THE SPREAD OF ELMINIUS-MODESTUS DARWIN IN NORTH-WEST EUROPE
THE SPREAD OF ELMINIUS-MODESTUS DARWIN IN NORTH-WEST EUROPE
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DOI：
10.1017/s0025315400023833
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发表时间：
1958-01-01
影响因子：
1.2
通讯作者：
CRISP, DJ
中科院分区：
文献类型：
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作者：
CRISP, DJ
澳大利亚移民藤壶E. modestus可能在1940年之前还没有出现在英国，但一定是在1940年之后不久到达的。它最初的中心可能是南安普顿水域。到1945年，它在英格兰南部广泛传播。到1950年，它到达亨伯河，在那里停止了。尽管到1946年在英格兰西南部和布里斯托尔海峡已经形成了独立的中心，但它并没有作为一个连续的人口向西扩散到波特兰以外。其他重要的传播中心是莫克姆湾，荷兰南部，法国北部海岸和布雷斯特贸易。边缘传播是指幼虫由正常机构在当地传播，而远距离传播是指幼虫由媒介（如船只）传播到更远的地方。在Elminius上的观察表明，在潮流较弱的海岸，种群可以以每年约20-30公里的边际扩散方式前进。在水流强的地方，物种分布得更广、更薄，因此同时出现在许多地方。它的蔓延可能因海岸线太暴露或缺乏底质而停止，也可能因公海、相反的海岸流而停止，也可能在某些有强烈潮汐流的岬角上，由于幼虫的过度扩散而停止。可以轻易跨越的不利栖息地的最大范围不超过30英里。引入Elminius后的生态后果主要是由于取代了本地藤壶Balanus balanoides。由于Elminius不像balanoides在整个夏季繁殖，在Elminius占主导地位的夏季浮游生物中，nauplii藤壶的比例上升，可能是以牺牲其他形式的幼虫为代价的。
E. modestus the Australasian immigrant barnacle, was probably not present in Britain before 1940, but must have arrived soon afterwards. Its original centre was probably Southampton Water. By 1945 it was widespread in Southern England. By 1950 it reached the Humber where it halted. It did not spread westwards as a continuous population beyond Portland, though separate centres had formed by 1946 in south west England and in the Bristol Channel. Other important centres of dissemination were Morecambe Bay, south Holland, the northern coast of France and the Rade de Brest. A distinction is made between marginal dispersal, in which the larvae are disseminated locally by normal agencies, and remote dispersal in which they are carried over greater distance by a vector, such as a ship. Observations on Elminius indicate that along coasts where tidal currents are weak, the population can advance by marginal dispersal at about 20-30km per year. Where the currents are strong the species is more widely and thinly scattered and so appears in a number of places simultaneously. Its spread may be halted by stretches of coast which are too exposed or lacking in substrata, by the open sea, by opposing coastal currents and probably also, at certain headlands where there are strong tidal currents, by excessive dispersal of the larvae. The maximum extent of unfavourable habitat that can easily be bridged is less than 30 miles. The ecological consequences following the introduction of Elminius result mainly from the displacement of the indigenous barnacle Balanus balanoides. Since Elminius, unlike B. balanoides breeds throughout the summer, the proportion of barnacle nauplii in the summer plankton rises wherever Elminius is dominant, presumably at the expense of the larvae of other forms.