Abstract: Objective　To examine the effects of plant communities on Oncomelania hupensis distribution and survival, and the regulatory effects of the microenvironment under plant communities on the morphology and population structure of O. hupensis in marshlands in Dongting Lake. Methods　Seven typical herbaceous plant communities were sampled from marshlands in Dongting Lake in Junshan District, Yueyang City, Hunan Province on June 2024, including Carex scabrifolia, Phragmites australis, Artemisia selengensis, Polygonum viviparum, Alternanthera philoxeroides, Erigeron annuus and Athyrium multidentatum. Sixty plant community quadrats, each measuring 1 m × 1 m, were selected to investigate the plant density, coverage and height in plant communities, and soil physiochemical properties, including soil pH, water content, bulk density, total soil porosity and heavy metal content, and snail population indicators, including total snail counts, count of living snails, snail gender, snail whorl count, snail length, snail width, aspect ratio of snails. The differences in snail population characteristics were compared under different types of plant communities, and the associations of living snail density, aspect ratio and whorl counts with plant population characteristics and soil physiochemical properties were examined. Results　A total of 9 quadrats of C. scabrifolia communities, 12 quadrats of P. australis communities, 9 quadrats of A. selengensis communities, 9 quadrats of P. viviparum communities, 9 quadrats of A. philoxeroides communities, 6 quadrats of E. annuus communities and 6 quadrats of A. multidentatum communities were investigated in June 2024. There were significant differences in the plant height across plant communities (F = 15.06, P < 0.001), with the highest height seen in P. australis communities (129.29 cm ± 26.56 cm) (all P values < 0.01), and there were significant differences in the plant community coverage (F = 4.45, P < 0.001) and density (F = 9.18, P < 0.001). There were significant differences in soil available potassium, available phosphorus, total nitrogen, total carbon, total phosphorus, total potassium, pH, soil water content, total soil porosity, soil bulk density and Mn, Ni, Cu, Zn contents across plant communities (F = 1.15 to 30.69, all P values < 0.05). A total of 836 snails were captured in 60 quadrats, including 546 living snails, with a living snail density of 1.01 snails/0.1 m2. There were significant differences in the living snail density (F = 2.83, P < 0.05) and snail length (F = 6.72, P < 0.05) across plant communities; however, no significant difference was seen in the snail width (F = 4.02, P > 0.05). There was a significant difference in the snail whorl count across plant communities (F = 1.68, P < 0.05), and high proportions of 6⁃, 7⁃ and 8⁃whorl snails were seen in P. australis communities (36.84%, 28/76), C. scabrifolia communities (53.70%, 29/54) and P. viviparum communities(52.03%, 77/148), respectively. The density of living snails positively correlated with herbaceous community density (rs = 0.485, P < 0.05), herbaceous community coverage (rs = 0.417, P < 0.05), total carbon (rs = 0.337, P < 0.05) and soil water content (rs = 0.409, P < 0.05), and the available potassium content negatively correlated with the density of living snails (rs = -0.370, P < 0.05). The aspect ratio of snails positively correlated with total potassium (r = 0.392, P < 0.05), available potassium (r = 0.462, P < 0.05) and total soil porosity (r = 0.424, P < 0.05), and the average snail whorl counts positively correlated with herbaceous community coverage (r = 0.369, P < 0.05) and soil water content (r = 0.423, P < 0.05). Smooth curve fitting revealed that the living snail density gradually increased with an increase in the herbaceous community coverage, with a smooth curve of y = 0.05x2 - 6.65x + 218.81 (t = 43.01, P < 0.05), and the aspect ratio of snails appeared a tendency towards a rise with the increase in total potassium (y = 0.05x + 2.19; t = 1.67, P < 0.05) and available potassium in soil (y = 0.02x + 2.03;  t = 1.20, P < 0.05), and total soil porosity (y = 0.44x + 2.07;  t = 2.13, P < 0.05). In addition, the average snail whorl counts appeared a tendency towards a rise with the increase in the herbaceous community coverage (y = 1.56x + 5.61;  t = 8.48, P < 0.05) and soil water content (y = 0.35x + 5.21; t = 3.01, P < 0.05). Conclusions　Plant communities may affect O. hupensis snail population characteristics by regulating the microenvironment. High coverage, high density and high soil water content are associated with the density and morphology of O. hupensis.

Key words: Oncomelania hupensis, Morphology;Population structure, Herbaceous community, Physiochemical property, Marshland in Dongting Lake

摘要： 目的　探究洞庭湖滩地植物群落对钉螺分布、存活状态的影响，以及植物群落生境微环境对钉螺形态和种群结构的调控效应。方法　2024年6月，在湖南省岳阳市君山区洞庭湖滩地的苔草、芦苇、蒌蒿、春蓼、喜旱莲子草、一年蓬群落和星毛蕨群落7 种典型草本植物群落中，选取60个1 m × 1 m的植物群落样方，调查群落样方中的植物密度、盖度、高度等特征，土壤pH值、含水率、容重、总孔隙度及重金属含量等土壤理化性质，以及钉螺总螺数、活螺数、性别、螺旋数、螺长、螺宽、长宽比等种群特征指标，比较不同植物群落生境中钉螺种群特征差异，对活螺密度、长宽比、螺旋数与植物种群特征、土壤理化性质进行相关分析。结果　累计调查苔草群落9个样方、芦苇群落12个样方、蒌蒿群落9个样方、春蓼群落9个样方、喜旱莲子草群落9个样方、一年蓬群落6个样方、星毛蕨群落6个样方。不同植物群落株高差异有统计学意义（F = 15.06，P < 0.001）；其中芦苇群落株高［（129.29 ± 26.56）cm］最高（P均< 0.01）。不同植物群落盖度（F = 4.45，P < 0.001）、密度（F = 9.18，P < 0.001）差异均有统计学意义。不同植物群落生境土壤速效钾、有效磷、全氮、全碳、全磷、全钾、pH值、土壤含水率、总孔隙度、土壤容重及锰、镍、铜、锌含量等理化性质差异均有统计学意义（F = 1.15 ~ 30.69，P均< 0.05）。累计于60个调查样方中捡获钉螺836只，其中活螺546只，活螺密度为1.01只/0.1 m2。不同植物群落生境活螺密度（F = 2.83，P < 0.05）、钉螺长度（F = 6.72，P < 0.05）差异有统计学意义，但钉螺宽度差异无统计学意义（F = 4.02，P > 0.05）。不同植物群落生境钉螺旋数差异有统计学意义（F = 1.68，P < 0.05）；6、7旋和8旋钉螺占比较高的群落分别为芦苇群落（36.84%，28/76）、苔草群落（53.70%，29/54）和春蓼群落（52.03%，77/148）。相关分析发现，活螺密度与草本群落密度、草本群落盖度、全碳和土壤含水率呈正相关（rs = 0.485、0.417、0.337、0.409，P均< 0.05）；而速效钾含量与活螺密度呈负相关（rs = -0.370，P < 0.05）。钉螺长宽比与全钾、速效钾、土壤总孔隙度呈正相关（r = 0.392、0.462、0.424，P均< 0.05）；钉螺平均螺旋数与草本群落盖度、土壤含水量呈正相关（r = 0.369、0.423，P均< 0.05）。拟合平滑曲线发现，随着草本群落盖度增高，活螺密度逐渐增高（y = 0.05x2 - 6.65x + 218.81；t = 43.01，P < 0.05）。随着土壤全钾（y = 0.05x + 2.19；t = 1.67，P < 0.05）、速效钾（y = 0.02x + 2.03；t = 1.20，P < 0.05）、土壤总孔隙度（y = 0.44x + 2.07；t = 2.13，P < 0.05）的增加，钉螺长宽比呈一定的上升趋势。随着草本群落盖度（y = 1.56x + 5.61；t = 8.48，P < 0.05）和土壤含水量（y = 0.35x + 5.21；t = 3.01，P < 0.05）的增高，钉螺平均螺旋数呈增多趋势。结论　植物群落可通过调控微环境影响群落生境钉螺种群特征，高盖度、高密度及高土壤含水率与活螺密度和形态相关。

关键词: 湖北钉螺, 形态, 种群结构, 草本群落, 理化性质, 洞庭湖滩地