The influence of fine-scale topography on the impacts of Holocene fire in a Tasmanian montane landscape

Abstract

Tasmania's montane temperate rainforests contain some of Australia's most ancient and endemic flora. Recent landscape-scale fires have impacted a significant portion of these rainforest ecosystems. The complex and rugged topography of Tasmania results in a highly variable influence of fire across the landscape, rendering predictions of ecosystem response to fire difficult. We assess the role of topographic variation in buffering the influence of fire in these endemic rainforest communities. We developed a new 14 000-year (14-ka) palaeoecological dataset from Lake Perry, southern Tasmania, and compared it to neighbouring Lake Osborne (<250 m distant) to examine how topographic variations influence fire and vegetation dynamics through time. Repeated fire events during the Holocene cause a decline in montane rainforest taxa at both sites; however, in the absence of fire, rainforest taxa are able to recover. Montane temperate rainforest taxa persisted at Lake Perry until European settlement, whilst these taxa were driven locally extinct and replaced by Eucalyptus species at Lake Osborne after 2.5 ka. Contiguous topographic fire refugia within the Lake Perry catchment probably provided areas of favourable microclimates that discouraged fire spread and supported the recovery of these montane temperate rainforests. Copyright © 2019 John Wiley & Sons, Ltd.