Document: WEN-3-15-3

Boundary permeability at land-water interfaces: The influence of 3-D structure.

ANDERSON, W.B.*

Drury University, Springfield, MO 65802 USA ¹

Abstract:
Aquatic or marine energy and nutrients are often important resources for terrestrial organisms, and can strongly influence population and community dynamics. The physical structure of the land-water interface is an important determinant of the ease with which abiotic and biotic vectors pass across the interface and the distance they carry the material inland. The three-dimensional structure of the ecotone is defined by its topography and the architecture of the ecotone's vegetation. Using coastal zones of islands in the Gulf of California and riparian zones of an Ozark reservoir, I demonstrate how slope angle and vegetative architecture facilitate or hinder movement of nutrients, detritus, insects, and mammals between water and land. On desert islands, coastal zones with slope angles less than 20 degrees accumulated more marine detritus than zones with steeper slopes. This detritus attracted more detritivorous insects than areas without this detritus. Islands with slope angles greater than 20 degrees attracted more roosting seabirds, which deposit large quantities of nutrient rich guano and support large populations of ectoparasitic flies. In riparian zones along the lakeshore, emerging aquatic insects were found further inland in areas with narrower zones of dense shrubs. Raccoon and coyote tracks were more common on the shallower slopes with less dense vegetation. Quantifying the movement of material from one system to another must take into account the mobility of the vector and the 3-D environment encountered by the vector.

Keywords: boundary permeability, ecotone, land-water interface

This abstract is being presented at: 9:10 AM in session:
Symposium # 3: Linking Communities Across Ecosystem Boundaries: A Symposium in Memory of Gary A. Polis.