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Developing a multi-stressor gradient for coral reefs
Citation:
Oliver, L., Debbie Santavy, AND P. Bradley. Developing a multi-stressor gradient for coral reefs. International Coral Reef Symposium, Honolulu, HI, June 19 - 24, 2016.
Impact/Purpose:
Development of multi-stressor gradient for coral reefs in the USVI and Puerto Rico accompanies development of the coral biological condition gradient. A generalized stressor gradient will complete the conceptual framework relating multiple anthropogenic stressors to health of coral reefs.
Description:
Coral reefs are often found near coastal waters where multiple anthropogenic stressors co-occur at areas of human disturbance. Developing coral reef biocriteria under the U.S. Clean Water Act requires relationships between anthropogenic stressors and coral reef condition to be established. Developing stressor gradients presents challenges including: stressors which co-occur but operate at different or unknown spatial and temporal scales, inconsistent data availability measuring stressor levels, and unknown effects on exposed reef biota. We are developing a generalized stressor model using Puerto Rico as case study location, to represent the cumulative spatial/temporal co-occurrence of multiple anthropogenic stressors. Our approach builds on multi-stressor research in streams and rivers, and focuses on three high-priority stressors identified by coral reef experts: land-based sources of pollution (LBSP), global climate change (GCC) related temperature anomalies, and fishing pressure. Landscape development intensity index, based on land use/land cover data, estimates human impact in watersheds adjacent to coral reefs and is proxy for LBSP. NOAA’s retrospective daily thermal anomaly data is used to determine GCC thermal anomalies. Fishing pressure is modeled using gear-specific and fishery landings data. Stressor data was adjusted to a common scale or weighted for relative importance, buffered to account for diminished impact further from source, and compared with coral condition data to provide a conceptual framework relating stressor gradients to effects on coral condition.