Abstract

The hydroperiod (i.e., the length of time ponded water is present) of prairie potholes is sensitive to climate change. Because snowmelt runoff is the largest contributor to ponded water amounts, a seasonal change in precipitation timing, even when annual amounts are unchanged, can affect wetland hydroperiod. We observed a change in precipitation timing in the Alberta Prairie Pothole Region from 2014 to 2015, though cumulative precipitation amounts were near equivalent. We sought to understand whether this change in precipitation timing could result in (1) a decline in wetland hydroperiod and (2) a change in the community composition of birds, aquatic macroinvertebrates, and plants. Our findings suggest a change in precipitation timing occurred in 2015 (i.e., delayed-precipitation year), which could be tied to a decline in wetland hydroperiod. Wetlands in the delayed-precipitation year were dominated by upland birds and drought-adapted aquatic macroinvertebrates. There was no change in the community composition of plants, and we hypothesize that this may be explained by their ability to use energy stored from the previous year to survive this one-year change in their growing season. We suspect that consecutive declines in hydroperiod year-to-year could shift vegetation communities to being dominated by wet meadow or terrestrial plants; this will ultimately lead to a further reduction of waterbird habitat in the northern PPR – the last refuge for this guild in the PPR.

中文翻译：

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一致但延迟的降水时间会影响草原坑洼鸟类和大型水生无脊椎动物的群落组成，但不会影响湿地植物

摘要

草原坑洼的水周期（即积水存在的时间长度）对气候变化很敏感。由于融雪径流是积水量的最大贡献者，因此即使年量不变，降水时间的季节性变化也会影响湿地水周期。我们观察到 2014 年至 2015 年阿尔伯塔草原坑洼地区的降水时间发生了变化，但累积降水量几乎相同。我们试图了解降水时间的这种变化是否会导致（1）湿地水周期下降和（2）鸟类、水生大型无脊椎动物和植物的群落组成发生变化。我们的研究结果表明，2015 年（即延迟降水年）降水时间发生了变化，这可能与湿地水周期的下降有关。延迟降水年的湿地以高地鸟类和适应干旱的大型水生无脊椎动物为主。植物的群落组成没有变化，我们假设这可能是因为它们能够利用前一年储存的能量来度过生长季节的一年变化。我们怀疑，水文周期逐年连续下降可能会使植被群落转变为以湿草甸或陆生植物为主；这最终将导致PPR北部水鸟栖息地的进一步减少——这是该行会在PPR的最后避难所。