青藏高原东北部边缘高原鳅属鱼类的多样性与分布格局

Biodiversity and distribution patterns of Triplophysa species in the northeastern margin of the Tibetan Plateau

为了了解青藏高原东北部边缘地区高原鳅属(Triplophysa)鱼类的多样性和分布格局,本文基于2012–2015年的野外调查数据,对该地区高原鳅属鱼类的分布情况进行了调查。结果发现:与历史记录相比,部分物种的分布区已经萎缩或破碎化。物种在整个区域的分布很不均匀,其中洮河、大通河和黑河的中上游是高原鳅分布较集中的地区;同时这3条河也有着较高的多样性水平。海拔梯度上,物种丰富度呈现随海拔上升先增后减的单峰分布模式,在2,200–2,400 m海拔区间最高;且峰值点出现在两个物种丰富的群落的过渡区,很好地印证了Lomolino对物种密度海拔分布的预测。多样性指数的海拔回归分析获得与物种丰富度的海拔分布相一致的结果。结合已有报道,我们认为这种中间海拔最大的单峰分布模式可能是青藏高原及其周边地区物种多样性分布的普遍规律。因而,中海拔地区需要优先保护。

The northeastern region of the Tibetan Plateau is a region with high genetic diversity for endemic species. To comprehensively document the patterns of diversity and the distribution of Triplophysa species in this area, we probed the allocation of Triplophysa species using field surveys from 2012 to 2015. We found that areal shrinkage and fragmentation had occurred in some species. Species richness in this area was uneven. But the middle to upper reaches of the Heihe River, Datong River and Taohe River were uncommon areas with high species-richness and high biodiversity. Along altitudinal gradients, species richness presented a unimodal pattern and peaked at mid-elevations （2,200-2,400 m）, which was the transition area between two community zones with high species richness. The unimodal pattern fit Lomolino＇s prediction regarding species density and altitude. Biodiversity indices displayed uniform patterns with species richness and elevation. Consistent with most studies, the unimodal shape may be the universal pattern of biodiversity distribution along elevational gradients in the Tibetan Plateau and its adjacent highlands. The intermediate elevational re gions should be conservation priorities.