New Zealand's potential forest pattern as predicted from current species-environment relationships

Abstract

New Zealand's potentid forest compoSition was predicted from regressions relating the distributions Of major canopy tree species to environment. Environmental variables, chosen for their correspondence to major tree physiological processes* inc1uded annual and seasod temperature and solar radiation, soil and atmospheric water deficit, soil leaching, slope, and Soil parent material and &ainage. Envkomend values were estimated both for a large set of irrgularly distributed plots describing fmest composition, and Points on a l-km grid across New Zealand. Regressions were fitted to the plot data sPsies by Species with those for the four Nithofagus species also Including terms to correct for the effects of their geographic disjunctions. Regressions for other species contained both environmental variables and terms to account for their competitive interactions with the patchily distributed but strongly competitive Nothofagus species. Predictions of species abundance were then made for the grid data set, and the resulting matrix was classified to derive groups of similar composition. Results agree closely with published descriptions of New Zealand's forests, including for Sites 10% deforested. They are exPected to Provide a context for both the assessment of the biodiversity value of surviving forest relnnants and for the subsequent management and/or restoration of these sites. © 2001 Taylor & Francis Group, LLC.