Geographical limits in zoogeography.pptx

Limits are the barriers for the distribution of animals to different regions.

1. Geographical limits BY: Prof. Asif Saleem

2. The Concept of Limit: It represents the border of a system which comes into contact with other systems. The limit is an extreme, fix value towards which tends the development of a process. The extreme taken as a limit means the maximum or the minimum values out of a range of data i.e : Meteorological Hydrological

3. Significance: It refers to the discontinuity between different natural or social-economical regions. They represent borders between two areas: rivers, embankments or excavations, extension limits or walls. To conserve the endangered species. This discontinuity implies a sudden modification of certain geographical characteristics: Climate Type of soil Vegetation

4. Other names: Limits of life (Biosphere) Margins Discontinuities Threshold slopes Border Frontier Barrier Interface Buffer zone

5. Categories of Limits: Artificial Limits Natural Limits

6. Natural limits: Coastline: The coastline represents the limit, the contact between the water and the land. The limit of the water and the limit of the land are two terms defining the position of the coastline at low tide, respectively at high tide. The low coastlines which have an extended continental shelf and are affected by the tide have different positions at low tide and at high tide.

7. Natural limits: Watershed: It is a line which separates two neighbor hydrographic basins and unites the highest points. Starting from this line/limit, the slopes and the surface drainage have different directions. There are two kinds of watershed: Superficial watershed Underground watershed Marks the limits of the hydrographic basin Marks the underground hydrographic basin

8. Natural limits: Climatic limit: It separates different climatic units and enables the formation of the next type of limit which is strongly determined by the maintaining of the same parameters. Permanent snow layer: It is that beyond which the snows fallen during a year time do not totally melt, only partially, during the warm season. This limit usually superposes the 0º isotherm, being situated at sea level in the Southern Hemisphere starting from the latitude of 62º and at the equator (latitude of 0-3º) at 4400-5200 m.

9. Natural limits: Thermic limits for life: It represent the minimum and maximum values between which life is possible. Physico -geographical limit: It follows the contact between geographical units, established through the interpretation of the limits of the systems’ natural components. The physical limits for soils, deposits are : the limit of adherence, the limit of aeration, the limit of flowing, the limit of plasticity given by the minimum or maximum content of water of a rock, in which it is plastic.

10. Natural limits: Pedological limit: It is a horizontal approach separates, on the maps, areas with different types of soil. According to a vertical approach, each layer of soil represents a limit for the upper or lower layers. Bio-geographic limit: It refers to bio-geographic units and sub-units, indicating areas with certain bio-geographic characteristics.

11. Natural limits: Upper limit of the forest: It is the line which unites, in mountain regions, the trees which are at least 5 m tall. The height of the trees must be tall enough. This limit appeared as a consequence of the interaction of the geographical factors, which give it a certain feature:

12. Natural limits: Upper limit of the forest: This limit appeared as a consequence of the interaction of the geographical factors, which give it a certain feature: Climatic Geomorphologic Anthropic Given by the 0º medium annual average isotherm or that of +10º of the warmest Appears due to the big slopes Man causes the descent of the upper limit of the forest, sometimes even with hundreds of meters, by clearing it.