基于无人机数据的滨海湿地互花米草(Spartina alterniflora)地上生物量反演研究

Inversion of Spartina alterniflora Above-ground Biomass in Coastal Wetland Based on UAV Data

互花米草(Spartina alterniflora)快速入侵的关键在于其生长繁殖以及对环境的适应能力,互花米草生物量的大小正是它入侵能力的重要体现。以无人机遥感影像为数据源,通过建立关于植被覆盖度和植株高度的模型对互花米草地上生物量进行估算研究。研究结果表明,在条子泥研究区内互花米草地上生物量在0~9.13 kg·m^(-2)之间,地上生物量平均值为0.73 kg·m^(-2),75.13%的互花米草地上生物量小于0.73 kg·m^(-2),地上生物量为0.73~3.00 kg·m^(-2)以及>3.00 kg·m^(-2)的互花米草分别占18.47%和6.40%,地上生物量较高的互花米草主要分布在靠近海堤区域与近海一侧潮滩,中间区域地上生物量较低。遥感影像景观分类结果Kappa系数为0.85,互花米草地上生物量估算的均方根误差为0.76,反演结果能够在一定程度上反映研究区互花米草地上生物量分布情况。互花米草分布多呈斑块状,部分呈丛分布,处于互花米草快速扩张阶段。研究所采用的无人机遥感能够同步获取采样时间点研究区的影像数据,可以很好地应用于时效性较强的生物量遥感反演。该研究为互花米草地上生物量的定量化反演提供了新的方法。

The key to the successful invasion of Spartina alterniflora lies in its ability to grow,reproduce and adaptability to the environment.The biomass of S.alterniflora is an important embodiment of its invasion ability.Taking the unmanned aerial vehicle(UAV)remote sensing image as the data source,this study estimated the above-ground biomass of S.alterniflora through the model which was composed by vegetation coverage and plant height.The results indicate that in the typical area of Tiaozini,the biomass of S.alterniflora is between 0 and 9.13 kg·m^(-2)and the average biomass is 0.73 kg·m^(-2)with 75.13%of S.alterniflora biomass being less than 0.73 kg·m^(-2),18.47%of S.alterniflora biomass being between 0.73 and 3.00 kg·m^(-2);and 6.40%of S.alterniflora biomass being greater than 3.00 kg·m^(-2).S.alterniflora with high biomass is mainly distributed in the area near the seawall and the tidal flat towards the seaside.The biomass of S.alterniflora is low between the seawall and the seaside flat.The root mean square error of biomass estimation is 0.76,and the absolute error is between 0.01 and 1.99 kg·m^(-2).The above-ground biomass distribution of S.alterniflora in the study area can reflect the inversion results.The distribution of S.alterniflora in the study area is irregular,most of them are distributed in patches.The young S.alterniflora distributed in clusters,which is in the expansion stage of S.alterniflora.The UAV remote sensing method used in this study could simultaneously obtain image of the study area at sampling time,which could be applied to the inversion of biomass with timeline.This study provides a new method for the quantitative inversion of S.alterniflora above-ground biomass.