2.3. Іmpact of human activity

Human activities significantly affect the species composition of biomes. Unrestricted hunting and gathering herbs can not only reduce the number of game animals and plants, but also bring them to the brink of extinction. Breeding crops causing mass outbreaks of pests. The use of chemical means of pest control reduces not only the number of pests and other insects, including pests and enemies. As a result, the group of populations of different species loses its identity and stability. Each type of organisms in biogeocoenose (no matter how insignificant it was not) has multiple relationships with a large number of other species. The disappearance of some animal species, especially plants may cause unintended consequences and destruction of all biogeocoenose.

Power Protection biogeocoenose much higher than biomes exposed to human activities. For example, one could argue that a hectare of forest emit oxygen is four times more than the same area of ​​the park. Attribute this to the fact that the species composition of biocenosis urban parks is much poorer than the forest. Diversity and stability of species composition of vegetation in forest ecosystems is closely associated not only with higher plants that grow there, but also fungi and animals, from the inhabitants of the soil - round and annelid worms and ssavtsivzemleryyiv and ending insects and birds that live on treetops.

From these examples it is clear how important and necessary to study the dynamics of processes in Biogeocenoses to control populations of useful and harmful to humans plants and animals. Invaluable assistance in this computer. Due to the high speed of work and the ability to accumulate and store huge amounts of information computers make it possible to simulate possible changes in ecosystems that occur in response to natural environmental change and human activity. Simulation in general terms - a method of knowledge or study of a process, phenomenon or body by playing his own material or its properties in the form of material or theoretical model. The latter category includes and models.

Conclusions

1. Progressive irreversible changes in the composition and structure biogeocoenose that are caused by external or internal factors, called succession. A classic example of succession - overgrown lake and turning it into a swamp.

2. Succession are slow (last millennium and tens of thousands of years), medium (century) and rapid (decades). They can come from internal causes (eg, the formation of new species) or by external factors (eg, salinity, flooding, occupancy types of "foreign" fauna and flora), a natural (eg, as a result of raising or lowering of the land) or anthropogenic (deforestation, plowing steppe) origin, be progressive (that is accompanied by an increase in productivity and species richness, as in the case of newly overgrown river sand spits) or, conversely, regressing. V.M.Sukachov identified four types of succession: 1) synhenetychni; 2) endoekohenetychni; 3) ekzohenetychni; 4) holohenetychni.

3. Primary succession - is overgrown space previously occupied by vegetation: bare rocks or frozen lava. Secondary succession is formed as a result of human intervention in natural processes.

4. Succession changes usually connect to the fact that the existing ecosystem (community) creates a hostile environment for her body that fills (ґruntovtomu, incomplete cycling of matter, self-poisoning or decomposition products selection, etc.). Such phenomena are real, but do not explain all cases of changes in ecosystems. In addition to natural factors cause the dynamics of ecosystems often serves all people. To the actual time they destroyed most indigenous (klimaksnyh) ecosystems. For example, steppes almost entirely under cultivation (preserved only in protected areas). Preferred areas of forests are transient (temporary) ecosystems from deciduous trees (birch, aspen, willow rarely, alder and other). These forests are commonly referred to as derivative or secondary.