Freitag, 6. Januar 2012

A short introducion to Ecology (January 6th, 2011)

Hi everybody,

it's time for a new “big” article. This time, I want to give you a general overlook about the basic terms of ecology.

1) Vegetation and Plant Communities

Plants are not growing alone, but in interaction with other plants, animals and their environment. The sum of all plants within a definite area is called a plant community and the sum of all plant communities is called vegetation.

2) Ecological factors

Plant communities are not existing randomly. In fact, the composition of vegetation within an definite area is determined by many different ecological factors, which have all an influence on a plant. The most important factors are the follow:

  • Climate: this factor includes everything to do with the weather. This includes precipitation, temperature, solar radiation and so on.

  • Soil: This factor is very important, because the most plants (except the epiphytes) are rooted in the soil. From the soil, they get nutrients and water. So, the factor “Soil” includes things like source rock, humus, pH, salinity or lime
  • Mechanic: This factor includes all things, which can have a mechanical influence on a plant like Wind, Snow, thunderstorms or sandstorms. It's very important factor, because it determines the shape and growing of a plant.
  • Relief: That means, if a plant grows on the south or north side of a slope or e. g. in a valley
  • biotically factors: The influence of other living things on a plant. This includes symbioses, parasitism, competition with other species or individuals and last but not least animal feeding, which can also be a mechanical factor

3) The Definition of an ecosystem

The first four factors are called the abiotical (lifeless) environment. Their entirety within an areal is called Ecotope. The last factor, the interactions between plants with animals or other plants, is the biotical or living environment and their entirety is called biocoenosis. Together, abiotical and biotical environment are forming an ecosystem.

So, the combination of this factors is forming a ecosystem. For example a rocky, south exposed slope on lime is a very hot and alkaline place, so you will find species, which can grow under these conditions. And in a bog, you will find species, which have no problems with wetness, high precipitation and low content of nutrients.

4) Types of Vegation

In the most cases, the climate is the most important factor. Depending on the prevailing climate, a typical vegetation will be formed. This vegetation is called zonal vegetation. For example, the beech forest is the typical form of vegetation in Germany; created by the warm and temperate climate. But in Canada, the coniferous forests are the zonal vegetation and so on.

Beech forrest are the typical vegetation in Germany

However, through the influence by other factors like relief or micro-climate, it's possible, that a vegetation will be created, which distinguishes from these zonal vegetation. For example, a meadow on a hot, south exposed slope in Germany is not the typical, zonal vegetation, but an exception with its own micro-climate. Such a vegetation is called extrazonal vegetation. Extrazonal vegetation includes often rare and unique ecosystems.

A special form of extrazonal vegetation is azonal vegetation. Unlike the other two types of vegetation, the climate is not most dominant factor for vegetation, but soil or mechanics. A good example for an azonal vegetation is a bog but also ruderal wasteland or heavy metal slopes.

heath is a good example for azonal vegatation,
because it's created by soil and mechanical factors
and not by the climate

5) Summary

I hope, that I was able to give you a first overlook about Ecology and phytosociology. In future Articles, I want to introduce you some plant communities and types of vegetation but for now, the most important thing is, that you've learned the basic definition

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