瑞士北部农田周围野花地小型兽类种群结构特征的研究

Study on Small Mammals Population Structure Characteristics in Wildflower Area Around Cultivated Land in Northern Switzerland

目的评价野花地等生态保留带对小型兽类种群动态的影响。方法我们在瑞士西北部选择3个野花地样地,采用标志重捕方法对普通田鼠种群结构特征和数量动态进行系统地研究。结果生态保留带适合于小型兽类特别是普通田鼠的生存,当周围耕地或农田受到人类干扰时普通田鼠和其他避难鼠种可生存在野花地中,但是,种群数量只有临时达到高峰。在3个野花地间普通田鼠种群数量有所差异,但是具有相同的季节性变化趋势,一般在春季随着植物盖度和食物丰富度的增加,种群数量也开始增加,中夏达到最高水平。秋季种群数量开始下降,但是进入冬季的个体数量相对也高。种群中雌雄个体年龄结构之间有明显的差异,雄性中亚成体的数量比雌性多,雌性中成体的数量比雄性多(χ2=44.09,df=10,P<0.001,n=236)。幼体的数量和繁殖期的雌性个体数量相关(r=0.894,P<0.0001,n=12),亚成体数量和繁殖前期雌性数量相关(r=0.893,P=0.002,n=12),繁殖期雌性数量和繁殖期雄性数量相关(r=0.99,P<0.0001,n=12)。种群性比基本保持1∶1,但具有月间波动趋势。结论生态保留带为小型兽类提供比较好的栖息地、食物、繁殖和隐蔽空间,因此,普通田鼠占优势地位并且种群数量有季节性变动趋势。

Objective In order to assess the effect of set aside on small mammal populations dynamics. Methods A one-year field study using mark and recapture techniques was performed in set aside and adjacent arable farmland. Results Small mammals and common voles, in particular made intensive use of the set asides, which seemed to play an important role as an alternative habitat and most probably serve as refuges or dispersal sinks, when the adjacent crops were disturbed. However, high animal abundance was only reached temporarily. Population size of common voles was different between the strips, but fluctuations in animal numbers were similar, showing a rapid increase as cover and food abundance increased in the strips during late spring, leading to peak in midsummer. Populations slowly declined during fall, showing still relative high numbers of animals during winter and a minimum in spring. Males and females were abundant in similar numbers throughout the year, but the age structure differed within the genders and females mostly represented adults, whereas males dominated in sub adults( χ 2 =44.09, df=10, P< 0.001,n=236). The number of juveniles correlated with the number of active females (r= 0.894, P<0.000 1, n= 12), the number of subadults correlated with the number of previously active females (r= 0.893, P = 0.002, n=12) and the number of sexually active females correlated strongly with the number of sexually active males (r =0.99, P<0.0001, n=12). Conclusions Set aside area can provide very high quality habitat, food resources, reproduction and hiding place for small mammal, therefore, in this habitat common vole becomes to dominant species and the population dynamics has seasonal fluctuation characteristics.