Southern Seas Ecology Laboratories, School of Biological Sciences, and The Environment Institute, The University of Adelaide, Adelaide, SA 5005, Australia.
Fish Ecology Lab, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia.
Proc Biol Sci. 2022 Mar 30;289(1971):20212676. doi: 10.1098/rspb.2021.2676. Epub 2022 Mar 23.
As climate warms, tropical species are expanding their distribution to temperate ecosystems where they are confronted with novel predators and habitats. Predation strongly regulates ecological communities, and range-extending species that adopt an effective antipredator strategy have a higher likelihood to persist in non-native environments. Here, we test this hypothesis by comparing various proxies of antipredator and other fitness-related behaviours between range-extending tropical fishes and native-temperate fishes at multiple sites across a 730 km latitudinal range. Although some behavioural proxies of risk aversion remained unaltered for individual tropical fish species, in general they became more risk-averse (increased sheltering and/or flight initiation distance), and their activity level decreased poleward. Nevertheless, they did not experience a decline in body condition or feeding rate in their temperate ranges. Temperate fishes did not show a consistently altered pattern in their behaviours across range locations, even though one species increased its flight initiation distance at the warm-temperate location and another one had lowest activity levels at the coldest range location. The maintenance of feeding and bite rate combined with a decreased activity level and increased sheltering may be behavioural strategies adopted by range-extending tropical fishes, to preserve energy and maintain fitness in their novel temperate ecosystems.
随着气候变暖，热带物种的分布范围扩大到了温带生态系统，在那里它们面临着新的捕食者和栖息地。捕食强烈地调节着生态群落，而采用有效防御策略的扩展物种在非本地环境中更有可能生存下来。在这里，我们通过在 730 公里的纬度范围内的多个地点比较扩展热带鱼类和本地温带鱼类之间的各种防御和其他与适应能力相关的行为指标，来验证这个假设。尽管一些个体热带鱼类的回避风险的行为指标保持不变，但总的来说，它们变得更加回避风险（增加了庇护和/或逃避启动距离），并且它们的活动水平向极地降低。然而，它们在温带地区的身体状况或摄食率并没有下降。温带鱼类在其分布地点的行为模式并没有表现出一致的变化，尽管有一种鱼类在暖温带地区增加了逃避启动距离，而另一种鱼类在最寒冷的分布地点则表现出最低的活动水平。在其新的温带生态系统中，保持摄食和咬食率，同时降低活动水平和增加庇护，可能是扩展热带鱼类采用的行为策略，以保存能量并维持其适应性。
