Abstract

The main phenological dates, including the unfolding of the first leaves, mass yellowing of the leaves, and the duration of the vegetation period, were evaluated for the silver birch Betula pendula in 2005–2018 in the central part of the European territory of Russia to identify possible phenological trends under global climate change. Evidence on a negative trend in the time of the unfolding of the first leaves and a positive trend for yellowing of the leaves has been obtained. The revealed pattern of phenological changes characterizing the earlier beginning and the later end of the vegetation season corresponds to the well-known trend of temperature increase. At the same time, the absence of a pronounced trend in a number of populations in the north and in the center of the territory under consideration indicates not so much an increase as a shift in the vegetation period to earlier dates. This may be caused by the need to maintain a certain optimal duration of the growing season and its relationship with the length of the organic dormancy period in changing climatic conditions. The absence or a weak reaction of an organism to a specific impact may be the result of homeostatic mechanisms, with their possibly different manifestation in the center and at the periphery of the range.

中文翻译：

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气候变化下白桦的物候指标稳定性评估

摘要

评价了桦树桦的主要物候日期，包括第一片叶子的展开，叶子的大量泛黄和植被的持续时间。2005-2018年在俄罗斯欧洲领土中部确定了全球气候变化下可能的物候趋势。已经获得了第一片叶子展开时的负趋势和叶子变黄的积极趋势的证据。揭示出的植被变化较早开始和结束的物候变化规律与温度升高的众所周知的趋势相对应。同时，所考虑领土的北部和中部的一些人口没有明显的趋势，表明增加的幅度不大，而是植被时期向较早日期的转移。这可能是由于在变化的气候条件下需要保持一定的生长季节最佳持续时间及其与有机休眠期长度的关系所致。有机体对特定影响的不存在或反应微弱可能是体内稳态机制的结果，它们在范围的中心和外围可能具有不同的表现。