Groce, Matthew Christopher, authorFausch, Kurt D., advisorBailey, Larissa L., committee memberPoff, N. LeRoy, committee member2007-01-032007-01-032011http://hdl.handle.net/10217/47310Like many fishes native to western Great Plains streams, the Arkansas darter Etheostoma cragini has declined, apparently in response to changes in flow regimes and habitat fragmentation. I investigated the effectiveness of translocation as a management strategy to conserve this threatened species in the Arkansas River basin of southeastern Colorado. I used a multiscale design to sample darters and several attributes of their habitat at the local 10-m site scale, the 3.25-km translocation segment scale, and the 10-km riverscape scale, in 19 streams where darters were previously translocated. I used multistate occupancy estimation, based on two consecutive dipnetting surveys, to determine habitat characteristics correlated with site occupancy and detectability of Arkansas darters. Darters were present in 11 of 19 streams, although 5 were completely dry when visited. Darters had reproduced in 10 of the 11 streams (one criterion in the state recovery plan), and 6 streams also met a second criterion for abundance (>500 individuals). However, populations in only two streams unequivocally met the third criterion of being self-sustaining, because the other four streams had been stocked annually with hatchery-reared darters. Detectability of darters at sites where water was present was high for both age groups, 91% for age-0 darters and 76% for age-1 darters, and was a function of Julian date (age-0) and habitat depth (age-1). Residual stream temperature (a site-scale variable) and the total length of available habitat (a riverscape-scale variable) were the strongest predictors of site occupancy for both age groups. The models were useful in identifying fragmentation by a road culvert as a potential impediment to success in another stream where conservation biologists have proposed translocating darters. These models can be used to guide habitat conservation and land management practices that seek to conserve, protect, and restore current and future critical habitat for Arkansas darters.born digitalmasters thesesengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.Text