What Are the Indicators of Human Impact on the Environment?

Written and verified by the biologist Miguel Mata Gallego

Last update: 21 December, 2022

The indicators of human impact on the environment are used to determine to what extent an ecosystem is affected by human action. Generally, these indicators are based on quantifiable parameters present in nature, which give us clues about its state in terms of pollution and sustainability.

What are these indicators? How do we measure them? From the physico-chemical characteristics of the environment to the presence and proliferation of various species, these parameters can alert us when an ecosystem is deteriorating before it’s too late.

The need to protect nature

The enormous environmental impact that we, as humans, have on ecosystems due to our actions, is undeniable. Construction, public infrastructure and resource extraction are just a few examples.

For all these reasons, environmental laws require a series of measures to protect the environment from human activities. Despite the fact that we are the dominant species on the planet, we can’t do just anything we feel like.

For years, the greater ecological awareness of the population has triggered greater respect for the environment in the laws of many countries. Therefore, a series of strict protocols were introduced for building or carrying out activities in the ecosystems.

Objectives of the environmental impact assessment

The governments of all countries and various administrations use environmental impact assessments (EIAs) in order to ascertain to what extent we’re altering the natural balance. In short, the objectives of an EIA are the following:

1. Report on the state of the environment affected by human action.
2. Scientifically predict the future of the ecosystems as a consequence of human activities.
3. Serve as a basis for decisions that may affect the environment in question.

Types of indicators and examples

The International Association for Impact Assessment (IAIA) defines an environmental impact assessment as “the process of identifying, predicting, evaluating and mitigating the biophysical, social, and other relevant effects of development proposals prior to major decisions being taken and commitments made.”

There are many ways to classify the indicators of human impact on the environment. To simplify this whole issue, we’ll look at the types of indicators by their specific nature:

• Physico-chemical: they’re based on physical or chemical parameters of the environment. The most often used are the pH, the concentration of nitrates, and the concentration of organic carbon.
• Bioindicators: the presence of these organisms informs about the state of the environment. There are many examples of bioindicators, which we’ll discuss shortly.
• Geomorphological: they evaluate the state of the soil and erosion, two key factors in nature’s health.

1. Physico-chemical indicators

As their name indicates, these indicators are based on the measurement of physical or chemical variables of the environment to be studied. As everything on earth is basically physics and chemistry, they can measure all kinds of impacts.

There are many physico-chemical factors that inform us of the state of nature. In aquatic environments, water quality indicators, turbidity and dissolved oxygen are especially important. In terrestrial environments, the pH of the soil and the concentrations of various molecules —nitrates and heavy metals, for example— are particularly important.

2. Bioindicators

One of the most important elements in determining the health of the ecosystem is the presence of bioindicator species. As its name indicates, the presence of these beings inform us of the proper functioning of an ecosystem.

These species have the particularity of being very sensitive to environmental disturbances. Some of these beings are plants —like lichens— but there are many morphologically complex animals that are also bioindicators.

In aquatic ecosystems, some invertebrate organisms, such as insect larvae, stand out as indicators of good water quality. In vertebrates, the otter is the bioindicator par excellence of healthy freshwater systems, as it quickly abandons them when conditions worsen.

3. Other indicators of human impact on the environment

Apart from those mentioned above, there’s a multitude of indicators taking into account many other factors that can affect the environment.

Here we can include indicators that have to do with the landscape: erosion and air pollution, for example. Likewise, biodiversity is an important factor in determining the environmental health of an area. Thus, biodiversity indicators help us know how many species there are in an area.

In conclusion, the indicators of human impact on the environment help us understand the state of a particular natural area. Consequently, we can make environmentally sound decisions about that region.