Ecosystem Thresholds and Alternate States In Great Plains Rivers and Streams: Cascading Effects of Anthropogenic Hydrologic DisturbanceEPA Grant Number: R832446
Title: Ecosystem Thresholds and Alternate States In Great Plains Rivers and Streams: Cascading Effects of Anthropogenic Hydrologic Disturbance
Investigators: Dodds, Walter , Gido, Keith , Koelliker, James , With, Kimberly A.
Institution: Kansas State University
EPA Project Officer: Hiscock, Michael
Project Period: April 1, 2005 through July 10, 2008
Project Amount: $299,566
RFA: Exploratory Research: Understanding Ecological Thresholds In Aquatic Systems Through Retrospective Analysis (2004) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Ecosystems , Water
We will document how a dramatic shift in the hydrologic state of Great Plains rivers and streams has produced a biotic state change in this system. This hydrologic change results from human alteration of surface water flow through agricultural diversion, groundwater pumping, construction of small impoundments, and changing cultivation techniques. We hypothesize that these hydrologic changes have fundamentally altered system connectivity, leading to observed declines in key species. We have observed two major state changes (thresholds) in our region of the Great Plains: (1) drying of major river channels, and (2) extirpation of fish and invertebrate species. Fragmentation of these river networks is postulated to have affected the distribution of fishes throughout the Great Plains, leading to extirpation of native species from some rivers and the introduction and spread of exotic species in others, resulting in a strong shift in community composition that may compromise the biotic integrity and ecosystem function of these lotic ecosystems.
We will utilize geomorphic (e.g., slope, geological characteristics), long-term hydrologic (40-100 years), and land-use data to construct hydrologic models to describe and predict the occurrence and duration of stream flows. We will also quantify presence of small impoundments, thus permitting quantification of the spatiotemporal connectivity of stream networks in the Kansas portion of the Great Plains. We will analyze a substantial, georeferenced fish database, and additional data on unionid mussels derived from collections taken over the last century, and link alterations in species distributions to the changes in hydrology that have occurred, particularly in the last 40 years. The hydrologic models will also form the basis for developing a general fish dispersal model for deriving functionally based definitions of stream connectivity and for explaining and predicting species distributions within and among stream networks.
Knowledge of the critical habitat requirements (with regard to hydrologic connectivity and in-stream flow) of species inhabiting Great Plains streams, and generation of information that will be necessary to protect the biotic integrity of these streams and rivers in the future will be key products of our research. The proposed research will develop new approaches for modeling network systems such as streams (an area explored by few landscape ecologists) and provide an approach to assess how disruption of connectivity of these networks can have biological effects.