Decision-support tool for managing endangered species in the face of uncertainty

Science Center Objects

Along the Santa Clara River in California, populations of the federally and state-listed Least Bell's Vireo (Vireo bellii pusillus) are recovering from near extirpation. Habitat protection and restoration, as well as reducing brood parasitism by Brown-headed Cowbirds (Molothrus ater), are thought to be the primary drivers of this recovery. The challenge going forward is to find the right balance of activities to restore and maintain the population of Least Bell’s Vireo in the face of uncertainty associated with: 

  • the highly dynamic and unpredictable nature of the riparian ecosystem,  
  • limited data on the life-history characteristics of Least Bell’s Vireos at the site, 
  • the lack of clearly defined and measurable recovery criteria 


We developed a decision support tool as a user interface for exploring the underlying uncertainty in a population viability analysis under an array of different management scenarios. The tool was designed to assist coordination among conservation partners in the region to accomplish three distinct aspects of the decision-making process:  

  • defining the problem and setting clear goals and objectives,  
  • exploring the consequences of potential alternative actions, and  
  • identifying criteria for ongoing evaluation and monitoring.  
Santa Clara River, southern California, USA

Map of the study area associated with recovery planning for the Least Bell's Vireo in the Santa Clara River valley of southern California.

(Public domain.)

The general framework for the design of this decision support tool is broadly applicable to many management and decision-making scenarios that share these common challenges.