Pressures on natural heritage


Pressures on natural heritage

Natural heritage is susceptible to the general pressures arising from climate change outlined above, as well as some of the pressures that flow from population and economic growth. However, other pressures apply, particularly to natural heritage.

Invasive species

Invasive species and organisms that cause disease place major pressure on natural ecosystems and their natural heritage values. Australia has a considerable legacy of such invasions—some species, such as cane toads, mimosa and feral cats, have firmly established themselves over wide areas. Others, like myrtle rust or Phytophthora, pose very serious emerging threats. Government responses to invasive species are uncoordinated at the national level, reactive, focused on larger animals, biased towards potential impact on primary industry at the expense of the total ecosystem, and critically under-resourced. This is not only poor environmental and heritage management, but poor economics, as prevention and rapid response to new arrivals and incursions can save vast expense over time (Box 9.11).

Box 9.11 Response to invasive species—prevention is better than cure

As with preventative health in human society, relatively small interventions to address hazards in these areas, done soon, will be many times more cost-effective than if left until later. Prime Minister's Science, Engineering and Innovation Council47

Preventing major ecological damage is far less expensive than resolving the issues afterwards. The spread of invasive species can cause major, expensive environmental impacts. For example, fire ant infestations in Texas have cost the United States Government an estimated $1.2 billion per year. Following the discovery of fire ant infestations in Queensland, the Natural Resource Management Ministerial Council undertook a major eradication program that cost close to $150 million.48 No other fire ant eradication program has obtained the level of success that has been observed in Queensland.

Another similar invasive species is also subject to a national eradication program. Electric ants are an aggressive environmental pest that have the potential to seriously affect Queensland ecological and agricultural systems. The government response to this ecological threat has been far smaller. Funding of only $4.067 million for 2006–08 was agreed, with a review to follow to validate the continuation of the program.49 In 2010, detection of electric ant infestations in new areas means that additional work will be required to ensure the ants are eradicated.

Loss of habitat

Australia's extraordinary flora and fauna are directly threatened by progressive loss of habitat. Two major drivers of habitat are land clearing and climate change. Land clearing is a legacy pressure that represents past human activity. Climate change will continue to exert pressure and will increase the severity of fires, invasive species and other events, such as droughts, floods, coral bleaching and saltwater intrusion into coastal freshwater systems.18 All these pressures reduce habitat and expose our biodiversity to greater risk.

Land use

Changing land use places pressures on both natural and cultural heritage. Changes may reduce compatibility with reserve values and connectivity between different reserves, alter wildlife corridors or reduce critical mass for niche ecosystems. There may be physical impacts from resource extraction or indirect effects such as from run-off or subsidence. Even within reserves, changes to allow new recreation uses can lead to unintended pressures and damage to the resource if they are not well planned and carefully managed. The pressure from changing land use may be greatly reduced by strategic land-use planning and decision-making that is informed by thorough natural resource assessment and inventory.

Soil erosion

Erosion is the process by which the surface of the earth is worn away by the action of water, wind, vehicles and recreational activities. Natural heritage places are affected by a variety of erosion forms: streambank, roadside, beach, track, gully, wind, mass movement and sheet erosion. Mass movement and sheet erosion have far greater potential adverse impacts on natural heritage values than other forms. Erosion is exacerbated by changing climate, especially desiccation and increased wind, but can also arise from economic factors such as development, changing land use and increased tourism.10

Mackay R (2011). Heritage: Pressures on natural heritage. In: Australia state of the environment 2011, Australian Government Department of the Environment and Energy, Canberra,, DOI 10.4226/94/58b658bbe13a0