Greatest Conservation Need Research Articles

Development of multi-species indicators for the Nevada Wildlife Action Plan

Wildlife managers, conservationists, and policy-makers are interested in indicators that aggregate population status and/or trend information for multiple species. Several multi-species indicators have been proposed, which either report species status ranks or rank changes (using either the International Union for the Conservation of Nature or NatureServe ranking systems), or which report the average direction or tendency of time series from multiple populations or species. We explore the utility of these indicators within the context of the Nevada Wildlife Action Plan, one of 56 state or territorial wildlife conservation plans that have recently been developed and published by state wildlife agencies in the USA. The Nevada Wildlife Action Plan identifies 186 “species of greatest conservation need,” including birds, mammals, reptiles, amphibians, fish, and mollusks. Significant deficiencies in the existing monitoring data for these taxa limit the applicability of nearly all of the multi-species indicators that have been described to date. However, we were able to populate a simple multi-species status indicator with data for all 186 species. We also describe a simple graphical indicator that summarizes information about the direction of population trends for suites of multiple species, and discuss how this tool could be populated with data in future revisions of the Nevada Wildlife Action Plan.

Distribution and Status of the Yellow-faced Pocket Gopher in Kansas

Previous research suggests that the yellow-faced pocket gopher (Cratogeomys castanops) occupies a restricted range in western Kansas that is surrounded by the range of the plains pocket gopher (Geomys bursarius), which is regarded as a superior competitor. To determine whether the plains pocket gopher has encroached on the range of the yellow-faced pocket gopher in the past 35 years and to better understand the geographic relationships of these species, we trapped pocket gophers in western Kansas and collected soil texture and land cover data. We used ArcView 3.2 to map the distributions of these species in the study area, as well as the kinds of soil and land cover found in their potential home ranges. Although the distributions of the 2 species overlap, they are strictly parapatric. The apparent cause of this parapatric relationship is differential tolerance of soil textures. The distribution of the yellow-faced pocket gopher in Kansas is limited to just 7 counties divided into 2 populations, both surrounded by the distribution of the plains pocket gopher. We found no evidence that the range of the plains pocket gopher has expanded at the expense of the yellow-faced pocket gopher in the past 35 years. Thus, although the yellow-faced pocket gopher remains a “species of greatest conservation need” in Kansas because of agricultural threats, it evidently is not imperiled at this time.