Life-history traits of invasive fish in small Mediterranean streams

We compared the life-history traits of native and invasive fish species from Catalan streams in order to identify the characters of successful invasive fish species. Most of the exotic fish species were characterized by large size, long longevity, late maturity, high fecundity, few spawnings per year, and short reproductive span, whereas Iberian native species exhibited predominantly the opposite suite of traits. Species native to the southeastern Pyrenees watershed were also significantly different from species native to the rest of the Iberian Peninsula but not native to this watershed. Iberian exotic species come predominantly from large river basins, whereas Catalan streams (and other small, coastal river basins) correspond to basins and streams of a smaller size and different hydrology, with differences in species composition and life-history traits of fish. The occurrence and spread of invasive species was not significantly related to life-history traits but to introduction date. The successful prediction of future invasive species is limited due to small differences in life-history and ecological traits between native and exotic species. Fecundity, age at maturity, water quality flexibility, tolerance to pollution and habitat seem the most discriminating life-history variables. This revised version was published online in July 2006 with corrections to the Cover Date.     

Large-scale intraspecific variation in life-history traits of European freshwater fish

Aims To test the magnitude and direction of the effects of large‐scale environmental factors (latitude and habitat type: lotic or lentic) on the intraspecific variations in multiple life‐history traits, across multiple European freshwater fish species. To test the relevance of defining species traits by quantifying the magnitude of interspecific vs. intraspecific variability in traits. Location Europe. Methods We obtained estimates of 11 fish traits from published sources for 1089 populations of 25 European freshwater fish species. Traits were: longevity, maximal length, growth rate, asymptotic length, mortality rate, age and length at maturation, fecundity, egg size, gonadosomatic index, and length of breeding season. We described population habitats by latitude and habitat type (lotic or lentic), when available. For each species we tested the combined effect of latitude and habitat type on the intraspecific variation of each trait using analysis of covariance (ancova ). We compared the intraspecific variation in traits with the variation between species using an analysis of variance (anova ) for each trait, all species pooled. Results We found a consistent effect in direction of latitude on six traits, but we showed that this effect is not always significant across species. Higher‐latitude populations often grew more slowly, matured later, had a longer life span and a higher maximal and asymptotic length, and allocated more energy to reproduction than populations at lower latitudes. By contrast, we noted only a slight effect of habitat type on the intraspecific variation in traits, except for Salmo trutta. All traits varied significantly between species. However, traits such as growth rate, mortality rate and length of breeding season varied more between populations than between species, whereas fecundity and traits associated with body length varied more between species. Main conclusions Latitude, in contrast to habitat type, is an important factor influencing several traits of geographically widely dispersed populations of multiple European freshwater fish species. Species traits that vary more between species than between populations are attractive variables for understanding and predicting the responses of stream fish communities to their environment.     

The onset of piscivory in a freshwater fish species: analysis of behavioural and physiological traits

The onset of piscivory in fish, resulting in a shift from zooplankton or invertebrate to fish prey, was studied on pikeperch (Sander lucioperca) larvae displaying and not displaying piscivorous behaviour at different ages (23, 30, 37, 44 and 52 days post-hatching) using behavioural (attack, capture and swimming activity), morphological (allometry) and digestive enzymatic (trypsin, α-amylase and pepsin) analyses. The shift from zooplanktonic food items (Artemia nauplii) to a piscivorous diet did not occur at the same time for all individuals within the same cohort. Predation tests, conducted under controlled conditions (20°C; ad libitum feeding), showed that some larvae attacked fish prey as early as the age of 3 weeks [11.0 ± 1.3 mm total length (TL)], whereas others did not start until the age of 6 weeks (16.6 ± 1.9 mm TL). Piscivorous individuals were bigger, with larger heads, longer tails, higher acid protease and lower alkaline protease activities, than non-piscivorous conspecifics. In conclusion, high interindividual variability in morphological and digestive system developments linked to the development of predatory abilities could induce cannibalism in fish.     

五种淡水鱼类幼鱼游泳能力的比较

为了探讨栖息于不同生境中鱼类的游泳能力和偏好游泳速度及其生理机制,本研究以中华倒刺鲃(Spinibarbus sinensis)、异育银鲫(Carassius auratus gibelio)、岩原鲤(Procypris rabaudi)、青鱼(Mylopharyngodon piceus)和胭脂鱼(Myxocryprinus asiaticus) 5种鱼的幼鱼为对象,在(25±1)℃条件下测定了5种鱼类的标准代谢率(SMR)、最大代谢率(MMR)、有氧代谢范围(MS)、临界游泳速度(U_crit)、最大匀加速游泳速度(U_cat)和偏好游泳速度(U_pref)。结果发现:5种实验鱼中,中华倒刺鲃的游泳能力最强,游泳能力较差的为青鱼和胭脂鱼; 5种鱼之间的代谢和游泳能力差异显著,其偏好游泳速度主要集中在(10～24.5cm·s^-1)区域。研究表明,鱼类游泳能力的种间差异可能主要由心鳃系统相关的呼吸能力和体型相关的游泳效率所决定。本研究提供的有关鱼类游泳能力、偏好游泳速度等资料对于鱼道设计等有一定的参考价值...     

Evidence of a genetically distinct population of Vrljika softmouth trout Salmo obtusirostris Heckel evolved by vicariance

Mitochondrial DNA haplotypes (control region, partial cytochrome b and ATPase6 genes) indicate a sister relationship between Vrljika and Neretva softmouth (Adriatic) trout Salmo obtusirostris . This relationship was supported by a tree of individuals based on microsatellite results [allele sharing distances ( D _AS)], which revealed three distinctive clusters, corresponding to Jadro softmouth, Neretva brown trout Salmo trutta and Neretva softmouth trout. Within the latter taxon, Vrljika trout are clearly separated from other trout. The genetic results contradict the synonymy of Jadro with Vrljika softmouth trout, as recently proposed in the Red Book of Freshwater Fish in Croatia. Vrljika softmouth trout appear to have originated from a vicariance that split a common ancestor into large (Neretva) and small (Vrljika) fragmented populations 135 000–270 000 years ago. Vrljika softmouth trout can be distinguished by an array of derived phenotypic and molecular character states. For conservation, this population should be recognized formally at the same taxonomic level as the other geographically separated populations of softmouth trout.     

Biogeography of Iberian freshwater fishes revisited: the roles of historical versus contemporary constraints

Aim The question of how much of the shared geographical distribution of biota is due to environmental vs. historical constraints remains unanswered. The aim of this paper is to disentangle the contribution of historical vs. contemporary factors to the distribution of freshwater fish species. In addition, it illustrates how quantifying the contribution of each type of factor improves the classification of biogeographical provinces. Location Iberian Peninsula, south‐western Europe (c. 581,000 km²). Methods We used the most comprehensive data on native fish distributions for the Iberian Peninsula, compiled from Portuguese and Spanish sources on a 20‐km grid‐cell resolution. Overall, 58 species were analysed after being categorized into three groups according to their ability to disperse through saltwater: (1) species strictly intolerant of saltwater (primary species); (2) species partially tolerant of saltwater, making limited incursions into saltwaters (secondary species); and (3) saltwater‐tolerant species that migrate back and forth from sea to freshwaters or have invaded freshwaters recently (peripheral species). Distance‐based multivariate analyses were used to test the role of historical (basin formation) vs. contemporary environmental (climate) conditions in explaining current patterns of native fish assemblage composition. Cluster analyses were performed to explore species co‐occurrence patterns and redefine biogeographical provinces based on the distributions of fishes. Results River basin boundaries were better at segregating species composition for all species groups than contemporary climate variables. This historical signal was especially evident for primary and secondary freshwater fishes. Eleven biogeographical provinces were delineated. Basins flowing to the Atlantic Ocean north of the Tagus Basin and those flowing to the Mediterranean Sea north of the Mijares Basin were the most dissimilar group. Primary and secondary freshwater species had higher province fidelity than peripheral species. Main conclusions The results support the hypothesis that historical factors exert greater constraints on native freshwater fish assemblages in the Iberian Peninsula than do current environmental factors. After examining patterns of assemblage variation across space, as evidenced by the biogeographical provinces, we discuss the likely dispersal and speciation events that underlie these patterns.     

Depth and temperature drive patterns of spatial overlap among fish thermal guilds in lakes across Ontario,Canada

Aim

The spatial distribution of ectotherms is strongly dependent on the temperature of their environments. In temperate lakes, fishes with different thermal optima can become spatially segregated during summer stratification. This habitat partitioning, or niche complementarity, may play a role in the coexistence of trophically similar species; however, the extent of partitioning is dependent on the resources available within each habitat. Although habitat partitioning of fish thermal guilds has been studied in individual lakes, broad-scale patterns of spatial overlap and segregation are not yet understood. In this study, we explore the patterns and drivers of spatial overlap among thermal guilds (cold-, cool-, and warm-water) at a broad scale.

Location

Ontario, Canada.

Methods

We built a multivariate regression tree to explore patterns and environmental drivers of spatial overlap in freshwater fishes across three thermal guilds from 438 lakes.

Results

We identified five clusters of lakes exhibiting different patterns of spatial overlap among the three thermal guilds. Temperature (growing degree days) and maximum lake depth were strong drivers of the spatial overlap patterns.

Main Conclusions

These findings provide a better understanding of broad-scale patterns of spatial overlap and allow us to predict how spatial overlap, and ultimately species interactions and competition, may change under a warming climate.     

Latitudinal variation in sexual dimorphism in life‐history traits of a freshwater fish

Sexual dimorphism is common across the animal kingdom, but the contribution of environmental factors shaping differences between the sexes remains controversial. In ectotherms, life‐history traits are known to correlate with latitude, but sex‐specific responses are not well understood. We analyzed life‐history trait variation between the sexes of European perch (Perca fluviatilis L.), a common freshwater fish displaying larger female size, by employing a wide latitudinal gradient. We expected to find sex‐dependent latitudinal variation in life‐history variables: length at age, length increment, and size at maturity, with females showing consistently higher values than males at all latitudes. We further anticipated that this gender difference would progressively decrease with the increasingly harsh environmental conditions toward higher latitude. We hypothesized that growth and length increment would decrease and size/age at maturity would increase at higher latitudes. Our results confirmed female‐biased sexual size dimorphism at all latitudes and the magnitude of sexual dimorphism diminished with increase in latitude. Growth of both sexes decreased with increase in latitude, and the female latitudinal clines were steeper than those of males. Hence, we challenge two predominant ecological rules (Rensch's and Bergmann's rules) that describe common large‐scale patterns of body size variation. Our data demonstrate that these two rules are not universally applicable in ectotherms or female‐biased species. Our study highlights the importance of sex‐specific differences in life‐history traits along a latitudinal gradient, with evident implications for a wide range of studies from individual to ecosystems level.     

鱼类生物群落对太子河流域土地利用、河岸带栖息地质量的响应

河流生态系统的退化是多空间尺度环境因子作用的结果。探讨不同尺度环境因子及水生生物之间的作用关系,识别影响水生生物群落完整性的尺度问题,是有效开展水生生物保护的基础。基于2009年对太子河流域15个样点的鱼类、河岸带栖息地质量评价,结合遥感影像解译的太子河流域土地利用情况(包括流域尺度和河段尺度),研究鱼类完整性指数(F-IBI)与两种尺度土地利用、栖息地质量参数之间的关系。结果表明太子河上游地区河岸栖息地质量较好,下游地区由于农业用地、城镇用地比例的增加河岸栖息地质量明显下降。F-IBI与自然用地比例呈正相关,与农业、城镇用地比例呈负相关。农业用地对F-IBI的影响体现在流域尺度,而城镇用地在两种尺度上都存在显著影响。相比于农业用地,城镇用地相同比例的增加会导致F-IBI更快的下降。底质、水质状况、人类活动强度是显著影响F-IBI的栖息地质量评价参数。3项参数均随农业和城镇用地比例增加而降低,农业用地主要在流域尺度上对3项参数产生影响,城镇用地主要影响底质和水质状况2项参数,而在两种尺度上的影响相差不大。     

Variability of functional traits and their syndromes in a freshwater fish species (Phoxinus phoxinus): The role of adaptive and nonadaptive processes

Functional traits can covary to form “functional syndromes.” Describing and understanding functional syndromes is an important prerequisite for predicting the effects of organisms on ecosystem functioning. At the intraspecific level, functional syndromes have recently been described, but very little is known about their variability among populations and—if they vary—what the ecological and evolutionary drivers of this variation are. Here, we quantified and compared the variability in four functional traits (body mass, metabolic rate, excretion rate, and boldness), their covariations and the subsequent syndromes among thirteen populations of a common freshwater fish (the European minnow, Phoxinus phoxinus). We then tested whether functional traits and their covariations, as well as the subsequent syndromes, were underpinned by the phylogenetic relatedness among populations (historical effects) or the local environment (i.e., temperature and predation pressure), and whether adaptive (selection or plasticity) or nonadaptive (genetic drift) processes sustained among‐population variability. We found substantial among‐population variability in functional traits and trait covariations, and in the emerging syndromes. We further found that adaptive mechanisms (plasticity and/or selection) related to water temperature and predation pressure modulated the covariation between body mass and metabolic rate. Other trait covariations were more likely driven by genetic drift, suggesting that nonadaptive processes can also lead to substantial differences in trait covariations among populations. Overall, we concluded that functional syndromes are population‐specific, and that both adaptive and nonadaptive processes are shaping functional traits. Given the pivotal role of functional traits, differences in functional syndromes within species provide interesting perspectives regarding the role of intraspecific diversity for ecosystem functioning.     

Estimates of niche position and breadth vary across spatial scales for native and alien inland fishes

Aim

We estimate and compare niche position, marginality and breadth of Iberian inland fishes at three geographical extents (regional, restricted to the species’ range and global) to understand the effect of spatial scale on niche metrics. Furthermore, we investigate differences in niche metrics between native and alien fish, and test for associations with introduction date of alien species and niche characterization to better understand their invasion process.

Location

Iberian Peninsula and global.

Time period

2000–2020.

Major taxa studied

Fifty-one native and 17 alien inland fish species from the Iberian Peninsula.

Methods

Outlying mean index (OMI) analyses were used to estimate the niche position, marginality and breadth of Iberian inland fishes. Climatic OMI analyses were computed at three different scales (regional, restricted to the species’ range and global). Permutational analyses of variance (PERMANOVAs) were used to test for differences in niche position, marginality and breath among native and alien species.

Results

Niche metrics differed depending on the geographical extent of the investigation, as well as with respect to species origin (native versus alien). Differences in climatic niche position between native and alien species observed at the global scale were non-existent at the regional scale. The niche breadth of widely distributed alien species was highly underestimated when only considering the invaded region, and further influenced by the first date of of species introduction.

Main conclusions

Estimating niches of freshwater species, especially of alien invaders, should carefully consider the geographical extent of the investigation. We suggest that analyses that jointly consider regional and global scales will improve the estimation of niche metrics of widely distributed organisms, particularly regarding species climatic niche, and the assessment of the invasive potential of species.     

Comparative analysis of fish environmental DNA reveals higher sensitivity achieved through targeted sequence-based metabarcoding

Environmental DNA (eDNA)-based methods of species detection are enabling various applications in ecology and conservation including large-scale biomonitoring efforts. qPCR is widely used as the standard approach for species-specific detection, often targeting a fish species of interest from aquatic eDNA. However, DNA metabarcoding has the potential to displace qPCR in certain eDNA applications. In this study, we compare the sensitivity of the latest Illumina NovaSeq 6000 NGS platform to qPCR TaqMan assays by measuring limits of detection and by analysing eDNA from water samples collected from Churchill River and Lake Melville, NL, Canada. Species-specific, targeted next generation sequencing (NGS) assays had significantly higher sensitivity than qPCR, with limits of detection 14- to 29-fold lower. For example, when analysing eDNA, qPCR detected Gadus ogac (Greenland cod) in 21% of samples, but targeted NGS detected this species in 29% of samples. General NGS assays were as sensitive as qPCR, while simultaneously detecting 15 fish species from eDNA samples. With over 34,000 fish species on the planet, parallel and sensitive methods such as NGS will be required to support effective biomonitoring at both regional and global scales.     

18S rRNA metabarcoding diet analysis of a predatory fish community across seasonal changes in prey availability

Predator–prey relationships are important ecological interactions, affecting biotic community composition and energy flow through a system, and are of interest to ecologists and managers. Morphological diet analysis has been the primary method used to quantify the diets of predators, but emerging molecular techniques using genetic data can provide more accurate estimates of relative diet composition. This study used sequences from the 18S V9 rRNA barcoding region to identify prey items in the gastrointestinal (GI) tracts of predatory fishes. Predator GI samples were taken from the Black River, Cheboygan Co., MI, USA (n = 367 samples, 12 predator species) during periods of high prey availability, including the larval stage of regionally threatened lake sturgeon (Acipenser fulvescens Rafinesque 1817) in late May/early June of 2015 and of relatively lower prey availability in early July of 2015. DNA was extracted and sequenced from 355 samples (96.7%), and prey DNA was identified in 286 of the 355 samples (80.6%). Prey were grouped into 33 ecologically significant taxonomic groups based on the lowest taxonomic level sequences that could be identified using sequences available on GenBank. Changes in the makeup of diet composition, dietary overlap, and predator preference were analyzed comparing the periods of high and low prey abundance. Some predator species exhibited significant seasonal changes in diet composition. Dietary overlap was slightly but significantly higher during the period of high prey abundance; however, there was little change in predator preference. This suggests that change in prey availability was the driving factor in changing predator diet composition and dietary overlap. This study demonstrates the utility of molecular diet analysis and how temporal variability in community composition adds complexity to predator–prey interactions.     

Specificity and host predictability: a comparative analysis among monogenean parasites of fish

1. This article compares generalist (parasite species found on two or more host species) and specialist (found on only one host species) monogenean parasite species of fish. The reduction of the host range – that is an increase in host specificity – may correspond with a better adaptation of the parasite to a more predictable host environment. A more predictable environment may allow the parasite species to develop specific adaptations.
2. We assume that the more predictable host environment can be evaluated by host body size, since numerous life-traits, such as longevity, are positively correlated with size.
3. We found that specialist parasites parasitize larger hosts species than generalist parasites. We also found a good relationship between host body size and parasite body size for specialist parasite species.
4. An adaptation to the mechanical problems encountered in the host's gill chamber may lead to an increase in parasite body size. The infection of a larger part of the host population in order to decrease the chances of local extinction due to fluctuations of host abundance may be another adaptive mechanism.
5. We found a negative correlation between parasite body size and prevalence for generalist parasite species. This relationship disappeared when using the comparative method controlling for phylogeny, which proved that it was a phylogenetic effect.     

Ecological drivers of body size evolution and sexual size dimorphism in short‐horned grasshoppers (Orthoptera: Acrididae)

Sexual size dimorphism (SSD) is widespread and variable in nature. Although female‐biased SSD predominates among insects, the proximate ecological and evolutionary factors promoting this phenomenon remain largely unstudied. Here, we employ modern phylogenetic comparative methods on eight subfamilies of Iberian grasshoppers (85 species) to examine the validity of different models of evolution of body size and SSD and explore how they are shaped by a suite of ecological variables (habitat specialization, substrate use, altitude) and/or constrained by different evolutionary pressures (female fecundity, strength of sexual selection, length of the breeding season). Body size disparity primarily accumulated late in the history of the group and did not follow a Brownian motion pattern, indicating the existence of directional evolution for this trait. We found support for the converse of Rensch's rule (i.e. females are proportionally bigger than males in large species) across all taxa but not within the two most speciose subfamilies (Gomphocerinae and Oedipodinae), which showed an isometric pattern. Our results do not provide support for the fecundity or sexual selection hypotheses, and we did not find evidence for significant effects of habitat use. Contrary to that expected, we found that species with narrower reproductive window are less dimorphic in size than those that exhibit a longer breeding cycle, suggesting that male protandry cannot solely account for the evolution of female‐biased SSD in Orthoptera. Our study highlights the need to consider alternatives to the classical evolutionary hypotheses when trying to explain why in certain insect groups males remain small.     

Effects of longitudinal variations in stream habitat structure on fish abundance: an analysis based on subunit-scale habitat classification

SUMMARY 1. Stream reaches contain assortments of various habitat types that can be defined at different spatial scales, such as channel unit (e.g. pools, riffles) and subunit (patches within channel units). We described longitudinal (upstream–downstream) patterns of stream habitat structure by considering subunits as structural elements, and examined their effects on the abundance of masu salmon ( Oncorhynchus masou ) and rosyface dace ( Leuciscus ezoe ) in a third-order tributary of the Teshio River in northern Hokkaido, Japan.
2. Nine subunit types were determined on the basis of water depth, current velocity and substrate, using 0.5 × 0.5 m grids. Although both masu salmon and rosyface dace used pools as a major habitat, the former preferred a subunit type occurring at pool heads (PH subunit) while the latter preferred a slow-current edge type (SE-2 subunit).
3. Along the course of the stream, slow-edge subunits (SE-1, 2 and 3) increased in frequency downstream while fast-edge subunits (FE-1 and 2) decreased, suggesting a downstream development of slow-current edges. Regression analyses indicated that longitudinal variation in masu salmon abundance was explained by the area of PH, rather than pools. Masu salmon density increased with the area of PH. Rosyface dace abundance was explained by a combination of water depth and the area of SE-2, both effects being positive.
4. Longitudinal variations in the abundance of both species were related to the abundance of their preferred habitat at the subunit scale, rather than channel-unit scale. The results emphasise the importance of fine-scale patchiness when examining stream fish habitats.     

The use of penrose's C for an intra- and inter-population analysis of quantitative dermatoglyphic traits

Results of a part of multidisciplinary studies in six villages on the island of Hvar (Yugoslavia) are presented. Six quantitative properties of dermatoglyphics were analysed (TRC, PII, a-b, b-c and c-d ridge counts, and atd angle). “Biological distances” among the surveyed couples from all six villages were analysed using Penrose's C²_H, and its components: C²_Q and (v-l/v)C²_Z with regard to sex and possibility of determining the direction of endogamy or exogamy. Significant correlation between “geographical distances” and (v-l/v)C²_Z is obtained for males, indicating that the social organisation in the examined rural population, from the point of view of demography, has some influence on the distribution of the dermatoglyphical characters.     

Isotope analysis reveals proportional change and site-selection variation of river- and lake-produced eggs of a landlocked migratory fish

Changes in the proportions of river- and lake-produced eggs of a landlocked amphidromous fish, ayu (Plecoglossus altivelis altivelis) in the Lake Biwa water system, Japan, were monitored by stable isotope analysis, based on different δ¹⁵N and δ¹³C values of prey organisms between the lake and its tributaries. During the 3 month reproduction season, the δ¹⁵N values of spawned eggs decreased with time. This result implies that there was a shift from lake-produced eggs to river-produced eggs within a reproductive season, based on the observation that adult fish in the lake had previously been shown to have eggs with distinctly higher δ¹⁵N values in their ovaries than those in the tributaries. This explanation was also supported by the change in δ¹³C values of the spawned eggs. Furthermore, eggs with lower δ¹⁵N and higher δ¹³C values tended to be spawned at less variable depths, suggesting that females spawning river-produced eggs selected the spawning sites from a narrower range. We conclude that stable isotope ratios of spawned eggs can be indicators of the relative contributions of different food chains and can enable comparisons of reproductive characteristics between types of egg.     

Genetic analysis of differentiation among breeding ponds reveals a candidate gene for local adaptation in Rana arvalis

One of the main questions in evolutionary and conservation biology is how geographical and environmental features of the landscape shape neutral and adaptive genetic variation in natural populations. The identification of genomic polymorphisms that account for adaptive variation can aid in finding candidate loci for local adaptation. Consequently, a comparison of spatial patterns in neutral markers and loci under selection may help disentangle the effects of gene flow, genetic drift and selection at the landscape scale. Many amphibians breed in wetlands, which differ in environmental conditions and in the degree of isolation, enhancing the potential for local adaptation. We used microsatellite markers to measure genetic differentiation among 17 local populations of Rana arvalis breeding in a network of wetlands. We found that locus RC08604 deviated from neutral expectations, suggesting that it is a good candidate for directional selection. We used a genetic network analysis to show that the allele distribution in this locus is correlated with habitat characteristics, whereas this was not the case at neutral markers that displayed a different allele distribution and population network in the study area. The graph approach illustrated the genomic heterogeneity (neutral loci vs. the candidate locus for directional selection) of gene exchange and genetic divergence among populations under directional selection. Limited gene flow between wetlands was only observed at the candidate genomic region under directional selection. RC08604 is partially located inside an up‐regulated thyroid‐hormone receptor (TRβ) gene coordinating the expression of other genes during metamorphosis and appears to be linked with variation in larval life‐history traits found among R. arvalis populations. We suggest that directional selection on genes coding larval life‐history traits is strong enough to maintain the divergence in these genomic regions, reducing the effective recombination of locally adapted alleles but not in other regions of the genome. Integrating this knowledge into conservation plans at the landscape scale will improve the design of management strategies to preserve adaptive genetic diversity in wetland networks.