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Aquatic Ecological Interaction Networks

Aquatic habitats contribute to ecosystem processes in every biome of Earth. In these systems there are notable bottom-up and top-down controls that often work synergistically to regulate ecosystem function and resilience to perturbations. Aquatic studies in the Benbow Lab are addressing mechanistic questions at several scales of inquiry. These studies range from top-down control of epiphytic biofilm development to collaborative efforts quantifying the role of hydraulic habitat templates on macroinvertebrate community assembly and the influence of native riparian plants on in-stream ecosystem processes. Additional studies are on-going in the Republic of Palau in understanding the factors that influence the resilience or change of watersheds to land use degradation and developing unique bioassessment methods to monitor such ecosystem responses.

Invasive Plant Impacts on Riparian-Aquatic Linkages

Exotic species have detrimental impacts on native ecosystems and cost human society nearly $137 billion per year.  Non-native invasive plants tend to degrade habitats by out competing native plants and reducing biodiversity within ecosystems.  Plant invaders are most successful in disturbed habitats such as flood plains and habitat edges.  Riparian zones (forested regions along stream banks) are regularly disturbed habitats, and therefore, easily invaded by invasive plants.  Due to this characteristic, riparian zones provide an area where invasive plants interact and impact aquatic systems.  Understanding how invasive riparian plants influence connections between terrestrial and aquatic habitats is the overarching goal in this research project. Aquatic systems depend on inputs from terrestrial environments (e.g. leaves, woody debris, and other detrital materials) to support aquatic food-webs and ecosystem processes.  Macroinvertebrate and microbial communities use terrestrial inputs for habitat and food resources.  Therefore, changes in leaf litter inputs from the terrestrial environment due to the introduction of a terrestrial invasive plant may result in substantial impacts on aquatic communities and food-web dynamics.  Changes in terrestrial leaf inputs may further influence stream organic matter processing, nutrient cycling, and light availability within streams. Amur honeysuckle (Lonicera maackii: a type of bush honeysuckle) is an invasive species that has rapidly become dominant in the forested areas of the Midwestern and eastern USA.  Once this species is established it 1) reduces the growth and reproductive success of native shrubs and trees, 2) negatively impacts the growth and survivorship of terrestrial insects, and 3) is responsible for the loss of native plant diversity through competition.  Quasi-monocultures of Amur honeysuckle have been found in riparian zones throughout the Miami Valley, OH region and create dense shrub canopies overarching streams.  These honeysuckle canopies contribute a substantial amount of leaf litter that enter streams, providing an excellent model system to identify the impacts riparian invasive plants have on aquatic food-webs and ecosystem processes. Our research objectives are 1) to identify the impacts of Amur honeysuckle on terrestrial-aquatic connections through examination of cross-system subsidies, food-web dynamics, and ecosystem processes and 2) to determine the potential toxicity effects of Amur honeysuckle on aquatic macroinvertebrates.  We are conducting a series of field and laboratory experiments to gain a pattern to process understanding of the impacts Amur honeysuckle has on aquatic systems.  We hope that our research findings will support local and regional restoration and management programs while broadening our understanding of how invasive species influence ecosystem dynamics.

Pacific Salmon Nutrient Input and Disturbance and Implications for Invertebrate Communities

To be added

Tropical Watershed Ecology

Tropical streams of the world are understudied compared to their continental counterparts. Many of these tropical areas are rapidly changing and are also threatened by development, introduced species and resource degradation. The Benbow lab research that takes place in Hawaii, Palau and West Africa is aimed at assessing the impacts of disturbance on these sensitive systems and through this assessment, providing insight on how to best protect and preserve these unique areas.

Hawai'i

The Hawaiian Islands are the most isolated island system in the world.  Home to thousands of endemic species, these islands are a hotspot of global biodiversity.  They are also popular for their tropical location, beautiful scenery and climate.  Increasing tourism in the area has resulted in a freshwater demand that has caused water diversions to be placed on the freshwater streams located on the windward sides several islands.  These water diversions remove streamflow and transport it to the opposite sides of the islands, often where resorts and tourist attractions are located.  The impact of this water removal on stream life in West Maui, Hawaii is the topic of the following two studies. Na Wai Eha is the Hawaiian term for our study sites in West Maui and means ;the four great waters: Waikapu Stream, Waiehu Stream, Iao Stream and Waihe’e River collectively represent the Na Wai Eha and their streamflow is currently under debate (see sources below for more information about the struggle for water in the Na Wai Eha).  The two companion studies that take place in West Maui are focused on assessing the impact of water removal and the changing hydraulic parameters on macroinvertebrate communities.  The first investigation used riffles as a study habitat and quantified flow at each sample location, along with conducting a general assessment of each watershed with the goal of comparing within stream variation of physical and biological variables.  The second study used cascade habitats to determine how endemic and introduced populations of aquatic insects were affected by decreased water flow and investigated the potential for cascade habitats in future biomonitoring of tropical, high gradient streams.

Palau

While perhaps best known for hosting a season of the CBS show "Survivor" the small island nation of Palau is known by ecologists and environmentalists for its stunning coral reefs, Giant Tridacnid clams, rock islands and mangrove forests.  The goal of our work in Palau is to develop a rapid bioassessment program and collaborate with local Palauans to monitor the freshwater resources on the largest island of Palau, Babeldaob.  Determining the native fauna in these streams and identifying their functional groupings will allow for a streamlined approach to their assessment.  The tourist influence has caused a demand for recent development, primarily that of a national, paved road that has, in part, altered nearby streams through sedimentation.  The need for a biomonitoring program exists so that data can be accurately and regularly collected and any shifts in stream communities can be tested as the nation undergoes future urbanization.  This isolated island has been commended for its protection of marine life but the linkage between the island's freshwater system and ocean populations has perhaps not been emphasized enough.  It is our hope that the information gained through the bioassessment program enhances the natural beauty of the island's freshwater and marine resources.

West Africa

While the primary objective of water body ecology in West Africa is related to Buruli Ulcer disease, this area is still widely understudied and understanding the ecology of West African streams and standing waterbodies can benefit researchers from many disciplines. Water quality criteria and appropriate water resource use and management are important in all areas of the world, but in the developing nations of Africa, this information and subsequent strategy can be especially important. The work of the Buruli Ulcer team of scientists will contribute to a fuller knowledge of temporary water body fluctuation, long term water quality risks, waterborne disease pathogen ecology and general tropical ecology as a whole.