This study examined tree species diversity, distribution, and community differentiation patterns along an elevation gradient in pine–oak forest in the Sierra Norte mountains in Oaxaca, Mexico. Pine and oak are ecologically and economically valuable both locally and globally, but their dynamics are poorly understood in seasonally dry montane forests. This is a biome that is both widespread, with high human use and importance, and widely understudied. The community‐managed forest we studied contained high levels of tree diversity (32 total species), with especially high levels of oak (10 species) and pine (eight species) diversity compared to other pine–oak forests in Mexico. Tree communities in the study area demonstrated high levels of species turnover across sites, especially at mid and low elevations, as well as high levels of oak species coexistence within communities, with a mean of three oak species per 1000 m². We identified three distinct tree vegetation types using multivariate ordination and cluster analyses and found that both tree distributions and community assemblages are primarily differentiated by elevation, but also by soil type, topography, and likely successional disturbance from historical land use. Oak communities in the study area followed patterns of phylogenetic overdispersion with species from different sections (red and white) co‐occurring more frequently than species from the same section, and demonstrated differences in reported reproductive phenology, with coexisting species alternately fruiting in rainy and dry seasons. This differentiation in both oak species' environmental associations and in fruiting phenology has important management and conservation implications as Mexico becomes more arid with climate change. This study also provided key information for local management as different forest types should have different silvicultural management regimes, as well as essential baseline data useful for a broader theoretical understanding of how closely related species coexist in communities.

中文翻译：

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墨西哥瓦哈卡州Sierra Norte混合松栎林的多样性和生态位分化

这项研究研究了墨西哥瓦哈卡州塞拉诺特山脉松树林中沿海拔梯度的树种多样性，分布和群落分化模式。松树和橡树在本地和全球范围内都具有生态和经济价值，但是在季节性干燥的山地森林中，人们对松树和橡树的动态了解甚少。这是一个广泛存在的生物群系，具有很高的人类使用率和重要性，并且受到了广泛的研究。与墨西哥的其他松橡森林相比，我们研究的社区管理森林中树木多样性较高（总共32种），其中橡木（10种）和松树（8种）的多样性尤其高。研究区域内的树木群落显示出各个地点的物种更新率很高，尤其是在中低海拔地区，^2个。我们使用多元排序和聚类分析确定了三种不同的树木植被类型，发现树木分布和群落组成主要是根据海拔高低来区分的，但也取决于土壤类型，地形和历史土地使用的可能的继发性干扰。研究区域的橡树群落遵循系统发育过度分散的模式，来自不同区域（红色和白色）的物种比同一区域的物种同时出现，并且在报告的生殖物候学上表现出差异，同时存在的物种在雨天和干旱时交替开花。季节。随着墨西哥对气候变化的日益干旱，橡树树种在环境关联和果树物候学方面的这种差异具有重要的管理和保护意义。