Abstract
Climate-induced expansion of invasive hybridization (breeding between invasive and native species) poses a significant threat to the persistence of many native species worldwide. In the northern U.S. Rocky Mountains, hybridization between native cutthroat trout and non-native rainbow trout has increased in recent decades due, in part, to climate-driven increases in water temperature. It has been postulated that invasive hybridization may enhance physiological tolerance to climate-induced thermal stress because laboratory studies indicate that rainbow trout have a higher thermal tolerance than cutthroat trout. Here, we assessed whether invasive hybridization improves cardiac performance response to acute water temperature stress of native wild trout populations. We collected trout from four streams with a wide range of non-native admixture among individuals and with different temperature and streamflow regimes in the upper Flathead River drainage, USA. We measured individual cardiac performance (maximum heart rate, “MaxHR”, and temperature at arrhythmia, “ArrTemp”) during laboratory trials with increasing water temperatures (10–28°C). Across the study populations, we observed substantial variation in cardiac performance of individual trout when exposed to thermal stress. Notably, we found significant differences in the cardiac response to thermal regimes among native cutthroat trout populations, suggesting the importance of genotype-by-environment interactions in shaping the physiological performance of native cutthroat trout. However, rainbow trout admixture had no significant effect on cardiac performance (MaxHR and ArrTemp) within any of the three populations. Our results indicate that invasive hybridization with a warmer-adapted species does not enhance the cardiac performance of native trout under warming conditions. Maintaining numerous populations across thermally and hydrologically diverse stream environments will be crucial for native trout to adapt and persist in a warming climate.
| Original language | English |
|---|---|
| Article number | e13663 |
| Pages (from-to) | e13663 |
| Journal | Evolutionary Applications |
| Volume | 17 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 2024 |
Funding
Funding and equipment were provided by the National Science Foundation DEB‐1258203, Montana Fish, Wildlife & Parks, and the U.S. Geological Survey. We thank field crew members Benjamin Triano, Will Jaques, Grant Bobo, and others for sample collection and lab experiments. For genetic laboratory analyses, we thank Angela Lodmell, Sally Painter, Dulaney Miller, and Rachel Walker. We especially thank Steve Amish and Seth Smith for advice on the development of the genetic marker panel and bioinformatic pipelines used in this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. government. This study was performed under the auspices of the Institutional Animal Care and Use Committee permit no. AUP 007‐19. Funding and equipment were provided by the National Science Foundation DEB-1258203, Montana Fish, Wildlife & Parks, and the U.S. Geological Survey. We thank field crew members Benjamin Triano, Will Jaques, Grant Bobo, and others for sample collection and lab experiments. For genetic laboratory analyses, we thank Angela Lodmell, Sally Painter, Dulaney Miller, and Rachel Walker. We especially thank Steve Amish and Seth Smith for advice on the development of the genetic marker panel and bioinformatic pipelines used in this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. government. This study was performed under the auspices of the Institutional Animal Care and Use Committee permit no. AUP 007-19.
| Funders | Funder number |
|---|---|
| AUP 007-19 | |
| DEB‐1258203 | |
| Montana Fish Wildlife and Parks |
Keywords
- Westslope cutthroat trout
- admixture
- cardiac performance
- climate change
- heart rate
- introgression
- invasive hybridization
- physiological stress
- rainbow trout
- thermal tolerance
