Managing grasslands biodiversity at a landscape level to foster ecosystem services in intensive cereal systems: from ecological knowledge to collective action

摘要

Effective solutions for integrating agricultural development and conservation of biodiversity at the landscape scale remain to be identified. We present a case study in an intensively farmed French cereal plain, where the reintroduction of grasslands has been proposed first for conservation purposes in order to protect the Little Bustard, a highly threatened bird species. Monitoring the effects of grassland “experimental” implementation revealed other beneficial effects on virtually all components of the trophic web in these agroecosystems, particularly at the landscape level. Indeed, in intensive cereal systems, perennial habitats such as grasslands are radically different from annual crops in terms of level and frequency of disturbance (plowing, planting, spraying etc.). In these highly fragmented and disturbed habitats, the presence, abundance and distribution of grasslands therefore have a critical role in ecological and environmental regulatory processes. We provide evidence that grasslands, particularly alfalfa, are the support of many ecosystem services, such as pollination, biological control, in addition to forage production. To maximize their provision, it is critical to rationalize the inclusion of grasslands in the cropping system (in time, space and according to management practices). However, currently, grasslands are severely depleted by farmers who privilege cereal crops for economic reasons (including CAP subsidies). We therefore raise the issue of whether crop allocation at the landscape scale can be changed without public funding, in order to increase the proportion of grasslands. In other words, how to overcome the reluctance of cereal farmers to produce forage crop? A solution explored here is to identify the interdependencies between farmers related to the ecosystem services grasslands provide at the landscape scale. The recognition of grassland emergent functions when considered at the landscape scale gives them a status of common good: a good that should be collectively managed to maximize ecosystem services. This consideration leads to involve new stakeholders such as citizens, scientists, government bodies or NGOs in the collective management of grasslands and opens an innovative way to reconcile agriculture and conservation at the landscape scale.