School of Natural Resources, 103 Anheuser-Busch Natural Resources Building, University of Missouri, Columbia, MO, 65211, USA; Missouri Department of Conservation, 3500 East Gans Road, Columbia, MO, 65201, USA.
Department of Veterinary Hygiene and Management, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt; School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA.
J Therm Biol. 2021 Apr;97:102864. doi: 10.1016/j.jtherbio.2021.102864. Epub 2021 Jan 30.
Ecologists require standardized, ecologically relevant information on the thermal ecology of aquatic ectotherms to address growing concerns related to changing climates, altered habitats, and introduced species. We measured multiple thermal endpoints to investigate potential for establishment of the invasive Ringed Crayfish (Faxonius neglectus) in thermally heterogeneous habitat of the narrowly distributed endemic Coldwater Crayfish (Faxonius eupunctus). For each species, we examined the relationships between thermal endpoints at the cellular and organismal levels. We then compared results between the two species to gain insight as to the generality of linkages between cellular and organismal-level endpoints, as well as the potential for thermal niche separation between the native and potential invader. At the cellular level, we found no differences in the temperature for maximum activity of electron transport system enzymes (ETS) between species. At the organismal level, F. neglectus preferred significantly warmer temperatures than F. eupunctus, but this difference was small (1.3 °C) and likely to have only limited biological significance. The critical thermal maximum (CTM) did not differ between species. For both species, the thermal performance curve for ETS enzyme activity served as a useful framework to link thermal endpoints and estimate the transition from optimal to stressful temperatures - organismal thermal preference and optimal temperature estimates consistently fell below ETS whereas CTM estimates fell above ETS. Taken together, the strong similarities in thermal endpoint patterns between the two species suggest habitats thermally suitable for the native F. eupunctus will also be thermally available to expanding populations of F. neglectus, thereby increasing the opportunity for negative interactions and population effects if F. neglectus invades one of the few remaining, uninvaded, critical habitats of F. eupunctus.
生态学家需要有关水生变温动物热生态学的标准化、与生态学相关的信息，以应对与气候变化、生境改变和引入物种相关的日益增长的关注。我们测量了多个热终点，以研究入侵的环纹淡水小龙虾（Faxonius neglectus）在分布狭窄的特有冷水小龙虾（Faxonius eupunctus）的热异质生境中建立的潜力。对于每个物种，我们研究了细胞和生物体水平的热终点之间的关系。然后，我们比较了两个物种的结果，以深入了解细胞和生物体水平终点之间联系的普遍性，以及本地物种和潜在入侵物种之间热生态位分离的可能性。在细胞水平上，我们没有发现两个物种之间电子传递系统酶（ETS）最大活性的温度存在差异。在生物体水平上，F. neglectus 比 F. eupunctus 更喜欢明显温暖的温度，但这种差异很小（1.3°C），可能具有有限的生物学意义。临界热最大值（CTM）在物种之间没有差异。对于这两个物种，ETS 酶活性的热性能曲线可作为有用的框架来连接热终点并估计从最佳温度到应激温度的转变 - 生物体的热偏好和最佳温度估计值始终低于 ETS，而 CTM 估计值高于 ETS。总的来说，这两个物种之间热终点模式的强烈相似性表明，对于本地 F. eupunctus 来说，热适宜的栖息地也将为 F. neglectus 不断扩大的种群提供热资源，从而增加了 F. neglectus 入侵 F. eupunctus 少数剩余的、未被入侵的关键栖息地之一时发生负面相互作用和种群效应的机会。
