J.F. Blumenbach Institute of Zoology and Anthropology, Department of Animal Ecology, University of Göttingen, Untere Karspüle 2, 37073, Göttingen, Germany.
Centre of Biodiversity and Sustainable Land Use, University of Göttingen, Büsgenweg 1, 37077, Göttingen, Germany.
Oecologia. 2024 Oct;206(1-2):87-100. doi: 10.1007/s00442-024-05615-x. Epub 2024 Sep 4.
Salt marshes represent a unique ecosystem at the marine-terrestrial boundary of shallow protected coastlines. Microarthropods form an essential component of soil food webs, but how they colonize new intertidal habitats is little understood. By establishing two experimental systems without animals, we investigated microarthropod colonization (1) at the seashore from the pioneer zone to the lower and upper salt marsh and (2) at the same tidal height on artificial islands 500 m from the seashore. Potential source populations of microarthropods in the respective zones were also investigated. Colonization of microarthropods after 5 years was consistently faster on the seashore than on the artificial islands. Collembola and Mesostigmata colonized all the zones both on the seashore and on the artificial islands, with colonization being faster in the upper salt marsh and in the pioneer zone than in the lower salt marsh. Oribatida colonized the new habitats on the seashore, but only little on the artificial islands. Variations in species composition were more pronounced between salt marsh zones than between experimental systems, indicating that local environmental conditions (i.e., inundation frequency) are more important for the assembly of microarthropod communities than the distance from source populations (i.e., dispersal processes). Variations in community body size of Oribatida and Mesostigmata indicated environmental filtering of traits, with smaller species suffering from frequent inundations. Notably, Mesostigmata most successfully colonized the new habitats across salt marsh zones on both systems. Overall, the results document major mechanisms of colonization of intertidal habitats by microarthropods with different life histories and feeding strategies.
盐沼是浅海保护海岸线陆海边界的独特生态系统。微型节肢动物是土壤食物网的重要组成部分，但它们如何在新的潮间带生境中定殖还知之甚少。通过建立两个没有动物的实验系统，我们研究了微型节肢动物的定殖：(1) 在从先锋区到下部和上部盐沼的海滨；(2) 在距离海滨 500 米的人工岛上，在相同的潮位上。还研究了各自区域中微型节肢动物的潜在源种群。经过 5 年的定殖，在海滨的定殖速度始终快于人工岛。在海滨和人工岛上，弹尾目和真螨目都可以定殖所有的区域，在上部盐沼和先锋区的定殖速度比在下部盐沼快。在海滨，潮间带新栖息地有圆皮蠹目昆虫定殖，但在人工岛上几乎没有。在盐沼区之间，物种组成的变化比在实验系统之间更为明显，这表明局部环境条件（即淹没频率）对微型节肢动物群落的组装比与源种群的距离（即扩散过程）更为重要。圆皮蠹目昆虫和真螨目的群落体型变化表明了对特征的环境过滤，较小的物种更容易受到频繁淹没的影响。值得注意的是，真螨目在两个系统的所有盐沼区都成功地定殖了新栖息地。总的来说，这些结果记录了具有不同生活史和摄食策略的微型节肢动物在潮间带生境中定殖的主要机制。
