Species turnover of corticolous bryophyte assemblages over 15 years in an Australian subtropical cloud forest

Abstract

Montane forest ecosystem characterized by frequent cloud or mist inundation are considered highly vulnerable to climatic change. Despite this, there is a paucity of long-term studies assessing community change within these important ecosystems. We present the first comparative analysis of corticolous bryophyte diversity over 15 years in high elevation forests of the Gondwana Rainforests of Australia World Heritage Area, south-east Queensland, Australia. We found limited evidence of change in species richness across the five isolated stands of microphyll fern forest studied. However, we document considerable species turnover within corticolous bryophyte communities with a large and coherent pattern of change in the liverwort flora in particular (43-62% species turnover). Liverworts, but not mosses, also exhibited strong spatial patterns in species assemblages that likely correspond to varying exposure to orographic moisture associated with south-easterly winds. We postulate that microclimatic factors are stronger determinants of liverwort assemblages than moss assemblages in this system and that documented directional change in liverwort communities is a response to temporal fluctuation in moisture inputs from orographic cloud that are not discernible from precipitation records.