User:N raci/Bioindicator

How Bioindicators are Used
In most instances, baseline data for biotic conditions within a pre-determined reference site is collected. Reference sites must be characterized by little to no outside disturbance (e.g. anthropogenic disturbances, land use change, invasive species). The biotic conditions of a specific indicator species are measured within both the reference site and the study region over time. Data collected from tehe study region are compared against similar data collected from the reference site in order to infer the relative environmental health or integrity of the study region (Lewin et al).

An important limitation of bioindicators in general is that they have been reported as inaccurate when applied to geographically and environmentally diverse regions (monteagudo). As a result, researchers who use bioindicators need to consistently ensure that each set of indices is relevant within the environmental conditions they plan to monitor (mazor et al).

The use of a biomonitor is described as biological monitoring. This refers to the measurement of specific properties of an organism to obtain information on the surrounding (typically abiotic) environment.

Macroinvertebrates

Macroinvertebrates are useful and convenient indicators of the ecological health of water bodies and terrestrial ecosystems. They are almost always present, and are easy to sample and identify. This is largely due to the fact that most macro-invertebrates are visible to the naked eye, they typically have a short life-cycle (often the length of a single season) and are generally sedentary (Dickens & Graham). Pre-existing river conditions such as river type and flow will affect macro-invertebrate assemblages and so various methods and indices will be appropriate for specific stream types and within specific eco-regions (Dickens & Graham). The sensitivity of the range of macro-invertebrates found will enable an objective judgement of the ecological condition to be made. Tolerance values are commonly used to assess water pollution and environmental degradation, such as human activities (e.g. selective logging and wildfires) in tropical forests.

Benthic Indicators for Water Quality Testing
Benthic macro-invertebrates are found within the benthic zone of a stream or river. Benthic indicators are often used to measure the biological components of freshwater streams and rivers. In general, if the biological functioning of a stream is considered to be in good standing, then it is assumed that the chemical and physical components of the stream are also in good condition (EPA). Benthic indicators are most frequently used for water quality testing in the United States of America (EPA).

Benthic indicators should not be used to track the origins of stressors in rivers and streams, though they can provide background on the types of sources that are often associated with the observed stressors (Smith et al)