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The Comprehensive Everglades Restoration Plan (CERP) is intended to restore the Everglades ecosystem (FL, USA) by altering its hydrology, with likely consequences for 'downstream' estuarine and marine communities in Florida Bay and the Florida Keys. Spiny lobsters ( Panulirus argus) are among several species of special concern with respect to CERP because they are of economic and ecological importance and because their nursery habitat may be impacted. We used agent-based, spatially explicit modeling to evaluate the possible impacts of changing water quality (temperature, salinity, harmful algal blooms (HABs)) on spiny lobsters and sponges, the latter of which provide shelter for juvenile lobsters. In our simulations, lobster abundance declined 6-24% in scenarios where salinity either decreased alone or in combination with HABs that kill sponges and are associated with changing water quality. The most severe decline in lobsters occurred when salinity was lowest and HABs occurred annually. One third of this decline was attributable to decreased salinity that increased lobster mortality and movement. However, the greatest impacts on lobsters were indirect. CERP-associated changes in salinity along with HABs caused a die-off of large sponges, resulting in higher predatory mortality on lobsters that depend on sponges for shelter in hard bottom nursery habitats. Sponges declined by ∼50% in simulations with HABs, whereas decreased salinity alone led to sponge mortality of 9-18%. In contrast, higher temperatures increased juvenile lobster growth and eventual recruitment by approximately 7%. Our results suggest that returning Florida Bay to more estuarine, pre-development conditions is likely to result in an ecosystem reversal that is detrimental to stenohaline marine taxa, a scenario with significant socioeconomic implications. [ABSTRACT FROM AUTHOR]

One of the goals of the Comprehensive Everglades Restoration Plan (CERP) is to restore more natural salinity regimes to the coastal bays of South Florida (USA) with the aim of improving their degraded estuarine function (e.g., as productive feeding and nursery areas). Here, we examined the occurrence (presence-absence) and concentration (presence-only fish density) of goldspotted killifish (Floridichthys carpio) observed in an ongoing fish survey as potential indicators of restoration performance in Biscayne Bay, Florida. To determine F. carpio salinity affinity, we applied regression analyses to field data and performed behavioral choice trials in the laboratory, whereby individuals were exposed to a salinity gradient (10-50). Analysis of field data indicated a parabolic relationship between killifish occurrence and salinity, where occurrence is maximized at salinity ~22. Killifish concentration was unrelated to salinity. Experimental salinity choice results tended to agree with field observations of occurrence and demonstrated a preference for intermediate salinity levels (10-30). Finally, we performed a simulation exercise to compare seasonal changes in habitat suitability within our study domain over the course of one year. Seasonal comparisons were performed as a proxy for assessing different freshwater management alternatives. We applied the relationship between killifish occurrence and salinity that resulted from analyses of field data to the output of a published hydrodynamic salinity transport model. This exercise provided areal estimates of suitable habitat gained or lost, as well as maps indicating the geographic distribution of habitat quality by season. We conclude that: (1) continued field monitoring of goldspotted killifish occurrence is warranted for its utility as a biological indicator of nearshore salinity conditions in an ecosystem-based management framework and (2) the regression relationships revealed by the present study may be useful in habitat suitability modeling exercises, especially those that compare impacts of different freshwater flow scenarios via simulation. [ABSTRACT FROM AUTHOR]

The article focuses on the resilience of the social-ecological system of the Everglades, Florida to climate change. Topics discussed the evolution of the water management system of the Everglades, the development in the Everglades SES during the twentieth century and the resilience of the water resource system to climate change. It mentions the development of the adaptive capacity and adaptive governance in the Everglades and the U.S Water Resources Development Act of 2000.

Nearshore benthic habitats of Biscayne Bay fit the prediction of communities at risk due to their location adjacent to a large metropolitan center (Miami) and being influenced by changes in hydrology through the activities of the Comprehensive Everglades Restoration Plan (CERP). We examine whether the proposed programmatic expansion of mesohaline salinities through the introduction of additional fresh water would result in: (1) increases in seagrass cover; (2) expansion in the distribution and cover of Halodule; and (3) a reduction in the dominance of Thalassia, as hypothesized by CERP. Seagrasses were present at 98 % of sites where they covered 23 % of the bottom. Salinity was the only physical variable with a significant relationship to the occurrence of all SAV taxa. Occurrence of Thalassia, Halimeda, and Penicillus increased significantly with increasing salinity, but Halodule, Syringodium, Laurencia, Udotea, Batophora, Caulerpa, and Acetabularia showed a significant negative relationship with salinity. Mesohaline habitats had higher cover of seagrass and Halodule, and reduced dominance by Thalassia. Thus, we expect increases in the extent of mesohaline habitats to achieve the established CERP goals. We also examined the nutrient content of seagrass blades to evaluate whether: (1) nutrient availability is higher in areas close to canal discharges; and (2) tissue nutrient levels are related to seagrass abundance. The low abundance of Thalassia along the shoreline is not only due to its exclusion from low-salinity environments but also by higher nutrient availability that favors Halodule. Percent N and P, and N:P ratios in seagrass tissue suggest that Biscayne Bay receives high N inputs and is P-limited. Thus, increased P availability may facilitate an expansion of Halodule. The data presented suggest that increased mesohaline salinities will increase seagrass abundance and support co-dominance by Halodule and Thalassia as hypothesized, but raise concerns that current high N availability and increases in P may prompt a shift away from seagrass-dominated to algal-dominated communities under scenarios of enhanced fresh water inputs. [ABSTRACT FROM AUTHOR]

The limits of phosphorus (P) removal from the 18,120 ha Stormwater Treatment Areas (STAs) for Everglades restoration depend largely on the performance of submerged aquatic vegetation (SAV) wetlands, as SAV treatment cells now provide final stage treatment for 85% of the STA project. A long-term internal P profile in STA-2 cell 3 (STA2C3), one of the longest-running and best performing SAV cells, demonstrated no further net removal in the back quarter of the cell once total P (TP) levels approached 15 μg L−1. Inflow-outflow performance data from STA2C3 were analyzed at monthly and annual scales and were pooled with data from an additional eight STA SAV treatment cells. The pooled data allowed inference of background TP concentrations in SAV treatment cells using existing Bayesian methods. Results showed a central tendency of 16 μg L−1 (13-17, 90% bounds), insensitivity to P loads less than ∼1.7 g m−2 yr−1, and interannual variability outside these bounds. Internal data from the STA2C3 profile provided validation. Background P concentrations of 7 and 6 μg L−1 were identified for dissolved organic and particulate P fractions in the data pool, respectively, again similar to values in the STA2C3 gradient. Existing simulation modeling approaches for STA evaluations were identified as ineffective at or near background TP concentrations. Instead, we use an empirical and probabilistic approach based on full-scale data from STAs that produces annual risk of exceedance statistics and is easy to update. The current analysis suggests tangible risks for exceeding proposed annual discharge criteria from the STAs in the range of 16-20 μg L−1. [ABSTRACT FROM AUTHOR]