of biodiversity in coastal environments

Parasitism is a highly successful life history strategy, and estimates suggest that as much as 40% of life on earth is parasitic. Healthy ecosystems have high parasite diversity, which in turn reflects underlying patterns of host diversity. Cumulatively, these host-parasite interactions span multiple trophic levels and are sensitive to disturbance, making trophically transmitted parasites useful as conservation tools for addressing a multitude of applied and theoretical questions. The four chapters in this dissertation advance the theory and practice of using trophically transmitted parasites as cross-taxon surrogates of biodiversity. Parasite diversity in key host species was used to assess overall community diversity, habitat heterogeneity, and ecosystem restoration outcomes in the short-term (20 years), and Natural reefs. Conversely, parasite diversity increased with elapsed time post-restoration, and parasite communities in older restored reefs were more similar to those found in natural reefs. In addition, oyster toadfish (Opsanus tau) were identified as a key host species capable of facilitating parasite transmission and trophic ascent in oyster reefs food webs. According to the parasite data, trophic complexity in restored oyster reefs required at least 10 years to resemble that found in natural reefs. Altogether, this dissertation adds to a growing body of evidence demonstrating how parasites can serve as conservation tools. It also advances the rationale for using trophically transmitted parasites as biodiversity surrogates. Surrogate species in biodiversity monitoring studies must be capable of predicting the presence of other, more elusive taxa. Preference should be given to taxonomic groups from different trophic levels, especially cross-taxon surrogates that represent the functional links between organisms. Trophically transmitted parasites are ideal cross-taxon surrogates of biodiversity and trophic complexity, particularly when parasite diversity can be quantified in one or more key host species