Pollen dispersal in fragmented populations of the dioecious wind-pollinated tree, Allocasuarina verticillata (drooping sheoak, drooping she-oak; Allocasuarinaceae)

Vegetation clearing, land modification and agricultural intensification have impacted on many ecological communities around the world. Understanding how species respond to fragmentation and the scales over which functionality is retained, can be critical for managing biodiversity in agricultural landscapes. Allocasuarina verticillata (drooping sheoak, drooping she-oak) is a dioecious, wind-pollinated and -dispersed species with key conservation values across southeastern Australia. But vegetation clearing associated with agricultural expansion has reduced the abundance and spatial distribution of this species in many regions. Spatial genetic structure, relatedness among trees, pollen dispersal and mating patterns were examined in fragmented A. verticillata populations selected to represent the types of remnants that now characterise this species. Short scale spatial genetic structure (5–25 m) and relatedness among trees were observed in most populations. Unexpectedly, the two male trees...

植被清除、土地改造与农业集约化已对全球诸多生态群落造成影响。阐明物种如何响应生境破碎化，以及生态功能得以维持的空间尺度，对农业景观中的生物多样性管理至关重要。垂枝木麻黄（*Allocasuarina verticillata*，英文俗名drooping sheoak、drooping she-oak）是一种雌雄异株、兼具风媒传粉与风媒传播特性的物种，在澳大利亚东南部具有重要的保护价值。但伴随农业扩张开展的植被清除活动，已导致该物种在诸多区域的种群数量与空间分布范围缩减。研究人员针对代表该物种现存残存生境类型的破碎化垂枝木麻黄种群，分析了其空间遗传结构、植株间亲缘关系、花粉扩散与交配模式。多数种群中均观测到小尺度空间遗传结构（5~25米）与植株间的亲缘关系。出乎意料的是，两株雄树……