基于开放性围栏研究洪湖退垸还湖区沉水植物生长限制因子

Enclosure study on the limiting factors of submerged macrophyte growth in restored sites of Honghu Lake

为探讨不同退垸还湖区的环境因子对沉水植物恢复的影响,本研究在两种不同类型的退垸还湖区(阳柴湖和八卦洲)内分别建立开放性围栏,选取3种不同生长型(共9种)沉水植物为实验对象,基于不同围栏、围栏内外及不同生长时间(7、30 d)的生长指标差异来评估限制不同沉水植物生长的环境因子并排序。结果显示,保留部分功能的单退垸区域风浪干扰较小,比完全去除圩垸的双退垸区域更适合沉水植物的生长。密刺苦草(Vallisneria denseserrulata Makino)是适合洪湖退垸还湖区沉水植物群落恢复的先锋物种。部分植物如黑藻(Hydrilla verticillata Royle)在围栏内外生长指标的显著差异也表明草(杂)食性鱼类的潜在影响。研究结果表明,退垸还湖工程应在去养殖功能化后保留现有围堤,这样更有利于沉水植被的恢复,此外,构建保护性围栏有助于沉水植物的迅速建群。

To explore the effects of different environmental factors on the recovery of submerged macrophytes,two enclosures were established in two different types of restored sites(Yangchaihu and Baguazhou)to investigate the roles of influencing factors,e.g.,types of restoration method,inner and outside enclosures,length of growing period(7 d and 30 d),and macrophyte species,on macrophyte growth.Results showed that restored sites retaining a partial bank from the former fishery enclosure,exhibiting an advantage of reduced wind,were more conducive to macrophyte community restoration than restored sites with total bank removal.Macrophyte species was also an important factor affecting macrophyte growth.Among the nine selected species,Vallisneria denseserrulata emerged as the best pioneer species for Honghu Lake.Certain species(e.g.,Hydrilla verticillata)showed differences between the interior and exterior of the enclosure,indicating that herbivorous or omnivorous fish were also potentially important for macrophyte growth.In summary,our study indicated that preserving the bank of fishery enclosures after fishery removal can facilitate the recovery of macrophyte communities.In addition,the construction of protective enclosures is critical for rapid establishment of macrophyte communities.