Temperate Plains Ecoregion - National Lakes Assessment Results
NLA 2022 Ecoregional Results
Key Results
An estimated 36,185 lakes in the Temperate Plains ecoregion are represented in the National Lakes Assessment (NLA). Of these lakes, 20% are natural and 80% 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 Temperate Plains, 50% of lakes are rated as hypereutrophic while 36% are eutrophic, 13% are mesotrophic and 2% are oligotrophic.
- The most widespread stressors assessed are atrazine detections and microcystin detections with 73% and 68% 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, detections occurred in 68% of lakes and 4% of lakes were above the recreational benchmark.
Change from 2017*
- For the Temperate Plains, the NLA reports that the percent of lakes in good condition for shallow water habitat decreased by 21 percentage points between 2017 and 2022.
- The percent of lakes in good condition based on the benthic macroinvertebrate indicator increased by 19 percentage points between 2017 and 2022.
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.
