|
1 - Suddenly, Bobby felt very alone in the world. (©
Gary Larson)
|
Rocks form the
basement underneath the vegetation and influence the characteristics of
the ecosystem. A few factors are briefly mentioned here and will be discussed
in more detail in this unit:
Tectonic processes are the main driving force
behind the formation of new mountains. The very high mountain ranges lie
along active tectonic plate margins. Tectonic activity often induces volcanism.
In active volcanic zones, rocks are young and hence, soils are very fertile
due to a strong nutrient flux. The vegetation in these zones can be quite
different from other regions.
Orogeny
through time: Mountains are built up, but also disappear over periods
of time. Hence, mountain belts show a great variety of age. Generally,
young mountains are the highest and steepest. Rocks can "survive" for
billions of years, while some life forms are extinct after what, in geologic
times, are short periods.
Relief defines landscape characteristics such
as the elevation and the gradient of slopes. The conditions for the ecosystem
are quite different on a flat plain compared to a steep slope.
Rocktypes play an important role in erosion.
Some rocks weather much faster
than others and are easily eroded and transported downhill by wind or
water. In addition, some rocktypes are favourable for vegetation, because
they deliver more minerals that provide important nutrients.
Overall, although rocks are abiotic, they clearly influence the character
of the corresponding ecosystem in a complex way. So let's have a closer
look at our rocky basement and its characteristics.
|
back
to top