Niemuth Neal D, Fleming Kathleen K, Reynolds Ronald E
United States Fish and Wildlife Service Habitat and Population Evaluation Team, Bismarck, North Dakota, United States of America.
United States Fish and Wildlife Service Division of Migratory Bird Management, Laurel, Maryland, United States of America.
PLoS One. 2014 Jun 17;9(6):e100034. doi: 10.1371/journal.pone.0100034. eCollection 2014.
The Prairie Pothole Region (PPR) is the most important waterfowl production area in North America. However, waterfowl populations there are predicted to decline because of climate-related drying of wetlands. Consequently, changes in the geographic focus of PPR waterfowl conservation have been recommended, which could have long-lasting and costly impacts. We used a 40-year dataset of pond counts collected in the PPR to test hypotheses about climate-related drying. We assessed May (1974-2013) and July (1974-2003) pond numbers in 20 waterfowl survey strata to determine if trends in pond numbers were consistent with predictions of drying. We also assessed trends in precipitation and temperature for the 20 strata and developed models describing May pond numbers from 1974 through 2010 as a function of precipitation, temperature, the previous year's pond numbers, and location. None of the 20 strata showed significant declines in May pond numbers, although seven strata showed increases over time. July pond numbers declined significantly in one stratum, and increased in seven strata. An index to hydroperiod showed significant increasing trends in three strata, and no strata had decreasing trends. Precipitation increased significantly in two strata and decreased in two from 1974 to 2010; no strata showed significant changes in temperature. The best linear model described pond numbers within all strata as a function of precipitation, temperature, the previous year's pond numbers, and the latitude and longitude of the stratum, and explained 62% of annual variation in pond numbers. We hypothesize that direct effects of climate change on prairie pothole wetlands and waterfowl may be overshadowed by indirect effects such as intensified land use and increased pressure to drain wetlands. We recommend that an adaptive, data-driven approach be used to resolve uncertainties regarding direct and indirect effects of climate change on prairie wetlands and waterfowl, and guide future conservation efforts.
草原坑洼地区（PPR）是北美最重要的水禽产区。然而，由于湿地因气候原因干涸，预计该地区的水禽数量将会减少。因此，有人建议改变PPR水禽保护的地理重点，这可能会产生持久且代价高昂的影响。我们利用在PPR收集的长达40年的池塘数量数据集，来检验与气候相关干涸有关的假设。我们评估了20个水禽调查分层中5月（1974 - 2013年）和7月（1974 - 2003年）的池塘数量，以确定池塘数量的趋势是否与干涸预测一致。我们还评估了这20个分层的降水和温度趋势，并建立了模型，将1974年至2010年的5月池塘数量描述为降水、温度、上一年池塘数量和位置的函数。20个分层中没有一个显示5月池塘数量有显著下降，不过有7个分层随时间增加。7月池塘数量在一个分层中显著下降，在7个分层中增加。一个水文周期指数在3个分层中显示出显著的上升趋势，没有分层呈下降趋势。从1974年到2010年，两个分层的降水显著增加，两个分层的降水减少；没有分层显示温度有显著变化。最佳线性模型将所有分层内的池塘数量描述为降水、温度、上一年池塘数量以及分层的纬度和经度的函数，并解释了池塘数量年度变化的62%。我们假设气候变化对草原坑洼湿地和水禽的直接影响可能会被诸如土地利用强化和湿地排水压力增加等间接影响所掩盖。我们建议采用一种适应性的、数据驱动的方法来解决关于气候变化对草原湿地和水禽的直接和间接影响的不确定性，并指导未来的保护工作。
