Aquatic Invertebrate Monitoring at Homestead National Historical Park

Cub Creek at Homestead National Historical Park.

NPS

Scientists track aquatic invertebrates to assess water quality. Invertebrates include insect larvae, worms, snails, crayfish, and other animals without backbones. Many invertebrates live in the stream for months. This exposes them to changing water quality conditions over time. Some species can live in poor water quality, while others need clean water. So, the aquatic invertebrate community is the “canary in the coal mine” for water quality of a creek. Since 1989, NPS scientists have monitored invertebrates in Cub Creek.

Long term monitoring: Using indices to determine conditions
Scientists use established methods to monitor aquatic invertebrates and water quality. Monitoring invertebrates tells us how streams change over time. We find out what species are there and their tolerance level to pollution and disturbances. This helps us estimate water quality conditions in the creek. Some impacts are often not detected using traditional water quality methods.

Status and trends:
Since 1989, there has been no change in stream integrity. Yet there is great variability between years. Scientists found that the number of species in Cub Creek has increased since 2006. But, species diversity is low compared to some streams in Nebraska and many tolerant species live there. This shows that Cub Creek is mildly impaired.

Graphs of measurements to determine invertebrate community health at Homestead National Historical Park

NPS

Potential threats to stream quality occur upstream and outside the park. For instance, row crop farming and wastewater discharge occur near the park. This presents managers with a problem, what should they do? Maintaining and widening the areas near streams can help protect the aquatic life and reduce erosion. This would decrease chemical runoff and sediment from entering the stream. Homestead National Historical Park has also works with multiple agencies to promote conservation in the watershed.

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Data in this report were collected and analyzed using methods based on established, peer-reviewed protocols and were analyzed and interpreted within the guidelines of the protocols.