Australian wattle species in the Drakensberg region of South Africa - An invasive alien or a natural resource?
Australian wattle species in the Drakensberg region of South Africa - An invasive alien or a natural resource?
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DOI：
10.1016/j.agsy.2005.06.009
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发表时间：
2005-09-01
影响因子：
6.6
通讯作者：
Birch-Thomsen, T
中科院分区：
文献类型：
--
作者：
de Neergaard, A;Saarnak, C;Birch-Thomsen, T
对南非Drakensberg地区农村地区两种外来荆树物种（黑荆树和银荆树）的传播情况以及这些树木对当地社区生计的重要性进行了调查。在空中摄影的帮助下，选择了村庄附近的两块地。荆树空中覆盖增加7%和20%，分别在两个地块，在1953年，超过21%和33%，在1975年，到2000年的48%和58%。1995年，设立了一个由政府赞助的国家方案，“为水而工作”，其明确目的是雇用据称来自最贫穷和处境不利的农村社区的人，清除河流集水区和水道上的外来入侵物种。虽然该计划为农村地区的数千个家庭提供了收入，但它也可能危及这些社区的生计。金合欢是农村家庭的重要资源;几乎所有家庭都将其作为主要热源和建筑材料。其他用途包括提取药物和20%的受访家庭通过出售木柴获得收入。从农村社区的看法来看，对外来物种最大的担忧是它的高耗水量（尽管这并没有直接影响他们），以及它为小偷和罪犯提供掩护。因此，大多数村民希望要么减少金合欢林（58%和86%，在2001年和2003年的研究中，分别），或他们保持目前（42%和10%，分别）。叶木本豆科植物已被证明是巨大的潜力，绿色肥料和饲料供应商在许多农业生态系统。在研究区丰富的荆树建议探索替代有益的用途，在低投入的农业系统实践。在分解试验中评价了金合欢作为绿色肥料的潜力。在所有的处理中，荆树凋落物固定氮从土壤中，尽管一个高的N含量的凋落物。土壤中植物有效磷在培养4-5个月后增加。我们认为，目前的做法，外部资助的荆树皮控制是不可持续的，从长远来看。我们讨论了更高水平的社区参与和所有权的替代方法，并得出结论，具有讽刺意味的是，目前的土地利用不足可能是一个可行的解决方案，以蔓延的荆树的最大限制之一。(c)2005爱思唯尔有限公司保留所有权利。
An investigation into the spread of two alien wattle species (Acacia mearnsii and Acacia dealbata) in rural parts of the Drakensberg region of South Africa and the importance of the trees to the livelihoods of the local communities was carried out. With the aid of aerial photography two plots near the village were selected. Wattle aerial cover increased from 7% and 20% in the two plots, respectively, in 1953, over 21% and 33% in 1975, to 48% and 58% in 2000. In 1995, a government-sponsored national programme, "Working for Water" was established, with the expressed purpose of employing people described as being from the poorest and disadvantaged rural communities to clear areas of invasive alien species from river catchments and water courses. Whilst the programme provides an income to thousands of families in rural areas, it may also be jeopardising the livelihoods of the same communities.The wattle is an important resource for village households; virtually all households used it as their primary heat source and for building materials. Other uses included medicine extraction and 20% of the interviewed households gained income from selling firewood.From the rural communities' perception, the greatest concern regarding the alien species is its high water consumption (although this did not affect them directly), and the fact that it provides cover to thieves and criminals. Consequently, most villagers wanted either a reduction of the wattle stands (58% and 86% in the 2001 and 2003 study, respectively), or that they remained as at present (42% and 10%, respectively).Leaves from woody legumes have demonstrated large potential as green manures and fodder providers in many agroecosystems. The abundance of the wattle in the study area suggested an exploration of alternative beneficial uses in the low input farming systems practiced. The wattle's potential as green manure was evaluated in a decomposition trial. In all treatments, the wattle litter immobilised nitrogen from soil, in spite of a high N content of the litter. Plant available P increased in soil after 4-5 months of incubation.We argue that the current practice of externally funded wattle control is not sustainable in the long term. We discuss alternative approaches with a higher level of community participation and ownership, and conclude that the current underutilization of land may, ironically, be one of the largest constraints for a viable solution to the spread of wattle. (c) 2005 Elsevier Ltd. All rights reserved.