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How to Assess the Health of the Ecosystem

An ecosystem refers to the living and nonliving components of an integrated ecological system. For example, a temperate deciduous-forest ecosystem involves not only the broad-leaved trees that define it structurally but also the underlying soils and bedrock, the birds that migrate through it, pollinating butterflies, stream-living salamanders and decomposing fungi. It can be difficult to define the health of an ecosystem, which changes naturally based on climatic, geologic and other factors, but by human standards a healthy ecosystem may be considered a highly varied, complex and sustainably functioning one.

Instructions

- 1
  Conduct species counts. There are numerous methods for estimating the total number of plant and animal types in a given ecosystem, including randomly selecting numerous small plots within which to identify each species. Some ecosystems are naturally deficient in species: The floral component of a desert, may be far less rich than a tropical forest. But often a species-poor environment indicates one degraded in some form, as by overhunting or human development. The presence of exotic, invasive species is another sign, at least, of a human-impacted landscape.
- 2
  Identify the presence and status of apex predators. These needn't always be big, flashy animals such as crocodiles or tigers. In a particular ecosystem the top predator may be a fox, a lizard, a starfish. These hunters at the summit of the food chain are important indicators of an ecosystem's health, as they tend to suffer from problems in lower rungs. The loss of top predators from an ecosystem can result in a flourishing of lower-level hunters they once kept in check, which, in turn, may reduce populations of other organisms.
- 3
  Survey the ecosystem's habitat diversity. Large, homogeneous swaths of habitat such as a tree plantation or an urban metropolis tend to reduce the number of available ecological niches. Most natural ecosystems exhibit high habitat diversity: Windstorms and wildfires produce clearings in a woodland, for example, while river floodplains offer a mosaic of waterlogged, seasonally inundated and dry landscapes. Human influence often aims to reduce variability in an ecosystem -- damming or channelizing rivers, for example, to moderate their seasonality -- which, in turn, can seriously degrade it.
- 4
  Measure for pollution. Ecosystems can reveal contamination from industrial or agricultural emissions and chemicals in a variety of ways. Lichens, which are symbiotic associations of a fungus and algae, are frequently used as gauges of air pollution, to which they are extremely sensitive. Test soil and water for their quality.

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