Upland, freshwater, and coastal ecosystems play an essential role in the cycling of nutrients through water, air, and soils. Changing land uses associated with farming and urbanization have reduced the capacity of natural systems to protect water quality. Declines in fish, shellfish, and bird populations fueled by habitat loss have further impacted the ability of natural ecosystems to process nutrients. Today, wetlands and upland forests comprise just 37% of the land in Sarasota County (SWFWMD 2017). Pastures, crops, and golf courses utilize 25%, while urban development accounts for the remaining 39% (Figure 8.1). Natural streams and wetlands have been both dredged and filled. As a result, freshwater that once percolated gradually into the ground now rushes to estuaries and bays, often carrying high nutrient loads. Infrastructure associated with drainage alterations is costly to install and maintain, degrades over time, and provides fewer ecosystem and economic services than natural ecosystems.
Figure 8.1. Sarasota County land cover and land use in 2017. Source: Southwest Florida Water Management District
Atmospheric deposition, sewage, and synthetic fertilizer are among anthropogenic (manmade) sources of excessive nutrients to ecosystems. Increasing the nutrient processing or storage capacity of natural systems can mitigate these impacts. Solutions include enhancements to wetland and upland vegetation (see Chapter 8.1, Chapter 8.3, and Chapter 8.4), animal biomass (see Chapter 8.2), and soil (see Chapter 4.7).
Perhaps no solution to nutrient management provides greater community return on investment than protecting, restoring, and enhancing natural lands. Habitat protection and restoration can filter pollutants and increase nutrient uptake/storage, while providing food and shelter for fish and wildlife, reducing erosion, increasing resilience to sea level rise, mitigating climate change, supporting groundwater recharge, contributing to floodplain management and storm protection, increasing neighborhood property values (ULI 2018), increasing public open space, and contributing to better community health outcomes. Conserving uplands, enhancing tributary habitats, and restoring freshwater and coastal wetlands and wildlife are explicit management priorities of the Sarasota Bay Estuary Program and the Coastal & Heartland National Estuary Partnership, of which Sarasota County Government, Municipalities, Southwest Florida Water Management District, Florida Fish and Wildlife Commission and Florida Department of Environmental Protection are partners (see Chapter 9.2).
Restore and Enhance Wetland and Shoreline Habitats to Increase Nutrient Uptake and Storage by Plants
Protecting, restoring and enhancing wetlands and shorelines is among the most cost-effective nutrient reduction and climate mitigation tools available to communities. New techniques for restoring wetlands, canals, ditches and shorelines to provide multiple ecosystem functions should be facilitated by public policies, regulations and outreach that expand and encourage their use.
Enhance Fish and Wildlife Populations to Increase Nutrient Uptake and Biomass Storage by Animals
Restoration of fish and wildlife through stocking programs and habitat creation or protection can directly and indirectly contribute to nutrient removal while providing other ecosystem benefits. Shellfish such as oysters and clams directly improve water quality by filtering nutrients and storing them in their bodies. Harvesting fish and shellfish, when appropriate, removes those nutrients from the environment. More research is needed to quantify these benefits. Regional partnerships could foster implementation of pilot projects.
Support Large-scale Land Conservation Programs
Conserving natural lands promotes natural cycling of nutrients through ecosystems, while providing a host of other community benefits. Currently, about 30% of Sarasota County lands have been protected by acquisition or conservation easement. Options for accelerating and diversifying funding for land conservation should be explored.
Support Urban Forestation Programs
Trees intercept and promote percolation of rainfall, reducing runoff. Policies that protect mature native trees, and encourage and incentivize tree plantings on both private and public property, can boost reforestation of urban areas with both economic and environmental dividends.