How do macroinvertebrates indicate water quality?

How do macroinvertebrates indicate water quality?

Aquatic macroinvertebrates are good indicators of stream quality because: They are affected by the physical, chemical, and biological conditions of the stream. They can’t escape pollution and show the effects of short- and long term pollution events. They may show the cumulative impacts of pollution.

What macroinvertebrates are referred to as indicator species?

If you are studying water quality, macroinvertebrates are an important indicator of the health of an aquatic ecosystem. We call oxygen-loving species like mayflies and stoneflies “indicator species” because they provide important clues about the water they are living in.

What are macroinvertebrates Why are they important?

Macroinvertebrates serve several important functions within the aquatic environment: They provide a valuable “cleaning” service by scavenging dead or decaying bacteria, plants, and animals, which helps recycle nutrients back into the system. They are an important food for fish, birds, amphibians and reptiles.

What does it mean for macroinvertebrates to be Bioindicators?

Aquatic macroinvertebrates are animals that do not have a backbone, can be seen with the naked eye and spend at least part of their lives in water. Aquatic macroinvertebrates are preferred over other freshwater organisms as bioindicators because they possess many of the hallmark traits of good bioindicators.

Why are EPT taxa useful as bioindicators?

The EPT index is the proportion of the benthic invertebrate community belonging to these taxa. Chironomids are generally considered to be pollution-tolerant; therefore, determining the ratio of chironomids to EPT species can be a good indicator of pollution levels.

What does it mean if a macroinvertebrate is sensitive?

Macroinvertebrate sensitivity index The macroinvertebrate species presence or absence in a sample will give an indication of the health of the river or wetland, generally, a greater diversity with numerous representatives of sensitive species indicates better health.

What determines macroinvertebrate abundance and diversity?

Vegetation cover, water depth, and conductivity were the most important variables determining the presence or absence of macroinvertebrate taxa. The sensitivity analysis, based on the regression tree models, also showed that vegetation cover and conductivity were affecting the abundance of some macroinvertebrate taxa.

What does the EPT index show?

The EPT Richness Index estimates water quality by the relative abundance of three major orders of stream insects that have low tolerance to water pollution. EPT can be expressed as a percentage of the sensitive orders (E= Ephemeroptera, P= Plecoptera, T= Tricoptera) to the total taxa found.

How do you interpret EPT index?

The EPT Index is the total number of distinct taxa within the groups, Trichoptera, Ephemeroptera, and Plecoptera. For example, if five species of Ephemeroptera (mayflies), five Plecoptera (stoneflies), and two Trichoptera (caddisflies) are found at a site, the total number of EPT taxa and Index would equal 12.

What do macroinvertebrates need to survive?

For example, they require an appropriate range of such abiotic factors as pH, dissolved oxygen, and temperature. Some aquatic macroinvertebrate species can tolerate wider fluctuations of pH, dissolved oxygen, and temperature, and can survive in a range of stream and water quality conditions.

What does it mean for a macroinvertebrate to be pollution tolerant?

Those that can survive in polluted water are said to be pollution tolerant. If the water contains pollution sensitive macroinvertebrates, then it is a good indication that the water is clean enough and of high enough quality for these sensitive individuals to survive.

What does EPT richness measure?

Which is an indicator of a healthy macroinvertebrate?

Generally, waterbodies in healthy biological condition support a wide variety and high number of macroinvertebrate taxa, including many that are intolerant of pollution. Samples yielding only pollution–tolerant species or very little diversity or abundance may indicate a less healthy waterbody.

What happens to macroinvertebrates when they die?

When these plants die, decomposition by microorganisms can use up dissolved oxygen in the water. pH- Dumping of industrial pollutants and runoff from mining activities can lower pH (making water more acidic). Low pH can weaken shells and exoskeletons and kill macroinvertebrates.

What kind of work is done on macroinvertebrate?

Numerous detailed scholarly works dedicated to macroinvertebrate collection and analysis also exist, such as collecting and sampling ( Merritt et al. 1996 ), sampling design ( Resh 1979, Norris et al. 1992 ), and statistical analyses and study design ( Elliott 1977, Norris 1995, Hawkins et al. 2000 ).

When is a macroinvertebrate absent from a stream?

Only the most extreme and harsh conditions or where stream waters flow for only hours before drying are the members of this component of stream systems absent.