The management of forest ecosystems to increase carbon storage is a global concern. Fire frequency has the potential to shift considerably in the future. These shifts may alter demographic processes and growth of tree species, and consequently carbon storage in forests. Examination of the sensitivity of forest carbon to the potential upper and lower extremes of fire frequency will provide crucial insight into the magnitude of possible change in carbon stocks associated with shifts in fire frequency. This study examines how tree biomass and demography of a eucalypt forest regenerating after harvest is affected by two experimentally manipulated extremes in fire frequency (i.e., ~3 year fire intervals vs. unburnt) sustained over a 23 year period. The rate of post-harvest biomass recovery of overstorey tree species, which constituted ~90% of total living tree biomass, was lower within frequently burnt plots than unburnt plots, resulting in approximately 20% lower biomass in frequently burnt plots by the end of the study. Significant differences in carbon biomass between the two extremes in frequency were only evident after >15–20 years of sustained treatment. Reduced growth rates and survivorship of smaller trees on the frequently burnt plots compared to unburnt plots appeared to be driving these patterns. The biomass of understorey trees, which constituted ~10% of total living tree biomass, was not affected by frequent burning. These findings suggest that future shifts toward more frequent fire will potentially result in considerable reductions in carbon sequestration across temperate forest ecosystems in Australia.

Context: Habitat loss and degradation has contributed significantly to the decline of many species worldwide. To address this loss, we first require a comprehensive understanding of habitat requirements and resource-use patterns of the species under threat. Aims: The study aimed to quantify variation in the habitat of a species threatened by habitat loss and degradation, the brush-tailed phascogale (Phascogale tapoatafa tapoatafa), by measuring several physical characteristics of trees and ground cover, as well as to determine potential foraging resource preferences using abundance data from a long-term monitoring study. Methods: Phascogale monitoring surveys were conducted over a 13-year period from 2000 to 2012. Habitat variables characterising tree communities, ground cover and coarse woody debris were used to develop explanatory models of phascogale abundance at the site scale. Tree species preference by foraging phascogales was evaluated by comparing usage (trees on which they were captured) and availability. Key results: The highest overall animal abundance was at sites characterised by associations of red stringybark, red box, grey box and broad-leaved and narrow-leaved peppermints. At these sites, red stringybark and grey box trees were of small diameter and tended to have small hollows. These sites also had low average tree height, low grass and/or herb and shrub cover and low volumes of coarse woody debris. From a resource-use perspective, phascogales foraged preferentially on certain species of Eucalyptus. Conclusions: Our study suggests that phascogale abundance is highly spatially and temporally variable, most likely as a response to heterogeneity in habitat and foraging resources operating at a range of spatial scales. Implications: This study has provided new information concerning spatial patterns of phascogale abundance and resource use within a forested area in central Victoria that has been subjected to multiple disturbances. Currently, the composition and age structure of tree communities and ground habitats are a response to severe disturbance due to past mining and harvesting activities. Successful conservation of this threatened species could be enhanced through active management of this forest to maintain the ongoing supply of nesting hollows and foraging resources.

Fire is a common feature of Australian forests and prescribed burning is a routine management strategy, often utilised to mitigate the effects of wildfire. However, the impacts of fire on terrestrial invertebrates are poorly understood. Here we provide an overview of continuing long-term fire studies in temperate and sub-tropical forest ecosystems, with a focus on terrestrial invertebrates. Longitudinal fire study sites exist in southern Queensland, New South Wales, Victoria, Western Australia and Tasmania. Most studies have focussed on fire frequency and have identified certain taxa or taxonomic groups that prefer either habitat associated with long unburnt areas, habitat associated with more frequently burnt areas or those that show no response to varied fire frequency. The limited number of studies investigating fire season report similar findings, but there are few studies that have focussed on other components of the fire regime. Long-term experiments are important when studying the effects of various fire regimes on invertebrate assemblages as responses often take time to be expressed, and may follow changes in habitat availability associated with interactions between components of the fire regime. We recommend that ecological studies continue to utilise long-term study sites through monitoring programs to improve our understanding of how invertebrate taxa respond to fire regimes; and to better identify the important role of invertebrate groups in ecosystem functioning (e.g. for nutrient cycling, pollination).