Effects of minor drainages on woody species distributions in a successional floodplain forest

Abstract

A complex gradient of environmental factors exists on river floodplains oriented perpendicular to and affected by the river system. Previous investigations on the development and structure of floodplain forests have not adequately considered the possible effects of minor drainages intersecting the floodplains on vegetation distributions. The density distributions of Fraxinusamericana and Cornusflorida in the lower floodplain region of a portion of the Raritan River system intersected by Chambers Brook in central New Jersey illustrate that minor drainages may be dominant landscape features affecting woody species distributions. Minor drainages appear to primarily affect flooding and drainage patterns and thereby alter the orientation of the complex environmental gradient associated with the river system. When sampling on a floodplain it is important to consider sampling position relative to all drainages to ensure that samples collected at various locations along the floodplain represent similar sets of environmental conditions.