Suchergebnisse

Large old hollow-bearing trees have a wide range of key ecological roles in forest and other ecosystems globally. Patterns and rates of mortality and decay of these trees had profound effects on the size and composition of their populations. Using an 18-year empirical study of large old trees in the Mountain Ash (Eucalyptus regnans) forests of the Central Highlands of Victoria, we sought to determine if there are particular patterns of decline that are shared by a proportion of the trees in a tree population. We also sought to identify drivers of decline of these trees by quantifying relationships between the condition state of trees (viz: tree form) and a range of covariates. We found that time, stand age and fire can individually and in combination, strongly affect the decay (and eventual collapse) of large old trees. In particular, we found compelling evidence that patterns of tree decline were markedly different in old growth forest (stands dating from ~ 1850) relative to three other younger age classes examined. Trees in older forest decayed less rapidly than trees of equivalent tree form in younger forest. Old growth stands also were characterized by trees in an overall much lower (more intact) form category than the other age classes of forest. A key pattern in our study was the rapid deterioration of large old trees in the youngest aged stands (viz: those regenerating after fires in 1939 and following disturbance between 1960 and 1990). In these forests, a very high proportion of large old trees were either in the most advanced state of tree decay (form 8) or had collapsed (form 9). This is a major concern given that 98.8% of the Mountain Ash forest ecosystem supports forest belonging to these (or even younger) age cohorts. Our investigation highlights the need for forest management to: (1) increase levels of protection for all existing large old hollow-bearing trees, (2) expand the protection of existing regrowth forest so there is the potential to significantly expand the currently very limited areas of remaining old growth forest. ; The work reported in this paper was funded by the Australian Research Council, The Australian Government (National Environmental Science Program Threatened Species Recovery Hub), and the Government of Victoria.

1. Forests worldwide are increasingly subject to natural and human disturbances, including wildfires and logging of varying intensity and frequency. Understanding how biodiversity responds to different kinds and combinations of natural and human disturbance is critical to enhanced forest management. 2. We completed an eight-year study of bird responses across a spectrum of disturbance types in Australian Mountain Ash (Eucalyptus regnans) forests following wildfires in 2009. 3. We found evidence of a gradient in bird species richness over the study duration. It was highest in unlogged and unburned (least disturbed) sites, decreasing through burnt unlogged forest (subject to high or low intensity fire), lower still in logged forest, and lowest in the most disturbed sites (subject to salvage logging without island retention). Retention of uncut islands within logged areas increased bird species richness above that found in areas that had been clearcut. 4. The greatest rate of increase per year after disturbance in bird species richness was on sites burnt by high severity fire but which were not subject to any form of logging. The level of disturbance affected the composition of the bird assemblage. Sites that were unlogged and unburned were more likely to support species that were larger, more mobile, and nested at greater heights above the ground. 5. Synthesis and applications. All forms of logging on burned sites impaired recovery in bird species richness relative to sites subject to high severity fire. Alterations in stand structure and plant species composition (and hence modification in bird habitat suitability) due to logging are the most likely reasons for reduced bird species richness and delayed patterns of recovery. This study highlights the importance for native bird species of retaining patches of unlogged forest not only within otherwise clearcut forest, but also in areas that are burned and subject to salvage logging. We therefore suggest that the adoption of retention harvesting be expanded to include stands disturbed by wildfires. ; Australian Research Council, the Government of Victoria (Department of Environment, Land, Water and Planning; Parks Victoria) and the Graeme Wood Foundation

A large-scale biodiversity monitoring program examining the response of herpetofauna to the Australian Government's Environmental Stewardship Program is taking place in south-eastern Australia within the critically endangered Box Gum Grassy Woodland veget

A large-scale biodiversity monitoring program examining the response of herpetofauna to the Australian Government's Environmental Stewardship Program is taking place in south-eastern Australia within the critically endangered Box Gum Grassy Woodland veget

A large-scale biodiversity monitoring program examining the response of herpetofauna to the Australian Government's Environmental Stewardship Program is taking place in south-eastern Australia within the critically endangered Box Gum Grassy Woodland vegetation community. Field surveys involve counting reptiles in areas under Environmental Stewardship management. These "Stewardship" areas have been matched with areas managed for primary production (domestic livestock grazing). We list reptiles recorded during surveys conducted between 2010 and 2012. We recorded sixty-nine species from ten families. The list will be useful for workers interested in the zoogeographical distribution of reptiles and amphibians in fragmented agricultural woodland ecosystems.