Southern Plains Ecoregion - National Lakes Assessment Results
Key Results
An estimated 26,760 lakes in the Southern Plains ecoregion are represented in the National Lakes Assessment (NLA). Of these lakes, 2% are natural and 98% are man-made.
The NLA uses trophic state as an important indicator of lake condition and assesses the extent of biological condition and key stressors in the nation’s lakes.
- In the Southern Plains, 35% of lakes are rated as hypereutrophic while 48% are eutrophic, 17% are mesotrophic and 1% are oligotrophic.
- The most widespread stressors assessed are nitrogen, phosphorus and lakeshore disturbance with 72%, 69% and 57% of lakes in poor condition respectively.
- Cyanobacteria are one-celled photosynthetic organisms that normally occur at low levels. Under eutrophic conditions, cyanobacteria can multiply. Not all cyanobacterial blooms are toxic, but some may release toxins, such as microcystins. For information about risks at specific locations, recreational water users should check with state, tribal or local governments.
- Based on microcystins, 1% of lakes in the Northern Plains are above the recreational benchmark.
Change from 2012*
- For the Southern Plains, the NLA reports that the percent of lakes in good condition based on the zooplankton indicator decreased by 30 percentage points between 2012 and 2017 and the percent of lakes in good condition based on lakeshore habitat complexity increased by 39 percentage points.
- The percent of lakes with microcystin detections decreased by 56 percentage points.
To access more ecoregional specific information, please visit the interactive NLA Dashboard.
* The change analysis is based on information from two points in time – 2012 and 2017.