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Biological invasions are one of the great threats to Earth’s ecosystems and biodiversity in the Anthropocene. However, species introductions and invasions extend deep into the human past, with the translocation of both wild and domestic species around the world. Here, we review the human translocation of wild plants and animals to the world’s islands. We focus on establishing criteria used to differentiate natural from human-assisted dispersals and the differences between non-native and invasive species. Our study demonstrates that, along with a suite of domesticates, ancient people transported numerous wild plants and animals to islands and helped shape ecosystems in ways that have important ramifications for modern conservation, restoration, and management.  相似文献   
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Bootstrapping methods have so far been rarely used to evaluate spatial datasets. Based on an extensive Monte Carlo study we find that also for spatial, cross‐sectional data, the wild bootstrap test proposed by Davidson and Flachaire ( 2008 ) based on restricted residuals clearly outperforms asymptotic as well as competing bootstrap tests, like the pairs bootstrap.  相似文献   
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Stable carbon (δ13C) and nitrogen (δ15N) isotope analyses of dog (Canis familiaris), island fox (Urocyon littoralis), and human bone collagen from CA-SRI-2 (AD 130–1830) on Santa Rosa Island, California provide a proxy of diet and the relationships between humans and these animals. Carbon isotopic signatures indicate that Native Americans and their dogs at CA-SRI-2 subsisted almost exclusively on marine resources, while the island fox ate primarily terrestrial foods. Nitrogen isotopes and archaeofaunal remains indicate that humans and dogs also ate higher trophic level foods, including finfishes, marine mammals, and seabirds with smaller amounts of shellfish. The CA-SRI-2 island foxes appear to have eaten higher amounts of terrestrial foods, similar to the diets observed in modern fox populations. These data generally confirm the commensal relationship assumed to exist between domesticated dogs and people, but the carbon isotopic composition of dogs is enriched ∼2‰ compared to humans. We hypothesize that the difference in carbon isotopes between dogs and humans may have resulted from a higher consumption of C3 plants with lower δ13C values by humans, or less likely from the ingestion by dogs of significant amounts of bone collagen, which is enriched by ∼4‰ over associated muscle.  相似文献   
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Clusters influence the way firms cooperate, organize and compete, but clusters and their related benefits rarely come spontaneously in a straight line of expansion. It is argued that clusters typically develop in accordance with a life cycle, which includes an evolutionary sequence of steps where actors from the private and public sectors are engaged and where one or more cluster facilitators are coordinating and promoting the process. In the literature, the role of cluster facilitators has almost exclusively been described as static, leaving a research gap about how this particular role changes during the life cycle of clusters. Inspired by that research gap, this paper contributes to the understanding of the relationship between cluster development and cluster facilitation. It brings forward a framework for describing and discussing the exact changes taking place in the role of cluster facilitators, including the facilitation focus, competencies and tasks that they make use of along the cluster life cycle. This investigation is based on a multiple case study consisting of nine different clusters located in Denmark.  相似文献   
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To investigate potential human impacts on California Channel Island shellfish stocks over the past 10,000 years, we measured 1718 owl limpet shells from 19 archaeological components on San Miguel Island. Inhabiting the middle intertidal zone of Pacific Coast rocky shores, owl limpets are slow-growing mollusks that can live for 30 years and reach lengths of over 100 mm. Recent ecological studies indicate that owl limpets are highly susceptible to heavy human predation, which results in reduced mean shell sizes among Lottia populations along the coasts of Alta and Baja California. On San Miguel Island, we identified a significant trans-Holocene reduction in mean owl limpet size, beginning more than 6500 years ago and accelerating at least 4400 years ago. Fluctuations in limpet size show no clear correlation with changes in sea surface temperature and marine productivity, suggesting that increased predation by growing human populations was primarily responsible for the reduction in Lottia size over time. Our results provide further evidence that prehistoric peoples significantly influenced nearshore fisheries long before the development of the commercial and industrialized fisheries of historic times.  相似文献   
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The starting point of this paper is an analysis of 66 Danish burials, which contain flint daggers and archery equipment. The paper examines whether this tradition should be seen as an indication of the presence of organised warriors in the Danish early Late Neolithic, or if it rather reflects some kind of general warrior status related to maleness. In a Danish perspective the archery burials are closely connected to the Bell Beaker Culture of northern Jutland, and the custom seems to originate in the European Bell Beaker Culture, where ranked societies and warrior institutions have been argued to exist.  相似文献   
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Whales have long been an important part of Pacific Northwest Coast human subsistence and lifeways. Native peoples on the Oregon Coast were not known to hunt whales, but a humpback whale phalange with an embedded bone harpoon at the Par-Tee site (35CLT20) and ethnographic accounts raised the possibility of opportunistic whale hunting. We analyzed a suite of whale remains from Par-Tee and performed ancient DNA-based species identifications on 30 specimens. The assemblage includes gray whales (Eschrichtius robustus, 60.7% of the assemblage), humpbacks (Megaptera novaeangliae, 32.1%), minkes (Balaenoptera acutorostrata, 3.6%), and orcas (Orcinus orca, 3.6%). While the species composition is similar to those found in archaeological deposits from systematic whaling areas in Washington and Vancouver Island, bone modification patterns and element representation reveal important differences. Our analysis demonstrates that whales were likely a supplementary part of human subsistence at Par-Tee and, while opportunistic whale hunting likely occurred, it may have been secondary to scavenging and utilization of beached and/or drift whales.  相似文献   
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The Ruhr area has advanced to the largest university region in Germany – often unnoticed within and outside. At the same time scientific institutions have become a major economic factor. Because of the higher and extra-university research institutions about 2.5 billion euros are effective as a demand potential in the region. 1.7 billion euros of this amount are directly associated with investments and operating expenditures of the scientific institutions as well as consumptions of employees and students. Additional 770 million euros result in revenues of many branches such as trade, housing, gastronomy sector, handcraft industry etc. It should not be underestimated that higher and extra-university research institutions generate with their research activities particular funding from the European Union or the rest of Germany for benefit of the region. Each euro spent by the state government for basic funding creates 39 cents third-party funding. These regional-economic effects result in noticeable employment impacts within the region. Around 25,000 people are directly employed in higher and extra-university research institutes or student unions (Studierendenwerke), about 22,000 jobs in other economic sectors are ensured or created by the induced demand. Science has thus become an important economic factor and represents an essential counterbalance to employment decline in shrinking industries of the region. The specific inclusion of science in a regional development strategy and targeted relining with appropriate measures to strengthen the science creates therefore an effective starting point for the design of structural change.  相似文献   
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