Based on their research in Japan, Naoki Katayama and colleagues highlight how organic rice farming supports more plants, spiders, dragonflies, frogs and waterbirds than conventional farming.
A version of this post in Japanese is available here.
The intensification of agriculture since the mid-20th century, and the more recent abandonment of farmlands, have presented major threats to farmland biodiversity. Organic farming and less strict low-input farming (i.e. reduced use of agrochemicals) are expected to protect farmland biodiversity from ongoing habitat loss and degradation. Despite this, knowledge of the wildlife benefits of organic and low-input farming systems is limited in Asia the worldwide leader in rice production.
We surveyed a variety of taxonomic groups (i.e. plants, spiders, dragonflies, frogs, fish and birds), which could potentially respond to organic and low-input farming, in rice fields, that were under organic or low-input farming and then compared to nearby fields that were not. Field surveys were conducted in more than a thousand of Japanese rice fields. In Japan, national and local governments have financially supported farmers implementing organic farming and low-input farming (up to 8,000 JPY per 0.1 ha = approximately 72.6 USD or 65.1 EUR at 21th May 2019) to provide environmental benefits, mainly for global warming prevention and biodiversity conservation.
We demonstrate that organic rice fields support the highest species richness and abundance in many taxonomic groups (native and Red List plants, Tetragnatha spiders, Sympetrum dragonflies, and Pelophylax frogs) on a per-area basis. In our research, species richness and abundance of waterbirds increased with the area of organic farming within a survey site, suggesting the importance of prey abundance at spatial scales larger than single fields. Low-input fields also supported higher plant richness and Tetragnatha and Sympetrum abundance than conventional fields. Furthermore, using data on farming practices in each field collected through farmer interviews, we show that rice farming can be wildlife friendly by not only reducing or avoiding pesticide applications but also avoiding crop rotation, maintaining levee vegetation, and spatially aggregating organic farming.
Our results indicate that organic and low-input rice cropping is richer in biodiversity than conventional farming. This provides the scientific basis of the current agri-environment schemes in Japan, subsidising organic and low-input farming for biodiversity. In addition, avoiding crop rotation, maintaining levee vegetation, and spatially aggregating organic farming were also found to be effective in conserving specific taxa, and it is desirable to promote such management efforts.
Read the full article, Organic farming and associated management practices benefit multiple wildlife taxa: A large-scale field study in rice paddy landscapes, in Journal of Applied Ecology.