纹沼螺对苦草生长的影响

Effects of Parafossarulus striatulus on the Growth of Vallisneria spiralis

在室外受控实验条件下,研究了不同密度(0,150,450个/m2)纹沼螺(Parafossarulus striatulus)对沉水植物苦草(Vallisneria spiralis)生长的影响。结果表明,螺类牧食活动促进了苦草生长,与无螺对照组相比,低密度螺处理组中苦草的相对生长率、株高均增加了20%;高密度组中苦草的相对生长率、叶片数和株高分别增加了28%、15%和27%。分析表明,纹沼螺通过牧食活动降低植物叶片上附着生物干重,从而促进了苦草生长。丰富了螺-草互利关系的研究内容,有助于加深理解水生态系统中生物之间的生态关系。

The outdoor experiment was conducted to investigate the effects of snail Parafossarulus striatulus （Benson） on the growth of Vallisneria spiralis, with three treatment groups （0, 150, 450 ind/m^2）. The results showed that the snails were beneficial for V. spiralis growth. Both of the relative growth rate and plant height in the low density snail group （ 150 ind/m^2） increased by 20% in comparison with the control group with no snails. The high density group improved further, compared to the control group, with increases in relative growth rate, number of leaves, and plant height of 28%, 15% and 27%, respectively. It is suggested that the snails may reduce the periphyton biomass on the leaves of the plant by grazing, contributing to the increased plant growth. This study is helpful for us to further understand the mutualistic relationship between freshwater snails and aquatic macrophytes, as well as the ecological relationships between organisms in aquatic ecosystems.