Year: 2026
Type: article
Abstract: ABSTRACT Environmental conditions vary longitudinally along a river continuum, shaping the structure and functioning of biological communities, as explained by the River Continuum Concept. Riparian zones are important transitional areas linking the aquatic and terrestrial ecosystems. Therefore, a meta‐ecosystem perspective predicts that the longitudinal patterns described by the RCC extend into riparian habitats, leading to systematic change in terrestrial communities. We conducted a field study on near‐natural forested sections of five streams in southwestern Germany, sampling spiders in the up‐, mid‐ and downstream sections. We examined how variation in aquatic and terrestrial abiotic parameters among stream sections influences riparian spider diversity and community composition using pitfall traps and hand‐catches. Spider abundance increased along the stream course, whereas alpha diversity remained unchanged, suggesting that larger and more extensive riparian habitats in midstream and downstream reaches support higher population densities through greater habitat quality and resource availability without increasing local species richness. Despite similar levels of alpha diversity, each stream section harbored a distinct spider community composed of varying proportions of riparian specialists and habitat generalists. Correspondingly, spider trait composition changed markedly along the stream course: upstream reaches were characterized by heterogeneous communities with a high proportion of shade‐tolerant and web‐building species, whereas midstream reaches were more homogeneous and dominated by large‐bodied active hunters. Downstream communities were again more heterogeneous and contained many web‐building and open land‐preferring species. In contrast, spider moisture preferences remained largely unchanged along the stream course. Our findings enhance the understanding of how environmental longitudinal gradients shape riparian habitats and communities under near‐natural conditions, a fundamental step in understanding human impacts on riparian biodiversity.
Source: Ecology and Evolution
DOI: 10.1002/ece3.74512
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life on land
Open Access status: gold
Estimated APC paid: $2,570
Funder: Deutsche Forschungsgemeinschaft
OpenAlex ID: W7222633440