Although the growth characteristics and preferred growth conditions of many of nitrogen-fixing species have been described, less is known of their natural species assemblages and associated soil status in natural or semi-natural conditions. The work studied plant communities and soil properties at locations where native N-fixers are naturally found in Canterbury, New Zealand. Four native N-fixers (Sophora microphylla (S. microphylla), Sophora prostrata (S. prostrata), Carmichaelia australis (C. australis) and Discaria toumotou (D. toumatou)) were investigated in 7 studying areas (25m2) within different landscapes in Canterbury. A total of 49 species were found growing in association with these N-fixers, and most of the species in the immediate vicinity of the N-fixers were native species (45 species). C. australis and D. toumatou were found and associated with the dry high country at Canterbury. Sophora microphylla was recorded in forest sites with higher soil moisture, nitrate and Olsen P than the sites of C. australis and D. toumatou. These findings indicate that these native N-fixing plants are an important component of diversity in natural plant communities and their distribution is primarily determined by climatic and edaphic factors.

Keywords: N-fixing plants, native species, soil quality, natural landscapes, plant communities.