In: Journal of risk research: the official journal of the Society for Risk Analysis Europe and the Society for Risk Analysis Japan, Band 18, Heft 9, S. 1184-1202
Irrigated pondfields and rainfed field systems represented alternative pathways of agricultural intensification that were unevenly distributed across the Hawaiian Archipelago prior to European contact, with pondfields on wetter soils and older islands and rainfed systems on fertile, moderate-rainfall upland sites on younger islands. The spatial separation of these systems is thought to have contributed to the dynamics of social and political organization in pre-contact Hawai'i. However, deep stream valleys on older Hawaiian Islands often retain the remains of rainfed dryland agriculture on their lower slopes. We evaluated why rainfed agriculture developed on valley slopes on older but not younger islands by comparing soils of Pololū Valley on the young island of Hawai'i with those of Hālawa Valley on the older island of Moloka'i. Alluvial valley-bottom and colluvial slope soils of both valleys are enriched 4–5-fold in base saturation and in P that can be weathered, and greater than 10-fold in resin-extractable P and weatherable Ca, compared to soils of their surrounding uplands. However, due to an interaction of volcanically driven subsidence of the young island of Hawai'i with post-glacial sea level rise, the side walls of Pololū Valley plunge directly into a flat valley floor, whereas the alluvial floor of Hālawa Valley is surrounded by a band of fertile colluvial soils where rainfed agricultural features were concentrated. Only 5% of Pololū Valley supports colluvial soils with slopes between 5° and 12° (suitable for rainfed agriculture), whereas 16% of Hālawa Valley does so. The potential for integrated pondfield/rainfed valley systems of the older Hawaiian Islands increased their advantage in productivity and sustainability over the predominantly rainfed systems of the younger islands.
A uniquely collaborative analysis of human adaptation to the Polynesian islands, told through oral histories, biophysical evidence, and historical records Humans began to settle the area we know as Polynesia between 3,000 and 800 years ago, bringing with them material culture, including plants and animals, and ideas about societal organization, and then adapting to the specific biophysical features of the islands they discovered. The authors of this book analyze the formation of their human-environment systems using oral histories, biophysical evidence, and historical records, arguing that the Polynesian islands can serve as useful models for how human societies in general interact with their environments. The islands' clearly defined (and relatively isolated) environments, comparatively recent discovery by humans, and innovative and dynamic societies allow for insights not available when studying other cultures. Kamana Beamer, Te Maire Tau, and Peter Vitousek have collaborated with a dozen other scholars, many of them Polynesian, to show how these cultures adapted to novel environments in the past and how we can draw insights for global sustainability today
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Belowground organisms play critical roles in maintaining multiple ecosystem processes, including plant productivity, decomposition, and nutrient cycling. Despite their importance, however, we have a limited understanding of how and why belowground biodiversity (bacteria, fungi, protists, and invertebrates) may change as soils develop over centuries to millennia (pedogenesis). Moreover, it is unclear whether belowground biodiversity changes during pedogenesis are similar to the patterns observed for aboveground plant diversity. Here we evaluated the roles of resource availability, nutrient stoichiometry, and soil abiotic factors in driving belowground biodiversity across 16 soil chronosequences (from centuries to millennia) spanning a wide range of globally distributed ecosystem types. Changes in belowground biodiversity during pedogenesis followed two main patterns. In lower-productivity ecosystems (i.e., drier and colder), increases in belowground biodiversity tracked increases in plant cover. In more productive ecosystems (i.e., wetter and warmer), increased acidification during pedogenesis was associated with declines in belowground biodiversity. Changes in the diversity of bacteria, fungi, protists, and invertebrates with pedogenesis were strongly and positively correlated worldwide, highlighting that belowground biodiversity shares similar ecological drivers as soils and ecosystems develop. In general, temporal changes in aboveground plant diversity and belowground biodiversity were not correlated, challenging the common perception that belowground biodiversity should follow similar patterns to those of plant diversity during ecosystem development. Taken together, our findings provide evidence that ecological patterns in belowground biodiversity are predictable across major globally distributed ecosystem types and suggest that shifts in plant cover and soil acidification during ecosystem development are associated with changes in belowground biodiversity over centuries to millennia. ; European Union's Horizon 2020 research and innovation program under Marie Sklodowska-Curie Grant [702057]; US National Science FoundationNational Science Foundation (NSF) [EAR1331828, DEB 1556090] ; This project received funding from the European Union's Horizon 2020 research and innovation program under Marie Sklodowska-Curie Grant Agreement 702057. N.F. was supported through grants from the US National Science Foundation (EAR1331828, DEB 1556090). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government. An extended version of the acknowledgments is provided in SI Appendix. ; Public domain authored by a U.S. government employee
The classic papers that laid the foundations of modern ecology alongside commentaries by noted ecologists. The period of 1970 to 1995 was a time of tremendous change in all areas of ecology—from an increased rigor for experimental design and analysis to the reevaluation of paradigms, new models for understanding, and theoretical advances. Edited by ecologists Thomas E. Miller and Joseph Travis, Foundations of Ecology II includes facsimiles of forty-six papers from this period alongside expert commentaries that discuss a total of fifty-three key studies, addressing topics of diversity, predation, complexity, competition, coexistence, extinction, productivity, resources, distribution, abundance, and conservation. The result is more than a catalog of historic firsts; this book offers diverse perspectives on the foundational papers that led to today's ecological work. Like this book's 1991 predecessor, Foundations of Ecology edited by Leslie A. Real and James H. Brown, Foundations of Ecology II promises to be the essential primer for graduate students and practicing ecologists for decades to come
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