高寒草甸牦牛皮毛种子库大小与组成的模拟研究

The Simulated Study on the Size and Composition of Yak Fur Seed Bank in Alpine Meadow

动物体外传播(Epizoochorous dispersal)是植物种子实现远距离传播的一种重要方式,尤其在放牧生态系统中,这种现象更为普遍。为探究放牧季节(暖季和冷季)及种子性状(质量、形状和附属结构)对高寒草甸牦牛皮毛种子库的大小及组成特征的调控作用,分别在2019年暖季(8月下旬)和冷季(10月中旬),模拟收集了牦牛皮毛附着的种子,并对皮毛种子库大小和组成及种子形态学特征(质量和形状)进行了统计。结果表明:暖季皮毛种子库大小(585.27±23.56粒/m ^(2))显著高于冷季(218.18±22.67粒/m ^(2))(P<0.05),并且暖季皮毛种子库物种丰富度(16)和多样性指数(1.85±0.19)均高于冷季(4和0.66±0.11)。暖季皮毛种子库主要由多年生植物构成(87.50%),冷季时只包括多年生植物。皮毛种子库主要由中等质量(1~10mg)、形状不规则(形状指数>0.01)的种子构成,并且附着的种子中有75%存在附属结构(芒、冠毛、翅和距)。在高寒草甸放牧生态系统中,植物种子可以通过牦牛进行体外传播,这是草-畜互作的一种表现形式,也是动物-植物共同进化的结果。

Epizoochorous dispersal is an important way of long-distance transmission of plant seeds,especially in grazing ecosystems.In order to explore the regulation of grazing season(warm season and cold season)and seed traits(mass,shape and accessory structure)on the size and composition of yak fur seed bank in alpine meadow,the seeds attached to yak fur were collected in warm season(late August)and cold season(middle October)in 2019.The size,composition and morphological characteristics(mass and shape)of yak fur seed bank were analyzed.The results showed that the size of fur seed bank in warm season(585.27±23.56 grain/m^(2))was significantly higher than that in cold season(218.18±22.67 grain/m^(2))(P<0.05).The species richness(16)and diversity index(1.85±0.19)of fur seed bank in warm season were also higher than those in cold season(4 and 0.66±0.11).The fur seed bank was mainly composed of perennial plants(87.50%)in warm season and only perennial plants in cold season.The fur seed bank was mainly composed of seeds with medium-quality(1~10 mg)and irregular shape(shape index>0.01),and 75.00%of attached seeds had accessory structures(awn,crested,wings and spurs or spike).In alpine meadow grazing ecosystem,plant seeds could be transmitted by epizoochorous dispersal of yaks,which is a form of grass-animal interaction and the result of animal-plant coevolution.