Widespread local chronic stressors in Caribbean coastal habitats

Abstract

Coastal ecosystems and the livelihoods they support are threatened by stressors acting at global and local scales. Here we used the data produced by the Caribbean Coastal Marine Productivity program (CARICOMP), the longest, largest monitoring program in the wider Caribbean, to evidence local-scale (decreases in water quality) and global-scale (increases in temperature) stressors across the basin. Trend analyses showed that visibility decreased at 42% of the stations, indicating that local-scale chronic stressors are widespread. On the other hand, only 18% of the stations showed increases in water temperature that would be expected from global warming, partially reflecting the limits in detecting trends due to inherent natural variability of temperature data. Decreases in visibility were associated with increased human density. However, this link can be decoupled by environmental factors, with conditions that increase the flush of water, dampening the effects of human influence. Besides documenting environmental stressors throughout the basin, our results can be used to inform future monitoring programs, if the desire is to identify stations that provide early warning signals of anthropogenic impacts. All CARICOMP environmental data are now available, providing an invaluable baseline that can be used to strengthen research, conservation, and management of coastal ecosystems in the Caribbean basin.

The CARICOMP Network of Caribbean Marine Laboratories (1985–2007): History, Key Findings, and Lessons Learned

“…A chronic decline in light attenuation (a proxy for deteriorating water quality) over the monitoring period of CARICOMP sites (1992-2015) was found to be widespread across the Caribbean, despite being caused by local level anthropogenic activities such as increased infrastructural development and other changes in land use. For example, decadal declines in water clarity were reported by 42% of CARICOMP sites (Chollett et al, 2017). They also reported that decadal increases in the water temperature of FIGURE 5 | Seasonal pattern of mangrove productivity in the Caribbean as indicated by litter fall and shown separately for the common species.…”

“…Physical environmental data were collected for at least 3 years and up to 22 years at 29 sites in coastal ecosystems (coral reefs, seagrasses, mangroves) in 13 countries across the Caribbean, beginning in 1992 (CARICOMP, 1997b;Chollett et al, 2017).…”

“…The most recent basin-scale analysis using the CARICOMP physical database revealed trends in both global and local level stressors of coastal ecosystems (Chollett et al, 2017). A chronic decline in light attenuation (a proxy for deteriorating water quality) over the monitoring period of CARICOMP sites (1992-2015) was found to be widespread across the Caribbean, despite being caused by local level anthropogenic activities such as increased infrastructural development and other changes in land use.…”

“…The low-cost methods of CARICOMP seagrass monitoring were sufficient to detect long-term shifts in the communities, and the recent published manuscript (Van Tussenbroek et al, 2014) was the first report on region-wide deterioration of the seagrasses throughout the Caribbean. However, it was unfortunate that water column nutrients were not included in the seagrass protocol from the beginning (Chollett et al, 2017). The causes for long-term shifts in seagrass communities had to be derived from other studies relating changes in the seagrasses and community to changes in nutrient input into the environment (Van Tussenbroek et al, 2014).…”

“…The in situ monitoring program for physical parameters, although simple, was unique in the Caribbean region not only for its broad geographical coverage, but also for the length of time it continued. The dataset has been useful for examining trends in support of local studies at many of the CARICOMP sites (CARICOMP, 2002a; see also Table 1), has provided in situ measurements in support of further development of more accurate ex situ (e.g., satellite derived) parameter estimates, has provided baseline measurements across the region from the early 1990s (CARICOMP, 1997b;Alcolado et al, 2001) and has allowed researchers to examine basin-scale trends over two decades (Chollett et al, 2017).…”