赣江流域洲滩和鄱阳湖草洲植被调查及其比较

目的 了解赣江洲滩植被与钉螺的分布情况，并与鄱阳湖草洲植被和钉螺分布进行比较。方法对赣江杨洪湖洲和鄱阳湖有螺草洲牛洲以分层和系统抽样的方法调查植被的种类、高度、盖度、频度以及钉螺的分布和感染情况。结果赣江杨洪湖洲原始滩地带，植被处于原始生长状态，生活强度良好，平均覆盖度最高可达80％左右，优势植被为灰化苔草与荻草，其次是稿草，其活螺密度最高在灰化苔草丛为0．571只／0．1m^2，感染螺密度均为0。鄱阳湖牛洲以南荻、稿草和灰化苔草等群丛为优势植被，钉螺主要分布于灰化苔草丛，活螺密度最高为10．700只／0．1m^2，感染螺密度为0．033只／0．1m^2。结论赣江流域草洲的植被与鄱阳湖有螺草洲十分相似，其为钉螺的生长繁殖提供了必要的生态环境和生存条件。

Vegetation survey and comparison in Ganjiang Valley and Poyang Lake marshland

Objective To understand the distribution of vegetation and Oncomelania snails in the marshlands of Ganjiang Valley and Poyang Lake. Methods The stratified and systematic sampling methods were employed to investigate the species, altitude, coverage, and frequency of vegetation, and the distribution and infection of the snails. Results The vegetation was in primitive growth state in the primitive marshlands of Yanghonghu in Ganjiang with about 80% of average coverage. Carex cinerascens and Miscanthus sacchariflorus were the preponderant vegetations. The second was Pha- laris arund inaceas. The density of living snails reached a maximum of 0. 571/0. 1 m^2 under Carex cinerascens association, the number of infected snails was 0. In the Niuzhou marshland of Poyang Lake, Carex cinerascens and Miscanthus sacchari florus and Phalaris arund inacea were the preponderant vegetations. The density of living snails reached a maximum of 10. 700/0. 1 m^2 under Carex cinerascens association, the density of infected snails was 0. 033/0. 1 m^2. Conclusion The vegetation of marshlands in Ganjiang Valley provides necessary ecological environment and survival condition for snail growth and reproduction as similarly as marshlands with the snails of Poyang Lake.