动物对松属植物种子的传播作用研究进展

松属植物约110种,根据种子传播方式可分为风传播松和动物传播松。风传播松占绝大多数,种子多具有适应风力的翅。动物传播松大约23种,都具有大、可食用、无翅或短翅的种子,无法借助风力传播。动物传播松的分布生境多为贫瘠的山地,而且多位于高海拔地区。目前已知9种松树的动物传播种类,其余14种可推测为动物传播。动物传播者包括鸦科鸟类和啮齿类动物,动物将获得的种子分散贮藏,未被重取的种子可能萌发,完成传播。动物传播是定向传播,微生境多适合种子萌发。啮齿类的传播距离可达数10 m,而鸦科鸟类的传播距离可达数公里。动物传播的松树会出现树丛和多树干现象,一般由同一贮点内贮藏的多粒种子萌发造成的。动物贮藏的种子大部分被重取,称传播后取食。一些具有大种子的风传播松在种子落地后,啮齿类和鸟类会再次埋藏而形成二次传播,可看做是一个单独的传播类型,即风-动物传播松。动物传播者与依赖传播松树之间可看作是互利共生关系。

Roles of animals in seed dispersal of Pinus: A review

In genus Pinus,there are approximately 110 species which can be classified into two groups according to the modes of their seed dispersal,i.e.,wind-dispersed and animal-dispersed.The former is in absolute majority,with the seeds small and having relatively large wings that have the potential to carry by the wind well beyond the canopy of parent trees,while the latter includes about 23 species,often with large,edible and wingless or nearly wingless seeds,and distributed in barren or infertile habitat,and in high elevation mountains.The seeds of nine species in this group are known to be dispersed by animals,and those of the other 14 species are presumed to be.Animal dispersers are corvidae(e.g.,jay and nutcracker) and rodents(e.g.,chipmunk,mouse,and squirrel).They store the seeds separately in many caches,with one or several seeds per cache,and the remained seeds may germinate and be dispersed.Many of the cache microhabitat are beneficial to seed germination,a directed dispersal.The dispersal distance may be several meters(by rodents) or kilometers(by birds).Tree cluster(clumping) or multi-trunk often occurs for animal-dispersed pines,due to the germination of several seeds in one cache.The seeds in most caches are recovered and eaten by hoarders,a post-dispersal predation.Some wind-dispersed pines with large seeds are not dispersed very far,and the seeds may be cached by animals and dispersed again,a secondary dispersal.Such pines can be also classified as a type of "wind plus animal dispersed pines".A mutualism exists between dispersing animals and pines.