BayCEER Workshop 2024
10/11 October 2024
No shift in the vegetation trait space despite impacts of human colonisation on Macaronesian islands
2 Universitat Autònoma de Barcelona, CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, España
3 CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Pólo dos Açores,Faculdade de Ciências e Tecnologia, Universidade dos Açores
4 Geosciences Barcelona (GEO3BCN), CSIC, Lluís Solé i Sabarís s/n, 08028 Barcelona, Spain
5 Department of Geography and History, Archaeological Micromorphology and Biomarker Research Lab, Instituto Universitario de Bio-Orgánica Antonio González, University of La Laguna, Island Ecology and Biogeography Group, Instituto Universitario de Enfermedades
6 Island Ecology and Biogeography Group, Instituto Universitario de Enfermedades
7 School of Culture, History and Language, College of Asia and the Pacific, Australian Research Council (ARC) Centre of Excellence for Australian Biodiversity and Heritage, Australian National University
8 German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Department of Computer Science, Martin Luther University Halle-Wittenberg
O 3.2 in From plant growth to ecosystems
10.10.2024, 17:05-17:20, H 36
Integrating fossil pollen data into biogeography helps to reconstruct the functional response of ecosystems to environmental change over large spatio-temporal scales including human colonisation events on islands. Palaeoecological analyses have described an increased turnover in taxonomic composition on islands worldwide. Here, using a latitudinal gradient expanding from the Açores to Cabo Verde archipelagos, our main question is: Does the trait composition of pollen assemblages change after the arrival of humans on islands as the observed turnover in taxonomic composition would suggest?
Making use of a detailed dataset on Plant Functional Traits on the Canarias, we inferred trait values describing plant height, leaf area, leaf mass per area, Nitrogen mass, seed mass and stem specific density for pollen taxa at overall 14 sites in the Açores, the Canárias, and Cabo Verde. Community weighted means for each trait were determined at each depth level based on pollen proportions. The resulting trait composition of pollen assemblages was correlated with human colonisation events across islands and archipelagos. Neither trait values nor trait composition changed uniformly after the arrival of humans across all archipelagos. In the Açores, individual traits and trait composition changed systematically across sites, whereas the response of traits at sites within other archipelagos varies. For example, Leaf mass per area decreased in the Açores, but remained constant in Cabo Verde and either increased or decreased in the Canarias. Nitrogen mass, seed mass and stem specific density were generally decreasing in at least two archipelagos. Although human presence has accelerated the change in taxonomic composition, no shift in trait space of vegetation is detectable across the archipelagos studied. Fossil pollen data not only can be used to reconstruct biodiversity dynamics on a taxonomic but also on a trait scale.
Keywords: fossil pollen, island biogeography, homogenisation, functional ecology
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