| 摘要: |
| 【目的】分析乌鲁木齐河流域基于Landsat数据的植被覆盖度时空分布特征及驱动因素，为乌鲁木齐河流域生态环境保护、社会生产等方面提供参考。【方法】以乌鲁木齐河流域为研究区，选取2000—2020年中2000、2005、2010、2015年和2020年5个时期Landsat TM/OLI遥感影像为数据源，用像元二分法、植被覆盖度转移矩阵，选取2000—2020年乌鲁木齐河流域植被覆盖度（FVC）的时空变化数据，定量分析了土地利用变化和地形分异特征对其影响程度，并基于地理探测器模型对流域高程、气温和降水等8种影响因子对流域FVC空间分异驱动力进行探测。【结果】乌鲁木齐河流域2000—2020年植被覆盖度总体上呈先减少后增长趋势，主要以高、低植被覆盖度为主，呈现上游极高，中、下游低的格局。研究区内不同土地利用类型的FVC表现为林地>耕地>草地>建设用地>未利用地。植被覆盖度变化受地形因子的影响明显，随高程升高而有所波动，高程在500 m以下和在2 000~2 500 m的植被覆盖度较大；FVC与坡度负相关，坡度越高植被覆盖度越低，并且随坡度增大而急剧减少。因子探测结果表明，解释力由大到小依次为土地利用>气温>高程>地表温度>降水>土壤湿度>坡度>坡向，土地利用的q值最大，对FVC具有较强影响力；交互探测结果表明，双因子交互对FVC的影响大于单因子，其中，高程和土地利用，土地利用和地表温度、气温对FVC的解释力最大。【结论】乌鲁木齐河流域2000—2020年来的FVC值在0.35~0.46之间波动变化，表现出显著的空间差异性，整体上呈上游极高，中、下游低的格局，人为因素（土地利用）比自然因素（高程、气温等）更能解释FVC的变化。 |
| 关键词: 植被覆盖度；土地利用；地形因子；地理探测器 |
| DOI：10.13522/j.cnki.ggps.2023008 |
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| 基金项目: |
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| Change in vegetation coverage in Urumqi River basin and theunderlying determinants |
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KAMILAN·Abulike, YANG Han
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1. Institute of Geography and Tourism, Xinjiang Normal University, Urumqi 830054, China;
2. Xinjiang Key Laboratory of Lake Environment and Resources in Arid Zone, Urumqi 830054, China
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| Abstract: |
| 【Objective】The Urumqi River is one of the most important rivers in northwestern China. The objective of this paper is to study the change in vegetation coverage in its basin and the underlying determinants in attempts to help improve its management.【Method】The study is based on the Landsat TM/OLI remote sensing imageries from 2000 to 2020. Spatiotemporal variations in vegetation coverage (FVC) in the basin during this period are extracted using the image dichotomy and vegetation cover transfer matrix, from which we analyze the changes in land use and topographic features in the basin. The factors that are responsible for the change in FVC in the basin are calculated using the geo-detector model, reclassification and other methods.【Result】 From 2000 to 2020, vegetation coverage in the basin decreased first and then increased. Vegetation coverage was high in the upper reaches and low in the middle and low reaches. Vegetation coverage in different land usage was ranked in the order of forest land > cropland > grassland > construction land > water bodies > unused land. The change in vegetation coverage was influenced by topographic factors and fluctuated with elevation, with the vegetation coverage being the highest in elevations <500m and between 2 000 to 2 500 m. Across the basin, vegetation coverage was negatively correlated to slope. The results of the factor detection analysis showed that environmental factors that affected vegetation coverage were ranked in the order of land use > air temperature > elevation > surface temperature > precipitation > soil moisture > slope > slope direction. The results of the interaction detection analysis show that elevation-land use, land use-temperature are the coupling factors that influenced vegetation coverages more than coupling of other factors.【Conclusion】The average vegetation coverage in the Urumqi River basin varied from 0.348 to 0.456 in 2000—2020; it varied spatially. Overall, it is high in the upper reach and low in the middle and lower reaches. Variation in land use explains the variation in the vegetation coverage more than any other natural factors. |
| Key words: vegetation coverage; land use; topographic factor; geographic detector |
