Habitat for species
Ecosystems provide living spaces for plants and animals; they also maintain a diversity of complex processes that underpin the other ecosystem services.. Some habitats have an exceptionally high number of species which makes them more genetically diverse than others; these are known as ‘biodiversity hotspots'
Well managed and diversified agro-ecosystems can reproduce the diversity and complexity of natural ecosystems creating great species habitat. This kind of systems can give high yields while ensuring long term production.
Semi natural grasslands can be among the habitats with highest biodiversity levels. They host a unique pool of species, specifically adapted to these open habitats. Extensive livestock management is often the only way to maintain these habitats. They are threatened by a double pressure of abandonment (for the less productive ones) and intensification (intensive management practices, conversion to cropland). In certain countries, they are disappearing at an alarming rate. Sustainable grassland management practices need to be promoted to keep these key ecosystems alive.
Marine and freshwater ecosystems are key habitats for millions of aquatic species (e.g. coral reefs are home to 25% of marine fish species and are a significant food source for over a billion people worldwide) exploited commercially or consumed locally. The main pressures on aquatic ecosystems are habitat destruction, pollution as well as overfishing impacts on ecosystem functioning.
Together, tropical, temperate and boreal forests offer very diverse habitats for plants, animals and micro-organisms. Forests provide more than 10% of the GDP in many of the poorest countries. Notwithstanding such a relevant role in world economy, progress towards sustainable forest management is still limited, and there is continuing loss and degradation of forests in many developing countries.
Maintenance of genetic diversity
Genetic diversity (the variety of genes between, and within, species populations) distinguishes different breeds or races from each other, providing the basis for locally well-adapted cultivars and a gene pool for developing commercial crops and livestock.
Conserving and using genetic diversity can provide the options needed for coping with stresses. The capacity of agro-ecosystems to maintain and increase their productivity, and to adapt to changing circumstances, remains vital to the food security of the word's population. Promoting the ecosystem approach contributes to the conservation and sustainable use of genetic resources for food and agriculture. Natural ecosystems hold important genetic resources which are of major significance through their potential to contribute beneficial traits to production systems, such as pest or disease resistance, yield improvement or stability. Thus, genetic diversity provides society with a greater range of options to meet future challenges.
Since the 1900s, some 75 percent of plant genetic diversity has been lost as farmers worldwide have left their multiple local varieties and landraces for genetically uniform, high-yielding varieties. Of the 4 percent of the 250 000 to 300 000 known edible plant species, only 150 to 200 are used by humans. Only three - rice, maize and wheat - contribute nearly 60 percent of calories and proteins obtained by humans from plants. It is key to keep plant diversity to be better prepare to adapt to changing condition and resist to external attacks (extreme weather, diseases,…)
Currently more than 20 percent of the breeds have been identified as being at risk of extinction. During the last five years, 60 breeds were lost – an average of one breed per month. Livestock keepers need a broad gene pool to draw upon if they are to improve the characteristics of their animals under changing conditions. Traditional breeds, suited to local conditions, survive times of drought and distress better than exotic breeds and, therefore, frequently offer poor farmers better protection against hunger.
Aquatic ecosystem biodiversity and sustainable fisheries can support the maintenance of genetic diversity in aquatic systems through appropriate harvest strategies. Aquaculture practices can also affect genetic diversity at the species, community, ecosystem and landscape levels. Aquaculture management should include the documentation of genetic resources used in aquaculture as well the compilation of interactions with natural aquatic genetic resources, in order to maintain genetic diversity.
Forests are among the most important repositories of terrestrial biological diversity.