Jacob Benjamin G, Muturi Ephantus, Halbig Patrick, Mwangangi Joseph, Wanjogu R K, Mpanga Enock, Funes Jose, Shililu Josephat, Githure John, Regens James L, Novak Robert J
Illinois Natural History Survey, Center for Ecological Entomology, Champaign, Illinois 61820, USA.
Am J Trop Med Hyg. 2007 Jan;76(1):73-80.
A study was carried out at Karima Village in the Mwea Rice Irrigation Scheme in Kenya to assess the impact of rice husbandry and associated land cover change for mosquito larval abundance. A multi-temporal, land use land cover (LULC) classification dataset incorporating distributions of Anopheles arabiensis aquatic larval habitats was produced in ERDAS Imagine version 8.7 using combined images from IKONOS at 4m spatial resolution from 2005 and Landsat Thematic Mapper (TM)trade mark classification data at 30-meters spatial resolution from 1988 for Karima. Of 207 larval habitats sampled, most were either canals (53.4%) or paddies (45.9%), and only one habitat was classified as a seep (0.5%). The proportion of habitats that were poorly drained was 55.1% compared with 44.9% for the habitats that were well drained. An LULC base map was generated. A grid incorporating each rice paddy was overlaid over the LULC maps stratifying each cell based on levels of irrigation. Paddies/grid cells were classified as 1) well irrigated and 2) poorly irrigated. Early stages of rice growth showed peak larval production during the early part of the cropping cycle (rainy season). Total LULC change for Karima over 16 years was 59.8%. Of those areas in which change was detected, the LULC change for Karima was 4.30% for rice field to built environment, 8.74% for fallow to built environment, 7.19% for rice field to fallow, 19.03% built to fallow, 5.52% for fallow to rice field, and 8.35% for built environment to rice field. Of 207 aquatic habitats in Karima, 54.1 (n = 112) were located in LULC change sites and 45.9 (n = 95) were located in LULC non-change sites. Rice crop LULC maps derived from IKONOS and TM data in geographic information systems can be used to investigate the relationship between rice cultivation practices and higher anopheline larval habitat distribution.
在肯尼亚姆韦亚水稻灌溉区的卡里马村开展了一项研究，以评估水稻种植及相关土地覆盖变化对蚊虫幼虫丰度的影响。利用2005年空间分辨率为4米的IKONOS卫星图像和1988年空间分辨率为30米的陆地卫星专题制图仪（TM）商标分类数据生成的组合图像，在ERDAS Imagine 8.7版本中制作了一个多时期土地利用土地覆盖（LULC）分类数据集，该数据集纳入了阿拉伯按蚊水生幼虫栖息地的分布情况。在抽样的207个幼虫栖息地中，大部分是运河（53.4%）或稻田（45.9%），只有一个栖息地被归类为渗水处（0.5%）。排水不良的栖息地比例为55.1%，而排水良好的栖息地比例为44.9%。生成了一幅LULC底图。将一个包含每个稻田的网格叠加在LULC地图上，根据灌溉水平对每个单元格进行分层。稻田/网格单元格被分类为：1）灌溉良好；2）灌溉不良。水稻生长早期在作物生长周期初期（雨季）显示出幼虫产量峰值。卡里马村16年间的LULC总变化率为59.8%。在检测到变化的区域中，卡里马村的LULC变化情况为：稻田变为建筑用地的比例为4.30%，休耕地变为建筑用地的比例为8.74%，稻田变为休耕地的比例为7.1%，建筑用地变为休耕地的比例为19.03%，休耕地变为稻田的比例为5.52%，建筑用地变为稻田的比例为8.35%。在卡里马村的207个水生生境中，54.1%（n = 112）位于LULC变化区域，45.9%（n = 95）位于LULC未变化区域。地理信息系统中源自IKONOS和TM数据的水稻作物LULC地图可用于研究水稻种植实践与较高按蚊幼虫栖息地分布之间的关系。
