CNRS - UMR 8172, Écologie des Forêts de Guyane, Campus Agronomique, BP 709 Kourou, France.
PLoS One. 2011;6(11):e27004. doi: 10.1371/journal.pone.0027004. Epub 2011 Nov 2.
Establishing a direct link between climate change and fluctuations in animal populations through long-term monitoring is difficult given the paucity of baseline data. We hypothesized that social wasps are sensitive to climatic variations, and thus studied the impact of ENSO events on social wasp populations in French Guiana. We noted that during the 2000 La Niña year there was a 77.1% decrease in their nest abundance along ca. 5 km of forest edges, and that 70.5% of the species were no longer present. Two simultaneous 13-year surveys (1997-2009) confirmed the decrease in social wasps during La Niña years (2000 and 2006), while an increase occurred during the 2009 El Niño year. A 30-year weather survey showed that these phenomena corresponded to particularly high levels of rainfall, and that temperature, humidity and global solar radiation were correlated with rainfall. Using the Self-Organizing Map algorithm, we show that heavy rainfall during an entire rainy season has a negative impact on social wasps. Strong contrasts in rainfall between the dry season and the short rainy season exacerbate this effect. Social wasp populations never recovered to their pre-2000 levels. This is probably because these conditions occurred over four years; heavy rainfall during the major rainy seasons during four other years also had a detrimental effect. On the contrary, low levels of rainfall during the major rainy season in 2009 spurred an increase in social wasp populations. We conclude that recent climatic changes have likely resulted in fewer social wasp colonies because they have lowered the wasps' resistance to parasitoids and pathogens. These results imply that Neotropical social wasps can be regarded as bio-indicators because they highlight the impact of climatic changes not yet perceptible in plants and other animals.
由于基线数据匮乏，通过长期监测在气候变化和动物种群波动之间建立直接联系具有一定难度。我们假设社会性黄蜂对气候变化敏感，因此研究了厄尔尼诺-南方涛动（ENSO）事件对法属圭亚那社会性黄蜂种群的影响。我们注意到，在 2000 年拉尼娜年，大约 5 公里长的森林边缘的黄蜂巢数量减少了 77.1%，70.5%的物种不再存在。同时进行的两项为期 13 年的调查（1997-2009 年）证实了拉尼娜年（2000 年和 2006 年）社会性黄蜂数量减少，而在 2009 年厄尔尼诺年则有所增加。一项 30 年的天气调查显示，这些现象与降雨量特别高相对应，并且温度、湿度和总太阳辐射与降雨量相关。使用自组织映射算法，我们表明整个雨季的强降雨对社会性黄蜂有负面影响。旱季和短雨季之间降雨量的强烈对比加剧了这种效应。社会性黄蜂种群从未恢复到 2000 年之前的水平。这可能是因为这些条件持续了四年；另外四年主要雨季的强降雨也产生了不利影响。相反，2009 年主要雨季降雨量低促使社会性黄蜂种群增加。我们得出结论，最近的气候变化可能导致社会性黄蜂的殖民地减少，因为它们降低了黄蜂对寄生虫和病原体的抵抗力。这些结果意味着新热带地区的社会性黄蜂可以被视为生物指标，因为它们突出了气候变化对植物和其他动物尚未察觉的影响。
