Q12: What is the status of keystone and foundation species and how is it changing?

FLORIDA KEYS NATIONAL MARINE SANCTAURY

## CONDITION REPORT DEMO PAGE

LIVING RESOURCES CATEGORY – Keystone and Foundation Species

Question 12: What is the status of keystone and foundation species and how is it changing?

Description of terms

Certain species are defined as “keystone” within ecosystems, meaning they are species on which the persistence of a large number of other species in the ecosystem depends. “Foundation” species are single species that define much of the structure of a community by creating locally stable conditions for other species, and by modulating and stabilizing fundamental ecosystem processes.

These are typically dominant biomass producers in an ecosystem and strongly influence the abundance and biomass of many other species. Examplesinclude krill and other zooplankton, kelp, forage fish such asrockfish, anchovy, sardines and coral. Foundation species exhibit similar control over ecosystems as keystone species, but their high abundance distinguishesthem.

Changes in either keystone or foundation species may transform ecosystem structure through disappearances of or dramatic increasesin the abundance of dependent species. Not only do the abundances of keystone and foundation species affect ecosystem integrity, but measures of condition can also be important to determining the likelihood that these species will persist and continue to provide vital ecosystem functions.

Measures of condition may include growth rates, fecundity, recruitment, age-specific survival, contaminant loads, pathologies (e.g., disease incidence, tumors, deformities), the presence and abundance of critical symbionts or parasite loads.

KEY SPECIES

The key species or taxa in the sanctuary selected for use in this section of the report include stony corals, seagrasses, queen conch, Caribbean spiny lobster, long-spined sea urchin, the snapper-grouper complex and sea turtles. These species are important for their ecological roles, and long-term datasets are available for assessing changes for these species. 2010 Reef Visual Census data from the GCOOS ERDDAP server is used to assess the status of key species.

Locations & Depths of data included in this analysis.

Stony Corals

SEAGRASSES

QUEEN CONCH

CARIBBEAN SPINY LOBSTER (Panulirus argus)

Spiny lobsters are one of the Florida Keys’ most economically important commercial fisheries, and the Florida Keys stock is heavily exploited by both the commercial fishery and by recreational divers and snorkelers. Between the two fisheries, a large percentage of the available adult population is removed each year (Cox and Hunt 2005).

SEA URCHINS (Diadema antillarum)

The long-spined sea urchin were historically one of the most important invertebrate grazers on coral reefs in the Florida Keys, helping control the abundance of algae. Though in some parts of the Caribbean the long-spined sea urchin played a major role in controlling algal biomass (Levitan 1988), the roles of both piscine herbivores and sea urchins in controlling algal dominance on coral reefs are still being discovered (Furman and Heck 2008). The long-spined sea urchin is considered an important herbivore on Caribbean coral reefs. Populations, especially in areas where overfishing has reduced populations of herbivorous fishes, suffered a mass mortality event in the Caribbean basin, including the Florida Keys, from 1983 to 1984 (Lessios et al. 1984, Lessios et al. 2001). This mortality event is recognized as “one of the most spatially expansive and prolonged disturbances to reef ecosystems in the region” (Carpenter 1988, Lessios 1988, 2005, Miller et al. 2008). The Florida Keys population suffered a second die-off event in 1991 (Forcucci 1994). Although long-term monitoring shows increased long-spined sea urchin occurrence and average size since 1999, there has been slow recovery of adult long-spined sea urchins in most habitats, with the exception of patch reefs (Miller et al. 2008, Chiappone et al. 2008).