ECOSYSTEMS
An ecosystem (short for "ecological system") is generally defined as a community of organisms living in a particular environment and the physical elements with which they interact. An ecosystem is an open functional unit that results from the interactions of abiotic (include soil, water, light, inorganic nutrients and weather), biotic (plants, animals, and microorganisms usually categorized as either producers or consumers), and cultural (anthropogenic) components.
An ecosystem can be as small as a field or as large as the ocean, depending on the scale that the researcher is examining. It is used to describe the world’s major different habitat types. Terrestrial ecosystems include: Arctic and alpine ecosystems, dominated by cold areas and lacking trees; forest ecosystems, which can be subdivided into a whole range of types including tropical rainforests, Mediterranean evergreen forests, temperate and boreal forests, and temperate deciduous forests; grasslands and savannahs; and deserts and semi-arid ecosystems. Freshwater ecosystems include lakes, rivers, and marshland. Marine ecosystems comprise an enormous range, from coral reefs, mangroves, sea-grass beds, and other coastal and shallow water ecosystems to open-water ecosystems and the mysterious, little-known systems of the abyssal plains and trenches of the world’s oceans.
Examples of ecosystems include:
- Aquatic ecosystem
- Coral reef
- Desert
- Large marine ecosystem
- Littoral zone
- Marine ecosystem
- Rainforest
- Savanna
- Taiga
- Tundra
- Urban ecosystem
Ecosystems sustain human societies and allow them to prosper. Human societies depend on ecosystems for the natural, cultural, spiritual, recreational and aesthetic resources they provide. We all depend directly or indirectly on the products and services provided by ecosystems—for example, crops, livestock, fish, wood, clean water, oxygen, and wildlife.
An example is coral reefs, which are vital for both preventing erosion and providing food and livelihood for millions of coastal people over 100 countries via the harvestable marine resources that they generate and through tourists attracted by their beauty, biodiversity and the white sand beaches that they support and protect. It is estimated that at least half a billion people around the world are thought to be partially or wholly reliant on coral reef resources for their livelihoods which include fishing, gleaning, mariculture, the marine aquarium trade, and a wide range of employment and commercial opportunities associated with tourism.
However, 20% of the world’s coral reefs have been effectively destroyed and show no immediate prospects of recovery, while 24% of the world’s reefs are under imminent risk of collapse through human pressures, as a result of global warming.
Climate is an integral part of ecosystems and organisms have adapted to their regional climate over time. Climate change is a factor that has the potential to alter ecosystems and the many resources and services they provide to each other and to society.
Climate change could benefit certain plant or insect species by increasing their ranges. The resulting impacts on ecosystems and humans, however, could be positive or negative depending on whether these species were invasive (e.g., weeds or mosquitoes) or if they were valuable to humans (e.g., food crops or pollinating insects).
The risk of extinction could increase for many species, especially those that are already endangered or at risk due to isolation by geography or human development, low population numbers, or a narrow temperature tolerance range. Human activities can also threaten biodiversity by altering habitats and introducing non-native species. Climate change disruptions (caused by human activities) are causing large losses to natural habitats and wildlife in developing countries.
According to the Fourth Assessment of the IPCC, there is a high confidence that the resilience of many ecosystems (their ability to adapt naturally) will be exceeded by an unprecedented combination of change in climate, associated disturbances including flooding, drought, wildfire, insects and ocean acidification in the course of the 21st century.
Additional Resources:
Ecosystems and Climate Change Research Priorities for the U.S. Climate Change Science Program -Recommendations from the Scientific Community
Environmental Literacy Council
Reef Restoration: Concepts and Guidelines
More Resources on Ecosystems
Whales: Even Giants Aren't Safe
Beetle-Battle: A Threat to the World's Forests Aggravated by Climate Change
Film Sparks Discussion of Fate of Penguins in the Face of Global Warming
Climate Change Threatens Reindeer and Arctic People
Will Climate Change Wipe Out the Polar Bear?
Where Will All the Fish Have Gone?
Videos:
Biodiversity and Climate Change
