无人机航测技术在海草床调查中的试点应用

通过无人机飞行参数、飞行高度、潮汐条件和调查范围等试验，采用无人机对东郊椰林近岸海域海草进行航拍，利用PIX4D软件处理得到了高分辨率海草分布影像图，利用ArcGIS软件对海草分布区进行了矢量化提取，选择有代表性的区块结合实地调查进行验证，得出了试验区的海草分布特征和海草种类。结果表明：海草分布在离岸300 m范围内的珊瑚礁砰上，呈斑块状、间隔式分布特征，在试验区中海草分布面积为2 449.6 m2，占比为24.5%。实地调查到海草种类有圆叶丝粉草（Cymodocea rotundata）、单脉二药草（Halodule uninervis）、海菖蒲（Enhalus acoroides）、泰来草（Thalassia hemprichii）和卵叶喜盐草（Halophila ovalis）等5种海草，泰来草为优势种，单脉二药草和卵叶喜盐草分布在潮间带有淤泥的低潮区；圆叶丝粉草分布在低潮带至潮下带的上部，海底堆积和冲刷区的交界处；泰来草在不同水深处均有分布，分布面积最大。

Pilot application of UAV aerial survey technique in seagrass bed investigation

Based on the flight condition tests of UAV flight parameters, flight height, tidal level and survey field, the UAV was used to take aerial photos of seagrass on the coastal sea area of Dongjiao Coconut Forest, and the PIX4D software was applied to obtain the high-resolution image of seagrass distribution. The ArcGIS software was used to extract the vector distribution area of the seagrass bed. The distribution characteristics and seagrass species in the test area were obtained. The results show that seagrass distributes on coral reef within 300 m offshore patchily and separately, and the distribution area of seagrass is 2 449.6 m², accounting for 24.5% of the total test area. According to the field survey, there are five species of seagrass: Cymodocea rotundata, Halodule uninervis, Enhalus acoroides, Thalassia hemprichii and Halophila Ovalis. Among them Thalassia hemprichii is the dominant species. Halodule uninervis and Halophila ovalis mainly distribute in the low tide silty area of intertidal zone. Cymodocea rotundata distributes from the low tide zone to the upper part of the subtidal zone at the junction of seabed accumulation and scouring area. Thalassia hemprichii distributes in different water depths occupying the largest area of seagrass bed.