Abiotic correlates with diversity and distinctiveness in Sunshine Coast heathlands: Moisture, volcanic landscapes and patterned mounds

Abstract

The ongoing management and protection of conservation areas can be informed by understanding factors that affect the integrity of these communities. Abiotic factors associated with diversity and phylogenetic dispersion within communities, as well as distinctiveness between communities, may potentially be impacted by climate change or changes in hydrology due to urbanization. This study used a range of diversity metrics, along with nominal and quantitative abiotic data, to examine correlates with diversity patterns in the Sunshine Coast heathlands, ecosystems under threat from urban development. Metrics for 80 heathland sites over a variety of substrates, moisture levels and topographic factors were compared using univariate and multivariate statistics. Moisture is a key abiotic factor correlated with the diversity and distinctiveness of heath, and also with higher phylogenetic dispersion of moist and wet sites, indicating possible refuges. Vegetation composition patterns were distinct in the heaths on Tertiary and Triassic rocky volcanic substrates, with the overlapping composition of heath on other substrates, confirming the tolerance of many heath species to a variety of substrates. Patterned natural ‘mounds’ and ‘trenches’ were associated with phylogenetic evenness and are possible refugia. Multivariate analysis had a weak positive correlation of environmental factors with vegetation and phylogenetic composition, emphasizing the complexity of correlates with diversity for the heathlands. This study suggests that both the management of hydrological changes and protection of potential refugial areas are likely to be critical in maintaining the integrity and diversity of the Sunshine Coast heathlands.