Biological resources

The biosphere is a closed system that consists of biotic and abiotic elements, such as air, water, soil, and organisms. The bioregions differ by their climate, plants, and animals. These are biomes on land and aquatic life zones for aquatic systems.

Forests are the major components of biomes. They provide a variety of resources and services. About 82.3 million km2 worldwide is covered by trees of which about 50% are areas with a canopy cover of more than 25% (Table 2).

Forest resources are basically divided into two main categories: timber products and nontimber products.

Table 2 Forest types and area

Forest types

Area (1000km2)

Evergreen

18338.46

Deciduous

4189.20

Mixed forest

9930.10

Shrublands

23343.16

Savannas

16013.31

Grasslands

10541.72

Main timber forest products are round wood and fuel wood. About 3400 million m of round wood was produced in 2004. The amount of fuel wood totalized 1770 million m3. Most of the environmental space for both round wood and fuel wood originates from developing countries (Figure 1).

Aquatic 'life zones' may be freshwater or saltwater. Freshwater ecosystems provide not only food and water but also services for agricultural development. The total annual world fish production amounts to 132.5 trillion tons; 98% of it comes from catching. Seas and oceans provide around 50% of the total world fish catch. Developing countries contribute 80% of all fish production.

Annually, a worldwide average of food supply for human consumption is about 610 kg per head of the population. Average global daily calories intake is around 12 kJ, an increase of 30% as compared to the average dietary intake in the 1960s. Around 85% of the food energy originates from vegetal products (cereals, vegetable, legumes, etc.) and 15% from animal products (Figure 2).

Biological resources are severely impacted by human activities. 'Over-exploitation' is a major factor that reduces the biodiversity. During the last two decades, the world witnessed the collapse of a number of marine fisheries. 'Pollution' has obviously local impacts on biodiversity in acutely affected areas. Long-term pollution, even at low levels, can affect whole ecosystems, with resultant impacts on biodiversity. 'Climate change' undoubtedly caused biodiversity changes in the past, both locally and globally. Today, the human-induced changes in the climate add new concerns, particularly at fast rates of change.

The environmental space for biological resources is difficult to quantify as the rates of reproduction depend on various elements of the ecosystems. With the disappearance of species and habitats, many ecosystems start to malfunction and therefore our environmental space is shrinking.

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