Vascular Epiphytes on Isolated Pasture Trees Along a Rainfall Gradient in the Lowlands of Panama
Vascular Epiphytes on Isolated Pasture Trees Along a Rainfall Gradient in the Lowlands of Panama
复制标题
巴拿马低地降雨梯度沿线孤立牧草树上的维管束附生植物
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
G. Zotz
中科院分区：
文献类型：
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作者：
Kerstin Poltz;G. Zotz
由于原始植被不断遭到破坏，次生生境在热带国家的重要性日益增加。尽管当前变化的幅度很大，但我们对其对非树的影响的理解（例如，非维管或维管附生植物）仍然非常零散，特别是在低地栖息地。在这里，我们报告了一项研究与孤立的牧场树木在巴拿马西南部。超过800棵被研究的树木，属于超过100个不同的物种，含有83个物种的近27,000种附生植物。兰科是物种最丰富的科，几乎占所有物种的60%，而凤梨科最丰富。在研究区域，从约1000到>3000 mm的降雨梯度更多地解释了物种丰度和丰富度的变化，而不是宿主特征（例如， 物种身份，树的大小）。在这些牧场的附生植物数量出乎意料的大仍然代表了一个相当大的变化，相对于自然环境，这是建议在类似的气候条件下与森林资源的比较。在牧场中，物种丰富度较低，从基于个体的稀疏曲线推断，更大比例的物种和个体表现出景天科酸代谢，附生植物丰度/物种丰富度与树木直径的关系不那么陡峭。然而，即使是已经减少的多样性，可能只是短暂的次生栖息地的附生植物种群在牧场的长期持续性是一个悬而未决的问题，必须通过反复监测来解决，以充分评估牧场树木对热带低地维管附生植物保护的重要性。
Secondary habitats are increasing in importance in tropical countries due to ongoing destruction of pristine vegetation. In spite of the magnitude of current changes, our understanding of their effects on nontrees (e.g., nonvascular or vascular epiphytes) is still very patchy, particularly in lowland habitats. Here, we report a study with isolated pasture trees in southwest Panama. The >800 studied trees, which belonged to >100 different species, harbored almost 27,000 epiphytes of 83 species. Orchidaceae was the most species‐rich family, with almost 60 percent of all species, while Bromeliaceae were most abundant. A rainfall gradient in the study region from ca 1000 to >3000 mm explained more of the variation in species abundance and richness than host characteristics (e.g., species identity, tree size). The unexpectedly large number of epiphytes in these pastures still represents a substantial change relative to a natural setting, which is suggested by a comparison with a forest inventory under similar climatic conditions. In pastures, species richness was lower as deduced from individual‐based rarefaction curves, a larger proportion of species and individuals showed crassulacean acid metabolism, and the relationship of epiphyte abundance/species richness and tree diameter was much less steep. Even the already reduced diversity, however, may be only transient in secondary habitats—the long‐term persistence of epiphyte populations in pastures is an open question and has to be addressed by repeated monitoring to fully evaluate the significance of pasture trees for the conservation of vascular epiphytes in tropical lowlands.