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A more complete understanding of stream and river ecosystems cannot ignore connectivity with their watershed and essential exchanges of nutrients, energy, organisms, and other matter that occur within a watershed. In fact, the principles and approaches of landscape ecology have begun to be applied to riverine ecosystems. It can be argued that it is time to take land out of landscape ecology, i.e., landscape ecology has important insights to offer the study of stream and river ecosystems. Evidence in support of this viewpoint has come in the form of many researchers adopting a riverscape perspective to the heterogeneity of stream and river corridors. Conducting watershed research to improve understandings of ecosystem condition and the production of ecological services associated with anthropogenic stressors is critical. Stressors of interest include, but are not limited to, changes in nutrient loading, habitat alterations, contaminants, climate change, and changing watershed and riparian attributes (e.g., changes and loss of forest cover). Given the systemic effects of watershed-level impairments, recognizing the myriad watershed connections from a landscape perspective is crucial in maintaining biodiversity, healthy fisheries, ecosystem services, and overall ecosystem resiliency. A more holistic understanding of aquatic ecosystems will encourage ecosystem-level conservation and management strategies that promote functional, process-based approaches to long-term watershed stewardship. Additionally, improving current understanding of complex aquatic ecosystems and their links to the terrestrial landscape will be crucial in making predictions for the outcomes of management alternatives.
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My research plan focuses on the investigating: 1) stream-riparian food webs, with a focus on understanding aquatic-terrestrial energy exchanges and transfers of energy from aquatic to forested and other terrestrial habitats; 2) relevant and timely questions relating to fisheries management in Ohio, with a focus on fish community ecology, habitat assessments, and indicator species; 3) relationships between land cover, land use, and land-use change; and aquatic ecosystem function and health; and 4) ecosystem (ecological) services in aquatic ecosystems at multiple spatial and temporal scales.
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Outcomes include further advances in the science of integrated watershed ecology; additional applications of remote sensing and lidar in watersheds; development of models that link landscape characteristics, riparian zones, in-stream habitat, and biota, and that target ecological thresholds; and science-based approaches to the management and conservation of fisheries and riverine resources.
NON-TECHNICAL SUMMARY: Riverine corridors represent complex ecosystems that can harbor considerable biodiversity, yet globally, these and other freshwater ecosystems are deteriorating at an alarming rate, largely because of dramatic habitat degradation. Worldwide, human activities have exposed stream and river systems to stress through various landuse practices (e.g., timber harvest, agriculture, urbanization, etc.) and habitat fragmentation. Numerous studies have shown that landscape alterations lead to increased peak flows and other changes in hydrologic regimes. These and other stressors have led to significant impacts on riverine biota. Particularly well-documented are the effects on aquatic macroinvertebrate and fish communities. In fact, 34% of all fish species, and 60% of riverine species, are now classified as rare or extinct in the U.S., and a holistic view of ecosystems has been cited as a leading cause in the current fisheries crisis. Food web structure and the flow of energy among systems is particularly vulnerable due to the close habitat coupling between streams and their adjacent terrestrial environments. Large-scale (i.e., landscape-level) influences on river ecosystems are receiving increasing attention. Over the last decade, multiple investigators have researched the impacts of watershed land use on various nutrient and water chemistry parameters. In recent years, suburban sprawl and forest fragmentation have emerged as factors with strong potential to affect freshwater ecosystems. Agriculture is yet another important factor affecting our stream and river resources. Agricultural practices have been identified as crucial nonpoint sources of sediment, nutrients, fecal bacteria and pesticides. Riparian forests have also been shown to be important to stream ecosystems as regulators of hydrologic fluxes and in-stream physical structure. Streams lacking riparian buffers tend to have increased nutrient and sediment loading. Interactions among riparian vegetation, geomorphology, and hydrology create the diversity of in-stream habitat conditions needed to sustain healthy aquatic communities. The need to investigate stream, river, and other aquatic ecosystems from a landscape perspective with a focus on both structure and process is critical. As human activity continues to place watersheds under increasing levels of stress, the need for targeted management actions and conservation efforts based on a clear, landscape-level understanding of ecological function and impairment becomes crucial. This work will involve laboratory work and fieldwork, combining traditional and emerging approaches and methods to help answer questions vital to the protection, conservation, and management of our rivers and their resources. Among other factors, the project will directly address ecosystem services, biodiversity, fisheries, and and ecosystem health.
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APPROACH: I will use a variety of methods to address my research questions. Methods will be used as appropriate for the needs of a specific objective. I will use a combination of field and laboratory methods, computer modeling, GIS and remote sensing applications, and statistical approaches: Stable isotope analysis is becoming an increasingly valuable tool in ecological studies. Together with gut-content analysis, stable isotope analysis enables characterizing fish and bird diet and tracing the origin of food sources, focusing on aquatic, riparian, and terrestrial/upland origins. Current watershed models are successfully being used to simulate hydrological processes, water quality, sediment transport, and other watershed functions. Two popular watershed-scale hydrologic and water quality simulation models are the Soil and Water Assessment Tool (SWAT) and the Hydrological Simulation Program FORTRAN (HSPF). Remote sensing is the science of obtaining information without being in direct contact with it. Remote sensing of the environment offers unique capabilities of spatial analysis and modeling of natural resources and the environment from regional to local scales. In conjunction with geographic information system (GIS) technology, remote sensing has powerful applications in watersheds. Laser altimetry, commonly known as light detection and ranging (LiDAR), is remote sensing technology that provides data relating to the three-dimensional habitat structure of both terrestrial and aquatic environments. The unprecedented level of detail and its potential to replace labor- and time-intensive field surveys make lidar of great interest. Because I will be investigating a variety of questions in my research plan, sampling locations will be located in streams and rivers in multiple watersheds throughout the state, as well as in select lakes and reservoirs. Streams will range from small headwater streams, to larger rivers such as the Cuyahoga, Mahoning, Sandusky and Maumee Rivers in the North; the Little Miami, Greater Miami, Muskingum, Hocking, Scioto, and Olentangy in the South, as well as the Ohio. Additionally, I plan to conduct fieldwork in other geographic regions including New England, the Northwest, and Puerto Rico. Some of my research questions may also involve international efforts. As part of my work, I will be sampling fish and other aquatic vertebrates, aquatic macroinvertebrates, as well as entire food webs. I will also be working extensively with waterbirds and riparian birds. In addition to the remote sensing and GIS-derived data for riparian zones, specific projects will likely require field inventories of vegetation as well. Where necessary stream physical habitat and water quality and chemistry measurements will be taken, following standard protocols.