Habitat Assessment and Restoration on the Peace River and Withlacoochee River
Habitat degradation is the primary factor causing the decline of biodiversity in aquatic ecosystems of the southeastern United States. Sedimentation is the leading issue causing degradation, loss of habitat complexity, and impairment of river habitat and biological communities. The initial step in restoring natural function and biodiversity of rivers affected by habitat degradation is identifying those areas contributing to impairment throughout the system. Once impaired areas are identified, management can correct the problem through prevention, mitigation, stabilization, or restoration. This need to identify areas of riverine habitat degradation led the FWRI to conduct threats assessment projects on the Peace River and Withlacoochee River watersheds.
The Peace River and Withlacoochee River are large blackwater rivers in peninsular Florida. Both watersheds have experienced high levels of habitat degradation due to urbanization, agriculture, industry, mining, and altered flow regimes. The objectives of this project were to identify and inventory the location and magnitude of habitat degradation within the Peace River and Withlacoochee River watersheds using methods developed by the United States Fish and Wildlife Service (USFWS). Based on the results, researchers developed a prioritized basin restoration plan for each watershed, which can guide entities to implement conservation and restoration efforts. Additionally, biologists conducted a fish assemblage assessment of the Withlacoochee River, since data were lacking on the system.
During the threats assessment study, biologists assessed approximately 168 river miles in the Peace River Watershed and evaluated 512 impairment sites and 62 unpaved road crossing sites. Results revealed that certain reaches of stream and riparian (border between water and land) habitats have been severely degraded, primarily due to ranching, agriculture, and denuded riparian forests. In the Withlacoochee River Watershed, biologists identified 24 impairment sites and 20 unpaved road crossing sites along 132 river miles. Overall, the assessed areas within the Withlacoochee River Watershed were stable and riparian buffers were in excellent condition. While biologists located few impairment sites within the Withlacoochee River Watershed, the dam structures at Lake Rousseau pose the single largest threat to the river system by negatively impacting water quality, aquatic species, sediment transport, and instream habitat.
Based on findings of the threats assessment survey (2015-2019), researchers from FWRI secured funding to restore and monitor two severely degraded streambank locations along the Peace River, as well as conduct a threats assessment and fish assemblage assessment on the Myakka River Watershed. FWRI researchers partnered with the USFWS to restore the streambanks and riparian habitat, utilizing Natural Channel Design. Natural Channel Design applies fluvial geomorphology to create resilient streams that maximize function by emulating natural conditions. The first streambank was restored in June 2020 and the second bank is scheduled for completion in 2021. In order to assess the benefits of restoration, researchers are monitoring pre-and-post fish assemblages, permanent cross-sections, erosion rates, photo-points, and side-scan-sonar. This project was funded by State Wildlife Grants through FWC’s Florida Legacy Initiative and matching funds by FWC’s Aquatic Habitat Restoration and Enhancement subsection.
Condition of degraded bank before 2020 restoration (left); Condition of improved bank after 2020 restoration (right).