Contents ix
Part 2
Fundamentals of Environmental Problems
83
5 Values, alterations and degradation of the
natural Landscape
85
5.1 Man’s Historical Influence on the Biosphere 85
5.2 Terrestrial Ecosystems 87
5.2.1 Forest Ecosystem 87
5.2.2 Grassland 89
5.2.3 Tundra 89
5.2.4 Desert 90
5.2.5 The Forest as a Natural Resource 90
5.2.5.1 Deforestation 91
5.2.6 Natural Vegetation in a
Mediterranean Environment 92
5.2.6.1 Forests 92
5.2.6.2 Scrubs 93
5.2.6.3 Alpine Meadows 93
5.2.6.4 Forest Fires and Restoration 93
5.2.7 Soil and Agricultural Activity 94
5.2.7.1 Erosion and Desertification 94
5.2.7.2 Transformation to Laterite 96
5.2.7.3 Salination of Soil 96
5.2.7.4 Agricultural Ecosystems 97
5.2.7.5 Plant Hedges in Agricultural Areas 97
5.3 Aquatic Environment 98
5.3.1 Marine Ecosystems 98
5.3.1.1 Ocean 98
5.3.1.2 Estuary 98
5.3.2 Freshwater Ecosystems 99
5.3.2.1 Water Course 99
5.3.2.2 Lake 99
5.3.2.3 Wetland 99
5.4 Coastal Zones 100
5.4.1 Characteristics of Coastal Ecosystems 100
5.4.1.1 Coastal Wetlands 101
5.4.2 Coast Degradation Factors and Protection Needs 102
5.4.3 The Mediterranean Coastal Environment 103