Population

Population growth contributes to all the pressures described in this report. Each person added to our population increases demand on natural resources to provide food, shelter and materials for living.

Direct threats to biodiversity associated with human activity include those related to accommodating a growing population in cities and regional areas, with associated urban development and infrastructure for transport, power and services. Pressures also include disturbances associated with recreation and tourism, hunting, fishing and collecting, which can impact biodiversity in even the most remote areas of Australia.

Australia’s population continues to increase – in September 2020 it was 25,693,059 people, with an annual growth rate of more than 220,000 people. Australia’s population is growing fastest in our capital cities. Although human-dominated landscapes sometimes have high biodiversity, the mix of species is markedly different from that in natural landscapes. Globally, as a result of human-caused changes, at least 20% of species in terrestrial ecosystems are estimated to have been lost, with key areas rich in species found nowhere else (endemic hotspots) tending to have lost even more (IPBES 2019).

Urban development

Population growth continues to put pressure on biodiversity in Australia’s urban areas and in the peri-urban spaces between suburbs and rural areas. Australia’s population is concentrated in our cities and this trend is increasing (see the Urban chapter). While population density is increasing in established inner urban areas, governments are supporting new greenfield developments offering larger and more affordable homes on the outskirts of urban areas. In contrast, growth in rural and remote areas of Australia is in decline.

The potential pressures from greater urban and peri-urban expansion include:

  • land clearing
  • less green space and tree canopy cover, at least in the early years, as existing vegetation is cleared for new development and new vegetation takes time to grow back
  • smaller gardens; new suburbs in Australia have significantly less cumulative areas of private gardens than established suburbs
  • greater pressure on our coasts and waterways; these high-value areas are attractive locations for homes.

The urban environment includes green spaces (e.g. parks, woodlands, nature conservation areas, gardens, sports fields) and blue spaces (e.g. creeks, rivers, dams, ponds, estuaries, wetlands). Green spaces in cities provide an important haven for biodiversity and may benefit both locally and nationally rare species (see the Urban chapter). It is estimated that 25% of all nationally listed threatened plants and 46% of nationally listed threatened animals can be found in Australia’s cities and towns (ACF 2020). Thirty-nine species listed under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) (37 plants and 2 animals) are thought to be urban-restricted in that their entire remaining distribution is contained within only 1 or 2 cities or towns (Soanes & Lentini 2019) (Figure 30). These species occur across many land types within cities, including roadsides, private land, golf courses and schools.

Figure 30 Locations of urban-restricted threatened species across Australia

Increasingly, state and local governments and communities, Indigenous people, and nongovernment organisations are playing key roles in managing and improving the green and blue networks in our urban environments. They are working collaboratively to reintroduce native species and plants, create urban forests, and instil principles of biodiversity-sensitive urban design in the design phase of urban infrastructure (see the Bringing nature and green back section in the Urban chapter).

Human activity

Increasing human activity creates demand for water, energy, fibre and timber, food products, metals, and minerals. It also generates a range of waste products at all stages of the production–consumption cycle, including solid waste, greenhouse and other gases, chemical waste, and sediment. Some of these may end up as pollutants in our land, air, water or marine environments (see the Land, Air Quality, Inland water and Marine chapters).

The impacts from roads, tourism, recreation, hunting, shipping, fishing and other disturbances can permeate into even the most remote protected areas. For example, millions of animals are struck and killed on Australian roads every year. Road mortality is the second biggest killer of endangered Tasmanian devils (Sarcophilus harrisii), with around 350 killed every year, and the largest cause of death of adult Endangered cassowaries (Casuarius casuarius johnsonii) in Queensland. Between 2006 and 2017, there were 31,626 admissions of 83 species of wildlife to the Australia Zoo Wildlife Hospital in Queensland (Taylor-Brown et al. 2019). Car strikes were the most common reason for admission (34.7%), with dog attacks (9.2%), entanglements (7.2%) and cat attacks (5.3%) also high.

Researchers have recently described a global restructuring of animal movement in response to human disturbances (Doherty et al. 2021). They found that human disturbance restricts the movement of some species where, for example, they encounter barriers such as roads or cannot move as efficiently through some altered habitats. On the other hand, movement may be increased if animals have to travel further to find food. For example, koala (Phascolarctos cinereus) movements are longer and more directed in areas where habitats are not well connected, because they have to travel further to reach food patches (Rus et al. 2021). Likewise, the daily movement distances of mountain brushtail possums (or bobuck – Trichosurus cunninghami) in central Victoria were 57% higher in remnant bushland along roadsides than in large forest areas. The consequences of altered movement can be profound, leading to declines in survival and reproductive rates, genetic isolation, and local extinction (Doherty et al. 2021).

Assessment Pressures from population
2021
2021 Assessment graphic showing that pressures are very high, meaning they strongly degrade the state of the environment, over a large extent and with a high degree of severity. The situation is deteriorating.
Adequate confidence

Human activity and population growth are major drivers of many pressures on biodiversity. Impacts are associated with urban expansion, tourism, industrial expansion, pollution, fishing, hunting and development of infrastructure. The impacts from population growth are extensive and increasing in many areas.
Related to United Nations Sustainable Development Goal targets 6.3, 11.6, 12.1, 12.4

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How was this assessment made