New Zealand Journal of Ecology (1989) 12: 89–94
©New Zealand Ecological Society

Research article
Empirical Measurement of Environmental Gradients in Ecological Surveys

D. Scott and R. H. Groves

¹ Grasslands Division, DSIR, Christchurch, New Zealand
² Division of Plant Industry, CSIRO, Canberra, ACT 2601, Australia

Abstract: Soil temperature, soil moisture and soil fertility were determined empirically at 63 predominantly hill sites in the South Island, New Zealand. Soil temperatures were measured at a depth of 0.5 m in four seasons and gave a standard deviation of mean annual temperature between sites of 2.2-degrees-C. Soil moisture levels, as available water in a 0-0.5 m profile, measured seasonally, gave a standard deviation between sites of 49 mm water. Soil fertility was measured in a common environment as yield of a test species grown in each soil expressed as a percentage of the yield in the same soil given complete nutrients. On this scale the standard deviation between sites was 19%. The trial showed that these environmental factors can be empirically measured in surveys.

Keywords: environmental factors; gradient analysis; temperature; moisture; soil fertility