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  • Local human pressures modulate turf sediment loads in a marginal warm-temperate oceanic island
    Publication . Lema, Mar Mourin De; Bosch, Dr. Néstor E.; Erzini, Karim
    Human activities are rapidly altering the structure and functioning of ecosystems around the globe, but the magnitude and extent of ecological impacts remain poorly understood. Algal turfs are expected to replace macroalgal forests and coral reefs as the dominant benthic state in the Anthropocene, a process that is already occurring in many disparate temperate and tropical regions worldwide. Turf seascapes play a key role in regulating ecosystem processes through sediment retention. However, our understanding of sediments trapped by turf on coastal reefs, particularly in marginal oceanic islands, remains limited. Here, we quantified turf seascape composition (algal structure and mean height) and sediment properties (total particulate load, grain size distribution, and organic content) at an insular scale, using a densely populated warm-temperate oceanic island as a model system. We further decoupled the role of geomorphological, habitat, and anthropogenic predictors in explaining variation in turf seascape properties. We revealed significant spatial variation in turf seascape properties event at relatively small spatial scales, with turf sediment loads varying by three orders of magnitude (~ 1 g/m² to 2000 g/m²). In contrast, organic load varied considerably less (~ 1 g/m² to 100 g/m²) and displayed no significant variations across our study sites. Human pressure and algal composition were the strongest predictors of turf sediment load, highlighting the coupled role of global climate change and local human stressors in modulating sediment dynamics in emerging turf seascapes. Our study provides baseline information on the patterns and drivers of turf sediments in marginal oceanic islands and calls for efforts to link variation in turf seascape properties with key ecological processes that maintain the functionality of these vulnerable systems.
    2024-12-16Dissertação de mestrado Acesso aberto Ver mais