A broad typology of dry rainforests on the western slopes of New South Wales

Abstract

Dry rainforests are those communities that have floristic and structural affinities to mesic rainforests and occur in parts of eastern and northern Australia where rainfall is comparatively low and often highly seasonal. The dry rainforests of the western slopes of New South Wales are poorly-understood compared to other dry rainforests in Australia, due to a lack of regional scale studies. This paper attempts to redress this by deriving a broad floristic and structural typology for this vegetation type. Phytogeographical analysis followed full floristic surveys conducted on 400 m² plots located within dry rainforest across the western slopes of NSW. Cluster analysis and ordination of 208 plots identified six floristic groups. Unlike in some other regional studies of dry rainforest these groups were readily assigned to Webb structural types, based on leaf size classes, leaf retention classes and canopy height. Five community types were described using both floristic and structural data: 1) 'Ficus rubiginosa'-'Notelaea microcarpa' notophyll vine thicket, 2) 'Ficus rubiginosa'-'Alectryon subcinereus'-'Notelaea microcarpa' notophyll vine forest, 3) 'Geijera parviflora'-'Ehretia membranifolia' semi-evergreen vine thicket, and 5) 'Cadellia pentastylis' low microphyll vine forest. Floristic groupings were consistent with those described by previous quantitative studies which examined smaller portions of this study area. There was also general agreement between the present analytical study and a previous intuitive classification of dry rainforest vegetation throughout the study area, but little concurrence with a continental scale floristic classification of rainforest.