Agro-ecosystem diversification: digging deeper

越来越多的证据表明，生物多样性对生态系统至关重要。大多数研究都集中在地上多样性对生态系统功能的重要性上。然而，生物多样性的很大一部分实际上隐藏在地下。对于地下生物多样性的丧失是否会影响生态系统功能，人们仍然知之甚少。对此进行调查是很重要的，因为最近的一些研究表明，土地利用集约化导致土壤生物多样性减少。本文探讨了农业生态系统多样化是否能够促进土壤生物多样性和生态系统服务的提供，并检验了四个假设：H1：农业生态系统多样化增强了生态系统的多功能性。H2：多样性低时，土壤生物多样性和土壤群落组成对生态系统多功能性和土壤功能更重要。H3：土壤生物多样性和土壤群落组成与其他非生物和管理驱动因素的相对重要性依赖于生态系统服务。H4：多样化的土壤群落增强生态系统对气候变化（如变暖和降水改变）的适应能力我们将建立一个由250个农田（每个国家50个）组成的欧洲网络，这些农田的地上多样性各不相同。该网络包括地上生物多样性低到农业生物多样性高的站点。我们将评估地下多样性（使用高通量测序）和一些生态系统功能（植物产量，土壤肥力，土壤聚集，土壤碳）在这些领域。随后，我们将使用先进的统计工具（如结构方程模型）来评估地上、地下多样性和管理对生态系统多功能性和单个生态系统服务的影响。我们将使用不同的生态系统多功能性指数，包括生产、生物多样性和环境可持续性导向指数。在下一组实验中，我们将采用更机械的方法。我们将从土壤生物多样性低、中、高的野外地点收集土壤芯。这些土壤芯将被带到温室，在那里通过淋滤和反硝化来评估养分损失。然后，我们将通过根据大小过滤生物体来操纵这些土壤的土壤生物多样性，并将这些土壤作为我们操纵土壤生物多样性的实验系统的接种物。我们将测试土壤生物多样性的变化是否影响生态系统的多功能性。我们还将测试在更高的地上多样性水平下管理的土壤是否能增强土壤生态系统功能。最后，我们将从选定的野外地点收集土壤，并将其置于不同的气候变化情景中。我们将与利益攸关方和决策者一起制定农业生态系统多样化的理论和应用框架，并将确定各种农业做法对生产力、生物多样性和可持续性的影响。

Mounting evidence suggests that biological diversity is of pivotal importance for ecosystems. Most studies have focused on the importance of above ground diversity for ecosystem functioning. However, a large part of biodiversity is literally hidden below ground. It is still poorly understood whether below ground biodiversity loss impacts ecosystem functioning. It is important to investigate this because a number of recent studies have shown reductions in soil biodiversity upon land use intensification. Here we explore whether agro-ecosystem diversification can promote soil biodiversity and the delivery of ecosystem services, testing four hypotheses:H1: Agro-ecosystem diversification enhances ecosystem multifunctionality.H2: Soil biodiversity and soil community composition is more important for ecosystem multifunctionality and soil functioning when diversity is low.H3: The relative importance of soil biodiversity and soil community composition vs. other abiotic and management drivers is ecosystem-service dependent.H4: Diverse soil communities enhance ecosystem resilience to climate change (e.g. warming and altered precipitationWe will establish a European network of 250 agricultural fields (50 per country) that vary in above ground diversity. This network includes sites with low above ground diversity to high agricultural diversity. We will assess below-ground diversity (using high throughput sequencing) and a number of ecosystem functions (plant yield, soil fertility, soil aggregation, soil carbon) in these fields. Subsequently, we will use advanced statistical tools (e.g. structural equation modelling) to assess the impact of above ground diversity, below ground diversity and management on ecosystem multifunctionality and on individual ecosystem services. We will use different ecosystem multifunctionality indexes, including a production, a biodiversity and an environmental sustainability oriented index. In a next set of experiments we take a more mechanistic approach. We will collect soil cores from field sites with low, medium and high soil biodiversity. These soil cores will be brought to the greenhouse where nutrient losses through leaching and denitrification will be assessed. We will then manipulate soil biodiversity of those soils by filtering organisms according to size and using these soils as inoculum for an experimental system in which we manipulate soil biodiversity. We will test whether changes in soil biodiversity influence ecosystem multifunctionality. We will also test if soils managed under higher levels of above ground diversity enhance soil ecosystem functions. Finally, we will collect soils from selected field sites and subject them to different climate change scenarios. Together with stakeholders and policy makers we will develop a theoretical and applied framework for agro-ecosystem diversification and will identify the impact of various agricultural practices on productivity, biodiversity and sustainability.