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Accueil du site → Doctorat → Allemagne → 2020 → Understanding geographies of threat : Impacts of habitat destruction and hunting on large mammals in the Chaco

Humboldt-Universität zu Berlin (2020)

Understanding geographies of threat : Impacts of habitat destruction and hunting on large mammals in the Chaco

Romero-Muñoz, Alfredo

Titre : Understanding geographies of threat : Impacts of habitat destruction and hunting on large mammals in the Chaco

Auteur : Romero-Muñoz, Alfredo

Université de soutenance : Humboldt-Universität zu Berlin

Grade : Doctor rerum naturalium (Dr. rer. nat.) 2020

Résumé
The main drivers of the current global biodiversity crisis are habitat destruction and overexploitation. Yet, we lack understanding of their individual and combined spatial impact on different aspects of biodiversity, and how they change over time. Because both threats are common, these knowledge gaps preclude building more effective conservation strategies. The overarching goal of this thesis was to understand how the impacts of habitat destruction and overexploitation on biodiversity change in space and over time. I assessed these geographies of threat at high spatial resolutions and over three decades for different biodiversity aspects : species, communities, and the taxonomic, phylogenetic, and functional facets of biodiversity. I focused on the 1.1 million km² Gran Chaco, the largest tropical dry forest globally, and a global deforestation hotspot. Results reveal that over 30 years, the spatial impacts of each threat expanded over larger areas than the area deforested. This resulted in widespread losses of high-quality and safe areas for the jaguar, the entire larger mammal community and for all facets of the mammalian diversity. Such declines suggest a generalized biotic impoverishment that includes the loss of species, evolutionary history, and ecological functions across much of the Chaco. Both threats contributed substantially to biodiversity declines, and their relative importance varied among species and biodiversity facets. Moreover, the areas where both threats synergize increased over time, likely exacerbating biodiversity losses. For each biodiversity aspect, I identified priority areas of safe and high-quality habitats, and hotspots of high threat impacts, which could guide more effective complementary proactive and reactive conservation strategies. This thesis highlights the importance of jointly assessing the impact of multiple threats over time to better understand the impact of humans on biodiversity and to identify effective ways to mitigate them.

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Page publiée le 11 novembre 2021