Wetland Use/Cover Changes and Local Perceptions in Uganda
Wetland Use/Cover Changes and Local Perceptions in Uganda
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乌干达湿地利用/覆盖变化和当地人的看法
DOI：
10.5539/sar.v2n4p95
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Bernard Barasa
中科院分区：
文献类型：
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作者：
N. Turyahabwe;D. M. Tumusiime;W. Kakuru;Bernard Barasa
随着人口的增加，加上土地短缺和天气变化，乌干达的湿地由于主要用于农业、工业和定居目的而继续面临退化。本研究的目的是确定湿地利用/覆盖的空间和时间变化以及这些变化引起的当地认知。该研究利用了 1986 年、2000 年和 2011 年的三组经过正射校正且无云的 Landsat TM/ETM+/MSS 时间图像 (30 m)。分类程序是使用综合土地和水信息系统 (ILWIS) 软件版本 3.7 进行的。乌干达采用 2003 年国家生物质研究开发的湿地分类系统来描述湿地利用/覆盖类型。使用全球定位系统 (GPS) 在地面实况演习中对分类图像进行了验证，以提高分类准确性。在乌干达十个农业生态区中的三个农业生态区中，与湿地相邻的社区进行了关键知情者访谈和焦点小组讨论，以确定湿地利用/覆盖变化的根本驱动因素，同时家庭访谈产生了有关当地对变化的看法的信息。 1986 年至 2011 年间，湿地利用/覆盖发生了显着变化。导致这些变化的主要因素是基奥加平原水稻种植集约化导致的自给农业、进入西南农田湿地维持日常生计（放牧牲畜）的移民涌入以及靠近维多利亚湖新月区城市中心。在所有抽样的农业生态区中，湿地作物种植的增加是由于现有的湿地作物大市场创造的机会发生了变化。大多数（60%）当地人认为，附近的湿地在过去 10 年内经历了高度退化，植被数量和质量、土壤肥力和水位均有所下降。采样的农业生态区存在显着差异，认为退化的当地社区比例最高的是基奥加平原（76%），其次是维多利亚湖新月区（63%）和西南农田（41%）。当地认为对湿地的威胁主要来自农作物种植（占所提及威胁频率的 33%）、湿地资源的收集（30%）以及长期的洪水和干旱（12%）。这项研究证实了新市场出口和各种形式的移民带来的经济机会作为土地利用变化的关键因素的重要性，特别是在几十年的时间尺度上。
With increasing population, coupled with land shortage and weather variations, wetlands in Uganda have continued to face degradation due to mainly conversion for agricultural, industrial and settlement purposes. The objective of this study was to determine the spatial and temporal wetland use/cover changes and local perceptions attributed to these changes. The study utilized three sets of ortho-rectified and cloud free Landsat TM/ETM+/MSS temporal images (30 m) of 1986, 2000 and 2011. The classification procedures were carried out using an Integrated Land and Water Information System (ILWIS) software version 3.7. A wetland classification system for Uganda developed by the National Biomass Study, 2003 was adopted to describe the wetland use/cover types. The classified images were validated in a ground truthing exercise using Global Positioning System (GPS) to improve on the classification accuracy. Key informant interviews and focus group discussions were conducted with communities adjacent to the wetlands in each of three of the ten Ugandan agro-ecological zones to determine the underlying drivers of wetland use/cover changes, while household interviews generated information on local perceptions of the changes. Significant changes were mainly observed in wetland use/cover between 1986 and 2011. Major factors responsible for these changes were subsistence farming due to intensification of growing paddy rice in Kyoga plains, an influx of migrants who accessed wetlands for daily subsistence (livestock grazing) in South western farmlands and proximity to urban centres in the Lake Victoria Crescent. In all the sampled agro-ecological zones, increased crop farming in wetlands was due to changing opportunities created by existent large markets for wetland crops. Majority (60%) of the local people perceived wetlands in their proximity to have undergone high degradation within the last 10 years, and to have declined in quantity and quality of vegetation, soil fertility and water levels. There was a noticeable variation across the sampled agro-ecological zones, with the highest proportion of local communities perceiving degradation being in Kyoga plains (76%), followed by Lake Victoria crescent (63%) and South-western farmlands (41%). Locally perceived threats to wetlands were mainly from crop growing that accounted for 33% of the frequency of mentioned threats, collection of wetland resources (30%), and prolonged floods and droughts (12%). This study confirms the importance of economic opportunities from new market outlets and migration in its various forms as key factors in land use change, especially at timescales of a couple of decades.