Waterbirds can transport aquatic invertebrates internally, contributing to metapopulation dynamics between aquatic habitats in a terrestrial matrix. However, research into this dispersal process to date has focused on individual field sites or laboratory studies. We investigated the invertebrates dispersed by endozoochory by the lesser black-backed gull Larus fuscus wintering in Andalusia, south-west Spain in 2016–2017, comparing seven sites interconnected by their movements, with different degrees of anthropogenization [three landfills, two saltpan complexes, a natural lake, and a large (370 km²) ricefield area]. In the ricefields, we also compared invertebrates dispersed by gulls with those dispersed by the larger white stork Ciconia ciconia. A total of 642 intact invertebrates and their propagules (mainly plumatellid bryozoans, cladocerans, and other branchiopods) were recorded in excreta (faeces and pellets) from gulls and storks. A greater diversity and abundance of invertebrates were recorded in ricefields, notably 43 individuals of the alien snail Physella acuta. One snail was still alive in a gull pellet 3 weeks after being stored in a fridge. This represents the first record of snail dispersal within waterbird pellets. Viability was also confirmed for the cladoceran Macrothrix rosea recorded in ricefields, and the alien brine shrimp Artemia franciscana recorded mainly in saltpans. In ricefields, gulls and pellets had significantly fewer propagules and fewer taxa per gram of excreta than storks and faeces, respectively. Through their high mobility, gulls and storks can disperse invertebrates between different natural and artificial habitats, and even to landfills. They can promote metapopulation dynamics for native bryozoans and branchiopods, but also the spread of invasive snails and brine shrimp.

水鸟可以在内部运输水生无脊椎动物，从而促进陆地矩阵中水生栖息地之间的复合种群动态。然而，迄今为止，对这种传播过程的研究主要集中在个别现场或实验室研究上。我们调查了2016 年至 2017 年在西班牙西南部安达卢西亚越冬的小黑背鸥Larus fuscus 所散布的无脊椎动物，比较了由它们的运动相互连接的七个地点，具有不同程度的人为化[三个垃圾填埋场，两个盐场复合体，一个天然湖泊，和大（370公里²）稻田面积]。在稻田中，我们还比较了海鸥散播的无脊椎动物与较大的白鹳散播的无脊椎动物Ciconia ciconia. 海鸥和鹳的排泄物（粪便和颗粒）中记录了总共 642 种完整的无脊椎动物及其繁殖体（主要是羽毛苔藓虫、枝角类动物和其他鳃足类动物）。在稻田中记录到的无脊椎动物的多样性和丰度更高，特别是有 43 只外来蜗牛Physella acuta。一只蜗牛在储存在冰箱中 3 周后仍然在海鸥丸中存活。这是蜗牛在水鸟颗粒中传播的第一个记录。稻田中记录的枝角类Macrothrix rosea和外来丰年虾Artemia franciscana 的生存能力也得到证实主要记录在盐田。在稻田中，海鸥和颗粒的繁殖体和每克排泄物的分类群分别显着少于鹳和粪便。通过它们的高机动性，海鸥和鹳可以将无脊椎动物分散到不同的自然和人工栖息地，甚至是垃圾填埋场。它们可以促进原生苔藓动物和鳃足类动物的集合种群动态，也可以促进入侵蜗牛和盐水虾的传播。