Bendik Nathan F
Watershed Protection Department City of Austin Austin TX USA.
Ecol Evol. 2017 May 31;7(13):5002-5015. doi: 10.1002/ece3.3056. eCollection 2017 Jul.
Insights into the ecology and natural history of the neotenic salamander, are provided from eight years of capture-recapture data from 10,041 captures of 7,315 individuals at 16 sites. exhibits seasonal reproduction, with peak gravidity occurring in the fall and winter. Size frequency data indicated recruitment occurred in the spring and summer. Open-population capture-recapture models revealed a similar seasonal pattern at two of three sites, while recruitment was dependent on flow at the third site. Females can reach sexual maturity within one year, and oviposition likely takes place below ground. The asymptotic body length of 1,290 individuals was estimated as 31.73 mm (at ca. two years of age), although there was substantial heterogeneity among growth trajectories. Longevity was approximately eight years, and the median age for a recaptured adult was 2.3 years. Abundance estimated from closed-population and robust-design capture-recapture models varied widely within and among sites (range 41-834), although, surprisingly, dramatic changes in abundance were not observed following prolonged dry periods. Seasonal migration patterns of second-year and older adults may help explain lower ratios of large individuals and higher temporary emigration during the latter half of the year, but further study is required. Low numbers of captures and recaptures precluded the use of open-population models to estimate demographic parameters at several sites; therefore, closed-population (or robust-design) methods are generally recommended. Based on observations of their life history and population demographics, seems well adapted to conditions where spring flow is variable and surface habitat periodically goes dry.
通过对16个地点7315只个体进行10041次捕获的八年标记重捕数据,我们对幼态蝾螈的生态和自然史有了深入了解。该物种表现出季节性繁殖,秋季和冬季怀孕率达到峰值。大小频率数据表明,春季和夏季有新个体加入。开放种群标记重捕模型显示,三个地点中的两个呈现出类似的季节性模式,而在第三个地点,新个体加入依赖于水流。雌性蝾螈一年内可达性成熟,产卵可能在地下进行。对1290只个体的渐近体长估计为31.73毫米(约两岁时),尽管生长轨迹存在很大差异。寿命约为八年,被重新捕获的成年个体的中位年龄为2.3岁。根据封闭种群和稳健设计标记重捕模型估计的丰度在不同地点和同一地点内差异很大(范围为41 - 834),不过令人惊讶的是,在长期干旱后并未观察到丰度的显著变化。第二年及以上成年个体的季节性迁移模式可能有助于解释下半年大型个体比例较低和临时迁出率较高的现象,但还需要进一步研究。由于捕获和重新捕获的数量较少,无法在几个地点使用开放种群模型来估计种群统计学参数;因此,通常建议采用封闭种群(或稳健设计)方法。基于对其生活史和种群统计学的观察,该物种似乎很好地适应了春季水流多变且地表栖息地周期性干涸的环境。