Fern endemism and its correlates: contribution from an elevational transect in Costa Rica
Fern endemism and its correlates: contribution from an elevational transect in Costa Rica
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DOI：
10.1111/j.1366-9516.2006.00231.x
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发表时间：
2006-09-01
影响因子：
4.6
通讯作者：
Kessler, Michael
中科院分区：
文献类型：
--
作者：
Kluge, Juergen;Kessler, Michael
我们研究了中美洲哥斯达黎加特有蕨类植物在海拔3400米梯度上的分布格局。描述了整个物种的特有格局，并根据地形和环境因素对生活型和微生境进行了划分和划分。调查了156个样地的蕨类物种，每个样地的面积为400m(2)，每个海拔100m的台阶上最多有5个样地。每个物种的全球范围大小是根据文献数据汇编的，仅限于哥斯达黎加和邻近的巴拿马西部山脉的物种被定义为特有种(占所有记录物种的24.5%)。我们发现，地方病流行的格局大多在中海拔达到峰值，但当按不同的生活型和微生境分开时，出现了一些与总体格局的偏差。较高的恒湿和较小的表面积与较高的地方病水平密切相关。高湿度被认为是与最高总体丰富度一致的高地方病发病率的一般预测因子。海拔带的限制区域，表明栖息地的碎片化，导致更高程度的种群隔离，从而导致物种分化。然而，这两种解释并不完全得到我们的数据的支持。最重要的是，在地形高度分散的环境中，可用面积最小的山顶上的地方病发病率相当低。相比之下，在最高海拔地区，特有物种比广布物种更常见。历史和气候变化被认为在这方面发挥了作用。
We studied the distribution patterns of endemic ferns along an elevational gradient of 3400 m in Costa Rica, Central America. We related the endemism patterns of the whole species set and separated for life forms and microhabitats according to topography and environmental factors. Fern species were surveyed in 156 plots each with an area of 400 m(2), with up to five plots at every elevational step of 100 m. Global range size for every species was compiled from literature data, and species restricted to the mountain range from Costa Rica and adjacent western Panama were defined as endemic (24.5% of all species recorded). We found patterns of endemism rates mostly peaking at mid-elevation, but when separated for different life forms and microhabitats, some deviations from the overall pattern emerged. High constant humidity and reduced surface area were closely related to high levels of endemism. High humidity is discussed as a general predictor for high endemism rates in concert with highest overall richness. Restricted area of elevational belts, indicating a fragmented habitat, leads to a higher degree of population isolation and thus species differentiation. However, both interpretations were not fully supported by our data. Most importantly, endemism rates were fairly low on mountain tops that have the smallest available area in a topographically highly fragmented setting. In contrast, endemic species were more common than widespread species at the highest elevations. History and climatic shifts are assumed to play a role in this respect.