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首页> 外文期刊>BMC Ecology >Developmental dynamics of Ambystoma tigrinum in a changing landscape
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Developmental dynamics of Ambystoma tigrinum in a changing landscape

机译：不断变化的景观中的虎斑小虾的发育动力学

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Background Loss of pond habitat is catastrophic to aquatic larval amphibians, but even reduction in the amount of time a breeding site holds water (hydroperiod) can influence amphibian development and limit reproductive success. Using the landscape variation of a glacial valley in the Greater Yellowstone Ecosystem as the context for a natural experiment, we examined variation in growth pattern and life history of the salamander Ambystoma tigrinum melanostictum and determined how these developmental characteristics varied with hydroperiod over several summers. Results In ponds that dried early in the season, maximum larval size was reduced relative to the sizes achieved in permanent ponds. Ephemeral ponds were associated with early metamorphosis at small body sizes, while permanent ponds facilitated longer larval periods and later metamorphosis. Paedomorphosis resulted from indefinite metamorphic postponement, and was identified only in the most permanent environments. Patterns of growth and allometry were similar between ponds with different hydroperiods, but considerable life history variation was derived from modulating the timing of and size at metamorphosis. Considering maximum rates of growth and inferring the minimum size at metamorphosis across 25 ponds over the course of three years, we calculated that hydroperiods longer than three months are necessary to support these populations through metamorphosis and/or reproductive maturity. Conclusions Landscape heterogeneity fosters life history variation in this natural population. Modulation of the complex ambystomatid life cycle allows this species to survive in unpredictable environments, but current trends towards rapid pond drying will promote metamorphosis at smaller sizes and could eliminate the paedomorphic phenotype from this region. Metamorphosis at small size is has been linked to altered fitness traits, including reduced survival and fecundity. Thus, widespread environmental truncation of larval periods may lead to decreased population persistence. We found that the hydroperiods of many ponds in this region are now shorter than the developmental period required for larvae to reach the minimum size for metamorphosis; these locations serve as reproductive sinks that may be detrimental for persistence of the species in the region.
机译：背景技术池塘栖息地的丧失对于水生幼体两栖动物来说是灾难性的，但是即使减少繁殖场所的持水时间（水周期）也会影响两栖动物的发育并限制繁殖成功。我们以大黄石生态系统中冰川谷的景观变化作为自然实验的背景，我们研究了the的黑变种Ambystoma tigrinum melanostictum的生长方式和生活史变化，并确定了这些发育特征在几个夏季随水周期如何变化。结果在季节初期干燥的池塘中，最大幼体尺寸相对于永久性池塘有所减小。临时池塘与较小体型的早期变态有关，而永久性池塘则有利于更长的幼体期和后期变态。变态起因于不确定的变质推迟，仅在最永久的环境中才被发现。在不同水周期的池塘之间，生长方式和异速生长方式相似，但是通过改变变态的时间和大小，可以得出相当大的生活史变化。考虑到三年中25个池塘的最大生长速率和推断的最小变体大小，我们计算出超过三个月的水文周期对于通过变态和/或生殖成熟来支持这些种群是必要的。结论景观异质性促进了这一自然种群的生活史变异。复杂的ambystomatid生命周期的调节使该物种能够在无法预测的环境中生存，但是当前池塘快速干燥的趋势将促进较小尺寸的变态，并可能消除该区域的古形表型。小规模的蜕变与适应性状的改变有关，包括降低的存活率和繁殖力。因此，幼虫期的广泛环境截短可能导致种群持久性下降。我们发现，该区域许多池塘的水周期现在比幼虫达到变态的最小大小所需的发育时期短。这些位置充当了生殖汇，可能对该地区物种的持久性有害。

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