Data from: Diverse guilds provide complementary dispersal services in a woodland expansion process after land abandonment

1. Land abandonment due to increasing depopulation of rural areas is an ongoing trend in developed countries worldwide. Abandoned lands represent an opportunity for ecosystem recovery, an urgent need for biodiversity conservation. Seed dispersal services provided by animals are a key feature for this process. Different dispersers may differentially contribute to plant recruitment under different ecological conditions, leading to complementary dispersal services. 2. We studied the dispersal services, quantified as the contribution to plant recruitment, provided by the main dispersal guilds of Spanish juniper Juniperus thurifera L.: small-to-medium sized strongly frugivorous birds (thrushes) and medium-to-large sized carnivorous mammals (red fox and stone marten). To do this, we studied seed fate from seed dispersal to seedling survival during two years and estimated seed dispersal effectiveness (seedlings recruited per m2) in two ecological contexts derived from ecosystem recovery after a historical period of degradation: remnant woodlands and old fields. 3. Results showed a clear shift in the contribution to plant recruitment between these guilds, resulting in complementary and non-redundant dispersal services. Thrushes were the main contributors to plant recruitment in woodlands (73%), leading to population growth but with a reduced impact on the colonization of old fields where carnivores contributed to 80% of recruitment (42% red fox, 38% stone marten). The dispersal complementarity observed for thrushes and carnivores is a consequence of their functional diversity, mainly driven by their differences in feeding and movement behaviour. 4. Synthesis and applications. The combination of short distance, strongly frugivorous dispersers (e.g. passerine birds) together with big generalist frugivores with long distance movements (e.g. carnivorous mammals) maintained (i) effective seed dispersal services in remnant woodlands and (ii) the connectivity between patches promoting old fields colonization and woodland expansion. Thus, it is in heterogeneous landscape mosaics ecosystems (e.g. agro-environments) where functionally diverse disperser communities play a key role in ecosystem recovery. By performing effective dispersal services across an array of habitat types, functionally diverse disperser communities assist natural restoration of human-impacted ecosystems all over the world. Thus, dispersal communities provide an important ecosystem service that may replace costly human-mediated restoration projects.

1. 全球发达国家正持续出现因农村人口不断流失而引发的土地撂荒现象。撂荒土地为生态系统恢复提供了重要契机，同时也是生物多样性保护的迫切需求。动物介导的种子扩散服务（seed dispersal services）是这一生态恢复过程的核心环节。不同扩散类群在不同生态条件下对植物定植的贡献存在差异，由此形成互补性的扩散服务。
2. 本研究以欧洲刺柏（Spanish juniper Juniperus thurifera L.）为研究对象，针对其主要的种子扩散功能群——中小型专性食果鸟类（鸫类）以及中大型肉食性哺乳动物（赤狐和石貂）——展开研究，以植物定植贡献度量化种子扩散服务。为达成研究目标，本研究历时两年追踪了从种子扩散至幼苗存活的种子命运，并在两类经历历史退化后处于生态恢复阶段的生境中估算了种子扩散有效性（seed dispersal effectiveness，即每平方米定植幼苗数）：残存林地与撂荒农田。
3. 研究结果显示，两类扩散功能群对植物定植的贡献度存在显著分化，最终形成互补且非冗余的种子扩散服务。在残存林地中，鸫类是欧洲刺柏定植的主要贡献者（占比73%），可推动种群扩张，但对撂荒农田的定植过程影响有限；而在撂荒农田中，肉食性哺乳动物贡献了80%的定植量（其中赤狐占42%，石貂占38%）。鸫类与肉食性哺乳动物所展现出的扩散互补性，源于二者的功能多样性，其核心驱动因素为取食与移动行为的差异。
4. 研究综合与实践应用。兼具短距离扩散的专性食果扩散者（如雀形目鸟类）与长距离移动的广食性食果扩散者（如肉食性哺乳动物）的组合，既维持了残存林地中高效的种子扩散服务，又保障了斑块间的连通性，从而促进撂荒农田的定植与林地扩张。因此，在异质性景观镶嵌生态系统（如农业复合生境）中，功能多样性的扩散者群落对生态系统恢复发挥着关键作用。通过在多样的生境类型中提供高效的种子扩散服务，功能多样的扩散者群落可助力全球受人类干扰生态系统的自然修复。由此可见，扩散者群落能够提供一项重要的生态系统服务，可替代成本高昂的人工介导修复工程。