The role of the regeneration niche for the vertical stratification of vascular epiphytes
The role of the regeneration niche for the vertical stratification of vascular epiphytes
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DOI：
10.1017/s0266467413000291
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发表时间：
2013-05
影响因子：
1.4
通讯作者：
K. Wagner;Wiebke Bogusch;G. Zotz
中科院分区：
文献类型：
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作者：
K. Wagner;Wiebke Bogusch;G. Zotz
摘要：维管附生植物的垂直分层常常归因于生态位划分沿着小气候梯度，但这一概念的实验证实是罕见的。研究了无梗凤梨、亚伞房凤梨、铁兰、铁兰、无梗凤梨、无bulbosa和Werauhia gladioliflora）和7种天南星科植物（Anthurium acutangulum，A. brownii、黑腹拟步行虫A. clavigerum、棒枝藻A. durandii、黑腹滨藜A. friedrichsthalii、黑腹隐翅虫A. hacumense和A.攀缘植物）在巴拿马雨林中。我们记录了温度梯度，蒸汽压赤字和光（n = 10天），以及物种高度分布（n = 11-120）。小气候梯度很大（层间最大T和RH差异分别为5 °C和18%），研究物种的平均附着高度（范围= 4-21 m）差异显著。我们测试了在萌发（所有物种，20粒种子，n = 3）和幼苗生长（四个天南星属物种，n = 25）周期性干旱（四种处理）的敏感性。对6种天南星科植物移植到3个高度（n = 27）的幼苗成活情况进行了原位监测。一些物种在严重的反复干旱下没有发芽，而另一些物种在所有处理中以相同的速度发芽。最暴露的物种幼苗生长最快的中间经常性干旱，而其他三个物种生长最快时，不断保持湿润。移植幼苗的存活率并不依赖于物种附着高度，但这可能是由于统计能力不足。两者合计，结果表明，分层可以解释在很大程度上由不同的敏感性，在再生阶段的垂直水分梯度。
Abstract: Vertical stratification of vascular epiphytes is frequently attributed to niche partitioning along microclimatic gradients but experimental confirmations of this notion are rare. This study investigates the role of the regeneration phase for the stratification of five bromeliad (Catopsis sessiliflora, Guzmania subcorymbosa, Tillandsia anceps, T. bulbosa and Werauhia gladioliflora) and seven aroid species (Anthurium acutangulum, A. brownii, A. clavigerum, A. durandii, A. friedrichsthalii, A. hacumense and A. scandens) in a Panamanian rain forest. We documented gradients of temperature, vapour pressure deficit and light (n = 10 d) as well as species height distributions (n = 11–120). Microclimatic gradients were substantial (maximal T and RH differences between strata: 5 °C and 18%, respectively) and mean attachment heights of the study species (range = 4–21 m) differed significantly. We tested sensitivity to recurrent drought (four treatments) during germination (all species, cumulative germination of 20 seeds, n = 3) and seedling growth (four aroid species, n = 25). Seedling survival of six aroid species transplanted to three heights (n = 27) was monitored in situ. Some species did not germinate under severe recurrent drought while others germinated at the same rate in all treatments. Seedlings of the most exposed species grew fastest under intermediate recurrent drought while those of the other three species grew fastest when kept constantly wet. Survival of transplanted seedlings did not depend on species attachment height, but this may be attributable to insufficient statistical power. Taken together, the results suggest that the stratification can be explained to a large degree by differential sensitivity to the vertical moisture gradient during the regeneration phase.