WCT Multi-state Assessment 



February 10,2003 



Table 6. Ranks and descriptions of population risks to designated conservation populations of 

 westslope cutthroat trout in 2002. 



Type of Risk 



Rank Criteria 



Population 

 Productivity 



Population is increasing or fluctuating around an equilibrium 

 that fills available habitat that is near potential. No nonnative 

 competing or predating species present. 



Population has been reduced from potential, but is fluctuating 

 2 around an equilibrium (population relatively stable and either 

 habitat quality is less than potential, or another factor - disease, 

 competition, etc. - is limiting the population). 



Population has been reduced and is declining (year-class 

 failures are periodic; competition may be reducing survival; 

 habitat limiting population). 



Population has been much reduced and has either been 

 4 declining over a long time period or has been declining at a fast 

 rate over a short time-period (year-class failures are common; 

 competition or habitat dramatically reducing survival). 



1 At least 75 km of connected habitats 



2 25-75 km of connected habitats 



3 10-25 km of connected habitats 



4 < 10 km of connected habitats 



2 Migratory forms must be present and migration corridors are 

 open (connectivity maintained). 



Migratory forms are present, but connection with other 

 2 migratory populations disrupted at a frequency that allows only 

 occasional spawning. 



Questionable whether migratory form exists within connected 

 ^ habitat; however, possible infrequent straying of adults from 

 other populations into area occupied by population. 



Population is isolated from any other population segment, 

 '^ usually due to barrier, but may be related to lack of movement 

 or distance to nearest population. 



1 > 2,000 adults 



2 500-2.000 adults 



3 50-500 adults 



4 < 50 adults 



Temporal Variability 



Isolation 



Population Size 



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