Threshold Distinctions Between Equilibrium and Nonequilibrium Pastoral Systems Along a Continuous Climatic Gradient |
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| Authors: | Tomoo Okayasu Toshiya Okuro Undarmaa Jamsran Kazuhiko Takeuchi |
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| Institution: | 1. Project Research Associate, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan;2. Associate Professor, and, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan;3. Associate Professor, Center for Ecosystem Studies, Mongolian State University of Agriculture, Zaisan 53, Ulaanbaatar 210153, Mongolia;4. Professor, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan;1. Intensive Care Unit, Hospital Universitario de Canarias, Ofra, s/n. La Laguna, 38320, Santa Cruz de Tenerife, Spain;2. Intensive Care Unit, Hospital Universitario Nuestra Señora Candelaria, Crta Rosario s/n. Santa Cruz Tenerife, 38010, Spain;3. Deparment of Phisiology, Faculty of Medicine, University of the La Laguna, Ofra, s/n. La Laguna, 38320, Santa Cruz de Tenerife, Spain;4. Faculty of Pharmacy, University of the La Laguna, Avda. Astrofísico Francisco Sánchez s/n, La Laguna, Tenerife, 38071, Spain;5. Intensive Care Unit, Hospital Clínico Universitario de Valencia, Avda. Blasco Ibáñez n°17-19, Valencia, 46004, Spain;6. Intensive Care Unit, Hospital Universitario Dr. Negrín, Barranco de la Ballena s/n. Las Palmas de Gran Canaria, 35010, Spain;7. Intensive Care Unit, Hospital San Jorge de Huesca, Avenida Martínez de Velasco n°36, Huesca, 22004, Spain;8. Intensive Care Unit, Hospital Insular, Plaza Dr. Pasteur s/n. Las Palmas de Gran Canaria, 35016, Spain;9. Research Unit, Hospital Universitario de Canarias, Ofra, s/n. La Laguna, 38320, Santa Cruz de Tenerife, Spain;10. Laboratory Department, Hospital Universitario de Canarias, La Laguna, Santa Cruz de Tenerife, Spain;1. Department of Surgery, Molecular Cardiology and Angiogenesis Laboratory, University of Connecticut Health Center, Farmington, CT, USA;2. ESSEN BioScience, Ann Arbor, MI, USA;3. Second Department of Internal Medicine Kansai Medical University, Moriguchi City, Japan;1. Departamento de Medicina Clínica, Hospital Universitário Onofre Lopes (HUOL), Natal, RN, Brazil;2. Health Graduate Program, Centro de Ciencias da Saúde, UFRN, Natal, RN, Brazil;3. Division of Endocrinology and Diabetes, University of Pernambuco Medical School, Recife, Brazil;4. Instituto de Medicina Tropical do Rio Grande do Norte, Natal, RN, Brazil;5. Departamento de Bioquímica, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil;6. Institute of Science and Technology of Tropical Diseases (INCT-DT), Natal, RN, Brazil |
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| Abstract: | In equilibrium environments where rainfall is relatively stable, grazing animal–vegetation dynamics are density-dependent; it is therefore appropriate to calculate carrying capacities and use them to define sustainable animal populations. In contrast, nonequilibrium environments are characterized by fluctuations in characteristics such as rainfall, resulting in fluctuations in plant biomass and in the corresponding carrying capacity. Herders adapt to such environments by moving opportunistically to pastures with better conditions. Studies since the 1990s have significantly improved our understanding of the continuity and integration of equilibrium and nonequilibrium systems. However, it remains unclear how and where such continuous, integrated rangeland systems result in qualitatively different land use patterns by local herders along a climatic gradient. Here, we developed a simple model that uses key environmental factors to predict a threshold representing the boundary between equilibrium and nonequilibrium land use systems, and we used an area of Mongolian rangeland as an example. We found a threshold in the proportion of usable pasture that corresponded to a specific range of rainfall values. Comparison of our results with previous ones supported our hypothesis about this threshold. The threshold behavior suggested that it is important to identify and monitor the boundary between equilibrium and nonequilibrium land use systems so that managers can respond to climatic change. National governments and aid agencies must understand the threshold process before they can identify focal areas where management regime change is required and propose appropriate policies that will support herders in the long term. Our study provides a simple, low-cost tool to evaluate ecosystems in this context. |
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