Evaluation of Decision Structures and Monitoring Programs for Managing Sandhill Cranes
July 2010 - December 2014
- DOI-USFWS Region 6
Harvest management of sandhill cranes currently uses simple threshold approaches based on three-year average population objectives.The primary objective of this study is to develop stage-based models of the Rocky Mountain and Mid-Continent Populations, to address two general questions about crane management. First and foremost, what are the risks to these populations, in light of management objectives, of continuing the current decision rules for harvest decisions? If the risks are unacceptable, should the decision rules be altered, and is additional monitoring information needed to better inform decisions? In addition, for any specified level of monitoring effort, what can be expected in terms of performance measures identified in management objectives (e.g., crane harvest and crane numbers)? Second, given the limitations of our knowledge of crane populations and the best-case scenario with respect to the monitoring effort that could be devoted to cranes, what are the potential advantages and limitations for using models to directly inform management decisions? As part of this effort, hypotheses about other important and measurable limiting factors on a population or subpopulation can be evaluated (e.g., the effect of climatic variables on recruitment). Results from an initial modeling effort using existing data will provide an assessment of these issues, as well as tools to build a decision-making framework that would be applicable to all hunted sandhill cranes populations, and ultimately would improve harvest management decisions that sustain sandhill cranes at identified abundance levels and distributions. Such sandhill crane models also could be informative for non-hunted populations of cranes, and could be further adapted to address their management needs.