Diversity and biogeography of vascular epiphytes in Western Amazonia, Yasuni, Ecuador
Diversity and biogeography of vascular epiphytes in Western Amazonia, Yasuni, Ecuador
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DOI：
10.1111/j.1365-2699.2004.01083.x
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发表时间：
2004-09-01
影响因子：
3.9
通讯作者：
Barthlott, W
中科院分区：
文献类型：
--
作者：
Kreft, H;Köster, N;Barthlott, W
目的维管附生植物是新热带森林物种丰富度和复杂性的重要组成部分，但在大规模的生物地理分析中，维管附生植物的代表性较低。研究了新热带背景下亚苏尼地区附生植物区系的多样性、生物地理和区系关系，重点研究了安第斯植物区系对周围低地森林植物区系组成和多样性的影响。地点：西亚马孙低地雨林，提普蒂尼生物多样性站(0°38‘S 76°09’W，230m a.s.l.，650ha)，厄瓜多尔亚苏尼国家公园。其次，基于采集自新热带地区的7万多个维管附生植物标本的植物区系数据库，对所选的8个名录的海拔组成进行了详细的分析。中等比例的物种是上纳波地区特有的(约10%)。然而，这个数字比之前主要基于木本植物的分析要高得多。这些物种的地理范围与拟议的更新世森林保护区相匹配。与亚马逊北部和中部地点相比，西部亚马逊附生植物群落的山地和亚山地物种所占比例较高。维管附生植物物种丰富度与降雨量呈正相关，与干旱月数呈负相关。主要结论现代和历史降雨模式是西亚马孙维管附生植物多样性和区系组成的驱动力，多年降雨量和低季节性为维管附生植物物种丰富度提供了适宜的条件。靠近安第斯山脉，这是大多数新热带附生植物物种形成的最重要中心，再加上气候环境，使该地区得以持续供应物种丰富的资源。至少对于附生植物来说，安第斯山脉和亚马逊植物区系之间的分界线比之前想象的要模糊得多。此外，与受影响较大的周边低地相比，更新世期间亚马孙西部相对潮湿的气候可能导致较少的物种灭绝和/或更多的物种形成。
Aim Although vascular epiphytes are important components of species richness and complexity of Neotropical forests, vascular epiphytes are under-represented in large scale biogeographical analyses. We studied the diversity, biogeography and floristic relationships of the epiphytic flora of the Yasuni region (Western Amazonia) in a Neotropical context, with special emphasis on the influence of the Andean flora on floristic composition and diversity of surrounding lowland forests.Location Western Amazonian lowland rainforest, Tiputini Biodiversity Station (0degrees38' S 76degrees09' W, 230 m a.s.l., 650 ha), Yasuni National Park, Ecuador.Methods We compared the vascular epiphyte flora of Yasuni with 16 published Neotropical epiphyte inventories. Secondly, based on a floristic database with records of more than 70,000 specimens of vascular epiphytes from the Neotropics the elevational composition of eight selected inventories was analysed in detail.Results The vascular epiphyte flora of Yasuni is characterized by a very high species richness (313 spp.). A moderate portion of species is endemic to the Upper Napo region (c. 10%). However, this figure is much higher than previous analyses primarily based on woody species suggested. Geographical ranges of these species match with a proposed Pleistocene forest refuge. Compared with Northern and Central Amazonian sites, Western Amazonian epiphyte communities are characterized by a higher portion of montane and submontane species. Species richness of vascular epiphytes at the sites was correlated with the amount of rainfall, which is negatively correlated with the number of dry months.Main conclusion Recent and historic patterns of rainfall are the driving forces behind diversity and floristic composition of vascular epiphytes in Western Amazonia: high annual rainfall in combination with low seasonality provides suitable conditions to harbour high species richness. The proximity to the Andes, the most important centre of speciation for most Neotropical epiphytic taxa, in combination with the climatic setting has allowed a continuous supply of species richness to the region. At least for epiphytes, the borderline between the Andean and Amazonian flora is much hazier than previously thought. Moreover, the comparatively moist climate in Western Amazonia during the Pleistocene has probably led to fewer extinctions and/or more speciation than in more affected surrounding lowlands.