Ecological segregation moderates a climactic conclusion to trout hybridization

渗入 虹鳟 分类单元 生态学 钩吻 消光(光学矿物学) 鳟鱼 繁殖体 生物 引进物种 局部消光 地理 渔业 人口 生物扩散 人口学 古生物学 社会学 基因 生物化学
作者
Michael K. Young,Daniel J. Isaak,Kevin S. McKelvey,Taylor M. Wilcox,Matthew R. Campbell,Matthew P. Corsi,Dona L. Horan,Michael K. Schwartz
出处
期刊:Global Change Biology [Wiley]
卷期号:23 (12): 5021-5023 被引量:8
标识
DOI:10.1111/gcb.13828
摘要

For decades, it has been assumed that introgressive hybridization between introduced rainbow trout and native cutthroat trout in western North America will lead to genomic extinction of the latter. A broad-scale re-examination of their interaction indicates that ecological differences between these species and demographic processes are dictating the location and extent of their hybrid zones, and that runaway introgression between these taxa is unlikely. Invasive hybridization, in which an introduced species may introgressively hybridize with a native taxon and threaten its persistence, is prominently featured in the conservation literature. One of the most frequently cited examples of this phenomenon involves interactions between native westslope cutthroat trout Oncorhynchus clarkii lewisi and introduced rainbow trout Oncorhynchus mykiss in a portion of the U.S. Northern Rocky Mountains (Allendorf & Leary, 1988). A recent paper by Muhlfeld et al. (2017) revisited this issue and concluded that introgressive hybridization between these taxa is ubiquitous and related primarily to climatic factors and propagule pressure from rainbow trout, findings which corroborate an earlier study (Young et al., 2016) that accurately quantified how broad riverscape gradients—not thresholds—in temperature, zoogeographic characteristics, and propagule pressure were related to levels of introgression. Yet, Muhlfeld et al. (2017) argued that there were deficiencies in that analysis and discounted that these same gradients can result in resistance of westslope cutthroat trout populations to invasive hybridization. Instead, based on extrapolation of decadal trends at nonrandom monitoring sites, they asserted that genomic extinction—the loss of all unhybridized parental forms—is inevitable for most populations of westslope cutthroat trout in the absence of physical obstacles to upstream dispersal by rainbow trout or human intervention to remove them. We question this assertion based on our field observations and critical review of the subject (McKelvey et al., 2016; Young et al., 2016), the emerging recognition of environmental constraints on introgression (Wang & Bradburd, 2014), and the ecophysiological differences between these taxa and their hybrids (Rasmussen, Robinson, Hontela, & Heath, 2012). Resolving this issue is crucial, because resources to effect conservation are limited and poorly informed efforts can be costly and have unintended consequences (Fausch, Rieman, Dunham, Young, & Peterson, 2009). Our uncertainty about the inevitability of genomic extinction stems from our own observations and a meta-analysis of 29 other studies involving hybridization between these species (McKelvey et al., 2016). Collectively, these studies revealed that apparently nonintrogressed cutthroat trout were common in most locations that also harbored rainbow trout or hybrids between the two. Moreover, the alleles of both taxa were strikingly nonrandomly distributed among samples of individuals (Figures 1 and 2) despite over a century of potential hybridization and the subsidy of rainbow trout propagules from the stocking of hundreds of millions of fish for anglers. That nonrandomness implies substantial resistance to introgression and likely reflects the ecological segregation of these taxa. Cutthroat trout tend to be found in smaller, colder, and less productive streams, whereas rainbow trout occupancy peaks in larger, warmer environments, preferences that probably arise from differences in their physiological traits (Rasmussen et al., 2012). Consequently, longitudinal gradients in hybridization between these species in streams are the norm and appear to represent environmentally mediated hybrid zones, a pattern observed between countless taxa in many environments, including historically sympatric species (Jiggins & Mallet, 2000). Also instructive, although not considered by Muhlfeld et al. (2017), is that rainbow trout have naturally co-occurred with westslope cutthroat trout elsewhere in the Northwest since the last glacial maximum or longer. There, these species also readily hybridize and patterns in allele distributions and hybrid zone structure along environmental gradients are nearly indistinguishable from those where rainbow trout are non-native, with one exception: levels of introgression are markedly higher within the native range of rainbow trout (Young et al., 2016). Yet this region remains a stronghold for effectively genetically intact populations of westslope cutthroat trout, despite thousands of generations for hybridization to spread (Figure 2). We are not blithely sanguine about the threats posed by invasive hybridization to populations of westslope cutthroat trout in this era of rapid environmental change and non-native species invasions (Isaak, Young, Nagel, Horan, & Groce, 2015). Instead, our emphasis is on critically weighing conservation risks to guide timely, strategic decision making. Examining hybridization risks between taxa in the spatial context of entire river networks or landscapes and the broad environmental gradients therein can greatly contribute to the realism and geographic generality of models and the inferences they provide. In the case of hybridization between rainbow trout and westslope cutthroat trout, we coupled those types of models (Young et al., 2016) with our understanding of the climate inertia of cold water mountain streams (Isaak et al., 2016) to make spatially explicit predictions about the current and future positions and characteristics of hybrid zones under a variety of climate and invasion scenarios. Those analyses suggested that nonintrogressed populations of westslope cutthroat trout will remain, albeit in fewer locations and smaller populations (in which they are relatively persistent; Isaak et al., 2015), because of their ecological differences and the geomorphological diversity inherent to mountainous terrain. Those predictions—and our dataset—are publically available online (https://www.fs.fed.us/rm/boise/AWAE/projects/CutthroatRainbowTrout.html) to permit fellow researchers to replicate, test, or expand on our results in the collective effort to develop a more nuanced and comprehensive understanding of environmental change and the eventual outcomes of species interactions.
最长约 10秒,即可获得该文献文件

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
PDF的下载单位、IP信息已删除 (2025-6-4)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
零零发布了新的文献求助50
1秒前
Ausna发布了新的文献求助10
1秒前
紫紫发布了新的文献求助10
2秒前
哈哈完成签到 ,获得积分10
4秒前
5秒前
Chocolate完成签到,获得积分10
5秒前
爱吃肉肉的蚂蚁完成签到,获得积分20
6秒前
韩瑶完成签到,获得积分20
7秒前
8秒前
研友_VZG7GZ应助体贴的靖仇采纳,获得10
8秒前
8秒前
BIESHUOHUA完成签到,获得积分10
10秒前
10秒前
希望天下0贩的0应助紫紫采纳,获得10
10秒前
量子星尘发布了新的文献求助10
12秒前
活泼稀发布了新的文献求助10
13秒前
斯文钢笔完成签到 ,获得积分10
13秒前
13秒前
Ava应助Chen二月三石采纳,获得10
14秒前
14秒前
英姑应助meng采纳,获得10
15秒前
冷艳芯完成签到,获得积分20
15秒前
聪慧小霜应助诸天蓉采纳,获得10
15秒前
科研开门完成签到,获得积分10
16秒前
16秒前
BIESHUOHUA发布了新的文献求助10
16秒前
啦啦啦完成签到,获得积分10
18秒前
zhangheng发布了新的文献求助10
19秒前
20秒前
22秒前
顾矜应助yanyifan采纳,获得10
22秒前
pipi发布了新的文献求助10
22秒前
22秒前
淡定从凝发布了新的文献求助10
22秒前
Good_小鬼完成签到,获得积分10
23秒前
风清扬发布了新的文献求助10
23秒前
Cecilia完成签到,获得积分10
23秒前
23秒前
wangnn完成签到,获得积分10
24秒前
24秒前
高分求助中
Picture Books with Same-sex Parented Families: Unintentional Censorship 700
ACSM’s Guidelines for Exercise Testing and Prescription, 12th edition 500
Nucleophilic substitution in azasydnone-modified dinitroanisoles 500
不知道标题是什么 500
Indomethacinのヒトにおける経皮吸収 400
Phylogenetic study of the order Polydesmida (Myriapoda: Diplopoda) 370
Effective Learning and Mental Wellbeing 300
热门求助领域 (近24小时)
化学 材料科学 医学 生物 工程类 有机化学 生物化学 物理 内科学 纳米技术 计算机科学 化学工程 复合材料 遗传学 基因 物理化学 催化作用 冶金 细胞生物学 免疫学
热门帖子
关注 科研通微信公众号,转发送积分 3975250
求助须知:如何正确求助?哪些是违规求助? 3519625
关于积分的说明 11199055
捐赠科研通 3255962
什么是DOI,文献DOI怎么找? 1798001
邀请新用户注册赠送积分活动 877358
科研通“疑难数据库(出版商)”最低求助积分说明 806298