造山運動創造生物多樣性
山區是地球上生物多樣性最高的地方之一，但科學家仍然無法完全瞭解它們在創造大量物種這方面為什麼具有如此重要的地位。包括四名阿姆斯特丹大學科學家(Daniel Kissling、Suzette Flantua、Henry Hooghiemstra和Carina Hoorn)在內的國際研究團隊對這個歷時已久的問題有了新的認識，文章發表於期刊《自然》(Nature)。
團隊發現造山運動造成的抬升和侵蝕可以持續改變地貌，並且在不同高度創造出棲地異質性(habitat
heterogeneity)。論文資深作者之一Carina
Hoorn表示：「山脈增高和氣候之間複雜的交互作用可以創造出大量機會產生新的物種。」他繼續解釋：「雖然之前認為山區具有生物多樣性的主因是氣候和地勢的崎嶇程度。但我們綜合全世界的資料之後清楚得出地質史在此過程當中具有關鍵地位。」
全球資料庫
團隊運用統計模型分析涵蓋全世界的生物、地質、氣候資料後得到了結論。論文中負責統計分析的Daniel
Kissling表示：「我們利用模型試著找出鳥類、哺乳類和兩棲類的物種豐富度跟全世界溫度、雨量、侵蝕速率、高程和土壤資料之間的關聯。」他接著說：「我們驚訝地發現生物多樣性不只一如既往的和氣候有關，也和侵蝕歷史、高程、土壤種類多寡有密切關聯。」雖然研究顯示全世界都可以明顯看出這些相關性，但不同的山脈系統表現出的相關度也會不同。Kissling說：「我們完全沒有預料到在不同區域地質作用力的重要程度也會有所變化。」
山脈位置和年代的重要性
研究進一步顯示山脈的地理位置(比方說是否跟大氣環流交會)以及造山運動的持續時間(古老或年輕)也是影響生物多樣性的重要因素。即使是在較短的地質時間之內，第四紀的氣候波動還是能促使山區形成新物種。Suzette
Flantua表示：「我們認為冰河的成長和消融可以強烈改變地形，使得動植物族群屢次分合，對於山區新物種的形成來說具有重要影響。」她在阿姆斯特丹大學就讀博士時研究了第四紀的氣候變遷對拉丁美洲山區生物多樣性的影響。
更好的地質研究方法
歸功於地質研究方法的進步，以及全球氣候、土壤、侵蝕歷史、物種豐富度資料的逐漸補齊，研究人員才能全面探討造山運動和生物多樣性的關係。科學家樂觀地認為有了新的方法和資料，在不久的將來我們就能對生物多樣性、氣候和造山運動三者之間的複雜關係有更加深入的瞭解。
Mountain building creates biodiversity
Mountains
are among the most biodiverse places on Earth, but scientists have struggled to
fully understand why they are so important in creating high species richness.
An international research team, including four scientists from the University
of Amsterdam (Daniel Kissling, Suzette Flantua, Henry Hooghiemstra and Carina
Hoorn), have now shed new light on answering this long-standing question. A
research article has been published by Nature.
The team found that mountain building, through a
process of uplift and erosion, continuously reshapes the landscape and is
responsible for creating habitat heterogeneity in an elevational gradient. ‘The
complex interplay between growing mountains and climate generates plenty of
opportunities for the creation of new species’, says Carina Hoorn, one of the
senior authors of the paper. ‘Although climate and ruggedness of the terrain
were previously thought to be the principal cause for mountain biodiversity,
our global synthesis now makes clear that geological history plays a paramount
role in this process’, explains Hoorn.
Global datasets
The team reached this conclusion by applying
statistical models to biological, geological and climatological datasets from
across the globe. ‘In our models, we related the species richness of birds,
mammals and amphibians to global datasets of temperature, precipitation,
erosion rates, relief and soil composition’, says Daniel Kissling, who
conducted the statistical analyses of the paper. ‘I was surprised to find not
only the usual correlations with climate, but a significant relation between
biodiversity, erosion history, relief and number of soil types’, he continues.
While the study shows that this is evident globally, it also revealed that the
relationship can vary depending on which mountain system is considered. ‘This
regional variation in the importance of geological drivers was really
unexpected’, says Kissling.
Position and age
of mountains plays a role
The study further showed that geographic position
(e.g. whether a mountain intercepts atmospheric currents or not) and the
duration of mountain building process (young or old) are also important
processes influencing biodiversity in mountains. On shorter geological time
scales, Quaternary climatic fluctuations can also promote the creation of new
species in mountains. ‘We suggest that the waxing and waning of glaciers, which
has strongly reshaped the landscape and repeatedly connected and disconnected animal
and plant populations, has played an important role for the creation of new
mountain species’, says Suzette Flantua who studied the effects of Quaternary
climate change on mountain biodiversity in Latin America for her PhD at the
University of Amsterdam.
Better geological
methods
The advances in geological methods and the
increasingly complete global data sets on climate, soils, erosion history, and
species richness only now have made it possible to gain such comprehensive
insights into the relation between mountain building and biodiversity. The
scientists are optimistic that with the new methods and datasets, further
insights into the complex relationship between biodiversity, climate and
mountain building can be expected in the near future.
原始論文：Alexandre
Antonelli, W. Daniel Kissling, Suzette G. A. Flantua, Mauricio A. Bermúdez,
Andreas Mulch, Alexandra N. Muellner-Riehl, Holger Kreft, H. Peter Linder,
Catherine Badgley, Jon Fjeldså, Susanne A. Fritz, Carsten Rahbek, Frédéric
Herman, Henry Hooghiemstra, Carina Hoorn. Geological
and climatic influences on mountain biodiversity. Nature Geoscience, 2018; DOI: 10.1038/s41561-018-0236-z
引用自：University
of Amsterdam. “Mountain building creates biodiversity.”
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