Henan Normal University, Xinxiang, Henan 453007, China; Puyang Field Scientific Observation and Research Station for Yellow River Wetland Ecosystem, Henan Province, China.
Henan Normal University, Xinxiang, Henan 453007, China.
Sci Total Environ. 2022 May 1;819:153059. doi: 10.1016/j.scitotenv.2022.153059. Epub 2022 Jan 11.
Accurate and timely acquisition of plant diversity information downstream of the reservoir is helpful to understand the impact mechanism of reservoir operation on wetland plant diversity and formulate reasonable water and sediment regulation strategies. In this study, we conducted field surveys in two communities (Phragmites australis and Tamarix chinensis) at a typical wetland in the lower reaches of Xiaolangdi Reservoir on the Yellow River, and employed UAV and Gaofen 1B multispectral images to estimate the wetland plant diversity. Results showed that most diversity indexes had a higher correlation with the mean of spectral vegetation indexes (DVI, RVI, NDVI, SAVI, and MSAVI). The diversity indexes (C_SP and C_SW) constructed by relative coverage had a better overall correlation with spectral indexes. Interestingly, opposite correlations were found between Tamarix chinensis and Phragmites australis plots. We further gave a deep insight into the interspecific associations in Phragmites australis and Tamarix chinensis plots with the variance ratio (VR) method. It was found that plant species in Tamarix chinensis plot showed positive association (VR > 1), with a VR value of 1.095. Plant species in Phragmites australis plot had a negative association (VR < 1), with a VR value of 0.983. In Phragmites australis plot, C_SP and C_SW showed a significant decreasing trend (r of 0.36 and 0.33 respectively, and P values less than 0.001) with the increase of Phragmites australis coverage. Moreover, the effect of spatial resolution was not significant on plant diversity estimation. Correlations between remote sensing indexes and diversity indexes were improved with the quadrat size changing from 2 m × 2 m to 4 m × 4 m. These findings demonstrate promising approaches for remote sensing of wetland plant diversity and indicate that the type of wetland plant community determines the relationship between diversity index and spectral index.
准确、及时地获取水库下游的植物多样性信息，有助于了解水库运行对湿地植物多样性的影响机制，制定合理的水沙调控策略。本研究在黄河小浪底水库下游典型湿地的芦苇（Phragmites australis）和柽柳（Tamarix chinensis）两个群落进行了野外调查，并利用无人机和高分 1B 多光谱影像估算湿地植物多样性。结果表明，多数多样性指数与光谱植被指数（DVI、RVI、NDVI、SAVI 和 MSAVI）的均值相关性较高。相对覆盖度构建的多样性指数（C_SP 和 C_SW）与光谱指数的整体相关性较好。有趣的是，柽柳和芦苇样地的多样性指数呈相反的相关关系。进一步利用方差比（VR）法深入分析了芦苇和柽柳样地的种间关联性。结果发现，柽柳样地的植物种间呈正关联（VR > 1），VR 值为 1.095。芦苇样地的植物种间呈负关联（VR < 1），VR 值为 0.983。在芦苇样地中，C_SP 和 C_SW 随芦苇盖度的增加呈显著减小趋势（r 值分别为 0.36 和 0.33，P 值均小于 0.001）。此外，空间分辨率对植物多样性估算的影响不显著。随着样方面积从 2 m×2 m 增大到 4 m×4 m，遥感指数与多样性指数的相关性有所提高。这些结果为湿地植物多样性的遥感监测提供了有前景的方法，并表明湿地植物群落的类型决定了多样性指数与光谱指数之间的关系。
