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Jos Barlow Toby A. Gardner Alexander C. Lees Luke Parry Carlos A. Peres 《Biological conservation》2012,151(1):45-49
Archeologists, paleoecologists and anthropologists argue that ecologists need to give greater consideration to the pre-historical influence of humans in shaping the current structure and composition of tropical forests. We examine these arguments within the context of Amazonia, and assess the extent to which (i) the concepts of “pristine forests” and “cultural parklands” are mutually exclusive, (ii) the aggregated distribution of some plants necessarily indicates enrichment planting, (iii) pre-Columbian human disturbance has increased forest biodiversity, (iv) pre-Columbian indigenous practices were always sustainable, and (v) if indeed, the ecological impacts of pre-Columbian peoples are relevant for modern biodiversity conservation. Overall, we reject the notion that “the pristine myth has been thoroughly debunked” by archeological evidence, and suggest that the environmental impacts of historical peoples occurred along gradients, with high-impacts in settlements and patches of Amazonian Dark Earth (ADE), lesser impacts where occasional enrichment planting took place in forests surrounding agricultural plots, and a very low influence (in terms of light hunting pressure and other types of resource extraction) across vast areas of Amazonia that may always have been far from permanent settlements and navigable rivers. We suggest that the spatial distribution of pre-Columbian finds is given more attention, and urge caution before case studies are extrapolated to the entire Basin. Above all, we feel that debates over “naturalness” and environmental impacts of pre-Columbian humans are of limited relevance to present and future biodiversity conservation, and can detract from the major challenges facing Amazonia and other tropical forest regions today. 相似文献
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为加强冬青属Ilex植物资源的保护和利用,采用标准样方法调查分析了浙江宁波天童4种冬青种群结构及更新类型。结果表明:1所调查群落共出现木本植物61种,除草本层外,林木层由下至上可分为灌木层和乔木层,其中在乔木层之上存在分别由小果冬青Ilex micrococca,马尾松Pinus massoniana,天童锐角槭Acer acutum构成的不连续的超高层。2所调查冬青属植物的年龄结构可分为4种类型:增长型(皱柄冬青Ilex kengii),稳定型(铁冬青Ilex rotunda),成熟型(冬青Ilex chinensis)和衰退型(小果冬青Ilex micrococca)。3冬青属植物总体生长良好,但有些种如小果冬青属于衰退型,无幼苗,无萌枝,种子更新困难,冬青幼苗难以通过环境筛导致幼树严重匮乏,需要采取适当人工育种以及栽培技术来加以繁殖保护,并对优良种质加以选育和利用。 相似文献
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G. Boiteau R. P. Singh R. H. Parry Y. Pelletier 《American Journal of Potato Research》1988,65(11):639-649
Field tests at three sites over a period of three to four years have shown that PVYo spread in New Brunswick starts in mid-to late July when plants reach maximum height. Some 62 different genera or species of aphids were collected in experimental plots. Only seven of these were known vector species. Of the colonizing species, the alate green peach aphid,Myzus persicae (Sulzer), seems to be the most important vector. However, because it is not always present when disease spread starts, non-colonizing aphids are probably responsible for the early spread of PVYo. Five of these species of aphids were tested in the laboratory to determine their vector efficiency. A list of potential vectors is presented. The impact of these findings on the management of PVYo is discussed. 相似文献
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Daniela Basso FACCO Edicarla TRENTIN Gerson Laerson DRESCHER Rodrigo Knevitz HAMMERSCHMITT Carlos Alberto CERETTA Leandro Souza DA SILVA Gustavo BRUNETTO Paulo Ademar Avelar FERREIRA 《土壤圈》2023,33(3):496-507
Copper(Cu)-based fungicide application to control foliar diseases in grapevine(Vitis vinifera L.) can increase soil Cu availability. Brazilian soils have high natural Cu and manganese(Mn) concentrations, increasing the potential for toxicity to grapevine plants. Application of amendment substances can reduce the concentrations of toxic chemical species of Cu and Mn in soil solution, especially for the soils grown with young plants. We evaluated the chemical speciation of Cu and Mn in soil soluti... 相似文献
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