The role of biodiversity

Biodiversity plays a crucial role in food security, nutrition, and livelihood and in the provision of ecosystem services. Biological diversity encompasses all species of plants, animals, and microorganisms and the ecosystems and ecological processes of which they are parts. In a common parlance, biodiversity may be defined as species richness (plants, animals, and microorganism) in a given habitat. It may be land, in freshwater or sea or as parasites or symbiosis. Biodiversity encompasses diversity of life on all levels: species diversity, genetic diversity as well as habitat and ecosystem diversity. A rich biological diversity is essential for preserving natural processes contributing to man’s ability to live, such as natural pest regulation, pollination of fruit biomass by insects, and the decomposition of organic matter. Agricultural policies are increasingly promoting ecological-oriented farming method that preserves biodiversity and conserves natural resources. In historic times, a more diverse landscape unfolded through farming from what was once an undifferentiated landscape dominated by forests. Today as well, regionally adapted and extensive forms of cultivation are essential prerequisites for a diverse species rich landscape.

A major tenet of sustainable agriculture is to mimic diversity that is commonly found in natural ecosystems but may be lost in agricultural terrain. Biodiversity refers to the variety of plants, animals and microorganisms above and below the soil that interact within an ecosystem. Plants and animals are consistently integrated into diverse landscapes. As a result, these systems are typically more stable, withstanding disturbances and recovering better than less diverse systems. Organic cropping systems promote a diverse, balanced ecosystem as a practice to enrich the soil and prevent weed, insect pest and disease problems. Crop diversity, crop rotations, intercropping, cover cropping, conservation tillage and incorporation of organic matter are all important components of farm biodiversity.

Benefits of encouraging diversity:

• Improves soil quality

Diverse crop rotations improve soil, increase farm biodiversity and boost crop yields. High-quality soils encourage dense populations of microorganisms, enhance natural biological control of pathogens, slow turnover of nutrients, encourage communities of beneficial insects and improve soil aeration and drainage. Crop rotations, management of crop residues, conservation tillage, incorporation of animal manures and the use of nitrogen-fixing crops can increase soil health and productivity.

• Enhances insect, weed and disease control

Diverse plantings often decrease insect pest populations. Specialized herbivores are more likely to find and remain on pure crop stands where food sources are concentrated. Fields containing a variety of crops are often rich in above- and below-ground beneficial organisms that naturally control pests, inhibit growth of disease organisms, boost a crop’s natural defenses and suppress some weeds. The use of crop diversity, crop rotations, scattered fields, adjacent uncultivated land and a perennial crop component are methods that can be used to reduce pest pressure.

• Encourages beneficial organisms

Planting crops that support natural enemies or directly inhibit insect attack helps to stabilize pest communities. Spatially and temporally diverse plantings ensure that natural enemy populations are provided continuous availability of resources. Beneficial insects, mites and nematodes can also be provided food and habitat by including areas of adjoining, uncultivated land and wild vegetation. Further, using ground covers and surface residues can enhance the abundance and efficiency of predators and parasitoids.

• Spreads economic risk

Increasing farm diversity offers the opportunity to increase profits while decreasing production costs. Adding new crops that fit the climate, geography and management requirements can increase profits by providing the opportunity to exploit niche markets, expand marketing opportunities and offset commodity price swings.