Hettinga Peter N, Arnason Arni Neil, Manseau Micheline, Cross Dale, Whaley Kent, Wilson Paul J
J Wildl Manage. 2012 Aug;76(6):1153-1164. doi: 10.1002/jwmg.380. Epub 2012 Apr 5.
A critical step in recovery efforts for endangered and threatened species is the monitoring of population demographic parameters. As part of these efforts, we evaluated the use of fecal-DNA based capture-recapture methods to estimate population sizes and population rate of change for the North Interlake woodland caribou herd (Rangifer tarandus caribou), Manitoba, Canada. This herd is part of the boreal population of woodland caribou, listed as threatened under the federal Species at Risk Act (2003) and the provincial Manitoba Endangered Species Act (2006). Between 2004 and 2009 (9 surveys), we collected 1,080 fecal samples and identified 180 unique genotypes (102 females and 78 males). We used a robust design survey plan with 2 surveys in most years and analysed the data with Program MARK to estimate encounter rates (p), apparent survival rates (ϕ), rates of population change (λ), and population sizes (N). We estimated these demographic parameters for males and females and for 2 genetic clusters within the North Interlake. The population size estimates were larger for the Lower than the Upper North Interlake area and the proportion of males was lower in the Lower (33%) than the Upper North Interlake (49%). Population rate of change for the entire North Interlake area (2005-2009) using the robust design Pradel model was significantly <1.0 (λ = 0.90, 95% CI: 0.82-0.99) and varied between sex and area with the highest being for males in Lower North Interlake (λ = 0.98, 95% CI: 0.83-1.13) and the lowest being for females in Upper North Interlake (λ = 0.83, 95% CI: 0.69-0.97). The additivity of λ between sex and area is supported on the log scale and translates into males having a λ that is 0.09 greater than females and independent of sex, Lower North Interlake having a λ that is 0.06 greater than Upper North Interlake. Population estimates paralleled these declining trends, which correspond to trends observed in other fragmented populations of woodland caribou along the southern part of their range. The results of this study clearly demonstrate the applicability and success of non-invasive genetic sampling in monitoring populations of woodland caribou. © 2012 The Wildlife Society.
对于濒危和受威胁物种的恢复工作而言，关键的一步是监测种群的人口统计学参数。作为这些工作的一部分，我们评估了基于粪便DNA的捕获-重捕方法在估计加拿大曼尼托巴省北湖林地驯鹿群（Rangifer tarandus caribou）的种群规模和种群变化率方面的应用。该鹿群是北方林地驯鹿种群的一部分，根据联邦《濒危物种法案》（2003年）和曼尼托巴省《濒危物种法案》（2006年）被列为受威胁物种。在2004年至2009年期间（共9次调查），我们收集了1080份粪便样本，并识别出180种独特的基因型（102只雌性和78只雄性）。我们采用了稳健设计的调查计划，大多数年份进行2次调查，并使用MARK程序分析数据，以估计相遇率（p）、表观存活率（ϕ）、种群变化率（λ）和种群规模（N）。我们针对雄性和雌性以及北湖地区内的2个基因簇估计了这些人口统计学参数。北湖下游地区的种群规模估计值高于上游地区，且下游地区雄性的比例（33%）低于北湖上游地区（49%）。使用稳健设计的普拉德尔模型对整个北湖地区（2005 - 2009年）的种群变化率进行估计，结果显著小于1.0（λ = 0.90，95%置信区间：0.82 - 0.99），并且在性别和区域之间存在差异，其中北湖下游地区雄性的种群变化率最高（λ = 0.98，95%置信区间：0.83 - 1.13），北湖上游地区雌性的种群变化率最低（λ = 0.83，95%置信区间：0.69 - 0.97）。在对数尺度上支持了λ在性别和区域之间的可加性，这意味着雄性的λ比雌性大0.09，且与性别无关，北湖下游地区的λ比北湖上游地区大0.06。种群估计值与这些下降趋势一致，这与在其分布范围南部其他碎片化的林地驯鹿种群中观察到的趋势相符。本研究结果清楚地证明了非侵入性基因采样在监测林地驯鹿种群方面的适用性和成功性。© 2012野生动物学会。
