Biodiversity, or the variety of life on Earth, is essential for the functioning and resilience of ecosystems, the provision of ecosystem services, and the well-being of humans. Agricultural landscapes, which cover over 37% of the world's land surface, play a crucial role in conserving and enhancing biodiversity, as they can provide habitats, resources, and connectivity for many species of plants, animals, and microorganisms. However, many agricultural practices, such as monoculture, mechanization, and chemical inputs, can also have negative impacts on biodiversity, by simplifying and homogenizing landscapes, reducing habitat quality and quantity, and disrupting ecological processes and interactions.
Biodiversity enhancement is a key strategy for sustainable agriculture that aims to support and increase the diversity of life within and around agricultural systems, while also maintaining or improving agricultural productivity, profitability, and sustainability. Biodiversity enhancement can provide multiple benefits for farmers and society, such as improving soil health and fertility, enhancing pest and disease control, increasing crop pollination and yield, and providing cultural and recreational values. Biodiversity enhancement can also contribute to various global goals and targets, such as the United Nations' Sustainable Development Goals, the Convention on Biological Diversity's Aichi Targets, and the Paris Agreement on climate change.
Principles of Biodiversity Enhancement
Biodiversity enhancement in agriculture is based on several key principles that guide the design, management, and monitoring of agricultural systems for biodiversity outcomes.
Biodiversity enhancement principles include:
- Landscape heterogeneity: Biodiversity enhancement requires the maintenance or creation of diverse and heterogeneous landscapes that provide a variety of habitats, resources, and niches for different species. This can be achieved by integrating different land uses, such as crops, pastures, forests, and wetlands, and by creating a mosaic of patches with different sizes, shapes, and arrangements. Landscape heterogeneity can also be enhanced by preserving or restoring natural and semi-natural habitats, such as hedgerows, field margins, riparian buffers, and woodlands, which can serve as refuges, corridors, and stepping stones for biodiversity.
- Species diversity: Biodiversity enhancement requires the conservation and promotion of a wide range of species, including crops, livestock, pollinators, natural enemies, soil organisms, and wild species. This can be achieved by using diverse crop rotations, intercropping, varietal mixtures, and agroforestry systems, and by protecting and managing natural and semi-natural habitats that support high levels of species diversity. Species diversity can also be enhanced by using local and traditional crop varieties and breeds, which are often better adapted to local environmental conditions and have unique genetic and cultural values.
- Functional diversity: Biodiversity enhancement requires the maintenance and promotion of diverse functional groups and traits that provide important ecosystem services and functions, such as nutrient cycling, pest and disease regulation, pollination, and soil formation. This can be achieved by using cover crops, green manures, and other soil-building practices that support diverse communities of soil organisms, and by providing floral and nesting resources for pollinators and natural enemies. Functional diversity can also be enhanced by using agroecological practices, such as integrated pest management, conservation biological control, and ecological intensification, which leverage the natural processes and interactions of biodiversity to support agricultural production.
- Connectivity: Biodiversity enhancement requires the maintenance and restoration of ecological connectivity, or the ability of species to move and interact across landscapes and habitats. This can be achieved by creating and protecting corridors, buffers, and stepping stones that facilitate the dispersal and migration of species, and by reducing the fragmentation and isolation of habitats caused by human activities, such as urbanization, deforestation, and agricultural intensification. Connectivity can also be enhanced by using landscape-level planning and management approaches, such as agroecological zoning, land-use planning, and eco-regional conservation, which consider the spatial and temporal dynamics of biodiversity at different scales.
- Adaptive management: Biodiversity enhancement requires the use of adaptive management, or the iterative process of planning, implementing, monitoring, and adjusting management practices based on feedback and learning from the system. This can be achieved by using participatory and collaborative approaches that engage farmers, researchers, and other stakeholders in the design, implementation, and evaluation of biodiversity enhancement strategies, and by using monitoring and assessment tools, such as biodiversity indicators, ecological models, and remote sensing, to track the outcomes and impacts of management practices on biodiversity and ecosystem services. Adaptive management can also be enhanced by using social and institutional innovations, such as farmer field schools, community-based conservation, and payment for ecosystem services, which create incentives and capacities for the adoption and scaling up of biodiversity-friendly practices.
Practices for Biodiversity Enhancement
There are many practices and strategies that farmers and land managers can use to enhance biodiversity in agricultural systems, depending on the local context, goals, and resources. Some of the key practices for biodiversity enhancement include:
Agroforestry
Agroforestry is the integration of trees and shrubs into agricultural systems, such as croplands, pastures, and rangelands, to provide multiple benefits for biodiversity, production, and livelihoods. Agroforestry can enhance biodiversity by creating diverse and multi-layered habitats that support a wide range of species, such as birds, bats, insects, and soil organisms, and by providing ecosystem services, such as carbon sequestration, water regulation, and erosion control. Agroforestry can also improve agricultural productivity and profitability by providing timber, fuelwood, fodder, and other tree products, and by enhancing soil fertility, water availability, and microclimate regulation.
There are many types of agroforestry systems, such as alley cropping, silvopasture, windbreaks, and riparian buffers, which can be adapted to different agroecological zones and farming systems. For example, in the temperate regions of Europe and North America, alley cropping systems, which involve planting rows of trees or shrubs between crops, can provide habitat for beneficial insects and birds, reduce wind and water erosion, and improve soil health and crop yields. In the tropical regions of Africa, Asia, and Latin America, multistrata agroforestry systems, which involve planting multiple layers of trees, shrubs, and crops, can provide habitat for a high diversity of species, including rare and endangered ones, and can also provide a range of products and services for local communities, such as food, medicine, and cultural values.
Crop Diversification
Crop diversification is the use of a variety of crops and cropping systems to enhance the diversity and resilience of agricultural systems. Crop diversification can enhance biodiversity by creating a mosaic of habitats and resources for different species, and by reducing the impacts of pests, diseases, and environmental stresses on individual crops. Crop diversification can also improve agricultural productivity and profitability by reducing the risks of crop failure, increasing the efficiency of resource use, and providing multiple income streams for farmers.
There are many ways to diversify crops, such as using crop rotations, intercropping, varietal mixtures, and cover crops. For example, in the dryland regions of the Middle East and North Africa, cereal-legume rotations, which involve alternating cereals (e.g., wheat, barley) with legumes (e.g., chickpea, lentil), can enhance soil fertility, water use efficiency, and biodiversity, by providing habitats and resources for pollinators, natural enemies, and soil organisms. In the rice-based systems of South and Southeast Asia, rice-fish co-culture, which involves raising fish in flooded rice fields, can enhance the diversity and abundance of aquatic species, such as fish, frogs, and invertebrates, and can also provide additional income and nutrition for farmers.
Habitat Management
Habitat management is the creation, protection, and restoration of natural and semi-natural habitats within and around agricultural systems to support biodiversity and ecosystem services. Habitat management can enhance biodiversity by providing food, shelter, and breeding sites for various species, and by facilitating their movement and dispersal across landscapes. Habitat management can also improve agricultural productivity and sustainability by providing ecosystem services, such as pest control, pollination, and nutrient cycling, and by reducing the impacts of environmental stresses, such as erosion, flooding, and climate change.
Many types of habitats can be managed for biodiversity in agriculture, such as field margins, hedgerows, woodlands, wetlands, and grasslands. For example, in the intensive agricultural landscapes of Europe, flower strips, which are planted with a mixture of native wildflowers along field margins, can provide nectar and pollen for pollinators and natural enemies, and can also enhance the aesthetic and cultural values of the landscape. In the arid and semi-arid regions of Australia, remnant vegetation, which are patches of native vegetation that have been preserved within agricultural landscapes, can provide critical habitats for many species of birds, mammals, and reptiles, and can also help to reduce soil erosion and salinity.
Integrated Pest Management
Integrated pest management (IPM) is an ecosystem-based approach to managing pests and diseases that combines biological, cultural, physical, and chemical strategies in a way that minimizes economic, health, and environmental risks. IPM can enhance biodiversity by reducing the use of broad-spectrum pesticides that can harm non-target species, and by promoting the conservation and augmentation of natural enemies, such as predators, parasitoids, and pathogens, that can regulate pest populations. IPM can also improve agricultural productivity and profitability by reducing the costs and risks of pest management, and by enhancing the resilience and sustainability of agricultural systems.
Many strategies and tactics can be used in IPM, such as monitoring, thresholds, cultural controls, biological controls, and selective pesticides. For example, in the horticultural systems of California, conservation biological control, which involves the management of non-crop habitats to support natural enemies, such as planting hedgerows, cover crops, and insectary plants, can enhance the diversity and abundance of predators and parasitoids and can reduce the need for insecticide applications. In the cotton systems of India, the use of pheromone traps, which attract and capture male moths, can help to monitor and control pink bollworm, a major pest of cotton, without the use of toxic insecticides.
Livestock Integration
Livestock integration is the incorporation of animals, such as cattle, sheep, goats, and poultry, into agricultural systems to enhance biodiversity, nutrient cycling, and other ecosystem services. Livestock integration can enhance biodiversity by creating and maintaining diverse habitats, such as grasslands, shrublands, and savannas, that support a wide range of plant and animal species, and by dispersing seeds and nutrients through grazing, trampling, and defecation. Livestock integration can also improve agricultural productivity and sustainability by providing animal products, such as meat, milk, and eggs, and by recycling nutrients and organic matter through manure and urine.
There are many ways to integrate livestock into agricultural systems, such as mixed crop-livestock systems, rotational grazing, and silvopasture. For example, in the rangeland systems of the western United States, rotational grazing, which involves moving livestock through a series of paddocks or pastures, can enhance the diversity and productivity of grasslands, by stimulating plant growth, reducing weed competition, and creating habitat heterogeneity. In the agroforestry systems of Central America, silvopasture, which involves the integration of trees, pastures, and livestock, can enhance the diversity and abundance of birds, bats, and other wildlife, and can also provide multiple products and services, such as timber, fodder, and carbon sequestration.
Benefits of Biodiversity Enhancement
Biodiversity enhancement in agriculture can provide multiple benefits for farmers, communities, and society, such as:
Improved ecosystem services
Biodiversity enhancement can improve the provision and regulation of ecosystem services, such as pollination, pest control, soil formation, water purification, and climate regulation, which are essential for agricultural production and human well-being. For example, a meta-analysis of 89 studies found that enhancing biodiversity in agroecosystems can increase crop yield by an average of 14%, and can also reduce crop damage by pests and diseases by an average of 23%.
Increased resilience and adaptability
Biodiversity enhancement can increase the resilience and adaptability of agricultural systems to environmental and economic stresses, such as droughts, floods, pests, and market fluctuations, by providing a diversity of species, functions, and responses that can buffer against shocks and disturbances. For example, a study in Ethiopia found that farmers who used a diversity of crops and varieties were more resilient to drought and had higher food security than those who relied on a single crop or variety.
Enhanced livelihoods and food security
Biodiversity enhancement can enhance the livelihoods and food security of farmers and rural communities, by providing a diversity of products and income sources, such as food, fiber, fuel, medicine, and cultural values, and by reducing the risks and costs of production. For example, a study in Mexico found that coffee farmers who used agroforestry systems had higher incomes, better nutrition, and more stable livelihoods than those who used monoculture systems.
Contribution to conservation goals
Biodiversity enhancement can contribute to the conservation of biodiversity at the genetic, species, and ecosystem levels, by providing habitats, resources, and connectivity for many species, including rare, threatened, and endangered ones. For example, a study in Europe found that agricultural landscapes with a high diversity of semi-natural habitats, such as hedgerows, grasslands, and woodlands, supported a higher diversity and abundance of birds, butterflies, and plants than those with a low diversity of habitats.
Climate change mitigation and adaptation
Biodiversity enhancement can contribute to climate change mitigation and adaptation, by sequestering carbon in soils and biomass, reducing greenhouse gas emissions from agriculture, and enhancing the resilience and adaptability of agricultural systems to climate variability and extremes. For example, a study in India found that agroforestry systems, which integrate trees with crops and livestock, can sequester up to 2.5 times more carbon than monoculture systems, and can also provide multiple benefits for biodiversity, water conservation, and soil health.
Challenges and Opportunities for Biodiversity Enhancement
Despite the many benefits of biodiversity enhancement in agriculture, several challenges and barriers can hinder its adoption and scaling up, such as:
- Limited awareness and knowledge: Many farmers, policymakers, and other stakeholders may have limited awareness and knowledge of the importance and benefits of biodiversity in agriculture, and may lack the skills, resources, and incentives to adopt and implement biodiversity-friendly practices. For example, a survey in the European Union found that only 30% of farmers were aware of the concept of biodiversity, and only 20% had adopted some form of biodiversity-friendly practices on their farms.
- Inadequate policies and incentives: Many policies and incentives in agriculture, such as subsidies, regulations, and markets, may not adequately recognize and reward the value of biodiversity and ecosystem services, and may instead encourage the intensification and simplification of agricultural systems. For example, a study in the United States found that the federal crop insurance program, which provides financial protection to farmers against crop losses, may discourage the adoption of diversified and sustainable farming practices, by favoring large-scale and specialized production systems.
- Trade-offs and synergies: Biodiversity enhancement in agriculture may involve trade-offs and synergies with other goals and values, such as productivity, profitability, and social equity, which may require careful consideration and negotiation among different stakeholders. For example, a study in Indonesia found that the adoption of agroforestry systems, which can enhance biodiversity and carbon sequestration, may also reduce the yields and incomes of farmers in the short term, and may require additional support and incentives to compensate for the costs and risks.
- Climate change and other global challenges: Biodiversity enhancement in agriculture may be affected by climate change and other global challenges, such as land degradation, water scarcity, and population growth, which may exacerbate the pressures and uncertainties on agricultural systems and biodiversity. For example, a study in Africa found that climate change, which is expected to increase the frequency and intensity of droughts and floods, may reduce the diversity and productivity of crops and livestock, and may require new strategies and technologies for adaptation and resilience.
Despite these challenges, there are also many opportunities and enablers for biodiversity enhancement in agriculture, such as:
- Growing public awareness and demand: There is a growing public awareness and demand for sustainable and biodiversity-friendly agricultural products, such as organic, fair trade, and eco-labeled foods, which can create new markets and incentives for farmers and businesses to adopt and promote biodiversity enhancement practices. For example, a study in the United Kingdom found that consumers are willing to pay a premium of up to 20% for food products that are labeled as biodiversity-friendly or environmentally sustainable.
- Innovative policies and partnerships: Many innovative policies and partnerships can support and incentivize biodiversity enhancement in agriculture, such as agri-environment schemes, payment for ecosystem services, and landscape-level collaborations, which can provide financial, technical, and social support for farmers and other stakeholders to adopt and scale up biodiversity-friendly practices. For example, a study in Costa Rica found that a national payment for ecosystem services program, which rewards farmers for protecting and restoring forests and other natural habitats, has enhanced the conservation of biodiversity and the provision of ecosystem services, such as water regulation and carbon sequestration.
- Advances in science and technology: Many advances in science and technology can enable and enhance biodiversity enhancement in agriculture, such as remote sensing, precision agriculture, and genetic resources, which can provide new tools and approaches for monitoring, managing, and conserving biodiversity in agricultural landscapes. For example, a study in Germany found that the use of high-resolution satellite imagery and machine learning algorithms can accurately map and predict the diversity and distribution of birds and butterflies in agricultural landscapes, and can inform the design and implementation of biodiversity conservation strategies.
- Synergies with other sustainability goals: Biodiversity enhancement in agriculture can create synergies with other sustainability goals, such as climate change mitigation, water conservation, and rural development, which can provide multiple benefits and co-benefits for farmers, communities, and society. For example, a study in Brazil found that the adoption of agroforestry systems in the Amazon region can enhance biodiversity, reduce deforestation, and improve the livelihoods and well-being of smallholder farmers, while also contributing to the global goals of climate change mitigation and sustainable development.
Conclusion
Biodiversity enhancement is a key strategy for sustainable agriculture that can provide multiple benefits for farmers, communities, and society, such as improving ecosystem services, increasing resilience and adaptability, enhancing livelihoods and food security, contributing to conservation goals, and mitigating and adapting to climate change. Many practices and approaches can be used to enhance biodiversity in agriculture, such as agroforestry, crop diversification, habitat management, integrated pest management, and livestock integration, which can be adapted to different agroecological and socioeconomic contexts.
However, the adoption and scaling up of biodiversity enhancement in agriculture also face several challenges and barriers, such as limited awareness and knowledge, inadequate policies and incentives, trade-offs and synergies with other goals and values, and climate change and other global challenges. To overcome these challenges and realize the full potential of biodiversity enhancement in agriculture, there is a need for concerted and collaborative efforts among different stakeholders, such as farmers, researchers, policymakers, businesses, and civil society, to create enabling conditions and incentives for biodiversity-friendly practices, and to harness the opportunities and synergies with other sustainability goals.
Biodiversity enhancement in agriculture is not a one-size-fits-all solution, but rather a context-specific and adaptive process that requires the integration of scientific, local, and indigenous knowledge, the participation and empowerment of farmers and communities, and the creation of supportive policies, markets, and institutions.
By embracing the diversity and complexity of agricultural systems and landscapes, and by working together to conserve and enhance the biodiversity that sustains us all, we can build a more sustainable, resilient, and equitable food system for the present and future generations.