Impact/Purpose:

To determine the temperature regimes that characterize habitats occupied or not occupied by bull trout and Lahontan cutthroat trout.

Description:

Interior salmonids are species of growing interest and concern in the Pacific Northwest. Evidence of population declines associated with habitat loss and fragmentation have culminate in every species being listed, or proposed or petitioned for listing under he Endangered Species Act. Because salmonids require cold water, temperature is a fundamental element defining the critical habitat. Although some species have been studied extensive in laboratory settings, very little information is actually available to characterize suitable temperature regimes in the wild. Because temperature may influence both the quality and availability of habitats, a better understanding of temperature requirements can be useful in both predicting the distribution of and conserving critical habitats. Because of the detail in the temperature records, a variety of metrics may be used to characterize temperature regimes. We propose to summarize daily and weekly mean, variance, maximum, and minimums as well as information representing cumulative daily and weekly exposure to potentially unsuitable temperatures, to determine which statistics provided the best discriminatory power. Results will be used to describe suitable temperature regimes for both species and to contrast those among species with comparable data a and with criteria developed in laboratory studies. The resulting models and their limitations will be described in detail to support application in the prediction of critical habitat..

Record Details: