Abstract. Forest structural complexity could be a good predictor of overall species diversity. Since tree harvesting has a negative effect on forest structure, it is important to analyse the effects of this disturbance on sensitive groups, as forest birds. In this study, we aimed to shed light on this aspect by analysing a set of univariate metrics in bird communities breeding in three coppiced forest habitats (coppiced of chestnut, coppiced of Turkey oak and high forest of beech) along a gradient in age classes. We hypothesised that, with increasing forest age, (i) breeding bird communities will progressively increase in diversity and, (ii) due to higher habitat heterogeneity due to coppicing, a higher species turnover in the first age classes could appear. In each forest habitat, all the metrics significantly increased, from recently coppiced to more mature forests, due to progressively higher availability of resources and niches along the gradient. When comparing paired forest habitats, abundance and richness were significantly different only in the two oldest age classes, highlighting that responses to different tree composition were more marked in the mature phase. In all forest habitats, species turnover ( βw diversity) decreased progressively along the age gradient and was highest in the youngest age classes where many vegetation layers were present. Due to different coppice management practices, growth regime and consequent habitat heterogeneity, chestnuts showed a different pattern when compared to other forest habitats, with an increase in species turnover ( βw diversity) at intermediate level. With increasing age of the forests, all the diversity metrics increased and species turnover decreased, highlighting the role of older forests as strategic habitats for highly structured bird communities.

中文翻译：

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越老越富：随着不同林木的年龄梯度，繁殖鸟类的多样性显着增加

摘要。森林结构复杂性可以很好地预测整体物种多样性。由于砍伐树木对森林结构有负面影响，因此分析这种干扰对敏感群体（如森林鸟类）的影响非常重要。在这项研究中，我们旨在通过分析在三个密林栖息地（栗树密林、土耳其橡树密林和山毛榉高林）沿年龄等级梯度繁殖的鸟类群落中的一组单变量指标来阐明这一方面。我们假设，随着森林年龄的增加，（i）繁殖鸟类群落的多样性将逐渐增加，（ii）由于栖息地的栖息地异质性更高，第一年龄段的物种周转率可能会更高。在每个森林栖息地，所有指标都显着增加，由于沿坡度越来越高的资源和生态位的可用性，从最近被砍伐的森林到更成熟的森林。在比较成对的森林栖息地时，丰度和丰富度仅在两个最古老的年龄类别中显着不同，这突出表明在成熟阶段对不同树木组成的反应更为明显。在所有森林栖息地中，物种周转率（βw 多样性）随着年龄梯度逐渐下降，并且在存在许多植被层的最年轻的年龄组中最高。由于不同的丛林管理实践、生长方式和随之而来的栖息地异质性，与其他森林栖息地相比，栗子表现出不同的模式，中间水平的物种周转率（βw 多样性）增加。随着森林年龄的增长，