Biological connectivity of streams and wetlands: Sharing of habitats by arthropods
Streams and wetlands commonly coexist in the landscape. A recent review of scientific literature concluded that streams are connected to wetlands physically, chemically, and biologically (U.S. EPA 2015), although the ecological connections resulting from movements of invertebrate species across wetland-stream habitat mosaics are poorly studied. Aquatic invertebrates play important functional roles in both wetlands and streams, as they largely serve as the connection between primary producers and vertebrate species in the food web. Here, we ask, do some invertebrate species rely on both wetland and stream habitat resources for persistence of populations on the Delmarva Peninsula?
Some species of aquatic invertebrates, especially insects that fly, are capable of utilizing both wetland and stream habitats and may even require both habitat types for life cycle completion or population persistence. Habitat permanence is strongly correlated with aquatic insect species’ potential for dispersal and migration and could also influence niche breadth. For example, water boatmen (Hemiptera: Corixidae spp.) that use seasonal wetlands to reproduce have been observed to migrate en masse into permanent, running water habitats when wetlands dry. By field sampling in wetland-stream habitats on the Delmarva Peninsula, and using DNA barcoding to relate immatures to adults, we plan to identify invertebrate species that: A) are confined to wetland habitats, B) are confined to stream habitats, C) reproduce in wetlands but migrate to streams when wetlands dry (habitat complementarity), D) are able to reproduce in either stream or wetland habitats, with limited (typically passive) movement between different habitat types, and E) are able to reproduce in either stream or wetland habitats and opportunistically colonize both habitats, with potential for long distance (active or passive) dispersal.