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This work offers a methodology based on statistical tools and GIS applications in a study of the adaptability of Opuntia to the environment, applied on the Mediterranean island of Sardinia. Detailed surveys of habitats containing naturalized populations of Opuntia spp. were made in order to select study sites. The topographic, soil and climatic features of these are described. The local biotypes are ascribed mainly to the spineless Opuntia ficus–indica (L.) Mill. and to the spiny Opuntia amyclaea Ten. Although introduced at different times, for different uses, they have adapted to the Sardinian environment and established in the wild. The distributions of the two species differed. The FloraMap® modelling approach was used to simulate Opuntia distribution as a function of the island's climate and produced individual distribution maps using the accession points for the two species. Our analysis showed that environmental conditions at elevations above 800 m are the main limiting factors for the presence and abundance of Opuntia in Sardinia. Spatial representation developed by GIS software indicated temperatures below 2 °C as the threshold impairing the species naturalized distribution. The statistic results also show that variation in rainfall does not affect Opuntia spatial distribution in Sardinia. 相似文献
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根据2012年夏季和2016年冬季在南黄海中部利用原位激光粒度仪(laser in situ scattering and transmissometry,LISST)进行调查获得的实测数据,对两种平均粒径计算方法的结果进行比较研究,并对产生差别的原因进行分析。结果表明:无论在夏季和冬季,在温度跃层以上粒度分布以粗颗粒为主,两种计算方法差值较小,可以相互替代。在温盐跃层以下层位,细颗粒组分增加,导致二者计算差值变大。端元分析表明较高的平均粒径值倾向于造成平均粒径差值增大。矩值法强调了粗颗粒组分的贡献,而平均粒级法对细颗粒组分的贡献更加敏感,后者是更适用于将LISST观测数据应用于陆架海区现代沉积环境研究的粒径参数计算方法。本文为使用LISST在陆架海区进行现代沉积过程研究提供了参考。 相似文献
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Eric C. Thompson 《Singapore journal of tropical geography》2020,41(1):136-153
‘Kebun culture’ is a distinctive, emergent form of rural sensibility and social-economic relations in Malaysia. As a contribution to theories of ‘planetary’ or thoroughgoing urbanization, the ethnographic evidence presented in the article illustrate a case of urban annexation of rurality, in which kebun (orchards) are detached from the social organization of rural villages and incorporated into urban-centered Malay society. Kebun, as productive land with non-rice crops, have traditionally been associated with rural kampung (village). In the late twentieth century, thoroughgoing urbanization, driven by both rural-to-urban migration and in situ urbanization of rural kampung, simultaneously produced a social disintegration of Malay kampung and increasingly urban-oriented Malay society. The kebun, which previously was an ancillary part of kampung social ecology has become dissociated from kampung and instead operates as an annex of urban-centered social lives. Kebun are also distinctively individuated rather than communal socio-economic projects. In both reserve lands and kampung areas, urban-based Malays and rural-to-urban return migrants are involved in kebun projects, through which they engage with nostalgic notions of rurality, but without the social entanglements of kampung social relations. At the same time, through kebun projects, urban Malay subjects enter into new social relations, albeit ones marked by commodification. 相似文献