Rm. Scheller et al., An analysis of the influence of annual thermal variables on the occurrenceof fifteen warmwater fishes, T AM FISH S, 128(2), 1999, pp. 257-264
Multisource fish-sampling data and U.S. Geological Survey temperature data
from streams throughout the United States were used to investigate the infl
uence of derived thermal regime variables on the presence or absence of 15
common warmwater fish species. The 3-year average annual thermal regime was
calculated for streams where presence or absence was known for these 15 sp
ecies. Six variables estimated to be of biological importance to the winter
and summer survival and recruitment of a species, including measures of fe
eding and nonfeeding periods, were calculated from these thermal regimes. S
tepwise discriminant analysis and multiple regression were used to select o
ptimal variables for creating multivariate models. Parametric and nonparame
tric multivariate discriminant analyses were then performed to test our abi
lity to correctly classify presence or absence using the thermal variables.
These statistical empirical models were able to correctly predict presence
or absence with greater than 90% accuracy for 13 of 15 species. Nonparamet
ric (Kth nearest neighbor) analyses had marginally more accurate prediction
s than parametric (linear) analyses. This technique may allow for an improv
ed estimation of potential changes in distribution under various global war
ming scenarios.