| Project Detail |
If agriculture provides essential resources to humanity, it is also a major disruptor of several Earth biogeochemical systems that nowadays operate outside the boundaries of sustainability. Intensive agriculture impacts climate regulation and triggers biodiversity collapse, calling for more environmentally-friendly farming practices. Semi-natural grasslands have for long harboured a rich biodiversity but belong now to the most affected and threatened ecosystems worldwide, making them a top conservation priority. Developing efficient restoration methods is thus an urgent scientific and management challenge. The main objective of the research proposed here is to assess and compare the mid- and long-term effects of current and novel grassland restoration methods with the aim to provide concrete guidance for converting species-poor grasslands into biodiversity-rich, stable-state ecosystems. This requires replicated, wide-scale and long-term experimental research focusing on multiple taxonomic groups (flora and invertebrate fauna) in order to embrace the whole ecosystem complexity, unveil underlying mechanisms, recognise possible antagonistic responses, and ultimately identify optimal management trade-offs so as to promote biodiversity while maintaining decent agricultural revenue.The proposed research consists of two modules, one focusing on lowland grasslands, the other one on mountain grasslands, both characterising the conditions typically encountered in the cultural landscapes of the Old World. Our lowland research module is devised under environmental circumstances that represent the modern biodiversity-impoverished grasslands of the Western World. Here we will experimentally (full-block design with random allocation of treatment to field) evaluate pro-active reseeding methods - that rely either on hay or seed transfer from biodiversity-rich donor meadows, or on locally produced, commercial seed mixtures - for pushing degraded grassland plant and invertebrate communities towards species-richer stable states. Our mountain research module is deployed in the traditional agro-ecosystems that have for long predominated in the cultural landscapes of European mountain ranges, but are currently subjected to rapid land-use changes; notably, where land is accessible to agricultural machinery, grassland management is intensified, causing a dramatic collapse of biodiversity. However, contrary to the situation in the lowlands, here the seed bank appears fairly intact due to a generally much less degraded landscape matrix, which provides many more opportunities for natural, passive grassland restoration. Here we shall therefore investigate the resilience of grasslands to an experimental relaxation of intensification, i.e. their ability to progressively return to a biodiversity-richer stable state. Both projected lowland and mountain experiments include a proper control, are carried out at the field-scale, i.e. with a given treatment being randomly attributed to a whole meadow. Baseline data had been collected at all study sites, i.e prior to launching the experimental manipulation, allowing a BACI (Before After Control Intervention) approach. Reseeding operations (lowland module) and the relaxation of the intensive management (mountain module) took place and started, respectively, in 2019. From 2023 onwards we shall investigate mid- and long-term changes, measuring various biotic and abiotic factors and operating with different metrics on multiple plant and animal taxa (species richness and diversity, functional traits, community and network analyses, etc.), without neglecting measures of hay productivity and quality. A pure experimental approach will enable us to avoid the caveats commonly faced by correlational studies, notably the classical confounding effects of environmental factors such as site-specific soil and landscape circumstances. Our ultimate objective is to provide end-users, notably conservation biologists, environmental managers, farmers and governmental authorities, with easily implementable, evidence-based recommendations for future grassland restoration strategies that maximize the return on investment of the agricultural subsidies targeting biodiversity, without jeopardizing agricultural revenue. |
