Department of Behavioural Ecology, University of Wroclaw, Wroclaw, Poland.
Polish Society of Wildlife Friends "pro Natura", Wroclaw, Poland.
PLoS One. 2020 Feb 18;15(2):e0227912. doi: 10.1371/journal.pone.0227912. eCollection 2020.
Warmer winters may lead to changes in the hibernation behaviour of bats, such as the barbastelle Barbastella barbastellus, which prefers to hibernate at low temperatures. The species is also known for its large annual fluctuations in the number of wintering individuals, so inference about population trends should be based on long-term data. Prior to 2005, analyses indicated stable or even increasing barbastelle population in Poland. We analysed the results of 13 winter bat counts (2005-2017) of the species from 15 of the largest hibernacula, and additional site of 47 small bunkers, in Poland. The total number of wintering individuals remained stable during the study period, because the barbastelle is not a long-distance migrant, this likely reflects the national population trend. On the basis of mean winter air temperatures we divided the country into four thermal regions. Analyses of barbastelle abundance in hibernacula in the four regions revealed a 4.8% annual mean increase in numbers in the coldest region, where mean winter temperatures were below -2°C, annual mean declines of 3.3% and 3.1% in two warmer regions of western Poland, but no trend in the region of intermediate mean winter temperatures of between -1°C and -2°C. Overall, there was a significant, but weak, negative correlation between the abundance of hibernating individuals and the mean winter temperature. On the other hand, the number of individuals hibernating in small bunkers increased, even though the site was located in one of the warm regions. The results indicate a warming climate will likely reduce the use of large, well-insulated winter roosts by species that prefer colder conditions-and that this is already happening. For forest-dwelling bats, such as the barbastelle, for which monitoring schemes are primarily based on winter surveys of large hibernacula, estimations of population trends may consequently become less reliable.
温暖的冬季可能导致蝙蝠的冬眠行为发生变化，例如巴氏亚种（Barbastella barbastellus），它更喜欢在低温下冬眠。该物种的冬季个体数量也存在较大的年度波动，因此对种群趋势的推断应该基于长期数据。在 2005 年之前，分析表明波兰的巴氏亚种数量稳定甚至在增加。我们分析了来自波兰 15 个最大冬眠地和 47 个小地堡的 13 次冬季蝙蝠计数（2005-2017 年）的结果。在研究期间，越冬个体数量保持稳定，因为巴氏亚种不是长距离迁徙者，这可能反映了全国的种群趋势。根据冬季平均气温，我们将波兰分为四个热量区。对四个区域冬眠地巴氏亚种丰度的分析表明，在冬季平均气温低于-2°C 的最寒冷地区，数量每年平均增加 4.8%，在波兰西部两个较温暖地区，数量每年平均分别下降 3.3%和 3.1%，而在冬季平均气温在-1°C 至-2°C 之间的中等温度地区则没有趋势。总体而言，冬眠个体数量与冬季平均温度之间存在显著但微弱的负相关。另一方面，尽管该地点位于温暖地区之一，但小型地堡中冬眠的个体数量增加了。这些结果表明，气候变暖可能会减少喜欢寒冷条件的物种对大型、绝缘良好的冬季栖息地的利用，这种情况已经在发生。对于森林栖息的蝙蝠，如巴氏亚种，其监测计划主要基于大型冬眠地的冬季调查，因此对种群趋势的估计可能变得不太可靠。
