What is biodiversity?
Biodiversity is simply the variety of all living things in an area, including species, genes and ecosystems.
The biodiversity of NSW is made up of all the different ecosystems that occur in NSW; the species that live within these, including animals, plants, fungi and micro-organisms; and the variation within each species’ gene pool.
You’re interacting with biodiversity every time you walk out into a national park or your back garden, eat a meal, buy a piece of wooden furniture or even take a breath.
How is it under threat?
Unique and vulnerable species
From the beginning of multicellular life on Earth, an estimated 30 billion species have occurred, but only about 0.01% of these remain today. It is estimated that up to 150 species become extinct every day. Australia has many endemic species: that is, species which are naturally found nowhere else on earth. These species are particularly vulnerable to extinction. Australia is also home to many threatened and endangered species.
Habitat loss is one of the biggest threats to biodiversity. Humans are the leading cause of habitat loss, and population growth plays a major role as more and more habitat is cleared for urbanisation, property development, agriculture and industrial expansion. These land uses also create waste and pollution. Habitat can also be lost through environmental changes caused by natural and unnatural factors like drought, fire or changes to water systems.
Invasive species are another significant threat to biodiversity. In NSW there are 1,665 naturalised plant species, and more than 340 of them have the potential to threaten biodiversity. Naturalised plant species are plants that are not native to Australia but have been introduced from other countries and spread into the wild. Some of these naturalised species can eventually become invasive species if they become abundant enough to outcompete native ones.
In Australia, invasive animal species such as feral bees, foxes, plague minnows, and rabbits significantly affect biodiversity. These pest plant and animal species spread diseases, increase competition, and disrupt food webs.
Climate change is a major threat to the biodiversity of NSW. It is predicted that it will change patterns of temperature and rainfall and alter the severity and frequency of fires, droughts and floods.
This can have effects on whole ecosystems, such as causing fragile wetlands to dry out. It can also affect individual species that depend on particular temperature ranges or moisture levels. For example, the endangered Mountain Pygmy-possum relies on snow cover to insulate it as it hibernates over winter. If climate change reduces snow cover, the possum is at an increased risk of freezing, starving or being found by predators.
Climate change is also likely to compound existing threats to biodiversity, by causing more extreme weather events, disrupting fire and water regimes, and allowing some invasive species to expand their ranges and compete for habitat and resources in new areas.
Why is it important?
Australia’s unique species
Part of Australia’s international appeal is our unique plant and animal species. Australia is home to about 7% of all species found on earth, which is more than twice the number found in Europe and North America combined. We also have more endemic and widespread species of reptiles than any other country in the world and more vascular plants than all of Europe. The Sydney region alone contains more plant species than the whole of Great Britain.
However, Australia’s biodiversity has declined severely in comparison to other countries. Currently Australia has 58 threatened species of birds; more threatened birds than 95% of the countries on earth. Over half of all mammal extinctions on the planet in the last 200 years have occurred in Australia. The number of animals on the Australian threatened species list has increased by 37% from 2000 – 2009, whilst the number of threatened plant species has increased by 17% over the same period.
In NSW alone, more than 50% of mammal species and about a third of all native birds and amphibians are listed as threatened, along with 14% of plant species. Reversing the dramatic decline in biodiversity is a huge and urgent issue facing our society.
Maintaining a healthy biodiversity is very important in making Australia’s ecosystems resilient to the many threats they face. Compared to areas with low biodiversity, diverse environments are genetically healthier, which prevents inbreeding and population declines. The greater the diversity of species and genetic material within an ecosystem, the better it can withstand and recover from damage. Conversely, because species and ecosystems are closely interconnected through nutrient cycles, food webs and across vast landscapes, even small interruptions can have a dramatic ripple effect.
Benefits to humans
Healthy, diverse ecosystems provide many benefits to society:
- Their nutrient storage cycles and recycling processes support local flora and fauna, purify water sources, and contribute to climate stability.
- As human population growth continues, food security will become an increasingly important issue. Less than 20 plant species currently feed the majority of the world’s population. Protecting the diversity of plant species on earth is important to ensure that our food sources can be supplemented with other species if diseases wipe out current crop species.
- About 40-50% of pharmaceuticals originate from natural resources, and the earth’s biodiversity is a vital resource for discovering more medicinal uses for natural products.
- At least 40% of the world’s economy is based on biological resources.
- The cost to benefit ratio of investments in protected areas is estimated to be between 1 to 25 and 1 to 100.
- Australia’s biodiversity is a large part of our culture. Industries such as tourism and recreation rely heavily on our unique landscape and iconic species.
Want to know more?
Biodiversity resources online
- The UN Convention on Biological Diversity
- Australian Museum webpage, What is biodiversity?
- Australian Museum webpage, What’s happening to Australia’s biodiversity?
- Australian Government publication: Biodiversity and its value
- Article on The Conversation (academic blog): What is biodiversity and why does it matter?
- World Wide Views on Biodiversity project
- “Issues in Ecology” scientific papers: Biodiversity and Ecosystem Functioning: Maintaining Natural Life Support Processes; and Ecosystem Services: Benefits Supplied to Human Societies by Natural Ecosystems
- Sustaining Life: How Human Health Depends on Biodiversity. Editors: Eric Chivian and Aaron Bernstein. Published 2008.
- World Atlas of Biodiversity: Earth’s Living Resources in the 21st Century. Authors: Brian Groombridge, Martin D. Jenkins. Published 2002.
- Biodiversity Hotspots: Distribution and Protection of Conservation Priority Areas. Editors: Frank E. Zachos, Jan Christian Habel. Published 2011.
- Australia’s Biodiversity and Climate Change. Lead Author: Will Steffen. Published 2009.