The Distribution of the Fishes of Arkansas: A Multivariate Analysis

Abstract

other ichthyologists. These collections, in 101 defined drainage units covering the entire state, permit detailed assessment of extant fish distribution patterns. Principal components analysis showed presence within the state of four distinct (but not mutually exclusive) groups of fishes. A complementary detrended correspondence analysis permitted definition of fish faunal regions within the state, and allowed clarification of patterns in fish distribution with respect to natural northwest-to-southeast gradients in environmental conditions. Many of the environmental variables and associated distributions of fishes corresponded to patterns contrasting upland with lowland species, but even within the upland or the lowland regions there were distinct groupings of fishes. The White River drainage, in uplands of north Arkansas, emerges as a distinct fish faunal region. The southern Ozark Mountains (i.e., streams tributary to the Arkansas River) and most of the Ouachita Mountains comprise another faunal region for fishes. A third fish faunal region exists at the ecotone between uplands and lowlands, and two distinct lowland faunal regions exist (including one of big rivers). Correlation and multiple regression analyses showed that fish distributions were significantly related to environmental variables, but comparison of upland fish faunas among major river drainages within the state showed that a strong component of historical zoogeography also influences patterns in fish distribution.