Patterns and Processes in Population Divergence of 'Microlaena stipoides' (Labill.) R. Br.

Abstract

The distribution of 'Microlaena stipoides' (Labill.) R. Br. on the Northern Tablelands of New South Wales was examined by surveying 101 paddocks on 33 commercial properties. Greater abundance of 'M. stipoides' was observed on the eastern side and the southern half of the Northern Tablelands where rainfall and altitude were higher. Pasture management correlates that were significantly associated with abundant 'M. stipoides' were high tree density, minimum soil disturbance and long period since last cultivation. Greater abundance of 'M. stipoides' was observed in paddocks containing other year-long green perennials, cool season annuals and exotic sown species in addition to warm season perennials and annuals. 'Microlaena stipoides' grew well in association with other perennial grasses found in permanent pastures, such as 'Lolium perenne', 'Damlis glomerata', 'Poa pratensis' and 'Phalaris aquatica', which may indicate the permanency of these species associations.