Department of Zoology, Tel Aviv University, Tel Aviv, Israel.
Glob Chang Biol. 2013 May;19(5):1373-82. doi: 10.1111/gcb.12132. Epub 2013 Feb 11.
Alien species are considered one of the prime threats to biodiversity, driving major changes in ecosystem structure and function. Identifying the traits associated with alien introduction has been largely restricted to comparing indigenous and alien species or comparing alien species that differ in abundance or impact. However, a more complete understanding may emerge when the entire pool of potential alien species is used as a control, information that is rarely available. In the eastern Mediterranean, the marine environment is undergoing an unparalleled species composition transformation, as a flood of aliens have entered from the Red Sea following the opening of the Suez Canal in 1869. In this study, we compile data on species traits, geographical distribution, and environmental affinity of the entire pool of reef-associated fish species in the Red Sea and more generally across the Indo-Pacific. We use this extensive data to identify the prime characteristics separating Red Sea species that have become alien in the Mediterranean from those that have not. We find that alien species occupy a larger range of environments in their native ranges, explaining their ability to colonize the seasonal Mediterranean. Red Sea species that naturally experience high maximum temperatures in their native range have a high probability of becoming alien. Thus, contrary to predictions of an accelerating number of aliens following increased water temperatures, hotter summers in this region may prevent the establishment of many alien species. We further find that ecological trait diversity of alien species is substantially more evenly spaced and more divergent than random samples from the pool of Red Sea species, pointing at additional processes, such as competition, promoting ecological diversity among alien species. We use these results to provide a first quantitative ranking of the potential of Red Sea species to become established in the eastern Mediterranean.
外来物种被认为是生物多样性的主要威胁之一，它们会导致生态系统结构和功能发生重大变化。确定与外来物种引入相关的特征主要局限于比较本地物种和外来物种，或者比较丰度或影响不同的外来物种。然而，当将整个潜在外来物种库作为对照时，可能会出现更全面的理解，而这种信息很少可用。在地中海东部，由于自 1869 年苏伊士运河开通以来，大量外来物种从红海涌入，海洋环境正在经历前所未有的物种组成转变。在这项研究中，我们汇编了红海和更广泛的印度洋-太平洋地区所有珊瑚礁相关鱼类物种的物种特征、地理分布和环境亲和力的数据。我们利用这些广泛的数据来确定将红海物种从非外来物种转变为地中海外来物种的主要特征。我们发现，外来物种在其原生范围内占据了更大范围的环境，这解释了它们在季节性地中海中能够进行殖民的能力。在原生范围内自然经历最高温度较高的红海物种有很大的可能性成为外来物种。因此，与随着水温升高而加速增加外来物种数量的预测相反，该地区夏季较热可能会阻止许多外来物种的建立。我们进一步发现，外来物种的生态特征多样性在空间上的分布更加均匀和发散，比从红海物种库中随机抽样的样本更加显著，这表明存在其他过程，如竞争，促进了外来物种之间的生态多样性。我们利用这些结果对红海物种在东地中海建立的潜力进行了首次定量排名。
