|Freshwater aquatic resource management is fraught with challenges, as managers of multiple-use, highly diverse systems must frequently make management decisions with limitations including unclear management objectives and inadequate knowledge of system state and response. In this dissertation, I present three different freshwater aquatic resource management problems and examine the application of quantitative methods to address specific limitations in each.
The first management context was a small wildlife refuge faced with making land use decisions that consider impacts to aquatic resource objectives. I examined hypotheses relating fish species occupancy to land use using multiple model comparison. Four species – striped shiner Luxilus chrysocephalus, redbreast sunfish Lepomis auritus, orangespotted sunfish L. humilis, and longear sunfish L. megalotis – had strong support for land use as a predictor of occupancy. However, only orangespotted sunfish had an estimated occupancy probability that was predicted to decrease with increasing urban and agricultural land use. Results suggest both the dominance of a mainstem reservoir in defining patterns of fish species distribution and the tolerance to urban and agricultural land use of most encountered species.
The second management context was a hydropower-regulated river in which an adaptive management program has been initiated. Also using multiple model comparison, I examined patterns of fish species occupancy to evaluate the potential response to an implemented management action and to inform the next adaptive management iteration. Nine of 13 fish species had distributions that reflected downstream impacts of the hydropower dam. Model results for three species – two minnows and one darter – indicated a potential positive response to management action, whereas up to five species – largescale stoneroller Campostoma oligolepis, Alabama hogsucker Hypentelium etowanum, speckled madtom Noturus leptacanthus, redbreast sunfish Lepomis auritus, and muscadine darter Percina smithvanizi – demonstrated potential negative responses. I hypothesize that an altered thermal regime may be inhibiting occupancy of several fish species, and recommend that the next iteration of adaptive management focus on thermal restoration.
The final management context considered statewide management of aquatic resources. In many states, established biomonitoring programs are expected to inform decision making. However, use of these data is often restricted to site classification decisions. To facilitate broader use, I provide a general framework to incorporate the index of biotic integrity (IBI), a widely used multi-metric index, into aquatic resource management decision making. I demonstrate use of the framework for a specific decision context wherein the IBI provides a basis for informing the selection of instream flow management alternatives that meet defined objectives of a state resource agency.
Data collected as part of a freshwater monitoring program may be used to inform and support management decision making by adding to our knowledge of system state and of system response to management actions. However, the most successful freshwater aquatic resource management program will include explicit definition of management objectives and hypotheses of system response, a monitoring plan linked directly these objectives and hypotheses, and a flexible management framework, such as adaptive management, that allows for the integration of monitoring data to update hypotheses and improve future management decision making.