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。然而，很大一部分生物多样性实际上隐藏在地下。地下生物多样性的丧失是否会影响生态系统的功能，目前还知之甚少。调查这一点很重要，因为最近的一些研究表明，由于土地利用集约化，土壤生物多样性减少。在这里，我们探索农业生态系统多样化是否可以促进土壤生物多样性和生态系统服务的提供，检验四个假设：H1：农业生态系统多样化增强了生态系统的多功能性。H2：土壤生物多样性和土壤群落组成对生态系统的多功能性和土壤功能更重要，当多样性较低时。H3：土壤生物多样性和土壤群落组成相对于其他非生物和管理驱动因素的相对重要性取决于生态系统服务。H4：多样化的土壤群落增强了生态系统对气候变化(例如，变暖和降水变化)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。这个网络包括地上多样性低到农业多样性高的地点。我们将评估这些领域的地下多样性(使用高通量测序)和一些生态系统功能(植物产量、土壤肥力、土壤团聚体、土壤碳)。随后，我们将使用先进的统计工具(例如结构方程模型)来评估地上多样性、地下多样性和管理对生态系统多功能和对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指数，包括生产型、生物多样性和环境可持续性导向型指数。在接下来的一组实验中，我们采取了更机械化的方法。从土壤生物多样性低、中、高的田间地块采集土芯。这些土芯将被带到温室，在那里将评估淋溶和反硝化过程中的养分损失。然后，我们将通过根据大小过滤有机体，并将这些土壤用作我们操纵土壤生物多样性的实验系统的接种物，来操纵这些土壤的土壤生物多样性。我们将测试土壤生物多样性的变化是否会影响生态系统的多功能。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会增强土壤生态系统功能。最后，我们将从选定的田野地点收集土壤，并将它们置于不同的气候变化情景中。我们将与利益攸关方和政策制定者一起，制定农业生态系统多样化的理论和应用框架，并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.