Diversity of species
What is species diversity?
The word biodiversity is primarily associated with the diversity of living organisms, meaning the abundance of different animal, plant and microbial species.
How do human activities affect species diversity?
Over-exploitation, pollution and habitat conversion are the main threats to species diversity. They cause a gradual loss of species on local, regional and global levels. Additionally, the introduction of species into new ecosystems destroys natural balance.
The evergrowing tendencies of tourism, transport, profit-oriented food production (e.g. single-crop agriculture, selective (?) aquaculture), and industry enforce these human activities.
Global warming and population growth continually increase these pressures on biodiversity.
These issues will be discussed in more detail in the chapter "Urgencies".
What is the significance of species diversity?
The composition of species in a given ecosystem is the result of longlasting evolution. Each species has adapted to its own niche, which is characterized by certain features (e.g. temperature range, availability of food or light) enabling the species to reproduce and thus maintain its population.
Living in an ecosystem, the species interacts with its environment (e.g. mussels take particles out of the water, reed forms root systems) and thus performs certain functions (increasing the light availability for plant growth, preventing sediment erosion). In a natural state, these interactions and consequently the system is in balance.
The loss of one species affects many other species and causes imbalance. As a result, several functions within and of the system are not carried out any more. Any species that will take over the lost specie's niche will most certainly not replace all of the functions it used to perform.
When species get extinct, their services for the global biosphere are lost for ever. It is impossible to replace it.
Why prevent the loss of species diversity?
It should have become clear that the loss of species is accompanied by a loss of functionality, some of which directly affect human life in a severe way: reduction of commercially used fish stocks, and erosion of soil and sediment are only two examples.
To date, scientists have counted and described some 1.7 million living organisms, but the planet's total number is estimated at between 5 and 30 million, with some scientists putting forward figures of 80 million or more.
Just as not even the whole inventory of the earths' species has been made, very little is known about the role and the potential that each of them has for increasing the quality of human life. It is therefore necessary to prevent the loss of species' diversity in order to avoid the loss of opportunities to gain from it.