Lawler Richard R, Caswell Hal, Richard Alison F, Ratsirarson Joelisoa, Dewar Robert E, Schwartz Marion
Department of Anthropology, Boston University, Boston, MA 02215, USA.
Oecologia. 2009 Sep;161(3):491-504. doi: 10.1007/s00442-009-1382-1. Epub 2009 Jun 16.
In this study, we use deterministic and stochastic models to analyze the demography of Verreaux's sifaka (Propithecus verreauxi verreauxi) in a fluctuating rainfall environment. The model is based on 16 years of data from Beza Mahafaly Special Reserve, southwest Madagascar. The parameters in the stage-classified life cycle were estimated using mark-recapture methods. Statistical models were evaluated using information-theoretic techniques and multi-model inference. The highest ranking model is time-invariant, but the averaged model includes rainfall-dependence of survival and breeding. We used a time-series model of rainfall to construct a stochastic demographic model. The time-invariant model and the stochastic model give a population growth rate of about 0.98. Bootstrap confidence intervals on the growth rates, both deterministic and stochastic, include 1. Growth rates are most elastic to changes in adult survival. Many demographic statistics show a nonlinear response to annual rainfall but are depressed when annual rainfall is low, or the variance in annual rainfall is high. Perturbation analyses from both the time-invariant and stochastic models indicate that recruitment and survival of older females are key determinants of population growth rate.
在本研究中，我们使用确定性和随机模型来分析在降雨波动环境下维氏冕狐猴（Propithecus verreauxi verreauxi）的种群统计学特征。该模型基于来自马达加斯加西南部贝扎马哈法利特别保护区的16年数据。使用标记重捕法估计阶段分类生命周期中的参数。使用信息论技术和多模型推断对统计模型进行评估。排名最高的模型是时间不变模型，但平均模型包括生存和繁殖对降雨的依赖性。我们使用降雨时间序列模型构建了一个随机种群统计模型。时间不变模型和随机模型给出的种群增长率约为0.98。确定性和随机增长率的自助置信区间都包含1。增长率对成年个体生存的变化最为敏感。许多种群统计数据显示出对年降雨量的非线性响应，但当年降雨量较低或年降雨量方差较高时，这些统计数据会受到抑制。来自时间不变模型和随机模型的扰动分析均表明，老年雌性的补充和生存是种群增长率的关键决定因素。
