Sizes, densities and age structures of Scottish Margaritifera margaritifera (L.) populations
Sizes, densities and age structures of Scottish Margaritifera margaritifera (L.) populations
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苏格兰 Margaritifera margaritifera (L.) 种群的规模、密度和年龄结构
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
B. Henninger
中科院分区：
文献类型：
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作者：
L. Hastie;M. Young;P. Boon;P. Cosgrove;B. Henninger
1.淡水珍珠蚌（Margaritifera margaritifera（L.））在苏格兰的12条河流中进行了调查（从已知含有可行种群的河流中选出）。不同河流中贻贝的总密度从0.27到30.01 m−2不等。中位密度介于2.5至14.5 m−2之间，其中一条河流中最多可观察到398 m−2的贻贝。
2.不同河流的总人口估计数从2000年到90万至370万不等。有一个种群特别密集，在一条4公里长的河流中估计有60万至120万只贻贝。
3.从9个种群的样本，以提供贻贝的大小/年龄数据。观察到尺寸分布与其相应的年龄分布之间存在显著差异。很难从招聘的角度来解释前者。
4.在调查的所有人口中，都有最近招募的迹象。在4条河流中发现了大量年龄≤20岁的贻贝幼贝。在任何特定地点，年龄≤10年的最大比例为67/219（30.6%），年龄≤20年的最大比例为191/219（87.2%），这两个数值均记录在同一条河流中。
5.预期的优势，年轻的贻贝没有实现在任何人口。据推测，由于抽样方法有偏差，对最年轻年龄组的估计被大大低估。然而，据认为，有几个种群的招募水平足以维持生存能力。
6.一个种群（F河）是“健康”、适度捕捞、补充种群的最佳例子，其年龄分布可用作今后比较的基准。
7.本研究的结果强调了苏格兰在M。珍珠层保护然而，在一些苏格兰河流中发现的少量幼鱼表明，许多种群容易下降，因此，它们的保护地位可能会受到长期威胁。版权所有© 2000约翰威利父子有限公司。
1. Populations of freshwater pearl mussels (Margaritifera margaritifera (L.)) were surveyed in 12 Scottish rivers (selected from those known to contain viable populations). Overall mussel densities in different rivers ranged from 0.27 to 30.01 m−2. Median densities ranged from 2.5 to 14.5 m−2 and a maximum of 398 mussels m−2 was observed in one river.
2. Total population estimates in different rivers ranged from 2000 to 0.9–3.7 million. One population is particularly dense, with an estimated 0.6–1.2 million mussels in a 4-km stretch of river.
3. Samples from nine populations were taken in order to provide mussel size/age data. Marked differences between size profiles and their corresponding age profiles were observed. It is difficult to interpret the former in terms of recruitment.
4. There were signs of recent recruitment in all of the populations investigated. Large numbers of young mussels (aged ≤20 years) were found in four rivers. The largest proportions at any particular site were 67/219 (30.6%) aged ≤10 years and 191/219 (87.2%) aged ≤20 years, both values being recorded in the same river.
5. The expected predominance of young mussels was not achieved in any population. Presumably, there is considerable underestimation of the youngest age classes owing to biased sampling techniques. However, several populations are thought to be recruiting at levels that are high enough to maintain viability.
6. One population (River F) is the best example of a ‘healthy’, moderately fished, recruiting population and its age profile could be used as a benchmark for future comparisons.
7. The results of this study emphasize the international importance of Scotland in terms of M. margaritifera conservation. However, the small numbers of juveniles found in some Scottish rivers indicates that many populations are vulnerable to decline and, therefore, their conservation status may be threatened in the long term. Copyright © 2000 John Wiley & Sons, Ltd.