Reif Jiří, Gamero Anna, Flousek Jiří, Hůnová Iva
Institute for Environmental Studies, Faculty of Science, Charles University, Prague, Czechia; Department of Zoology, Faculty of Science, Palacký University, Olomouc, Czechia.
Czech Society for Ornithology, Prague, Czechia.
Sci Total Environ. 2023 Jun 10;876:162711. doi: 10.1016/j.scitotenv.2023.162711. Epub 2023 Mar 10.
Mountain ecosystems are inhabited by species with specific characteristics enabling survival at high altitudes, which make them at risk from various pressures. In order to study these pressures, birds represent excellent model organisms due to their high diversity and position at the top of food chains. The pressures upon mountain bird populations include climate change, human disturbance, land abandonment, and air pollution, whose impacts are little understood. Ambient ozone (O) is one of the most important air pollutants occurring in elevated concentrations in mountain conditions. Although laboratory experiments and indirect course-scale evidence suggest its negative effects on birds, population-level impacts remain unknown. To fill this knowledge gap, we analysed a unique 25-years long time series of annual monitoring of bird populations conducted at fixed sites under constant effort in a Central European mountain range, the Giant Mountains, Czechia. We related annual population growth rates of 51 bird species to O concentrations measured during the breeding season and hypothesized (i) an overall negative relationship across all species, and (ii) more negative O effects at higher altitudes due to increasing O concentration along altitudinal gradient. After controlling for the influence of weather conditions on bird population growth rates, we found an indication of the overall negative effect of O concentration, but it was insignificant. However, the effect became stronger and significant when we performed a separate analysis of upland species occupying the alpine zone above treeline. In these species, populations growth rates were lower after the years experiencing higher O concentration indicating an adverse impact of O on bird breeding. This impact corresponds well to O behaviour and mountain bird ecology. Our study thus represents the first step towards mechanistic understanding of O impacts on animal populations in nature linking the experimental results with indirect indications at the country-level.
山区生态系统中栖息着具有特定特征的物种，这些特征使它们能够在高海拔地区生存，但也使它们面临各种压力。为了研究这些压力，鸟类因其高度的多样性和处于食物链顶端的位置，成为了优秀的模式生物。山区鸟类种群面临的压力包括气候变化、人类干扰、土地荒废和空气污染，而这些压力的影响却鲜为人知。环境臭氧（O）是山区环境中浓度升高的最重要空气污染物之一。尽管实验室实验和间接的宏观尺度证据表明其对鸟类有负面影响，但在种群水平上的影响仍然未知。为了填补这一知识空白，我们分析了在捷克共和国巨人山脉这一中欧山脉中，在固定地点持续进行的长达25年的鸟类种群年度监测的独特时间序列。我们将51种鸟类的年度种群增长率与繁殖季节测量的臭氧浓度相关联，并假设：（i）所有物种之间总体呈负相关；（ii）由于臭氧浓度沿海拔梯度增加，在较高海拔处臭氧的负面影响更大。在控制了天气条件对鸟类种群增长率的影响后，我们发现了臭氧浓度总体负面影响的迹象，但并不显著。然而，当我们对占据林线以上高山区域的山地物种进行单独分析时，这种影响变得更强且显著。在这些物种中，经历较高臭氧浓度年份后的种群增长率较低，这表明臭氧对鸟类繁殖有不利影响。这种影响与臭氧的特性和山地鸟类生态学非常吻合。因此，我们的研究代表了在将实验结果与国家层面的间接证据联系起来，从机制上理解臭氧对自然界动物种群影响方面迈出的第一步。
