Files
Abstract
Many wetlands exist between completely aquatic and terrestrial environments, often acting as ecotonal zones harboring water, flora and fauna from both terrestrial and aquatic origins. These ecotones are renowned for providing ecosystem services such as water retention, nutrient processing, and for acting as extended landscapes for colonization. However, climate change and anthropogenic changes to the wetland landscape threaten ecotonal wetlands and their capability and efficiency to carry out those ecosystem services. Hence, it is important to study the dynamics of ecosystem services in these wetlands and to identify and describe the environmental factors that influence them.
Here, I assessed ecosystem services mitigated by ecotonal wetlands in an agricultural landscape, and in a river-floodplain system in Georgia, USA. In the Iron Horse Farm, I described how an ecotonal wetland adjacent to an agricultural landscape acted as refugia for arthropods known to predate on agricultural pests. This ecosystem service is not as well-known as those related to hydrology. During flood pulses In the Lower Ogeechee River, I observed how macroinvertebrate assemblages were present in both the river and the floodplain, and both were strongly influenced by their location along the river. Each habitat had specific indicator taxa across the locations, though rivers were also influenced by seasonality, and floodplains by pulse size. In the same flood pulses, I also assessed how different water quality measures varied in the riverine-floodplain system. Most metrics were influenced by pulse size such that most evidence of nutrient processing between the river and the floodplain habitats was detectable during smaller pulses. On the other hand, large pulses displayed a level of homogenization where water quality measures were comparable between the two habitats. This shows that established paradigms describing riverine floodplain interaction (e.g. the River Continuum Concept, Vannote et al. 1980, and the Flood pulse concept, Junk et al. 1989) require further development.
Here, I assessed ecosystem services mitigated by ecotonal wetlands in an agricultural landscape, and in a river-floodplain system in Georgia, USA. In the Iron Horse Farm, I described how an ecotonal wetland adjacent to an agricultural landscape acted as refugia for arthropods known to predate on agricultural pests. This ecosystem service is not as well-known as those related to hydrology. During flood pulses In the Lower Ogeechee River, I observed how macroinvertebrate assemblages were present in both the river and the floodplain, and both were strongly influenced by their location along the river. Each habitat had specific indicator taxa across the locations, though rivers were also influenced by seasonality, and floodplains by pulse size. In the same flood pulses, I also assessed how different water quality measures varied in the riverine-floodplain system. Most metrics were influenced by pulse size such that most evidence of nutrient processing between the river and the floodplain habitats was detectable during smaller pulses. On the other hand, large pulses displayed a level of homogenization where water quality measures were comparable between the two habitats. This shows that established paradigms describing riverine floodplain interaction (e.g. the River Continuum Concept, Vannote et al. 1980, and the Flood pulse concept, Junk et al. 1989) require further development.