Studies on relationship between vegetation and snail distribution inside and outside embankment of Poyang Lake region / 中国血吸虫病防治杂志

ABSTRACT

Objective To explore the relationship between vegetation and the distribution of Oncomelania snails inside and outside the embankments of Poyang Lake region. Methods The plantation and Oncomelania snails were surveyed at 4 villages and their related marshlands in Yugan, Nanchang and Jinxian counties by the stratified systematic sampling method. The investigation was targeted to the vegetation species,height,coverage and frequency of plantation and synchronously to the distribution of snails and infection of snails in marshland of high, middle and low altitudes,adjacent beaches as well in cultivated and waste land inside embankment. The relationship between vegetation dominant association and the distribution of snails in those area was analyzed. Results The vegetation inside and outside the embankment were remarkably diverse. Inside the embankment, the species of vegetation varied greatly and distributed randomly,and no snail was found. While outside the embankment,the distribution of vegetation characterized an unregulated annulus or patch. Plant's association types were distinct on marshlands. The snails mainly distributed in areas at 15-17 m altitude,closely related to the species of vegetation. The coverage of dominant plants,Carex cinerascen and Miscanthus sacchariflorus showed a quadratic curve correlation with the density of snails. Conclusions In the Poyang Lake region,plants and snails are impacted by common environmental factors,which then lead to their close association in distribution. It might be attributed to integrated impacts of changes in ecological factors that Oncomelania snails disappear gradually in areas inside embankment after construction of embankment.