Responses of four submerged macrophytes to freshwater snail density (Radix swinhoei) under clear-water conditions: A mesocosm study
Responses of four submerged macrophytes to freshwater snail density (Radix swinhoei) under clear-water conditions: A mesocosm study
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清水条件下四种沉水植物对淡水蜗牛密度（Radix swinhoei）的响应：中生态系统研究
DOI：
10.1002/ece3.6489
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发表时间：
2020
影响因子：
2.6
通讯作者：
Cao Yu
中科院分区：
文献类型：
--
作者：
Zhi Yongwei;Liu Yang;Li Wei;Cao Yu
大型植物在稳定浅水生态系统的清水条件方面发挥着关键作用。它们的种群是通过植物放牧和植物生长之间的平衡来维持的。水螅螺是一种常见于浅水湖泊的淡水螺类，通过直接啃食水生植物的器官和去除水生植物表面的附着物，影响沉水植物的生长。因此，我们进行了长期的（11个月）的实验，以探索室外清水围隔系统中蜗牛密度对具有独特结构的水生植物的影响（总氮（TN）和总磷（TP）含量较低（0.66 ± 0.27 mg/L结果表明，两种钉螺密度下的总磷（TP）为36 ± 20 μg/L，叶绿素a（Chla）为14.8 ± 4.9 μg/L（低、高）和4种植物处理（狐尾藻（Myriophyllum spicatum）、眼子菜（Potamogeton wrightii）、菜（P. crispus）和菜（P. oxyphyllus）。在高密度处理中，蜗牛生物量和丰度（分别为36.5 ± 16.5 g/m2和169 ± 92 ind/m2）约为低密度处理中观察到的两倍，导致水生植物中的总生物量和地上生物量以及分株数较低。此外，植物高度和植物体积栖息（PVI）表现出物种特异性的反应蜗牛密度，即高度的P。oxyphyllus和M.穗状花序在低密度处理下均较高。因此，与低密度处理相比，通过直接摄食长期高蜗牛密度对大型植物的抑制作用可能大于在具有低附生生物量的清水条件下由附生生物清除产生的积极作用。因此，在清水条件下，沉水植物的生长和群落组成可能会通过人工添加无脊椎动物（即，蜗牛）到湖泊，如果来自食肉鱼类的抑制作用是轻微的。
Macrophytes play a key role in stabilizing clear‐water conditions in shallow freshwater ecosystems. Their populations are maintained by a balance between plant grazing and plant growth. As a freshwater snail commonly found in shallow lakes,Radix swinhoeican affect the growth of submerged macrophytes by removing epiphyton from the surface of aquatic plants and by grazing directly on macrophyte organs. Thus, we conducted a long‐term (11‐month) experiment to explore the effects of snail density on macrophytes with distinctive structures in an outdoor clear‐water mesocosm system (with relatively low total nitrogen (TN, 0.66 ± 0.27 mg/L) and total phosphorus (TP, 36 ± 20 μg/L) and a phytoplankton chlorophylla(Chla) range of 14.8 ± 4.9 μg/L) based on two different snail densities (low and high) and four macrophyte species treatments (Myriophyllum spicatum,Potamogeton wrightii,P. crispus, andP. oxyphyllus). In the high‐density treatment, snail biomass and abundance (36.5 ± 16.5 g/m2and 169 ± 92 ind/m2, respectively) were approximately twice that observed in the low‐density treatment, resulting in lower total and aboveground biomass and ramet number in the macrophytes. In addition, plant height and plant volume inhabited (PVI) showed species‐specific responses to snail densities, that is, the height ofP. oxyphyllusand PVI ofM. spicatumwere both higher under low‐density treatment. Thus, compared with low‐density treatment, the inhibitory effects of long‐term high snail density on macrophytes by direct feeding may be greater than the positive effects resulting from epiphyton clearance when under clear‐water conditions with low epiphyton biomass. Thus, under clear‐water conditions, the growth and community composition of submerged macrophytes could be potentially modified by the manual addition of invertebrates (i.e., snails) to lakes if the inhibitory effects from predatory fish are minor.