Wetland vs. Stream Macroinvertebrates - Discussion Questions

    Wetland vs. Stream Macroinvertebrates - Discussion Questions

    Discussion Questions

    1. Were there some types of organisms found in both biomes and other types of organisms not found in one or the other?

    Larvae

    The most obvious difference in large macroinvertebrates in a wetland is the presence of dragonfly and damselfly larvae. These are rarely found in moving streams because they require emergent vegetation such as cattails for resting, and for laying their eggs. You may also find considerably more swimming beetles (Order Coleoptera) or boatmen and backswimmers

    (Order Hemiptera) in a wetland than in a stream, because they do better in still water.

    Caddisfly

    Zooplankton are also typically found in wetland ponds. Look for Daphnia and other microscopic animals swimming in the water.

    Animals found in moving water may be more stream lined or have adaptations for clinging to rocks compared to animals who live in still water. They may be less streamlined and have adaptations for swimming.

    2. What features of those habitats might have caused these differences?

    The most obvious difference between the two habitats is flow. Water slowly moves through a wetland, but there is not any measurable velocity. Materials settle in these conditions, typically resulting in a soft, mucky bottom rather than the rocky bottom of many fast streams. Standing water may warm up faster than running water, resulting in changes in oxygen. Both systems have standing plants and mats of plants that cover some of the surfaces, but a pond/wetland is much more likely to have an abundance of suspended single celled plants (algae).