Rowe Christopher L, Dunson William A
Department of Biology, The Pennsylvania State University, 208 Mueller Laboratory, 16802, University Park, PA, USA.
Oecologia. 1995 Jun;102(4):397-403. doi: 10.1007/BF00341351.
The effects of variable hydroperiod (three levels) and initial density of amphibians (two levels) on survival, growth rate, and time to and mass at metamorphosis were studied for wood frogs (Rana sylvatica), Jefferson salamanders (Ambystoma jeffersonianum), and spotted salamanders (A. maculatum). Experiments were carried out in 260-1 mesocosms set up outdoors in a forest. These pond simulations were designed to mimic conditions that occur in palustrine temporary wetlands in central Pennsylvania. No animals reached metamorphosis in the short hydroperiod (56 days). However a greater proportion (66%) of tadpoles of R. sylvatica survived to the end of the 56-day, treatment than the 84- or 158-day treatments (29 and 14%, respectively), from which all survivors metamorphosed. In contrast, neither of the salamanders metamorphosed by 84 days; survival to metamorphosis at 158 days was 15% for A. jeffersonianum and 10% for A. maculatum. Average instantaneous growth rates for A. jeffersonianum decreased with each increase in hydroperiod. Growth of R. sylvatica was greater in the 56-day hydroperiod than in hydroperiods of 84 or 158 days. Initial amphibian density had no effect on growth or survival of any species. It appears that salamander larvae were predatory on tadpoles, since survival of R. sylvatica was negatively correlated with survival of A. jeffersonianum in 84-day treatments and with growth of A. maculatum in 158-day treatments.
研究了可变水文周期（三个水平）和两栖动物初始密度（两个水平）对林蛙（Rana sylvatica）、杰斐逊蝾螈（Ambystoma jeffersonianum）和虎纹钝口螈（A. maculatum）的存活、生长速率以及变态时间和变态时体重的影响。实验在森林中户外设置的260升中型生态箱中进行。这些池塘模拟旨在模仿宾夕法尼亚州中部淡水湿地临时湿地中出现的条件。在短水文周期（56天）内没有动物达到变态。然而，林蛙蝌蚪在56天处理结束时存活的比例（66%）高于84天或158天处理（分别为29%和14%），所有存活者都在这些处理中变态。相比之下，两种蝾螈在84天内都没有变态；在158天时，杰斐逊蝾螈变态的存活率为15%，虎纹钝口螈为10%。杰斐逊蝾螈的平均瞬时生长速率随着水文周期的每次增加而降低。林蛙在56天水文周期中的生长大于84天或158天的水文周期。两栖动物的初始密度对任何物种的生长或存活都没有影响。似乎蝾螈幼体以蝌蚪为食，因为在84天处理中，林蛙的存活与杰斐逊蝾螈的存活呈负相关，在158天处理中，与虎纹钝口螈的生长呈负相关。
