BackgroundLatitudinal and altitudinal patterns of plant species richness have frequently been related to different climate variables such as precipitation, temperature and evapotranspiration. However, studies assessing this relationship have mostly compared different regions and used regional scales of richness (in quadrants of several km2). It is less known the relationship between climate and geographical patterns of species richness in local scales (richness in < 1 ha plots). For central Chile some studies have described geographical patterns of plant species richness, but only using regional scales to quantify richness. It is not known how local richness of plant species varies geographically and if climate variables are related to this variation. In this paper I evaluated latitudinal and altitudinal trends of local richness of woody species within forest ecosystems of the Mediterranean-type climate region in central Chile, and explored if these patterns are related to climatic variables. We used data collected in the field as well as published data of composition of woody species in plots of 100 m2 collected in different localities within this region. Climatic variables were obtained for each locality from isoclimate curves published for the whole region.ResultsLocal woody species richness was positively related to latitude and negatively related to elevation. Also, it was positively related to annual precipitation and atmospheric relative moisture, and negatively to mean minimal temperature of winter. In addition, precipitation increased with latitude, and minimal temperature of winter decreased with elevation.ConclusionThese results suggest that climate may be an important driver of altitudinal and latitudinal patterns of local species richness of woody species in central Chile.

中文翻译：

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智利地中海型地区当地木本物种丰富度的气候与地理变异的关系

背景植物物种丰富度的纬度和海拔模式经常与不同的气候变量有关，如降水、温度和蒸发量。然而，评估这种关系的研究大多比较了不同区域并使用了区域丰富度尺度（在几平方公里的象限内）。气候与地方尺度物种丰富度（< 1 公顷地块的丰富度）的地理模式之间的关系鲜为人知。对于智利中部，一些研究描述了植物物种丰富度的地理模式，但仅使用区域尺度来量化丰富度。目前尚不清楚当地植物物种丰富度如何在地理上发生变化，以及气候变量是否与这种变化有关。在本文中，我评估了智利中部地中海型气候区森林生态系统内木本物种当地丰富度的纬度和海拔趋势，并探讨了这些模式是否与气候变量有关。我们使用了实地收集的数据以及在该地区不同地点收集的 100 平方米样地中已发布的木本物种组成数据。从全区公布的等气候曲线中获得每个地点的气候变量。结果当地木本物种丰富度与纬度呈正相关，与海拔呈负相关。此外，它与年降水量和大气相对湿度呈正相关，与冬季平均最低温度呈负相关。此外，降水随纬度增加，