YCT Multi-state Assessment 



February 10,2003 



Variable 



Description 



Rank 



Criteria 



Size- 

 whole 

 population 



50 - 500 



<50 



Population 

 Production 

 (Growth/ 

 Survival) 



Influence of 



deterministic 



demographic 



factors on 



whole 



population 



Factors that influence population production 

 include habitat quality, disease, competition, 

 and predation. 



Isolation 



How isolated or connected is the conservation 

 population from other conservation populations? 



i 



Population is increasing or 

 fluctuating around an 

 equilibrium that fills a habitat 

 that is near potential 



Population has been reduced, 

 but is fluctuating around an 

 equilibrium value that 

 indicates the population is at a 

 level that is less than its 

 potential (i.e. habitat quality is 

 less than potential or another 

 factor is limiting the 

 population - competition 

 and/or disease) 



Population has been reduced 

 and is declining (year-class 

 failures may be periodic; e.g. 

 competition reducing survival 

 and/or disease) 



Population has been much 

 reduced and declining over 

 long-term or at a fast rate 

 (year-class failures common; 

 e.g. competition dramatically 

 reducing survival) 



Migratory forms must be 

 present and migration 

 corridors must be open 

 (connected) 



Migratory forms are present, 

 but connection with migratory 

 populations disrupted at a 

 frequency that allows only 

 occasional genetic exchange. 



Questionable whether 

 migratory form exists within 

 connected habitat; howe\er. 

 possible infrequent stra>ing of 

 adults into area occupied by 

 population 



Page - 57 



