Synthesizing ecological and human use information to understand and manage coastal change
Abstract Coastal systems are constantly in flux, and feedback from monitoring is necessary to support decision making for effective sustainable natural resource management. Frequently natural resources are the ultimate target of management actions, but management programs work through the proximate step of regulating human behavior towards those resources. For example, a marine reserve is considered a conservation success when the abundance and diversity of organisms increase within reserve boundaries, all relative to existing trends that would have affected ecological communities in the absence of a reserve. Biological monitoring can assesses whether reserve management achieves these goals. However, when monitoring data are inconclusive or do not match expectations, managers face uncertainty in understanding why particular biological patterns occurred, whether a reserve is a biologically appropriate management strategy for the system, and what steps to take moving forward. Monitoring human behavior can provide information that may alleviate some uncertainty and help explain observed biological patterns. In this study we illustrate the utility of complimenting biological monitoring data with monitoring of human behavior. We used a before-after control-impact analysis to test for effects of a no-take reserve in the Gulf of California, Mexico on the density and biomass of seven fished species. We failed to detect a positive biological effect of the reserve, and found the density of five monitored species had declined. These results indicated that the reserve was not succeeding, but provided no insight into why. Evaluation of recreational angler use of the reserve provided a possible explanation: first, the frequency of angler visits to the study area was increasing over time. Second, the reserve reduced the propensity of anglers to visit the reserve, but not by enough to offset the overall increasing visitation trend. Biological and human use monitoring results in tandem indicated that a reserve could potentially be an effective conservation tool for the system, and allowed us to suggest modifications that could help the reserve succeed. Our work illustrates the necessity of monitoring human use changes alongside biological responses to a reserve for a holistic portrait of reserve functioning, providing a concrete example of the importance of human behavioral aspects of marine reserve success.