Gradient Analysis in Nature Reserve Design: A New Zealand Example

Abstract

Abstract: Direct and indirect gradient analysis methods were tested to assist in nature reserve design in New Zealand Graphic descriptions were made of community‐environment relationships. Environmental factors considered included altitude, solar radiation, geologic substrate, soil drainage, and landformClassification identified 21 lowland forest community types in the northwestern South Island study area. These community types and their composite species appear to be arranged along soil fertility, landform, and temperature gradients. Direct gradient analysis was particularly useful in portraying the relationship of the plant communities to perceived environmental gradients.Comprehensive gradient diagrams for an ecological district may be compared with gradient diagrams depicting the districts current reserves, if any. A representative reserve system may be achieved if “gaps” between the two diagrams are filled in by expanding the reserve system and/or modifying existing reserve boundaries. Based on this technique, a recommendation is made to incorporate a unique coastal forest remnant in a national park proposal for the study area.