Aim - To assess the range size patterns of ferns and lycophytes along elevational gradients at different latitudes in an ecographical transition zone and search for predictors of range size from a set of environmental factors. Location -Mexico, from 15° to 23° N. Taxon - Ferns and lycophytes. Methods - All terrestrial and epiphytic species were recorded in 658 plots of 400 m2 along eight elevational gradients. To test whether the range size within assemblages increases with elevation and latitude, we calculated the latitudinal range using the northern and southern limits of each species and averaged the latitudinal range of all species within assemblages weighted by their abundances. We related climatic factors and the changes with latitude and elevation with range size using linear mixed‐effects models. Results - Species richness per plot increased with elevation up to about 1,500–2,000 m, with strong differences in overall species richness between transects and a reduction with increasing latitude. The mean weighted range size of species within assemblages declined with elevation, and increased with latitude, as predicted by theory. However, we also found marked differences between the Atlantic and Pacific slopes of Mexico, as well as low range size in humid regions. The best models described about 76%–80% of the variability in range size and included the seasonality in both temperature and precipitation, and annual cloud cover. Main conclusion - Latitudinal and elevational patterns of range size in fern assemblages are driven by an interplay of factors favouring wide‐ranging species (higher latitudes with increasing temperature seasonality; dryer habitat conditions) and those favouring species with restricted ranges (higher elevations; humid habitat conditions), with additional variation introduced by the specific conditions of individual mountain ranges. Climatically stable, humid habitats apparently provide favourable conditions for small‐ranged fern species, and should accordingly be given high priority in regional conservation planning.

中文翻译：

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从热带到亚热带过渡时沿海拔梯度的蕨类植物物种丰富度和范围大小的纬度模式

目的 - 评估生态过渡区不同纬度的蕨类植物和石松植物的分布范围大小模式，并从一组环境因素中寻找分布范围大小的预测因子。位置 - 墨西哥，北纬 15° 至 23°。 分类群 - 蕨类植物和石松植物。方法 - 沿 8 个海拔梯度在 658 个 400 平方米的地块中记录了所有陆生和附生物种。为了测试组合内的范围大小是否随着海拔和纬度的增加而增加，我们使用每个物种的南北界限计算了纬度范围，并按其丰度加权平均了组合内所有物种的纬度范围。我们使用线性混合效应模型将气候因素以及纬度和海拔的变化与范围大小联系起来。结果 - 每块样地的物种丰富度随着海拔升高至约 1,500-2,000 米而增加，横断面之间的整体物种丰富度差异很大，随着纬度的增加而减少。正如理论所预测的那样，组合内物种的平均加权范围大小随着海拔的升高而下降，并随着纬度的增加而增加。然而，我们还发现墨西哥大西洋和太平洋斜坡之间的显着差异，以及潮湿地区的低范围大小。最好的模型描述了大约 76%–80% 的范围大小可变性，包括温度和降水的季节性以及年云量。主要结论 - 蕨类植物群落范围大小的纬度和海拔模式是由有利于广泛物种的因素相互作用驱动的（纬度越高，温度季节性越强；干燥的栖息地条件）和那些偏爱范围有限的物种（更高的海拔；潮湿的栖息地条件），个别山脉的特定条件引入了额外的变化。气候稳定、潮湿的栖息地显然为小型蕨类植物提供了有利条件，因此应在区域保护规划中给予高度重视。