HABITAT DIFFERENCES AFFECTING AGE CLASS DISTRIBUTIONS OF THE HELLBENDER SALAMANDER, CRYPTOBRANCHUS ALLEGANIENSIS
HABITAT DIFFERENCES AFFECTING AGE CLASS DISTRIBUTIONS OF THE HELLBENDER SALAMANDER, CRYPTOBRANCHUS ALLEGANIENSIS
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影响大蝾螈、Cryptobranchus alleganiensis 年龄级分布的栖息地差异
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
R. Owen
中科院分区：
文献类型：
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作者：
M. Nickerson;K. Krysko;R. Owen
摘要在过去的几十年里，隐鳃鲵（Cryptobranchus alleganiensis）的种群受到了相当大的关注，最近的研究表明，下降。我们比较了C。对美国田纳西州大烟山国家公园（GSMNP）小河（LR）和密苏里州怀特河北支流（NFWR）的黑翅石首鱼（alleganiensis）种群和生境特征进行了比较研究。我们还比较了两种不同的采样方法获得小个体< 20厘米总长度（TL）和鳃幼虫的结果。幼虫和成虫在LR中的出现频率无显著差异。在NFWR种群中幼虫和成虫的频率以及LR和NFWR之间幼虫和成虫的比例上存在非常显著的差异。流底基板，特别是深砾石床的NFWR，提供了一个更安全的幼虫栖息地比在LR。我们认为，这种安全的幼虫栖息地是维持NFWR大型成年人口的一个主要因素。LR内较不安全的幼虫栖息地使幼虫更容易被捕获，再加上小龙虾种群减少，转化为更少的成年C。阿利加尼种在这些生境中，皮肤潜水比涉水和翻岩更有效地收集幼虫。除了LR种群，其中48%是由鳃或鳃大小的幼虫，所有记录的种群几乎完全由成年和亚成年年龄组和小幼虫，特别是鳃幼虫是罕见或未知的。
Abstract Hellbender salamander (Cryptobranchus alleganiensis) populations have received considerable attention over the last few decades and recent studies show declines. We compared C. alleganiensis populations and habitat characteristics of the Little River (LR) in the Great Smoky Mountains National Park (GSMNP) of Tennessee, with those of the North Fork of the White River (NFWR), Missouri. We also compared the results of two different sampling methods for obtaining small individuals < 20 cm total length (TL) and gilled larvae. There was no significant difference in the frequency of larvae and adults in LR. There were highly significant differences in the frequency of larvae and adults in the NFWR population and in the proportion of larvae and adults between LR and NFWR. The stream bottom substrate, especially the deep gravel beds of the NFWR, provided a more secure larval habitat than in the LR. We believe this secure larval habitat was a major factor in maintaining large adult populations in NFWR. The less secure larval habitat within the LR makes larvae more susceptible to capture, and coupled with reduced crayfish populations, translates to fewer adult C. alleganiensis. Larvae were more efficiently collected by skin-diving than wading and turning rocks in these habitats. With the exception of the LR population, which is composed of 48% gilled or gilled sized larvae, all recorded populations are almost entirely composed of adult and sub-adult age groups and small larvae, especially gilled larvae are either uncommon or unknown.