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Biodiversity and agro-ecology - reducing risk in food systems?

Around three-quarters of the world’s cultivated plants and 690 livestock breeds have been lost since the middle of the 19th century and around 20% of livestock breeds now thought to be at risk of extinction[1]. An FAO report in 2011, with particular reference to Africa’s biodiversity, pointed to threats mentioned above on habitat losses etc. while highlighting the added impact of displacement of wild land races by genetically uniform crops and the long-term effects of relief food (often maize) on the local gene pools. In an emergency, local seeds are sold or eaten by local communities, and imported seeds are subsequently used in subsequent crop cycles.[2]  Genetic diversity is an anchor in climate change adaption in terrestrial, freshwater and marine ecosystems. Species extinction, even of a single species, impacts ecosystems, including agro-ecosystems. Intermediate levels of extinctions (21-40% loss) can reduce plant productivity and decomposition in the associated ecosystem by 5-10%, comparable to results from global warming and raised ultra-violet radiation. Vulnerability to extinction varies among species. As extinction rates grow to between 41-60%, the effects were comparable to those of acidification, ozone, elevated CO2 and nutrient pollution.[3] Vulnerability and risks in food production systems cause food insecurity and malnutrition. Food access, utilization and stable supply are each affected with local or wider production constraints and uncertainties.

The following highlights some additional points on the role of an agro-ecological approach and genetic diversity in stabilizing food security and nutrient diversity and the value of understanding the biodiversity-DRR-climate change interaction in this process.

1.       Maintenance of diversity within and among species and breeds stabilizes production and food availability and builds resilience within the eco-system (such as cropping, fisheries, livestock) against stresses - including pressure exerted by humans and climatic variability and its extremes. Availability of diverse nutrient-rich foods improves health and well-being. For communities living around or within forests, they derive up to 85% of their protein intake through consumption of edible mammals, reptiles, birds and insects living in trees and forests.

2.       Vulnerability and risk of long-term food insecurity is considerably raised through reliance on a small number of species and varieties often with a narrow genetic base. Crop varieties with a narrow genetic base can be destroyed by diseases and not even advanced genetic technology can replace genetic variation, as it is irretrievable[4]. We rely heavily on cereals worldwide, maize, rice, wheat, millet and sorghum. One outcome of ‘development’ driven by globalization in food production and its trading, by urbanization and changing lifestyles and genetic engineering is a simplification in human and livestock diets – across race, gender, age, religion and wealth classes.

3.       In Thailand, the number of rice varieties cultivated has fallen from >16,000 to 37 with up to 50% of the area cultivated supporting only two varieties. Apart from widespread loss of wild relatives in the wild, it can take up to 10 years to breed a new crop variety. Wild crop relatives are known to hold essential traits crucial for effective adaptation to heat, drought, salinity, pests, diseases including climate change. In the wild, they must adapt to varying climatic and other conditions. A one degree rise in temperature can cut yields of high-yielding rice varieties by 10 per cent. The critical stage is at flowering and high-yielding varieties flower during the day. Wild varieties flower at night-time giving them an advantage in the event of raised temperatures[5]. Yet, natural populations of many wild crops are at risk of extinction through habitat loss, degradation and fragmentation[6].

4.       That biodiversity has a direct measurable value for food security and nutrient diversity is well exemplified through the role of pollinators. Up to 100,000 species of insects, birds, mammals and reptiles pollinate around 2/3 of food plants and are responsible for around 35% of global crop production. Up to 85% of all known Angiosperms (flowering plants) are pollinated by wild pollinators (e.g. bumblebees, wasps, wild bees, solitary bees, moths, butterflies, bats, lizards, birds, flies, beetles and ants). While the honey-bee is “the species charged with protecting global food security”, there are risks associated with over-reliance on honey-bee colonies due to disease losses. In addition, a single species cannot adapt well to changing environments and shocks. Wild pollinators are known to be at least twice as effective as honey-bees as they use a wider variety of pollination techniques and they visit more plants, ensuring effective cross-pollination – honey-bees tend to carry pollen from one flower to another but most commonly on the same plant. The effectiveness of wild pollinators was proven in a study across all the continents for 40 crops in 600 farms for crops such as almond, coffee, tomato, onion and strawberry[7]. Wild insects and other pollinators are in decline however as habitats are lost through deforestation and fragmentation, expansion of intensively managed agricultural area and  climate change, placing food security and nutrition at risk.[8] One element of climate change worth noting is that flowering times and time for optimum bee activity is increasingly showing a mismatch.

5.       Genetic depletion in centres of origin compromises future food security for millions of people. Widespread genetic erosion of maize diversity in Mexico was reported in 2014.[9] This is an important finding, as Mexico is the centre of origin of maize (Zea mays) that is used by millions of people as a staple food. Furthermore, through such genetic erosion, the option of ‘falling back’ on a diverse gene pool to maintain important food crops is compromised. It is essential to increase the number of relevant agricultural/forest crop species and animal breeds and to maintain variability within species. With one-fifth of the world’s plants threatened with extinction, “..there is a two-fold race against time – the race to adapt agriculture to climate change and the race to collect biodiversity before it is lost forever..”[10].

6.       An inverse relationship between intensive agriculture and biodiversity invalidates the sustainability of large-scale and intensive food production systems in food security and nutrition. Small farms almost always have higher yields per unit area than larger intensively-managed farms. Smaller farms commonly feature multiple crops and crop biodiversity, quality labour and supervision, lower input costs and more efficient use of resources[11]. Research in Tigray (Ethiopia) on 10 barley landraces cultivated by small-holders found that maintaining crop diversity reduced risk exposure and its costs while boosting crop productivity. Significantly, benefits were most notable on farmland where soils were degraded and fertility levels were low[12].

7.       Agricultural biodiversity[13] is fostered by the principles and practice of ecological agriculture with considerable potential in mitigation and adaptation to drivers such as climate change in addition to addressing food insecurity and malnutrition at local levels. It builds resilience and provides for in situ conservation of genera, species, varieties and breeds. It allows for a continuous adaptation process through cross-pollination for example from the wild, while maintaining a broad gene pool in a varied production mosaic e.g. woodland, orchards, fallows, home gardens, niche areas or fields. The role of local communities and their knowledge are naturally close to agro-biodiversity principles and practice although the merging of new information and germplasm is important for the future. One interesting development in this area is the Potato Park Project in Cusco, Peru in which local communities have successfully returned 400 local potato varieties to ensure food security in the light of climate change.[14]

8.       Biological pest control is underpinned by wild biodiversity. Species abundance and richness tends to be higher in more diverse farming systems and diverse landscapes incorporating mosaics with natural, semi-natural (including fallow, rotational pasture, protected areas) and cultivated or grazed lands.

9.       Soil biodiversity and health is essential for stable and productive farming systems. The higher the crop and non-crop diversity (flora and fauna), decomposition and nutrient cycling are enhanced increasing yield status and soil fertility levels. Agro-biodiversity allows for growth in soil organic matter which in turn captures CO2 through sequestration while enhancing soils structure and crop performance.

10.    Biodiversity works against invasions by alien species, an important attribute, given that the IPCC Assessment Report 5 (IPCC AR5, 2014) indicated that increasing climate change and elevated CO2 levels enhance the competitiveness and distribution of obnoxious weeds in farming systems.[15]

11.    Healthy ecosystems ncluding agro-ecosystems are known to reduce the potential for human and wildlife conflict[16]. Protected areas, while safeguarding biodiversity, can contribute to eco-peace initiatives and strengthened socio-ecological resilience within and between communities, between communities and commercial stakeholders with enhanced partnerships with Governments and others[17].