At a glance
Although a changing climate has shaped the Australian landscape and its vegetation, the current rate of climate change is likely to result in changes in the distribution and composition of vegetation communities. Some communities are likely to disappear, and others will be transformed as different species mix together to form novel communities, in some of which exotic species are likely to play a significant role. Many agricultural and forestry systems are likely to be adversely affected.
Rates of land clearing, although decreasing in many states, are still increasing in some states in response to relaxation of legislative controls. There is recognition that land clearing can affect environmental services, such as control of erosion and maintenance of soil quality, and that habitat fragmentation, which is a typical consequence of land clearing, places increased pressures on the survival of remnant patches of natural vegetation.
Widespread landscape-scale pressures (including invasive species and changed bushfire regimes) continue to threaten land managed for environmental values, conservation and extensive agriculture. Bushfire frequencies are increasing, as are the number of invasive species that are threatening Australian landscapes and industries. Increasing resistance of invasive weeds to herbicides is recognised as a growing problem. Pressures on the land environment associated with grazing—Australia’s most extensive land use—have decreased somewhat, with a decrease in the size of the national cattle herd and in the area grazed.
Although better management of many agricultural systems has reduced their impacts on the land environment, a number of issues relating to nutrient and soil management remain. Low-tillage conservation agriculture approaches have been successful, but uptake appears to be declining in some areas. Management of native and plantation forestry faces challenges as the industry ceases to expand, and the delivery of long-term management agreements falls short of expectations.
Urban and peri-urban expansion continues to threaten agricultural land and the viability of some horticultural industries. Legislative approaches are in place in some jurisdictions to help manage these tensions.
Mining developments have slowed in recent years, although the management of former mining sites is an emerging concern. So too is the expansion of unconventional gas extraction, particularly because of concerns about safety, but also because of competition for land with other uses.
Waste production continues to increase, although recycling and re-use are also increasing, in some cases supported by innovative commercial opportunities for recycled products.
Pressures affecting Australia’s land environment come from each of the drivers discussed in the Drivers report, as well as from the interactions between them. The growing human population and levels of consumption, both domestically and globally, will increase demand for food and fibre. Expanding cities and new infrastructure also continue to affect the environment. Economic growth demands greater extraction of natural resources, although conditions placed on extractors are resulting in increased investment and new technologies for environmental management.
Changed climate regimes and sea level rise associated with global warming are expected to place new pressures on both the natural environment and primary production systems. These pressures and drivers interact—for example, fire regimes are influenced by both climate change, and changing patterns of settlement and land use associated with population and economic growth. Coastal ecosystems will be affected by the interaction between sea level rise and human settlements.
The major pressures affecting Australian soils and vegetation have been identified in previous SoE reports, and in a series of assessments and reviews over the past decade. These pressures are:
- those resulting from climate change, which include increased average temperatures, warmer minimum and maximum temperatures, less predictable rainfall patterns, and more extreme weather events—all of these affect the timing and success of biological processes such as growth, timing of flowering, effective pollination and seed dispersal
- vegetation clearing and associated habitat fragmentation, with consequences for ecosystem services (such as carbon sequestration), soil erosion and biodiversity persistence
- altered fire frequency and intensity, and the extent of both bushfires and managed fires
- changes in land uses and land management practices, including farming and forestry systems, which compete for space with natural systems, affecting ecosystem function and provision of services
- invasive diseases, pests and weeds, which infect, prey on, replace or compete with native species, and reduce agricultural viability
- urban expansion, which competes for land space and affects a range of environmental processes and services; it also requires substantial investment to deal with provisioning and waste services, and infrastructure maintenance
- mining activities, resource exploration and the legacy of abandoned mine sites, and their impacts on landscape, biodiversity and human health
- waste disposal, including landfill and recycling
- water diversions, and changed hydrology and salinity.