川西平原大足鼠的种群生态学Ⅰ．种群动态和个体大小

POPULATION ECOLOGY OF RATTUS NITIDUS IN THE WESTERN SICHUAN PLAIN I. POPULATION DYNAMICS AND BODY SIZE

我们利用标志重捕、夹捕解剖和笼养等三种方法于１９８９年１月至１９９５年６月对川西平原的大足鼠的种群密度、个体大小、生长和生物量进行了研究。种群密度最高１１．３只／ｈａ，最低０．７只／ｈａ，平均３．６只／ｈａ，并显示出与农作物相同的季节变动特征。雌雄性比由幼年组和亚成体组约１：１到成体组１：０．７８到老年组１：０．５３。雌雄个体的平均质量分别为１３６ｇ和１１４ｇ，两性的个体质量和后足长有明显差异，体长和耳长差异不明显。饲养的幼体及亚成体个体质量和尾长均持续增长，并可分别用Ｌｏｇｉｓｔｉｃ和对数方程较好地拟合。生物量则显示出比种群密度和个体质量更稳定的特征。

Mark-recapture, trap-dissection and captive feeding methods provided data on population density,body size, growth and biomass for a population of Rattus nitidus in the Western Sichuan Plain from January 1989 through June 1995. With highest 11.3 individuals/ha and lowest 0.7 individuals/ha, population density showed the same seasonal fluctuations patterns as crops and averaged 3. 6 individuals/ha.Sex ratio of males to females decreased from 1:1 of juveniles and subadults to 1 1 0.78 of adults to 1:0. 53 of clders. Body mass of males and females averaged, respectively, 136 and 114 g, and showed apparent sex dimorphism in body mass, and hind-foot length as well, but not in body length or ear length. Body mass and tail length of juveniles and subadults kept growing during study period can be fitted adequately fitted by logistic and power equations, respectively. Biomass was more stable than population density and mean body mass.