Do traits follow taxonomy? Biodiversity and community assembly in marine ecosystems
More than 2/3 of the Earth’s surface is covered by oceans, encompassing vast environmental gradients and variability in habitats. Thousands of species inhabit this seemingly endless space, yet we know surprisingly little about its stunning diversity, how it is shaped, assembled and structured. Conse...
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| Format: | Book |
| Language: | English |
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Technical University of Denmarik
2019
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| Online Access: | https://orbit.dtu.dk/en/publications/4f30ec34-2442-429e-bcab-bba8b141a7a6 https://backend.orbit.dtu.dk/ws/files/179419714/PhD_Thesis_Tim_Spaanheden_Dencker_DTU_Aqua.pdf |
| Summary: | More than 2/3 of the Earth’s surface is covered by oceans, encompassing vast environmental gradients and variability in habitats. Thousands of species inhabit this seemingly endless space, yet we know surprisingly little about its stunning diversity, how it is shaped, assembled and structured. Consequently, understanding these mechanisms and how they vary in space and time is a key objective in ecology. These questions have traditionally been approached with a species-centric focus. However, this taxonomic approach is inherently limited, as the mere presence of a species reveals little to nothing about why the species is present and able to persist. Instead, species can be characterized by their traits, describing phenotypical characteristics that determine the species’ response to environmental conditions, its interactions in a food web and ultimately its effect on ecosystem functioning. This trait-based approach has emerged as a promising field of research allowing for a more causal and mechanistic understanding of marine biodiversity and ecosystems. In this thesis, I have explored marine demersal (bottom-living) fish communities across spatial and temporal scales in the North Atlantic and Northeast Pacific with regard to patterns and trends in biodiversity, community assembly processes, and environmental and anthropogenic drivers. Structuring of communities has been suggested to follow deterministic processes associated with responses to abiotic factors (environmental filtering) and interactions with other species (limiting similarity). An interplay between these two assembly processes shape and maintain community compositions. We used spatially and temporally resolved survey data on species abundances and traits to investigate temporal spatial patterns of species and trait diversity and the underlying community assembly mechanisms in the North Sea. Our results show that overall temporal trends in species richness and trait richness were highly correlated but varied considerably in space, indicating different ... |
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