内蒙古土默特平原生境变化对草原沙蜥种群的影响

Effects of Habitat Changes on Pasture Lizard (Phrynocephalus frontalis) Population in Tumote Plain of NeiMongol

对内蒙古土默特平原(40～41°N,109～112°E)由于生境变化引起的草原沙蜥(Phryno-cephalusfrontalis)种群特征的变化作了研究.在植被盖度<10%的沙地生境,草原沙蜥密度较高,当沙地种植柠条(Caraganakorshinskii)7～8年后,植被盖度变为>40%且食物较以前丰富充足,其密度下降,低年龄组死亡率增高是种群衰退的主要原因.营养生态位宽度指数增大,但沙蜥对鞘翅类昆虫的取食频次有所减少.

The effects of habitat changes on pasture lizard (Phrynocephalus frontalis) population were studied from 1989~1992 and from 2000~2001 in Tumote plain(40~41°N,109~112°E),NeiMongol.In the sandy habitat,the density of P.frontalis was higher when the vegetation coverdegree was <10%,whereas the density of P.frontalis population declined gradually when Caragana korshinskii was planted at the habitat 7~8 years later,the vegetation coverdegree rose to >40% and the diet became more abundant for pasture lizard.The higher mortality of the 2-year old group was the main reason for degeneration of lizard population.When the width of the trophic niche enlarged,the eating frequency of pasture lizard to insects Coleoptera decreased obviously.