Gw. Minshall et Ct. Robinson, MACROINVERTEBRATE COMMUNITY STRUCTURE IN RELATION TO MEASURES OF LOTIC HABITAT HETEROGENEITY, Archiv fur Hydrobiologie, 141(2), 1998, pp. 129-151
We examined the relationship between habitat heterogeneity and benthic
macroinvertebrate assemblages in thirty-two 2nd to 6th order wilderne
ss streams in central Idaho. Twenty-one environmental measures were ev
aluated for each stream with their heterogeneity expressed in terms of
coefficients of variation (CV's). Although the annual range in water
temperature was greater in the larger (5th and 6th order) streams, mos
t other habitat measures showed greater variation among smaller stream
s (2nd order) than larger streams. Mean habitat-CV's also were about 2
0 % greater for smaller (2nd order) than larger (5th and 6th order) st
reams, suggesting a homogenizing influence of stream size on habitat h
eterogeneity. Multivariate analyses of the habitat measures clearly se
parated 5th and 6th order streams from less than or equal to 4th order
streams, further indicating major environmental differences between l
arger and smaller stream systems. Multiple regression and canonical co
rrespondence analysis revealed that some biotic properties, e.g. % shr
edders, were associated with stream size, reflecting longitudinal chan
ges in food resource availability or annual variation in temperature,
while others, e.g. Shannon's diversity, were more dependent on measure
s of within-reach habitat heterogeneity.