How can habitat destruction affect the ecosystem


Dr. Dirk S. Schmeller

To person

Born in 1970, has worked as a scientist for the French Center for Science (CNRS) since 2007. Main areas of work: nature conservation research, population biology, evolutionary ecology.

The extinction of the dinosaurs dragged on over a long period of time, in many animal species this process is much faster today. Human beings are largely responsible for this.

The ray is critically endangered. (& copy AP)

The diversity of species and habitats represents an incalculable benefit for mankind. However, an ever-increasing population has an extremely negative impact on biodiversity.

The loss of animal species in particular has reached a level that is unique in geological history. This may surprise some, as many believe that the mass extinction of dinosaurs also followed a dramatic development. What is forgotten, however, is that the extinction of dinosaurs spanned several million years, while species are currently disappearing from the earth in a much shorter time. It is assumed that there are around 50,000 animal and plant species every year, an extinction rate that is 100 to 1,000 times higher than in any other epoch in the geological history of our earth. The main factors for species loss can be divided into four groups:

1. Exploitation of nature, i.e. the direct extermination of a species, for example through hunting and extensive fishing;

2. Habitat loss and degeneration, that is, the destruction or damage to the habitats of animals;

3. Introduction of foreign animal species, for example by hobby pet owners or by deliveries of goods from distant regions;

4. Extinction cascades: This describes the effect in which an extinct species leads to the loss of other species, as it takes on fundamentally important functions for the preservation of the other species, for example as food.

The main reasons for the current loss of animal species are the high population numbers and the increasing human population. The extent of agriculture, industry, tourism and international trade are also responsible.

What does loss of species mean?

The biodiversity of a region can be determined through the loss of animal or plant species, which is a yardstick for biodiversity. Biodiversity describes how many species are observed in a certain area, but not how often the individual individuals of a species occur. Biodiversity plays a key role in ecosystem functions. These functions include, for example, the cleaning of water and the air. The loss of a species might seem bearable at first glance. However, since each species takes on a specific task in a highly complex system, the consequences can only be assessed in very few cases (see "Extinction Cascades"). If this one species is lost, the ecosystem becomes unstable due to the loss of its function - with potentially far-reaching consequences.

Disruptive human factor

The influence of humans on biodiversity dates back 100,000 to 200,000 years and is not only a problem in modern society. As early as the Pleistocene (Ice Age), the early Homo sapiens sapiens caused the extinction of many large bird and mammal species by he colonized all major land areas on earth, hunted animals and changed ecosystems.

A good example is the colonization of the Pacific Islands, which began around 30,000 years ago. Has started. About 50 percent of all bird species there fell victim to it, the causes were hunting, deforestation and the introduction of alien species. Today's biodiversity, which we still find impressive, therefore only shows a fraction of the species that would populate the earth today without the influence of humans.

Over the past 400 years, 1,000 of the most famous species have officially been registered as extinct. This impressive figure is very likely a gross underestimation of the actual number of species lost, since
  • we don't know all animal species
  • we do not observe all habitats with the same intensity,
  • an animal species extinction only becomes official when sufficient evidence has been gathered.
The increasing influence of humans on the survival of animals is also clearly reflected in the so-called mean lifespan of an animal species, which indicates how long a species has existed on average (e). The end of an animal species can be due to extinction or a species formation process from which two or more species emerge. The mean lifespan of fossil species has been estimated at around 5 to 10 million years. This was shortened for birds and mammals in the last century to only about 10,000 years and will only be 200 to 400 years in the future if the human influence remains the same. Applied to humans, this would mean that relatives of this type - i.e. all of us - would die within the first year of life.