Random and systematic land-cover transitions in northern Ghana
Random and systematic land-cover transitions in northern Ghana
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DOI：
10.1016/j.agee.2005.10.019
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发表时间：
2006-04-01
影响因子：
6.6
通讯作者：
Braimoh, AK
中科院分区：
文献类型：
--
作者：
Braimoh, AK
本文的目的是探测加纳北方5400平方公里区域内的主要景观变化。传统的过渡矩阵的深入分析被用来分离景观转换随机和系统的过渡。如果一个土地覆盖类别从其他类别获得的土地覆盖与其他损失类别的可用性成比例，或者如果一个类别输给其他类别与其他增加类别的大小成比例，则景观过渡是随机的。任何偏离这些比例的大的偏差都被认为是系统性的转变。最高的系统过渡涉及约12%的景观从草地到耕地的转换。其他系统的景观过渡包括封闭林地的开放林地（景观的11%），从开放林地到封闭林地（景观的8%），和开放林地到草地（景观的6%）的退化的生物量的增加退化。草地向农田过渡的脆弱性可能反映了与其他自然植被相比，草地易于清除。耕地系统地避免从林地获得，林地系统地避免失去耕地，这表明砍伐木炭和木柴收集是林地减少的主要近因。大多数随机景观转变发生在受以下因素影响的地区：移民的自发占领、农民流离失所导致的城郊农田扩张以及消除水传播疾病后沿着白色沃尔特河的家庭重新定居。联合收割机结合系统和随机景观变化的分析是必要的，以提高对土地利用变化过程的理解。这将有助于将模式与进程联系起来，并有助于设计旨在减少急剧土地变化的不利影响的政策干预措施。(c)2005 Elsevier B.V.保留所有权利。
The objective of this paper is to detect the dominant landscape changes in a 5400 km(2) area in northern Ghana. An in-depth analysis of the conventional transition matrix was used to separate landscape transformations to random and systematic transitions. A landscape transition is random if a land-cover category gains from other categories in proportion to the availability of those other losing categories, or if a category loses to other categories in proportion to the size of those other gaining categories. Any large deviation from those proportions is refer-red to as systematic transition. The highest systematic transition involved the conversion of about 12% of landscape from grassland to cropland. Other systematic landscape transitions included degradation of closed woodland to open woodland (11% of landscape), gain in biomass from open woodland to closed woodland (8% of landscape), and the degradation of open woodland to grassland (6% of landscape). The vulnerability of grassland to transition to cropland probably reflects the ease of clearing grassland compared to other natural vegetation. Cropland systematically avoided gaining from woodland and woodland systematically avoided losing to cropland, suggesting that woodcutting for charcoal and firewood collection is the major proximate cause of decline in woodland. Most of the random landscape transitions occurred in areas affected by spontaneous occupation by migrants, peri-urban cropland expansion as a result of displacement of farmers, and the resettlement of households along the White Volta River after the eradication of water-borne diseases. It is essential to combine systematic and random landscape change analyses for improved understanding of the processes of land use change. This will help in linking patterns to processes and in designing policy interventions aimed at reducing the unfavorable effects of dramatic land change. (c) 2005 Elsevier B.V. All rights reserved.