An objective Method of Measuring the Vegetation Structure of Animal Habitats

Abstract

The importance of habitat structure has been illustrated for many groups of animals. A method to objectively measure the vegetation structure of animal habitats is presented. Factors contributing to the index are evaluated and an attempt is made to show how this index relates to other methods of measuring habitat structure. A technique to measure crop leaf area is adapted and applied to assessing structure (the vertical distribution of vegetation) in natural vegetation. A light meter is used to determine a vegetation index for each of several layers. The index is compared with projected cover, cover estimated with a cover board and cover repetition using pin contacts. All correlations are highly significant. In heath the dry weight of clipped vegetation contributed more to the vegetation index than did the leaf area, reflecting a greater contribution of woody stems and branches than of the small ericoid leaves. The technique has been successfully applied to the measurement of habitat requirements for small mammals and an example of such an application is included.