TEMPORAL OVERLAP, COMPETITION, AND PRIORITY EFFECTS IN LARVAL ANURANS
TEMPORAL OVERLAP, COMPETITION, AND PRIORITY EFFECTS IN LARVAL ANURANS
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DOI：
10.2307/1939512
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发表时间：
1993-01-01
期刊：
影响因子：
4.8
通讯作者：
MORIN, PJ
中科院分区：
文献类型：
--
作者：
LAWLER, SP;MORIN, PJ
种间竞争对手通常在不同的时间殖民群落，但很少有研究通过实验测试种间竞争的强度是否取决于物种到达的顺序或时间分离。我们在三个不同的日期将两种同域无脊椎动物（Hyla [= Pseudacris] crucifer和Bufo woodhousii）的幼体放入人工池塘，以控制它们到达的顺序和时间间隔。在第二个物种同时到达的池塘（第0天），或延迟7或14天后，测量每个物种的生长和存活，表明引入历史的差异是否影响种间竞争。其他池塘仅含有十字花科植物，在相同的三个日期引入，或单独的woodhousii，在第一次或第二次日期引入。这为在没有其他无尾动物竞争的情况下，表现的季节性差异提供了控制。在不同时间引入的蝌蚪在生长速度和幼虫期上产生了微小的差异，当每个无尾猿物种单独发生时。在两个物种同时存在的池塘中，引种顺序和时间分离的差异对种间竞争的强度有复杂的影响。当蟾蜍先于海螅虫时，海螅虫的幼虫期延长，质量和生长减少。当海拉先于布福时，它不受布福的影响。海拉对Bufo没有影响，无论是在Bufo引入之前还是之后。不对称优先效应不容易解释为早期到达者的简单规模依赖竞争优势。提前到达增加了布福对海拉的竞争影响，但未能产生海拉对布福的竞争影响。Bufo蝌蚪比Hyla更活跃，因此可能以更高的速度消耗资源，这不能被时间优势所抵消。当海拉晚7 d到达时，来自蟾蜍的竞争最激烈，这表明海拉比蟾蜍晚14 d到达，从蟾蜍从池塘蜕变后较长时间的竞争减少中受益。海拉先于蟾蜍或与蟾蜍同时繁殖的自然模式，允许海拉最小化来自蟾蜍的竞争，而蟾蜍没有从竞争较弱的海拉蝌蚪获得的尺寸优势中遭受可测量的成本。由于生理上的限制作用于卵或正在繁殖的成虫，瓢虫可能无法在繁殖季节更早的时候繁殖。
Interspecific competitors often colonize communities at different times, but few studies have experimentally tested whether the strength of interspecific competition hinges on the order or temporal separation of species' arrivals. We added hatchlings of two sympatric anuran species (Hyla [= Pseudacris] crucifer and Bufo woodhousii) to artificial ponds on three different dates to manipulate the order and temporal separation of their arrival. Measurement of the growth and survival of each species in ponds where the second species arrived simultaneously (day 0), or after a delay of 7 or 14 d, indicated whether differences in the history of introductions affected interspecific competition. Other ponds contained H. crucifer alone, introduced on the same three dates, or B. woodhousii alone, introduced on the first or second date. These provided controls for seasonal differences in performance in the absence of competition from the other anuran species.Introductions of tadpoles at different times produced small differences in growth rates and larval periods when each anuran species occurred alone. In ponds containing both species, differences in the order and temporal separation of introductions had complex effects on the intensity of interspecific competition. When Bufo preceded Hyla, Hyla had prolonged larval periods and reduced mass and growth. When Hyla preceded Bufo, it was unaffected by Bufo. Hyla had no effects on Bufo, whether its introduction preceded or followed the introduction of Bufo.Asymmetric priority effects were not easily explained as a simple size-dependent competitive advantage of earlier arrivals. Early arrival increased the competitive impact of Bufo on Hyla, but failed to generate a competitive effect of Hyla on Bufo. Bufo tadpoles are more active than Hyla, and so may consume resources at higher rates that cannot be offset by a temporal advantage. Competition from Bufo was strongest when Hyla arrived 7 d later, suggesting that Hyla arriving 14 d after Bufo benefited from a longer period of reduced competition after Bufo metamorphosed from the ponds. The natural pattern, where Hyla breeds before or simultaneously with Bufo, permits Hyla to minimize competition from Bufo, while Bufo suffers no measurable cost from the size advantage obtained by competitively weaker Hyla tadpoles. Bufo may be prevented from breeding any earlier in the season by physiological constraints acting on eggs or breeding adults.