River corridor plants revisited: What drives their unique distribution patterns?

The phenomenon whereby some plant species display a river corridor distribution pattern has long been recognized but is still poorly understood. The goals of this study were to supplement the list of river corridor plants for Central Europe, analyse their habitats and compare their ecological features with those of their widely distributed counterparts. The ATPOL (<i>Atlas of Poland</i>) database was used to compile a list of river corridor plants of Poland and calculate their river corridor-specificity indices (RCSIs). The Ellenberg indicator values, dispersal modes and life forms of river corridor and widely distributed species were compared using generalized linear mixed models (GLMMs). Eighty-five species were classified as river corridor species. The most numerous habitat groups were meadow species (19%), wet-habitat therophytes (15%), riverside tall herbs (13%) and species of dry, sandy soils (12%). These species had mostly requirements for a higher temperature and alkalinity than widespread species. Among river corridor plants, there were a few eurytopic species. Corridor species had usually only one life form and less dispersal modes than widespread species. Hence, specific demands of corridor plants and lower phenotypic plasticity may explain their restricted geographical distribution. The definition of the river corridor plant species needs modification.

部分植物物种呈现河流廊道分布格局的现象早已为学界所认知，但迄今仍未得到充分解析。本研究旨在补充中欧河流廊道植物名录、解析其生境特征，并将其生态特征与广布同类物种进行对比。本研究借助ATPOL数据库（全称为《波兰地图集》，Atlas of Poland），整理了波兰境内的河流廊道植物名录并计算其河流廊道特异性指数（RCSIs），同时采用广义线性混合模型（GLMMs）对比了河流廊道物种与广布物种的埃伦贝格指示值（Ellenberg indicator values）、传播方式及生活型。共计85个物种被归类为河流廊道物种，其中占比最高的生境类群依次为草甸物种（19%）、湿生一年生植物（therophytes）（15%）、河岸高大草本植物（13%）及干旱沙生生境物种（12%）。相较于广布物种，此类物种大多需要更高的温度与碱度条件；且在河流廊道植物中仅存在少量广适性物种。河流廊道物种通常仅具备一种生活型，且传播方式的种类少于广布物种。因此，河流廊道植物的特异性生境需求与较低的表型可塑性，或可解释其地理分布受限的现象。目前，河流廊道植物物种的定义仍有待完善。