Contrary to the countries of northern coast, the forest formations on Southern and East coast of the Mediterranean are in regression. With the combined action of the ax, fire and pasture, these ecosystems are subjecte...Contrary to the countries of northern coast, the forest formations on Southern and East coast of the Mediterranean are in regression. With the combined action of the ax, fire and pasture, these ecosystems are subjected to a pressure of permanent degradation. Indeed, the degradation of the forest ecosystems represents one of the most important causes of reduction and erosion of the biodiversity in the world. The massif of Aur6s is located in the North-East of Algeria. The analysis of the spatiotemporal dynamics of this vulnerable vegetation is not approached yet. This study proposes a focus on the analysis of the dynamics of this vegetation and to study the factors of its degradation. For that, a methodological approach of diachronic follow-up between two dates was adopted by using any kind of old information sources （archives, aerial photographs, topographic maps） and recent （Images satellite of American Landsat and data of land）. The results reveal a degradation of vegetable cover thus expressing a very thorough reduction of the formations forest replaced by herbaceous formations very sensitive and threatened by the overgrazing.展开更多
The vegetation cover in highlands is rather peculiar and complicated in its structure. The experience gained in mapping of alpine vegetation shows that the schematic small-scale maps reflect only the very common featu...The vegetation cover in highlands is rather peculiar and complicated in its structure. The experience gained in mapping of alpine vegetation shows that the schematic small-scale maps reflect only the very common features. In boreal forest mountains of Siberia there are four systems of alpine vegetation including alpine-meadow, goltsy-tundra, island near the Pacific Ocean and tundra-steppe ones. Every system is represented by several geographical variants, characterized by regional phytogeographical peculiar features of this vegetation. The geographical variant includes a number of altitudinal belts （zones）, each of them has its floristic peculiarities and complexes of plant formations （for instance, Altai-Sayan variant composes of subalpine-alpine-subnival-nival belts）. Such geographical variants of alpine vegetation may be indicated as chorological units on a new Circum-Boreal Vegetation Map. Under discussion is the possible use of ecological-geographical approach to reflect the alpine vegetation as chorological （structural） units of the vegetation cover being exemplified by high mountains of the Siberia. This map may be more informative in terms of regional peculiarities in alpine vegetation within the boreal biome.展开更多
文摘Contrary to the countries of northern coast, the forest formations on Southern and East coast of the Mediterranean are in regression. With the combined action of the ax, fire and pasture, these ecosystems are subjected to a pressure of permanent degradation. Indeed, the degradation of the forest ecosystems represents one of the most important causes of reduction and erosion of the biodiversity in the world. The massif of Aur6s is located in the North-East of Algeria. The analysis of the spatiotemporal dynamics of this vulnerable vegetation is not approached yet. This study proposes a focus on the analysis of the dynamics of this vegetation and to study the factors of its degradation. For that, a methodological approach of diachronic follow-up between two dates was adopted by using any kind of old information sources （archives, aerial photographs, topographic maps） and recent （Images satellite of American Landsat and data of land）. The results reveal a degradation of vegetable cover thus expressing a very thorough reduction of the formations forest replaced by herbaceous formations very sensitive and threatened by the overgrazing.
文摘The vegetation cover in highlands is rather peculiar and complicated in its structure. The experience gained in mapping of alpine vegetation shows that the schematic small-scale maps reflect only the very common features. In boreal forest mountains of Siberia there are four systems of alpine vegetation including alpine-meadow, goltsy-tundra, island near the Pacific Ocean and tundra-steppe ones. Every system is represented by several geographical variants, characterized by regional phytogeographical peculiar features of this vegetation. The geographical variant includes a number of altitudinal belts （zones）, each of them has its floristic peculiarities and complexes of plant formations （for instance, Altai-Sayan variant composes of subalpine-alpine-subnival-nival belts）. Such geographical variants of alpine vegetation may be indicated as chorological units on a new Circum-Boreal Vegetation Map. Under discussion is the possible use of ecological-geographical approach to reflect the alpine vegetation as chorological （structural） units of the vegetation cover being exemplified by high mountains of the Siberia. This map may be more informative in terms of regional peculiarities in alpine vegetation within the boreal biome.
