Lophophora williamsii (Cactaceae) is thought to be threatened by habitat loss and overharvesting. However, basic demographic and habitat information to evaluate its conservation status has been lacking. We surveyed six wild populations of this species, three in South Texas and three in West Texas, to begin to address this gap. We found high levels of heterogeneity in plant presence and density at multiple spatial scales. While plant densities were not consistently different between South and West Texas, plants were significantly larger in West Texas. The two regions differ strongly in precipitation, temperature, elevation, and topography, all of which are correlated at the regional scale. Therefore, it was not possible to identify which of these variables, or other factors such as competition and human harvesting, may be responsible for the regional differences in plant size. However, our results provide initial information for determining the conservation status of this species.

中文翻译：

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美国得克萨斯州PH的六种野生种群的密度，植物大小和空间分布

Lophophora williamsii（仙人掌科）被认为受到栖息地丧失和过度采伐的威胁。但是，缺乏评估其保护状况的基本人口和栖息地信息。我们调查了该物种的六个野生种群，其中三个在南德克萨斯，三个在西德克萨斯，以解决这一差距。我们发现植物存在的高度异质性和在多个空间尺度上的密度。虽然南德克萨斯州和西德克萨斯州之间的植物密度并不一致，但西德克萨斯州的植物明显更大。这两个地区在降水，温度，海拔和地形方面存在很大差异，所有这些在区域范围内都是相关的。因此，无法确定其中哪些变量或其他因素（例如竞争和人类收获，可能是造成工厂规模区域差异的原因。但是，我们的结果为确定该物种的保护状况提供了初步信息。