Survival and population growth of a long-lived threatened snake species, Drymarchon couperi (Eastern Indigo Snake)
Survival and population growth of a long-lived threatened snake species, Drymarchon couperi (Eastern Indigo Snake)
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DOI：
10.1007/s10144-011-0292-3
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发表时间：
2012-01-01
影响因子：
1.7
通讯作者：
Oli, Madan K.
中科院分区：
文献类型：
--
作者：
Hyslop, Natalie L.;Stevenson, Dirk J.;Oli, Madan K.
人口统计数据为了解物种的生活史和生态提供了基础，这些因素对于为保护工作提供信息至关重要；然而，人们对大多数蛇类的种群生态知之甚少，包括受威胁的东靛蓝蛇（Drymarchon couperi）。我们在 CMR 建模框架中使用了美国佐治亚州东南部 11 年（1999-2009 年）的捕获-标记-重捕获（CMR）和 2.5 年（2003-2005 年）的无线电遥测数据来估计表观生存、捕获和转移概率，并评估影响这些参数的因素。总体表观年生存概率的模型平均估计值为 0.700 (+/- 0.030 SE)，与同一地点已知的命运分析（无线电遥测）获得的结果相当。无论性别如何，体型都会对生存产生积极影响。捕获概率因性别而存在季节性差异，表明秋季雌性捕获概率较低，冬季雄性捕获概率较低。没有证据表明降水或特定地点的生存差异的影响。使用多状态 CMR 模型估计的年成人生存率的模型平均估计值为 0.738 +/- A 0.030，亚成人为 0.515 +/- A 0.189。我们使用阶段结构矩阵人口模型估计了人口增长率 (lambda) 和 lambda 对生命率的弹性（比例敏感性）。人口增长率在 0.96 至 1.03 之间，具体取决于从亚成年阶段过渡到成年阶段的概率值。 lambda 对成体存活率的变化比例最敏感，其次是亚成体存活率。我们的研究结果表明，保护成年蛇及其栖息地最有可能实现种群的长期稳定和增长。
Demographic data provide a basis for understanding the life history and ecology of species, factors which are vital for informing conservation efforts; however, little is known regarding the population ecology of most snake species, including the threatened Eastern Indigo Snake (Drymarchon couperi). We used 11 years (1999-2009) of capture-mark-recapture (CMR) and 2.5 years (2003-2005) of radiotelemetry data from southeastern Georgia, USA, in a CMR modeling framework to estimate apparent survival, capture and transition probabilities, and evaluate factors influencing these parameters. The model-averaged estimate of overall apparent annual survival probability was 0.700 (+/- 0.030 SE) and is comparable to that obtained from known fate analysis (radiotelemetry) at the same site. Body size positively influenced survival, regardless of sex. Capture probability differed seasonally by sex, suggesting lower capture probability for females in fall and males in winter. There was no evidence for effect of precipitation or site-specific differences in survival. Model averaged estimate of annual adult survival estimated using multistate CMR models was 0.738 +/- A 0.030 and 0.515 +/- A 0.189 for subadults. We estimated population growth rate (lambda) and elasticity (proportional sensitivity) of lambda to vital rates using a stage-structured matrix population model. Population growth rate ranged from 0.96 to 1.03 depending on the value of the probability of transitioning from subadult to adult stage. The lambda was proportionally most sensitive to changes in adult survival rate, followed by subadult survival. Our results suggest that protecting adult snakes and their habitats would result in the highest likelihood of long-term population stability and growth.