Lima Mauricio, Marquet Pablo A, Jaksic Fabian M
Departamento de Ecología, P. Universidad Católica de Chile, Casilla 114-D, Santiago, Chile Fax: +56-2-686 2615; e-mail:
Oecologia. 1998 Jun;115(1-2):120-126. doi: 10.1007/s004420050498.
The population persistence and extinction probabilities of three small mammal species were analyzed by estimating growth and extinction properties obtained from 10 years of live-trapping data at two different habitat types in semiarid Chile. We used a stochastic formulation with an exponential growth model known as a Wiener-drift process, out of which growth and extinction quantities were estimated. The rodent Phyllotis darwini showed the lowest rates of growth, and the lowest infinitesimal variances, whereas the opposite trend was found for the rodent Akodonolivaceus. The marsupial Thylamys elegans showed intermediate values for growth rates and infinitesimal variances. The rodent P. darwini showed the lowest extinction risk in the study site. We also detected spatial differences between mesic and xeric habitats in the growth rates of P. darwini and T. elegans, and in the extinction risks of the three species studied. Although the population growth of these three species can be approximated by purely stochastic processes, the introduction of density dependence through autoregressive log-linear models reduced the extinction times of all species analyzed.
通过估计从智利半干旱地区两种不同栖息地类型的10年活体诱捕数据中获得的增长和灭绝特性，分析了三种小型哺乳动物物种的种群持续存在和灭绝概率。我们使用了一种具有指数增长模型的随机公式，即维纳漂移过程，从中估计增长和灭绝量。啮齿动物达尔文叶耳鼠的增长率最低，无穷小方差也最低，而橄榄色阿根廷鼠则呈现相反的趋势。有袋动物优雅袋鼬的增长率和无穷小方差处于中间值。在研究地点，啮齿动物达尔文叶耳鼠的灭绝风险最低。我们还检测到达尔文叶耳鼠和优雅袋鼬在潮湿和干旱栖息地的增长率之间以及所研究的三种物种的灭绝风险之间存在空间差异。尽管这三种物种的种群增长可以通过纯随机过程近似，但通过自回归对数线性模型引入密度依赖性减少了所有分析物种的灭绝时间。
