| 高原河谷城市植被变化及驱动因素分析 |
| 摘要点击 589 全文点击 70 投稿时间：2024-01-25 修订日期：2024-08-04 |
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| 中文关键词 归一化植被指数（NDVI） 地理探测器 植被覆盖度变化 高原河谷城市 兰州 |
| 英文关键词 normalized difference vegetation index（NDVI） geodetector vegetation cover change plateau valley cities Lanzhou |
| DOI 10.13227/j.hjkx.20250629 |
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| 中文摘要 |
| 兰州市属于典型带状高原河谷城市，研究其植被变化可为高原河谷城市植被恢复、水土保持和生态环境保护提供参考，为兰州可持续发展提供支撑. 以2000~2020年遥感影像数据为基础，采用R/S指数、Sen斜率分析、MK检验和变异系数等方法探究2000~2020年兰州地区生长季归一化植被指数的时空变化趋势，用地理探测器综合分析自然因素和人为因素对NDVI空间分异的影响. 结果表明：①2000~2020年，人类活动区域内植被NDVI主要为中等级，增长速率为0.004 8 a-1，呈现“不显著退化”和“持续退化”趋势. ②非人类活动区域内植被NDVI主要为中低和低等级，增长速率为0.005 8 a-1，呈现“不显著改善”和“持续改善”的趋势. ③兰州地区植被NDVI改善区域面积占比为83.5%，退化面积占比为16.3%，高波动变化面积占比为51.1%，低波动变化面积占比仅为5.7%，植被生长稳定性较差. ④在自然因子中土壤类型、植被类型和降水量为影响植被变化的主要影响因子；在人为因子中，土地利用类型和人口密度为影响植被变化的主要影响因子. ⑤因子交互作用分析中，植被类型和降水量是影响植被NDVI空间分布的主要因子，坡度、坡向、人口密度、GDP、农业增加值和工业增加值为间接影响因子. ⑥通过因子适宜范围分析还可以看出土壤类型的最适类型为淋溶土，最适土地类型为林地，最适植被类型为针叶林，最适高程范围是3 500~3 671 m. 整体上，兰州地区植被NDVI处于中低等级，植被生长稳定性较差，未来整体呈现改善趋势. 相比之下人类活动区域内植被NDVI等级和植被生长稳定性较高；土壤对植被的生长影响最大且起到负面作用. 人为因子的单因子影响力均呈现缓慢上涨趋势，并且在人为影响力与其他因子交互过程中交互影响力均大于其单独的影响力，说明人类活动对植被生长的干扰也应当被重视. |
| 英文摘要 |
| Lanzhou is a typical banded plateau river valley city. This study provides a reference for vegetation restoration， soil and water conservation， and ecological environmental protection of the plateau river valley city. It also supports the sustainable development of Lanzhou. Using remote sensing image data from 2000 to 2020， we analyzed the spatial and temporal trends of vegetation NDVI during the growing season in Lanzhou. We employed the R/S index， Sen slope analysis， MK test， and coefficient of variation to conduct our analysis. Additionally， we used geodetic probes to comprehensively analyze the effects of both natural and anthropogenic factors on the spatial variation of vegetation NDVI. The results indicate that： ① From 2000 to 2020， the vegetation NDVI in the anthropogenic area was mainly of medium grade， with a growth rate of 0.004 8 a-1. The trends observed were ‘insignificant degradation’ and ‘continuous degradation’. ② The vegetation in the inactive area showed mainly medium-low and low grades of NDVI， with a growth rate of 0.005 8 a-1， indicating a trend of ‘not significantly improved’ and ‘continuously improved’. The stability of vegetation growth was poor. ③ In Lanzhou， the NDVI of the vegetation in the improvement area accounted for 83.5%， while the degradation area accounted for 16.3%. The high fluctuation change area accounted for 51.1%， and the low fluctuation change area accounted for only 5.7%. ④ Soil type， vegetation type， and precipitation were natural factors that affected vegetation change. Meanwhile， land use type and population density were anthropogenic factors that also had an impact on vegetation change. ⑤ In the factor interaction analysis， vegetation type and precipitation were the main factors affecting the spatial distribution of vegetation NDVI， and slope， slope direction， population density， GDP， agricultural value added， and industrial value added were the indirect factors. ⑥ Based on the analysis of various factors， it is evident that the optimal soil type was drench soil， the preferred land type was woodland， the suitable vegetation type was coniferous forest， and the ideal elevation range was between 3 500 to 3 671 meters. Overall， the NDVI of vegetation in Lanzhou was in the middle to low grade， and the growth stability of the vegetation was relatively poor. However， there is a trend of improvement for the future. In contrast， the vegetation growth stability was higher， and the vegetation NDVI grade was higher in the anthropogenic area， while the non-anthropogenic area had lower vegetation growth stability and NDVI grade. Soil had the greatest influence on vegetation growth， making it a key challenge for ecological management in Lanzhou. This highlights the need to consider human activities when assessing vegetation growth. Anthropogenic factors have a slow but steady impact， surpassing other factors in their influence. |
