Estimating and interpreting migration of Amazonian forests using spatially implicit and semi‐explicit neutral models |
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| Authors: | Edwin Pos Juan Ernesto Guevara Andino Daniel Sabatier Jean‐François Molino Nigel Pitman Hugo Mogollón David Neill Carlos Cerón Gonzalo Rivas‐Torres Anthony Di Fiore Raquel Thomas Milton Tirado Kenneth R. Young Ophelia Wang Rodrigo Sierra Roosevelt García‐Villacorta Roderick Zagt Walter Palacios Cuenca Milton Aulestia Hans ter Steege |
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| Affiliation: | 1. Ecology and Biodiversity Group, Utrecht University, Utrecht, The Netherlands;2. Group of Dynamic Biodiversity, Naturalis Biodiversity Center, Leiden, The Netherlands;3. Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA;4. IRD, UMR AMAP, Montpellier, France;5. The Field Museum, Chicago, IL, USA;6. Center for Tropical Conservation, Nicholas School of the Environment, Duke University, Durham, NC, USA;7. Endangered Species Coalition, Silver Spring, MD, USA;8. Universidad Estatal Amazónica, Puyo, Ecuador;9. Escuela de Biología Herbario Alfredo Paredes, Universidad Central Herbario Alfredo Paredes, Quito, Ecuador;10. Colegio de Ciencias Biológicas y Ambientales and Galápagos, Academic Institute for the Arts and Sciences, Universidad San Francisco de Quito, Quito, Ecuador;11. Department of Wildlife Ecology and Conservation, 110 Newins‐Ziegler Hall, University of Florida, Gainesville, FL;12. Department of Anthropology, University of Texas at Austin, Austin, TX, USA;13. Iwokrama International Programme for Rainforest Conservation, Georgetown, Guyana;14. GeoIS, Quito, Ecuador;15. Geography and the Environment, University of Texas at Austin, Austin, TX, USA;16. Northern Arizona University, Flagstaff, AZ, USA;17. Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, UK;18. Royal Botanic Garden of Edinburgh, Edinburgh, UK;19. Tropenbos International, Wageningen, The Netherlands;20. Herbario Nacional del Euador, Universidad Técnica del Norte, Quito, Ecuador;21. Herbario Nacional del Ecuador, Quito, Ecuador;22. Systems Ecology, Free University Amsterdam, The Netherlands |
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| Abstract: | With many sophisticated methods available for estimating migration, ecologists face the difficult decision of choosing for their specific line of work. Here we test and compare several methods, performing sanity and robustness tests, applying to large‐scale data and discussing the results and interpretation. Five methods were selected to compare for their ability to estimate migration from spatially implicit and semi‐explicit simulations based on three large‐scale field datasets from South America (Guyana, Suriname, French Guiana and Ecuador). Space was incorporated semi‐explicitly by a discrete probability mass function for local recruitment, migration from adjacent plots or from a metacommunity. Most methods were able to accurately estimate migration from spatially implicit simulations. For spatially semi‐explicit simulations, estimation was shown to be the additive effect of migration from adjacent plots and the metacommunity. It was only accurate when migration from the metacommunity outweighed that of adjacent plots, discrimination, however, proved to be impossible. We show that migration should be considered more an approximation of the resemblance between communities and the summed regional species pool. Application of migration estimates to simulate field datasets did show reasonably good fits and indicated consistent differences between sets in comparison with earlier studies. We conclude that estimates of migration using these methods are more an approximation of the homogenization among local communities over time rather than a direct measurement of migration and hence have a direct relationship with beta diversity. As betadiversity is the result of many (non)‐neutral processes, we have to admit that migration as estimated in a spatial explicit world encompasses not only direct migration but is an ecological aggregate of these processes. The parameter m of neutral models then appears more as an emerging property revealed by neutral theory instead of being an effective mechanistic parameter and spatially implicit models should be rejected as an approximation of forest dynamics. |
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| Keywords: | betadiversity migration neutral theory parameter estimation species composition species diversity |
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