Ecological Risks in the Caloosahatchee Estuary: A Conceptual Model Developed through the Southwest Florida Feasibility Study Darren Rumbold, Ph. D Professor of Marine Science Depart. of Marine and Ecological Sciences Coastal Watershed Institute Florida Gulf Coast University

Southwest Florida Feasibility Study (SWFFS) Purpose and Relationship to Comprehensive Everglades Restoration Plan (CERP) and Critical Projects The Restudy recommended a separate Comprehensive watershed study for Southwest Florida with the following purposes Health of aquatic ecosystems Water flows Water quality (including appropriate pollution reduction targets) Water supply (Lower West Coast Water Supply Plan) Flood damage reduction Wildlife and biological diversity Natural habitat Recreation (opportunity)

Barnes, 2005

Benefits of Developing Conceptual Models? The process of creating a conceptual model is a powerful learning tool. Conceptual models are easily modified as knowledge increases. Conceptual models highlight what is known and not known and can be used to plan future work. Conceptual models can be a powerful communication tool. They provide an explicit expression of the assumptions and understanding of a system for others to evaluate. Conceptual models provide a framework for prediction and are the template for generating more risk hypotheses.

Barnes, 2005

Stressors Sea Level RiseSea Level Rise Water ManagementWater Management Land Use & ManagementLand Use & Management Maintaining NavigationMaintaining Navigation Altered Estuarine SalinityAltered Estuarine Salinity Altered HydrologyAltered Hydrology Input & Elevated Levels of Nutrients, Dissolved Organics & ToxinsInput & Elevated Levels of Nutrients, Dissolved Organics & Toxins Boating & Fishing PressureBoating & Fishing Pressure Physical Alteration to EstuaryPhysical Alteration to Estuary Drivers

Altered Salinity Regime While estuarine species are generally well adapted to cope with varying salinity conditions, larger shifts and timing of freshwater discharges can be a problem. –impacts the community structure and function of phytoplankton, submerged aquatic vegetation (SAV), macroalgae, benthos- particularly oysters and fisheries Secondary, or indirect, effects on manatee demographics and wading bird community structure

Important to Clearly Identify and Communicate Cascading Adverse Effects Primary, or direct, effects:Primary, or direct, effects: –occur when a stressor acts directly on the assessment endpoint and causes an adverse response Secondary, or indirect, effects:Secondary, or indirect, effects: –occur when the entity’s response becomes a stressor to another entity –are often a series of effects among a diversity of organisms and processes that cascade through the ecosystem –may have greater ecological significance than primary effect

Increased Nutrients & Contaminants Biostimulants, e.g., inorganic and organic nutrients, influence growth and community structure of phytoplankton, macroalgae, and microbes.Biostimulants, e.g., inorganic and organic nutrients, influence growth and community structure of phytoplankton, macroalgae, and microbes. –Indirect effects on SAV, zooplankton, fish and other aquatic organisms from: 1) light attenuation, 2) altered dissolved oxygen concentrations, and 3) biotoxins which, in turn, can have cascading effects on manatee, dolphins and wading bird community structurewhich, in turn, can have cascading effects on manatee, dolphins and wading bird community structure

Cloern 2001, Marine Ecology Progress Series

Table 1. Summary of findings of water quality assessments in the Caloosahatchee Estuary, San Carlos Bay, Pine Island Sound and Matlacha Pass.

Table 1. Continued.

Increased Nutrients & Contaminants Toxicants, both metals and organics (e.g., pesticides, pharmaceuticals and personal care products) could be having insidious effects on individuals (e.g., immunosuppression, behavior, etc.) populations and community structure.Toxicants, both metals and organics (e.g., pesticides, pharmaceuticals and personal care products) could be having insidious effects on individuals (e.g., immunosuppression, behavior, etc.) populations and community structure. –Loss or contamination of prey can have indirect effects on fish and wildlife predators (e.g., sharks, dolphins, birds), as well as human consumers

WQ PERFORMANCE MEASURE Loading model Process model, e.g., ECOlab BMP effectiveness as % reduction Parameter ; causal, response or both HSI model; BPJ Eco-resource, e.g., SAV, oysters, redfish; sawgrass Reference site, e.g., 10K Island, 25 th - 75 th percentile for a given salinity regime Historical-based, e.g., natural systems, OFW, etc. WQS; Inflow v. outflow Target Habitat Units, e.g., acres, lbs, Catch per unit effort TSS; Turbidity DOC / DOM; TN (NO x + TKN); TP, SRP Empirical model, e.g., regression Empirical model, e.g., regression Process model, e.g., ECOlab Input parameters will include: Land use Soils Topography Land use-specific event mean conc. Land use-sp. runoff coefficient Many other simplifying assump. Input parameters might include: water-column BOD, COD; sediment oxygen demand; adsorption coeff., particle-size distribution, settling coeff.; rates of nitrification, denitrification, mineralization and fixation; reaeration rate (SA/vol., temp., turbulence, stratification, algal growth, photosynthesis, respiration, settling rates; light avail. (note, inter-dependence). Output Scale ??? Instantaneous minimum ---Seasonal means Point - River segment - Spatially explicit Constraint Dissolved Oxygen; Chl-a; Color; Clarity / PAR concentration loads NEED TO CONNECT THE DOTs Basin e.g., C43, Tidal Caloosahatchee, Estero, and BCB Component specific loads Fraction of Freshwater Method, i.e., mass balance concentration BPJ Coordinate w/ Natural Systems Group

Cloern 2001, Marine Ecology Progress Series Simultaneous Effects of Multiple Stressors “The presence of multiple stressors may either increase or dampen the temporal and spatial variability seen in aquatic systems, depending on the interactions among stressors and the influence of background environmental conditions and sensitive species on the expression of stressor effects.” (Breitburg et al. 1999)

Breitburg et al. 1999

Barnes, 2005

Take Home Message Many people invested an incredible amount of time and energy in the SWFFS developing decision-support products such as the conceptual modelMany people invested an incredible amount of time and energy in the SWFFS developing decision-support products such as the conceptual model Although those products should serve as a strong foundation, they can be improved upon and expanded, especially the predictive models linking stressors with eco-resourcesAlthough those products should serve as a strong foundation, they can be improved upon and expanded, especially the predictive models linking stressors with eco-resources We are not under the same constraints as SWFFS and so can develop an analysis plan for research to fill data gaps, particularly on simultaneous effects of multiple stressors and indirect effectsWe are not under the same constraints as SWFFS and so can develop an analysis plan for research to fill data gaps, particularly on simultaneous effects of multiple stressors and indirect effects