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Increasing synergistic effects of habitat destruction and hunting on mammals over three decades in the Gran Chaco |
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| Authors: | Alfredo Romero-Muñoz Ana Benítez-López Damaris Zurell Matthias Baumann Micaela Camino Julieta Decarre Hugo Castillo del Anthony J Giordano Bibiana Gómez-Valencia Christian Levers Andrew J Noss Verónica Quiroga J Jeffrey Thompson Ricardo Torres Marianela Velilla Andrea Weiler Tobias Kuemmerle |
| Institution: | 1. Geography Dept, Humboldt-Univ., Berlin, Berlin, Germany;2. Dept of Environmental Science, Inst. for Wetland and Water Research, Radboud Univ., Nijmegen, the Netherlands
Integrative Ecology Group, Estación Biológica de Doñana, (EBD-CSIC), Sevilla, Spain;3. Proyecto Quimilero, Resistencia, Argentina;4. Inst. de Recursos Biológicos, Inst. Nacional de Tecnología Agropecuaria (INTA), Buenos Aires, Argentina;5. Guyra Paraguay, Asunción, Paraguay;6. S.P.E.C.I.E.S. (The Society for the Preservation of Endangered Carnivores and their International Ecological Study), Ventura, CA, USA Center for Tropical Research, UCLA Inst. of the Environment and Sustainability, Los Angeles, CA, USA;7. Inst. de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, Colombia Grupo de Estudios de Sistemas Ecológicos en Ambientes Agrícolas, Facultad de Ciencias Exactas y Naturales, Univ. de Buenos Aires, Argentina;8. Geography Dept, Humboldt-Univ., Berlin, Berlin, Germany Inst. for Resources, Environment and Sustainability (IRES), Univ. of British Columbia, Vancouver, BC, Canada Dept Computational Landscape Ecology, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany;9. Dept of Geography, Univ. of Florida, Gainesville, FL, USA;10. Inst. de Diversidad y Ecología Animal (IDEA – CONICET), Centro de Zoología Aplicada, Univ. Nacional de Córdoba, Córdoba, Argentina Proyecto Yaguareté-Centro de Investigaciones del Bosque Atlántico, Puerto Iguazú, Misiones, Argentina;11. Guyra Paraguay-CONACYT, Asunción, Paraguay Inst. Saite, Asunción, Paraguay;12. Proyecto Yaguareté-Centro de Investigaciones del Bosque Atlántico, Puerto Iguazú, Misiones, Argentina Museo de Zoología, Univ. Nacional de Córdoba, Córdoba, Argentina;13. Guyra Paraguay-CONACYT, Asunción, Paraguay Inst. Saite, Asunción, Paraguay School of Natural Resources and the Environment, Univ. of Arizona,, Tucson, AZ, USA;14. Depto de Biología, Univ. Nacional de Asunción, San Lorenzo, Paraguay;15. Geography Dept, Humboldt-Univ., Berlin, Berlin, Germany Integrative Research Inst. on Transformations of Human-Environment Systems (IRI THESys), Berlin, Germany |
| Abstract: | Habitat destruction and overexploitation are the main threats to biodiversity and where they co-occur, their combined impact is often larger than their individual one. Yet, detailed knowledge of the spatial footprints of these threats is lacking, including where they overlap and how they change over time. These knowledge gaps are real barriers for effective conservation planning. Here, we develop a novel approach to reconstruct the individual and combined footprints of both threats over time. We combine satellite-based land-cover change maps, habitat suitability models and hunting pressure models to demonstrate our approach for the community of larger mammals (48 species > 1 kg) across the 1.1 million km2 Gran Chaco region, a global deforestation hotspot covering parts of Argentina, Bolivia and Paraguay. This provides three key insights. First, we find that the footprints of habitat destruction and hunting pressure expanded considerably between 1985 and 2015, across ~40% of the entire Chaco – twice the area affected by deforestation. Second, both threats increasingly acted together within the ranges of larger mammals in the Chaco (17% increase on average, ± 20% SD, cumulative increase of co-occurring threats across 465 000 km2), suggesting large synergistic effects. Conversely, core areas of high-quality habitats declined on average by 38%. Third, we identified remaining priority areas for conservation in the northern and central Chaco, many of which are outside the protected area network. We also identify hotspots of high threat impacts in central Paraguay and northern Argentina, providing a spatial template for threat-specific conservation action. Overall, our findings suggest increasing synergistic effects between habitat destruction and hunting pressure in the Chaco, a situation likely common in many tropical deforestation frontiers. Our work highlights how threats can be traced in space and time to understand their individual and combined impact, even in situations where data are sparse. |
| Keywords: | conservation planning defaunation deforestation habitat loss land-use change overexploitation |