Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus, Vehari, 61100, Pakistan.
US-Pakistan Centre for Advanced Studies in Agriculture and Food Security, University of Agriculture, Faisalabad, Pakistan.
Environ Sci Pollut Res Int. 2020 Nov;27(32):39676-39692. doi: 10.1007/s11356-019-06072-3. Epub 2019 Aug 5.
Land use/land cover (LULC) change has serious implications for environment as LULC is directly related to land degradation over a period of time and results in many changes in the environment. Monitoring the locations and distributions of LULC changes is important for establishing links between regulatory actions, policy decisions, and subsequent LULC activities. The normalized difference vegetation index (NDVI) has the potential ability to identify the vegetation features of various eco-regions and provides valuable information as a remote sensing tool in studying vegetation phenology cycles. Similarly, the normalized difference built-up index (NDBI) may be used for quoting built-up land. This study aims to detect the pattern of LULC, NDBI, and NDVI change in Lodhran district, Pakistan, from the Landsat images taken over 40 years, considering four major LULC types as follows: water bodies, built-up area, bare soil, and vegetation. Supervised classification was applied to detect LULC changes observed over Lodhran district as it explains the maximum likelihood algorithm in software ERDAS imagine 15. Most farmers (46.6%) perceived that there have been extreme changes of onset of temperature, planting season, and less precipitation amount in Lodhran district in the last few years. In 2017, building areas increased (4.3%) as compared to 1977. NDVI values for Lodhran district were highest in 1977 (up to + 0.86) and lowest in 1997 (up to - 0.33). Overall accuracy for classification was 86% for 1977, 85% for 1987, 86% for 1997, 88% for 2007, and 95% for 2017. LULC change with soil types, temperature, and NDVI, NDBI, and slope classes was common in the study area, and the conversions of bare soil into vegetation area and built-up area were major changes in the past 40 years in Lodhran district. Lodhran district faces rising temperatures, less irrigation water, and low rainfall. Farmers are aware of these climatic changes and are adapting strategies to cope with the effects but require support from government.
土地利用/土地覆盖(LULC)变化对环境有严重影响,因为 LULC 与一段时间内的土地退化直接相关,导致环境发生许多变化。监测 LULC 变化的位置和分布对于建立监管行动、政策决策和随后的 LULC 活动之间的联系非常重要。归一化植被指数(NDVI)具有识别各个生态区植被特征的潜在能力,并作为研究植被物候周期的遥感工具提供有价值的信息。同样,归一化差异建成指数(NDBI)可用于引用建成区。本研究旨在利用 Landsat 图像检测巴基斯坦洛德拉区 40 年来的 LULC、NDBI 和 NDVI 变化模式,考虑以下四种主要 LULC 类型:水体、建成区、裸土和植被。应用监督分类来检测洛德拉区的 LULC 变化,因为它解释了 ERDAS imagine 15 软件中的最大似然算法。大多数农民(46.6%)认为,在过去几年中,洛德拉区的温度、种植季节和降雨量都发生了极端变化。与 1977 年相比,2017 年的建筑区域增加了(4.3%)。洛德拉区的 NDVI 值在 1977 年最高(高达+0.86),在 1997 年最低(高达-0.33)。1977 年、1987 年、1997 年、2007 年和 2017 年的分类总体准确率分别为 86%、85%、86%、88%和 95%。研究区存在 LULC 变化与土壤类型、温度以及 NDVI、NDBI 和坡度等级之间的关系,在过去的 40 年中,裸土向植被区和建成区的转化是洛德拉区的主要变化。洛德拉区面临气温上升、灌溉用水减少和降雨量低的问题。农民已经意识到这些气候变化,并正在采取策略来应对这些影响,但需要政府的支持。