Ecosystem Health

Texas has a unique array of river, spring, lake, bay and estuary ecosystems that support a diversity of aquatic species and provide an equally diverse set of ecosystem services such as recreation and clean water. The Texas Water Explorer examines the health of Texas' aquatic ecosystems by analyzing some common threats and highlighting their value.

What does the Texas Water Explorer tell us about Ecosystem Health?

Native Biological Communities

This indicator describes the native biological diversity of Texas freshwater ecosystems and summarizes the conservation status of aquatic biological communities.

Native Fishes - There are 190 freshwater fish species native to Texas. The basins with the highest number of native freshwater fish species are the Red River Basin (101 species), the Sabine River Basin (93 species) and the Neches River Basin (90 species).

83 of the 207 sub-basins in Texas have more than 15% of their native freshwater fishes in need of conservation effort. The basins with the highest proportion of sub-basins with high degree of imperilment are the Rio Grande (34 of 37 over 25% imperiled), Red River (25 of 26 over 15% imperiled) and Canadian River (10 of 15 over 15% imperiled).

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Fishes of Texas

Invasive Species Assessment

This indicator examines the potential for severe impact of invasive aquatic species on aquatic systems and ecosystem services.

Invasive Species - 158 of the 207 sub-basins in Texas have at least one invasive aquatic species with the potential to significantly harm its aquatic ecosystems. Fifty-five of the sub-basins have at least five species.

The highest percentage of sub-basins with multiple invasive species are in the Guadalupe, Rio Grande, Neches, Trinity, Brazos and Sabine basins; the Canadian, Red and Nueces basins have the lowest percentage.

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U.S. Geological Survey: Nonindigenous Aquatic Species

Priority Conservation Areas

Maintaining the aquatic species and ecosystems of Texas is an important aspect of balanced water conservation. The Nature Conservancy's freshwater biodiversity conservation blueprint represents important areas in the state's push to protect freshwater biodiversity.

Conservation Areas - The Conservancy has defined 181 priority areas for freshwater biodiversity conservation in Texas.

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The Nature Conservancy: Ecoregional Planning

River Fragmentation

Nearly all Texas rivers are interrupted by dams, culverts or other structures, which can reduce fish populations and make rivers more vulnerable to drought and various human impacts. This indicator examines the impact of large dams on Texas rivers in two ways: by mapping segments of connected river network and mapping areas of river basin networks that are undammed and connect downstream to the Gulf of Mexico.

River Fragmentation - Of the 46,945 kilometers of Texas rivers and streams that we evaluated, only 18% (8,552 kilometers) have no downstream dam and are therefore open to the Gulf of Mexico; 55% (25,932 kilometers) occur in a large river network (at least 2,500 km of stream length) that is not fragmented by large dams.

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Michigan State University: Effects of dams on streams of the conterminous United States: Characterizing patterns in habitat fragmentation nationally and fluvial fish response in the Midwest

Texas Paddling Trails

Many types of recreational and outdoor activities depend on healthy aquatic ecosystems. As one indicator of this value, we mapped the locations of Texas' paddling trails.

Paddling Trails - There are 65 designated TPWD-designated Paddling Trails in Texas.

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Texas Parks and Wildlife Department: Texas Paddling Trails