Forest Meadow Steppe ecosystems

North American Forest-Meadow Steppe ecosystems... 

These ecosystems fall entirely within the continent. It is a crescent opening to the south, with the northern fringe at 50-58° N the southern tip of the long western arm of the crescent is at 38° N. The other boundary of the Forest-Meadow Steppe ecosystems coincides with the boundaries of the Boreal Taiga and Sub-Boreal Forest ecosystems. The inner edge of the crescent borders the closed Steppe ecosystems of the continent. 

Grasses, small shrubs and shrubs, whose number of xerophytic and ephemeral forms increases with aridity, are the chief representatives of Arid ecosystems. At the north and south peripheries of the arid zone, herbaceous ecosystems are predominant. In regions with a well balanced atmospheric humidity prior to human activities, of wide occurrence were Meadow Steppe ecosystems intermixed with Broad-leaved Forests. With an increase in climate continental properties, the Meadow Steppe ecosystems of Eurasia grade into Forb-Fescue-Stipa and Fescue-Stipa Steppe ecosystems. In turn, the natural vegetation has been destroyed by humans and replaced by pastures and... 

This is a zone of poorly drained alluvial-lacustrine plains, where features of continental salt accumulation are clearly expressed. Broad-Leafed Aspen Forest and Meadow Steppe ecosystems on Phaeozems and Chernozems with association with meadow-bog soils and Solods are characteristic of this region. 

The water deficiency in Arid ecosystems is the main restricting factor for biogeochem-ical exposure processes. We know that many links of the biogeochemical food web are connected in Steppe soils with invertebrates. Their population varies very much in Steppe ecosystems depending on the moisture conditions (Table 6). For instance, the wet biomass of soil invertebrates in the Meadow Steppe and Forest Steppe ecosystems exceeds that for the Extra-Dry Rocky Desert ecosystems by 150-300 times. 

In some mountain districts or elevated areas, the distribution of the low-Se ecosystems is also associated with vertical distribution of such mountain landscapes, as mountain forest, forest steppe, and meadow steppes. 

This sub-region of the biosphere occupies the northern part of the Chuvash administrative region with predominance of Broad-Leafed Forest and Meadow Steppe natural ecosystems and agroecosystems. The prevalent soils are Podsoluvisols. The scheme of the biogeochemical food web is shown in Figure 4. 

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