Agriculture as the human activity occupying the largest share of the total land area for nearly all OECD countries, plays a key role with regard to biodiversity which is highly dependent on land use. The expansion of farm production and intensification of input use are considered a major cause of the loss of biodiversity, while at the same time certain agro-ecosystems can serve to maintain biodiversity. Farming is also dependent on many biological services, such as the provision of genes to develop improved crop varieties and livestock breeds, crop pollination, and soil fertility provided by micro-organisms. In some cases non-native species cause damage to crops from alien pests and competition for livestock forage.
The main focus of policy actions in the area of biodiversity has been to protect and conserve endangered species and habitats, but some countries have also begun to develop more holistic national biodiversity strategy plans. These plans usually incorporate the agricultural sector in biodiversity conservation. At the international level a range of agreements are also important in the context of agriculture and biodiversity, most notably, the International Convention on Biological Diversity.
Indicators and recent trends
A number of biodiversity indicators are being established by OECD within the general framework of genetic, species and ecosystem diversity (the latter is covered under Wildlife Habitat indicators). The indicators provide a coherent, but initial, picture of biodiversity in relation to agriculture.
Concerning genetic diversity, three indicators cover the diversity of crop varieties and livestock breeds used by agriculture. Overall these indicators reveal that diversity has increased for many OECD countries since the mid-1980s, in terms of the share of varieties/breeds in total crop production/livestock numbers. This suggests agriculture has improved its resilience to environmental changes through diversifying the number of varieties/breeds used in production.
A fourth genetic diversity indicator provides information on the extent of genetic erosion and loss of agricultural plants and livestock. While information on genetic erosion or loss is incomplete, evidence for a limited number of countries suggests significant losses and/or the endangerment of loss of genetic resources in agriculture over recent decades. The collections in genebanks, however, in general continue to grow, both public and private collections.
Indicators for species diversity cover trends in population distributions and numbers of: (i) wildlife species dependent on or affected by agriculture, and (ii) non-native species threatening agricultural production and agro-ecosystems.
While information on the impact of agriculture on wild species is limited for many OECD countries, it appears agricultural land provides an important habitat area for the wildlife that remains following the conversion to agricultural land use, but especially birds, vascular plants and some invertebrates, such as butterflies. Also, the population trends of wildlife species using agricultural land as habitat indicate in most cases a reduction over the past decade. This represents the continuation of a longer-term trend, although the decline has slowed or even reversed over recent years in some countries. Even so considerable numbers of wildlife species using agricultural land as habitat are under threat of being lost.
For non-native species, there is no systematic time series available across OECD countries, although their harmful effects on agricultural production and agro-ecosystems are reported for many countries. There has been a long history of non-native species introductions across countries, with the extent of economic losses to farming and damage to native biodiversity from their introduction varying widely.