Compared with conventional agriculture, organic farming has clear advantages for insects and for biodiversity in general. A 2015 study related to the EU Biodiversity Strategy found that organic farms generally have 30 per cent higher species richness and 50 per cent higher abundance of organisms than conventional farms. A study from Germany summarising many individual investigations found that 23 per cent more insect species that visit flowers were present on organically farmed fields than on those subject to conventional management. The organic fields had an average of 30 per cent more types of wild bees and 18 per cent more butterfly species.
Organically managed land not only had a greater diversity of insects, it also had more insects in total. On average there are 26 per cent more flower-visitors and almost 60 per cent more butterflies on organic fields. Farmland birds are commonly used as indicators of biodiversity and of insects. A 2010 EU wide study showed a higher number of farmland birds on organic farms than on conventional farms.
Recent data from Germany indicate that there were 35 per cent more such bird species on organically managed land, and they were 24 per cent more numerous in terms of population. Overall, there has been a decrease in bird species that feed on small insects and spiders during the breeding season in Germany in recent years. Scientists attribute this to a lack of food in conventionally managed fields and to the widespread use of insecticides.
Organic farming has a positive effect on biodiversity and on insects for various reasons. It avoids using synthetic pesticides that conventionally managed farms apply to control weeds and pests. Instead, it removes weeds mechanically, or controls them by rotating and switching crop types each season.
Organic farms also do not use artificial nitrogen fertiliser. Instead, they sow clover, lucerne or lupins. These plants fix nitrogen in the soil and therefore make a good green manure. At the same time they provide insects with both food and habitat. The German metastudy found that the number of wild plant species on organically farmed fields averaged 94 per cent higher than on conventional fields, and 21 per cent more plant species were found in the field margins.
In cereal growing, the effects of organic farming on biodiversity are far-reaching because conventionally grown grain relies on heavy applications of mineral fertilisers and pesticides. Pollinators are very sensitive to pesticides. Because organic farms abstain from using chemicals, local pollinators become more abundant. But since pesticides may drift with the wind, and insects naturally visit conventionally managed farms nearby, the negative effects of pesticides may overshadow the positive ones. This may also be true if hedges, flowering field margins and other ecological niches are missing.
Overall, though, organic farming has a bigger positive effect on insect numbers if the surrounding area is monotonous: i.e., if it has few variegated landscape elements and is only covered with a single type of crop. Critics argue that the lower yields of organic farming would make it necessary to expand the area of cultivated land worldwide by converting previously unused land that is high in biodiversity. This would make the net effect of organic farming negative, because uncultivated land has greater biodiversity than organically managed fields. Such criticism is justified in that, in temperate latitudes, yields from organic farming are lower than those from conventional farms.
Nature would benefit from 100 per cent organic farming only if land is saved through lower meat consumption and if food losses are reduced. The production of 327 million tonnes of meat a year, the world’s current consumption, takes up almost 80 per cent of the global agricultural area. Therefore, lower meat consumption is of central importance to sustainable land management. Organic farming has so far been a niche business in many developed and emerging countries. Worldwide, it covers only 1.5 per cent of the agricultural area; in the European Union the figure is 7 per cent – though it is growing quickly.
Major differences exist among the EU’s members: in Malta, organic farmland covers a minuscule 0.4 per cent of the total, while in Austria it accounts for over 23 per cent. These figures only include areas that are certified as organic. But many farms worldwide follow the basic principles of organic farming: maintenance of soil fertility, the cycle of soil–plants–animals and humans, and farms’ independence from external inputs such as fodder and synthetic fertiliser.
Few of these farms are certified as organic. The broader concept known as “agroecology” is promoted by many civil society organisations around the world, along with international organisations such as the Food and Agriculture Organization of the United Nations. They all support the ecological and social restructuring of the agricultural and food system, including marketing and power structures – thus promoting an insect-friendly future.
Source: Insect Atlas by H einrich Böll Foundation, www.boell.de/insectatlas
and Friends of the Earth Europe foeeurope.org
