394 North American Journal of Fisheries Management 20:394–398, 2000  Copyright by the American Fisheries Society 2000 Effort Needed to Estimate Species Richness in Small Streams on the Great Plains in Wyoming TIM M. PATTON* 1 AND WAYNE A. HUBERT U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, 2 University of Wyoming, Laramie, Wyoming 82071-3166, USA FRANK J. RAHEL Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming 82071-13166, USA KENNETH G. GEROW Department of Zoology and Physiology and Department of Statistics, University of Wyoming, Laramie, Wyoming 82071-3166, USA Abstract.—Our objective was to define the sampling effort needed with electrofishing gear or seines to capture all of the fish species present in sampling reaches on small streams of the Great Plains. The study was conducted because of recent interest in assessing the status of fishes in small streams of the Great Plains, which have lacked information that would enable sampling protocols to be developed. Based on the wetted widths (2–11 m) of sampling reaches, we defined the sampling effort needed to capture 90% and 100% of the fish species present. For electrofishing gear, sampling three 50-m-long units of the stream assured capture of 90% of the fish species present, and sampling four 50-m-units assured capture of 100%. When seines were used, sampling of four 50-m-long units captured 90% of the fish species present, and six 50-m-long units assured capture of 100%. As wetted width increased, the length of stream that needed to be sampled remained relatively constant; accordingly, the surface area of stream that needed to be sampled increased. This was true for both electrofishing gear and seines. The necessary sampling effort was less than that indicated for streams in the southeastern and midwestern United States. Our results can be useful to managers and researchers designing surveys of fishes in small streams on the Great Plains. Information on the spatial distribution patterns of fish species and species richness at sampling sites is important to the conservation and man- agement of fishes. Such data can be used to define temporal trends in species occurrence, to identify species whose ranges are expanding or contract- ing, and to prioritize areas for conservation efforts. Accurate data on the presence and absence of fish- es at sampling sites requires sufficient sampling to assure that all species present are captured, but there is a need to avoid excessive sampling and to promote efficient sampling protocols. Guidelines for developing sampling protocols are needed by managers when designing surveys. Research has been conducted to assess the ef- * Corresponding author: tpatton@sosu.edu 1 Present address: Department of Biological Sciences, Southeast Oklahoma State University, Durant, Oklahoma 74701, USA. 2 The Unit is jointly supported by the Wyoming Game and Fish Department, University of Wyoming, U.S. Geo- logical Survey, and Wildlife Management Institute. Received February 18, 1999; accepted November 6, 1999 ficiency of electrofishing protocols and to define the needed sampling effort to determine the pres- ence or absence of fish in sample reaches of small streams (Layher et al. 1991; Lyons 1992; Anger- meier and Smogor 1995; Paller 1995). Similarly, the efficiency of seines has been evaluated (Gold- stein 1978; Dauble and Gray 1980; Wiley and Tsai 1983; Parsley et al. 1989; Vadas 1991; Vadas and Orth 1993), but additional guidelines that assist managers in the design of surveys of fish in small streams are needed. A growing interest in the status of native fish communities in streams of the Great Plains has exacerbated a need for guidelines to determine the electrofishing and seining effort necessary to de- tect the presence or absence of fish in these streams. Compared with streams of similar size in the midwestern or southeastern United States, streams on the Great Plains tend to have silt, sand, or gravel substrates; little or no woody debris or boulders; relatively homogenous pool-run habitat; and relatively low species richness. It is likely that less effort is needed to assess species richness in