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Jamie B Kirkpatrick 《Geographical Research》2023,61(1):127-137
Isolation effects on the distributions of plant species in fragmented forests appear to be weak over tens to hundreds of years and strong over geological eras. The 250 km wide, 6.5 millennia old Bass Strait, and other millennium-scale disjunctions in the range of Eucalyptus regnans forests, were used to determine the effects of intermediate periods of isolation on plant species occurrence and composition. Three of six floristic communities were found on both sides of Bass Strait. The residuals from multiple regression models using climatic variables on the latitude vector were not explained by latitude, indicating negligible isolation effects from Bass Strait. However, there was a lesser compositional effect of disjunctions within land masses than between land masses, suggesting some effect of the larger barrier. No species that commonly occurred with E. regnans and were largely confined to wet forest exhibited absences from any region where the climate and soils were within their range. If areas isolated from each other for millennia can maintain their vascular plant biota, the expenditure of conservation funds on creating corridors to connect large areas separated by anthropogenic landscape modification might require more justification than it is currently afforded. 相似文献
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Vern Baxter 《对极》2014,46(4):1014-1031
This paper presents results from a study of environmental harm created in the collision of real estate speculation and the political process that governed extension of the urban frontier of New Orleans into its eastern wetlands. Near term concerns of rent‐seeking real estate capital and the contested politics of urban infrastructure expansion challenged a fragmented state charged with regulatory oversight and protection of investments in land and citizens. The paper engages theoretically the relative inattention of urban political ecology theory to rent as a way to theorize how capital flows through land, and argues for increased attention to the problem of land rent and the multiple scales of political engagement that manage ecological crisis immanent in the metabolism of nature and society under capitalism. 相似文献
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以色列12
以色列航空工业公司微型机器人实验室研制出一款新型机器人——“机械蝴蝶”。它属于接近纳米技术的微电子科技产品。“机械蝴蝶”长20厘米,仅重12克,内含发动机、传感器、通讯及转向系统,模拟蝴蝶煽动四片翅膀推动其前进。 相似文献