Succession in the microflora of leaves and litter of three plant species in sub-Antarctic Macquarie Island.

Abstract

Microbial ecology and succession were studied on leaves and litter of Poa foliosa, Stilbocarpa polaris and Pleurophyllum hookeri, the dominant species of flowering plant of the herbfields of Macquarie Island. The patterns of microbial succession were similar, and resembled those on most plants from temperate and tropical regions, except that most primary saprophytes became established on leaves before senescence. Despite similarity as to the types of micro-organisms and classes of filamentous fungi occurring at certain stages of the succession, there were obvious differences both between the plant species and in comparison with plants from other parts of the world in the fungal species involved. The main differences referred to the fungal species which dominated the primary saprophytic microflora, viz. Ascomycetes with Coelmycete anamorphs, which were often either host-specific or host- restricted, and included unidentified and probably new endemic species of Phoma (3 spp) and Mycosphaerella (1 sp), and Ascochyta stilbocarpae. Other primary saprophytes, including Mycosphaerella tassiana and Leptosphaeria eustoma occur worldwide, but appear to favour cold climates. -from Authors