鄂西桑寄生植物多样性的海拔格局

Diversity of mistletoes along elevation gradient in western Hubei

桑寄生植物(桑寄生科)的分布与寄主选择性和生境相关。本研究沿海拔梯度(175~3106 m)设置3条样带共292个样方(20 m×20 m),调查了鄂西亚热带森林群落中桑寄生的分布,记录桑寄生植物多样性。结果表明:在研究区内共调查到7种桑寄生科植物,40种寄主植物;桑寄生植物分布的最低海拔是194 m,最高海拔是2011 m;物种多样性在海拔梯度上先上升后下降,相对集中分布在海拔600~1000 m范围内,呈现单峰分布格局;不同桑寄生科植物在不同寄主植物上的寄生强度不同,更偏好选择高大的落叶乔木作为寄主;桑寄生科植物在鄂西地区海拔梯度上呈"中度膨胀"(mid-elevation peak)的分布格局,可能与寄生植物偏好性及寄主多样性有关。

The distribution of mistletoe species(Loranthaceae)correlates to specific host plants and habitats.Here,we investigated the distribution of mistletoe species over 292 plots(20 m×20 m)of subtropical forest community with three transects along an elevation gradient(175-3106 m)in western Hubei.Results showed that there were seven species parasitizing 40 different host plant species.Mistletoes were distributed between the elevation of 194 m and 2011 m.Species diversity increased and then decreased with increasing elevation,and concentrated from 600 m to 1000 m,showing a unimodal pattern.The parasitic intensity of different mistletoes on host plants depended on specific species,with mistletoes being generally found on the tall deciduous trees.The"mid-elevation peak"in mistletoe diversity was observed along the elevation gradient in western Hubei,which may be related with host availability and diversity.