Impacts of a Flood Pulsing Hydrology on Plants and Invertebrates in Riparian Wetlands

Download or read book Impacts of a Flood Pulsing Hydrology on Plants and Invertebrates in Riparian Wetlands written by Maureen K. Drinkard and published by . This book was released on 2012 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: I tested the impacts of flood-pulsing on wetland invertebrates and plants along small streams in northeast Ohio. The Flood Pulse Concept (FPC) was developed in large rivers (e.g. Amazon, Danube, and Mississippi rivers). It describes the ecological impacts when rivers flood adjacent riparian habitats, which are a mosaic of permanent flooded wetlands, intermittently flooded wetlands, and terrestrial habitats. Flood-pulsing produces resource subsidies (e.g., water, nutrients, organic matter). Flooding also creates stresses (anoxia, desiccation, high levels of toxins, sediment erosion and deposition) in the wetlands. Floodplain biota are adapted to the predictable flood regime in large rivers. Furthermore, coarse woody debris (CWD) from fallen trees provides a microclimatic refugia for soil organisms in floodplains. As a result, biodiversity and production are usually higher in flood-pulsing wetlands than other wetland habitats. In my dissertation, I used wetland mesocosms at the on-campus Herrick Aquatic Ecology Research Facility (HAERF) to test how the short unpredictable floods in small streams affect wetland plants and invertebrates. I found that flood pulsing creates stresses that control plant community structure in the intermittently flooded zone. There was lower emergent plant diversity and plant cover in the flood-pulse treatment. However, aquatic invertebrates and plants in permanently flooded pools were not affected. I also sampled emerging insects in flood-plain wetlands at Mud Brook Preserve (MBP) and at HAERF. Insect communities were different in permanent pools and intermittently flooded zone at MBP showing that drawdowns are an important environmental factor. The permanent pools at HAERF and MBP were also different, suggesting that mesocosms did not simulate all natural environmental conditions. I tested the impact of CWD by testing naturally and artificially felled trees. Invertebrate communities were varied by region of the floodplain. However, there were few differences in sites with and without CWD suggesting that habitat conditions (soil moisture, temperature) structure soil invertebrate communities. While CWD had few short-term impacts it may be significant at a landscape scale. Overall, the unpredictable short floods in headwater wetlands create both benefits and stressors, but the net impact was negative. Therefore, some aspects of the Flood pulse concept are not applicable to headwater systems.