Stream Invertebrates       

Damselflies are one of many invertebrates inhabiting streams on Konza Prairie

Kings Creek on Konza Prairie offers an interesting look at the diversity of organisms found in tallgrass prairie streams. Prairie stream fauna include fishes, crustaceans, insects, macro-invertebrates, and other non-insect invertebrates.

Common fish species in Kings Creek include creek chub, southern redbelly dace, common stoneroller, and orangethroat darter. There are crustaceans too small to see with the naked eye, like the microscopic water flea, and the readily visible crayfish or crawdad. Some other non-insect invertebrates include small oligochaetes, turbellarians, and snails.

About 200 species of aquatic macro-invertebrates have been recorded on Konza Prairie by LTER researchers. Many of these invertebrates havenít been identified completely to species. Some of the known insect orders include mayflies, stoneflies, caddisflies, true flies, dragonflies, damselflies, and beetles. Over half of the known groups found are midges.











Caddisfly Mayfly

Midge Fly Larva

 Macro-invertebrates live in the water and the substrate of the stream bottom. They are an important part of the stream food web. The sun provides energy for plant growth in and around the stream. Bacteria and fungi feed on dead plant material. Herbivorous invertebrates feed on bacteria, fungi, algae, and partially decomposed leaves. These invertebrates provide food for predators, such as other invertebrates, fish, reptiles, amphibians and birds.

The location of stream invertebrate communities varies between three Kings Creek prairie stream habitats. As Kings Creek flows from the upland headwaters, to the middle reaches, and through the gallery forest, the stream channel, stream bed and streamside vegetation changes. Invertebrates prefer particular habitats depending on how they feed. The upper reaches of Kings Creek are surrounded by grassland. Little organic debris falls into the stream, so organisms called collectors must filter fine organic matter from the water. Other organisms called scrappers or grazers feed on diatoms and algae. The mid-reaches of the stream are surrounded by grasses and shrubs, and the lower reaches of the stream are surrounded by a gallery forest. In the gallery forest, trees such as bur oak, chinquapin oak, hackberry and elms shade the stream and drop their leaves into the water. Organisms called shredders dominate in the lower reaches and feed on the larger leaf and woody debris. Predators, which feed on animal tissue, such as insects, crustaceans, and fish live throughout Kings Creek.

Other factors that may affect the dispersion of stream invertebrates are patterns of stream flow and water temperature. Floods also affect stream invertebrate populations because the fast moving water scours the stream bed. Up to 95% of the macroinvertebrate population can be washed downstream in a high water event. Depending on the frequency of high water events, plant life, such as algae, and macroinvertebrates often fully recover within two weeks.

The life cycle of aquatic macro-invertebrates can span days to years, and while some species spend their whole lives in the water, others do not. Aquatic macro-invertebrates, such as caddisflies, true flies and beetles undergo complete metamorphosis, which includes four stages of growth: egg, larvae, pupa and adult. During complete metamorphosis, larval insects look very different from the adult and then go through a non-feeding pupal stage before emerging as adults. Stoneflies, mayflies, and dragonflies undergo incomplete metamorphosis and pass through three growth stages: egg, nymph and adult. All insects change and grow during metamorphosis. They molt, or shed their exoskeleton. Some aquatic insects emerge from the water as adults and live on the land, such as dragonflies and mosquitoes. Other adult aquatic insects continue to live in the water, like water striders.

Macro-invertebrates act as biological indicators because they react quickly to changing water quality conditions. Ecologists can determine if a stream is ecologically healthy by knowing which species live in a particular reach of the stream. For example, an abundance of pollution tolerant species such as oligochaetes, midge fly larvae, and leeches may indicate a high level of unwanted pollutants in the water. On the other hand, a healthy stream will have numerous pollution sensitive species such as mayflies, caddisflies and stoneflies.



PURPOSE: Researchers maintain a long-term inventory of diversity and abundance of stream invertebrates along reaches of King's Creek on Konza Prairie.  Student collections will benefit the LTER researchers by archiving these aquatic insects in a quantitative measure that will aid them in their work.



Click to view the Konza Prairie Biological Station aquatic macro-invertebrate species list.

METHODS: Students use Surber bottom samplers to collect stream invertebrates from selected areas along Kings Creek. Samples will be examined on white- bottomed trays used to carefully separate and identify the specimens.  This process is called "picking". Using forceps and plastic pipettes to pick all aquatic invertebrates, any collected insects will be placed in vials and labeled for date, location, and collector.  These specimens will be kept for future reference as part of the archive. Visit the aquatic macro-invertebrate species list to find the species found for the first time on Konza Prairie by students of the Schoolyard LTER program in 1999.




Aquatic - Refers to an organism that grows or lives in water. 

Archiving - Collecting and preserving specimens for future reference. 

Biological indicator - An organism whose occurrence in a particular area indicates whether or not that environment is ecologically healthy. 

CollectorAquatic insects that feed on fine material.  Types of collectors include filterers and gatherers. 

Community - Group of interacting organisms in a particular ecosystem. 

Crustacean An aquatic organism with jointed limbs, segmented body and an exoskeleton made of chitin. 

Diatom A microscopic one-celled alga whose walls are made of silica. 

Dispersion - Spreading out or scattering. 

Diversity - Number of different kinds of species in a particular habitat; a measure of biological differences. 

Exoskeleton The hard outside covering of an insect. 

Fauna - Animals or animal life of a region or ecosystem. 

Food web The pathway of food sources between communities of different organisms where energy and nutrients are passed from one organism to another. 

Gallery forest - Forested or wooded area that lines a stream or river. 

Headwaters The source of a stream. 

Herbivorous An animal that feeds on plants. 

Invertebrate - Animal without a backbone or internal skeleton, but with an external skeleton made of chitin. 

Macro-invertebrate -  An invertebrate large enough to be seen without magnification.

Oligochaete - Any of a class of segmented worms such as the earthworm. 

Population - Group of organisms of the same species living in a particular region. 

Predator An organism that hunts and kills other animals for food. 

Quantitative - How much there is of something you can measure and represent with numbers. 

Reach - A uniform section of stream with a repeating chain of physical characteristics and habitat types, such as pool-riffle-pool. 

Scours Erosive action of flowing water in streams that removes and carries away material from the stream bed and stream banks. 

Scrapper Organisms that feed by removing organic material from objects in the creek. 

Shredder Organisms that feed by cutting and tearing organic matter. 

Substrate Inorganic material that forms the stream bed. 

Surber bottom sampler - Specialized net with a defined sample area used to collect stream invertebrates. 

Turbellarian - Any of a class of free-living flatworms such as planaria. 



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