%0 Journal Article %T 不同密度团头鲂(Megalobrama amblycephala)对轮叶黑藻(Hydrilla verticillata)和密刺苦草(Vallisneria denseserrulata)群落结构的影响 %T Effects of different densities of Wuchang bream on community structure of Hydrilla verticillata and Vallisneria denseserrulata %A 王倩红 %A 刘正文 %A 甄伟 %A 张秀梅 %A 郝征 %A 莫家勇 %A 赵雪枫 %A WANG,Qianhong %A LIU,Zhengwen %A ZHEN,Wei %A ZHANG,Xiumei %A HAO,Zheng %A MO,Jiayong %A ZHAO,Xuefeng %J 湖泊科学 %J Journal of Lake Sciences %@ 1003-5427 %V 31 %N 3 %D 2019 %P 862-868 %K 团头鲂;选择性牧食;放养密度;沉水植物群落结构;无人机影像;数字图像处理 %K Wuchang bream;selective grazing;stocking density;submerged macrophytes community structure;UAV image;digital image processing %X 冠层型水草轮叶黑藻在富营养情况下,生长迅速,覆盖水面,对于草甸型水草密刺苦草具有明显的竞争优势.为控制轮叶黑藻的竞争优势,于湖北省鄂州市团头鲂原种场的一个池塘进行了原位围隔(10 m×10 m)实验,研究不同密度(0、0.5和1尾/m2)团头鲂牧食作用对轮叶黑藻和密刺苦草群落结构的影响,并通过无人机数字图像处理获取水草覆盖度信息.实验过程中,沉水植物总覆盖度未发生变化.研究发现,团头鲂选择性牧食使得密刺苦草生物量和覆盖度显著增加.随着牧食强度的加大,团头鲂对轮叶黑藻的控制效果显著,放养密度为1尾/m2的围隔中轮叶黑藻比例降幅最明显.群落中轮叶黑藻与密刺苦草的生物量之比迅速下降,由6.14减少至0.002,覆盖度之比由4.88左右减少至约1.44.图像处理结果与实际采样情况相吻合,且通过误差矩阵得到图像分类平均精度达到90%以上,表明无人机数字图像处理在一定条件下可以作为获取沉水植物覆盖度的一种有效辅助手段.实验结束后,1尾/m2组的围隔中密刺苦草成为优势种,其植株密度、株高、株重和单株叶片数均显著增加,草甸更加密实.实验结果表明,放养1尾/m2密度的团头鲂可以有效控制轮叶黑藻并维持密刺苦草种群优势,结果为团头鲂对湖泊沉水植物群落的控制提供了参考. %X Under the condition of eutrophication, canopy-forming Hydrilla verticillata grows fast and covers the water surface rapidly. It has an obvious competitive advantage over meadow-forming Vallisneria denseserrulata. In order to control the competitive advantage of H. verticillata, an in-situ enclosure (10 m×10 m) experiment was conducted in Dushan Town, Ezhou City, Hubei Province to study the effects of herbivory by Wuchang bream (Megalobrama amblycephala) on the community structure of H. verticillata and V. denseserrulata with different densities of the fish (0, 0.5 and 1 ind./m2), UAV digital image processing was used to obtain the coverage information of macrophytes. The results showed that the biomass and coverage of V. denseserrulata increased significantly after fish grazing while the total coverage remained unchanged. With the increase of grazing intensity, the control effect of Wuchang bream on H. verticillata was significant, and the proportion of H. verticillata decreased most significantly in the enclosures with 1 fish/m2. The ratio of biomass of H. verticillata to V. denseserrulata decreased rapidly from 6.14 to 0.002, and the ratio of coverage decreased from 4.88 to 1.44. The image processing results are consistent with the actual sampling situation, and the average classification accuracy of the image obtained by error matrix is more than 90%. It shows that the UAV digital image processing can be used as an effective means to obtain the coverage of submerged plants under certain conditions. At the end of the experiment, plant density, the length, weight and leaf number per plant of V. denseserrulata in the enclosure with 1 fish/m2 treatment significantly increased, and the meadow became denser. The results showed that the dominance of H. verticillata could be controlled by stocking Wuchang bream. The results provides a useful information for a better control of submerged plant communities in lakes. %R 10.18307/2019.0324 %U http://www.jlakes.org/ch/reader/view_abstract.aspx %1 JIS Version 3.0.0