Trait Divergence Research Articles

Disentangling genetic, plastic and social learning drivers of sex-specific foraging behaviour in Trinidadian guppies (Poecilia reticulata).

Evolutionary biologists have long been interested in parsing out the roles of genetics, plasticity and their interaction on adaptive trait divergence. Since males and females often have different ecological and reproductive roles, separating how their traits are shaped by interactions between their genes and environment is necessary and important. Here, we disentangle the sex-specific effects of genetic divergence, developmental plasticity, social learning and contextual plasticity on foraging behaviour in Trinidadian guppies (Poecilia reticulata) adapted to high- or low-predation habitats. We reared second-generation siblings from both predation regimes with or without predator chemical cues, and with adult conspecifics from either high- or low-predation habitats. We then quantified their foraging behaviour in water with and without predator chemical cues. We found that high-predation guppies forage more efficiently than low-predation guppies, but this behavioural difference is context-dependent and shaped by different mechanisms in males and females. Higher foraging efficiency in high-predation females is largely genetically determined, and to a smaller extent socially learned from conspecifics. However, in high-predation males, higher foraging efficiency is plastically induced by predator cues during development. Our study demonstrates sex-specific differences in genetic versus plastic responses in foraging behaviour, a trait of significance in organismal fitness and ecosystem dynamics.

ROLE OF ANTIOXIDENTS ACCUMULATION AND PHOTOSYNTHETIC STABILITY FOR SUSTAINABLE COTTON PRODUCTION AND FIBRE QUALITY UNDER WATER STRESS CONDITIONS

One of the significant steps in developing water stress-tolerant, climate-smart cotton genotypes is evaluating and screening available cultivated germplasm. The current study was designed to evaluate the elite cotton strains developed for release in drought-prone areas of Punjab and Pakistan. Twenty-four cotton strains, along with two check varieties BH-184 and FH-142 were sown under RCBD in triplicates. The plant-to-plant and row-to-row distances were maintained at 30 cm and 70 cm, respectively. The recommended dosage of fertilizers N-P-K @ 100-36-37 kgs per acre was applied to all the treatments in all replications. The results revealed the presence of highly significant variations among cotton strains for studied plant parameters in twenty-four cotton strains. Correlation analysis unveiled the presence of highly significant and positive correlation of seed cotton yield with nodes per plant (r = 0.988**), sympodia per plant (r = 0.987**), transpiration rate (r = 0.983**), flavonoids (r = 0.982**), net photosynthetic rate (r = 0.979**), peroxidases (r = 0.968**), superoxide dismutase (r = 0.968**), bolls per plant (r = 0.914**), plant height (r = 0.885**), monopodia per plant (r = 0.725**) and ginning out turn (r = 0.430**) while the significantly negative correlation with CLCuV occurrence percentage (r = -0.526**). Cluster, principal component, and biplot analysis classify cotton strains into groups based on their performance under water-stress conditions. The results from PC1/PC2 biplot also verified the results obtained through correlations and further revealed that transpiration rate, net photosynthetic rate, peroxidases, superoxide dismutase, plant height, flavonoids, sympodia per plant, and superoxide dismutase were the most divergent traits and must be considered in developing a scheme to develop heat-tolerant cotton genotypes.

GENETIC CHARACTERIZATION AND PERFORMANCE EVALUATION OF ELITE COTTON STRAINS FOR MORPHOLOGICAL AND PHYSIO-CHEMICAL TRAITS UNDER HEAT STRESS CONDITIONS

One of the key steps in developing heat-tolerant, climate-smart cotton genotypes is evaluating and screening available cultivated germplasm. The current study was designed to evaluate the key cotton strains developed for release in heat-prone areas of Punjab and Pakistan. Thirteen cotton strains, along with check variety BH-184, were sown under randomized complete block design (RCBD) in triplicates. The plant-to-plant and row-to-row distances were maintained at 30 cm and 70 cm, respectively. The results revealed the presence of highly significant variations among cotton strains for studied plant traits in 13 cotton strains. Correlation analysis unveiled the presence of highly significant and positive correlation of seed cotton yield with net photosynthetic rate (r = 0.982**), total chlorophyll contents (r = 0.976**), superoxide dismutase (r = 0.966**), bolls per plant (r = 0.786**), nodes per plant (r = 0.683**), plant height (r = 0.653**) and sympodia per plant (r = 0.623**) while strong negative correlation with superoxide dismutase (r = -0.952**). Cluster, principal component and biplot analysis classify cotton strains into groups based on their performance under heat stress conditions. These analyses verified the results obtained through correlations and further revealed that net photosynthetic rate, total chlorophyll contents, superoxide dismutase, plant height and sympodia per plant and superoxide dismutase were the most divergent traits and must be considered in developing a scheme to develop heat-tolerant cotton genotypes.

Effect of residence time on trait evolution in invasive plants: review and meta-analysis

The success of invasive species is often attributed to rapid post-introduction evolution, due to novel selection pressures at the introduced range. However, evolutionary shifts in invasion-promoting traits can also take place within the introduced range over time. Here, we first present a review of the proposed hypotheses regarding the selection pressures and trait divergence along gradients of invasion history and the studies that examined them. In addition, we present the results of a meta-analysis aimed to provide a more general overview of current knowledge on trait evolution with time since introduction. Invasion-promoting traits, including growth, competitive ability and dispersal ability, were proposed to decline in more established populations with a long invasion history due to the attenuation of selection pressures, such as enemy release or interspecific competition, while herbivore defence was suggested to increase. Our meta-analysis results reveal a general indication for the evolution of invasive plants with residence time for most of the studied traits. However, this divergence did not have a consistent direction in most traits, except for growth, which, in contrast with our prediction, increased with residence time. The lack of empirical support for the predicted change in most of the studied traits over time suggests trait evolution might be affected by other context-dependent factors such as climatic gradients along invasion routes. Similarly, the increased allocation to size in older and more established populations may be driven by increased conspecific competition pressure experienced in these populations. The general temporal effect found in our meta-analysis stresses the need to consider population age when comparing attributes of invasive plants between native and invasive ranges. Moreover, the increased size of invasive plants in older populations, suggests that the dominance of these plants might not attenuate with time since introduction, thus highlighting the need to further explore the long-term dynamics between invasive plants and their recipient native communities.

A test of trade-offs in dispersal and reproduction within and between a sister species pair of specialist insect herbivores.

Understanding the drivers of trade-offs among traits is vital for comprehending the evolution and maintenance of trait variation. Theoretical frameworks propose that evolutionary mechanisms governing trade-offs frequently exhibit a scale-dependent nature. However, empirical tests of whether trade-offs exhibited across various biological scales (i.e. individuals, populations, species, genera, etc.) remains scarce. In this study, we explore trade-off between dispersal and reproductive effort among sympatric sister species of wasps in the genus Belonocnema (Hymenoptera: Cynipini: Cynipidae) that form galls on live oaks: B. fossoria, which specializes on Quercus geminata, and B. treatae, which specializes on Q. virginiana. Specifically, our results suggest that B. fossoria has evolved reduced flight capability and smaller wings, but a larger abdomen and greater total reproductive effort than B. treatae, which has larger wings and is a stronger flier, but has a smaller abdomen and reduced total reproductive effort. These traits and the relationships among them remain unchanged when B. fossoria and B. treatae are transplanted and reared onto the alternative host plant, suggesting that trait divergence is genetically based as opposed to being a plastic response to the different rearing environments. However, when looking within species, we found no evidence of intraspecific trade-offs between wing length and reproductive traits within either B. fossoria or B. treatae. Overall, our results indicate that observed trade-offs in life history traits between the two gall former species are likely a result of independent adaptations in response to different environments as opposed to the amplified expression of within species intrinsic tradeoffs.

Genetic Coupling of Mate Recognition Systems in the Genomic Era.

The concept of "genetic coupling" in mate recognition systems arose in the 1960s as a potential mechanism to maintain coordination between signals and receivers during evolutionary divergence. At its most basic it proposed that the same genes might influence trait and preference, and therefore mutations could result in coordinated changes in both traits. Since then, the concept has expanded in scope and is often used to include linkage or genetic correlation between recognition system components. Here we review evidence for genetic coupling, concentrating on proposed examples of a common genetic basis for signals and preferences. Mapping studies have identified several examples of tight genetic linkage between genomic regions influencing signals and preferences, or assortative mating. Whether this extends as far as demonstrating pleiotropy remains a more open question. Some studies, notably of Drosophila, have identified genes in the sex determination pathway and in pheromonal communication where single loci can influence both signals and preferences. This may be based on isoform divergence, in which sex- and tissue-specific effects are facilitated by alternative spicing, or on regulatory divergence. Hence it is not clear that such examples provide compelling evidence of pleiotropy in the sense that "magic mutations" could maintain trait coordination. Rather, coevolution may be facilitated by regulatory divergence but require different mutations or coevolution across isoforms. Reconsidering the logic of genetic coupling, it may be that pleiotropy could actually be less effective than linkage if distinct but associated variants allow molecular coevolution to occur more readily than potentially "unbalanced" mutations in single genes. Genetic manipulation or studies of mutation order effects during divergence are challenging but perhaps the only way to disentangle the role of pleiotropy versus close linkage in coordinated trait divergence.

Habitat diversification associated with urban development has a little effect on genetic structure in the annual native plant Commelina communis in an East Asian megacity.

Urban development greatly alters the natural and semi-natural habitats of native plants. Urbanisation results in a range of diverse habitats including remnant agricultural lands, urban parks, and roadside habitats. This habitat diversity often promotes trait divergence within urban areas. However, the mechanisms by which diverse urban habitats influence the population genetic structure of individual plant species remain poorly understood. We investigated the effects of urbanisation on genetic diversity and structure within 24 Commelina communis populations across diverse habitat types (rural agricultural land, urban agricultural land, urban park land, and urban roadsides) within the Kyoto-Osaka-Kobe megacity in Japan. We conducted multiplexed inter-simple sequence repeat genotyping to compare genetic diversity among populations in different habitats. We also examined the correlation between Nei's genetic distance and geographic and environmental distances and performed principal coordinate analysis (PCoA) to evaluate genetic differentiation among urban habitats. There were no significant differences in genetic diversity indices between urban and rural populations and among urban habitat types. Although we detected no isolation-by-distance structure in population pairs of the same habitat type and in those of different habitats, the difference in surrounding landscape facilitated genetic differentiation not only between urban and rural habitats but also between different urban habitats. PCoA revealed no clear genetic differentiation among rural and urban habitat populations. Our findings indicate that the establishment of diverse habitat types through urbanisation has no and little impact on genetic diversity and structure, respectively, in C. communis, likely due to its high selfing rate and ability to adapt to urban conditions.

Wright was right: leveraging old data and new methods to illustrate the critical role of epistasis in genetics and evolution.

Much of evolutionary theory is predicated on assumptions about the relative importance of simple additive versus complex epistatic genetic architectures. Previous work suggests traits strongly associated with fitness will lack additive genetic variation, whereas traits less strongly associated with fitness are expected to exhibit more additive genetic variation. We use a quantitative genetics method, line cross analysis, to infer genetic architectures that contribute to trait divergence. By parsing over 1,600 datasets by trait type, clade, and cross divergence, we estimated the relative importance of epistasis across the tree of life. In our comparison between life-history traits and morphological traits, we found greater epistatic contributions to life-history traits. Our comparison between plants and animals showed that animals have more epistatic contribution to trait divergence than plants. In our comparison of within-species versus between-species crosses, we found that only animals exhibit a greater epistatic contribution to trait divergence as divergence increases. While many scientists have argued that epistasis is ultimately of little importance, our results show that epistasis underlies much of trait divergence and must be accounted for in theory and practical applications like domestication, conservation breeding design, and understanding complex diseases.

Ecological character displacement among Nothobranchius annual killifishes in Tanzania.

Divergent ecological character displacement (ECD) is the competition-driven divergence in resource use-related phenotypic traits between coexisting species. It is considered one of the primary drivers of ecological diversification and adaptive radiation. We analyzed phenotypic and ecological variation in 2 African annual killifish species of the genus Nothobranchius: N. eggersi and N. melanospilus in sympatry and N. melanospilus in allopatry. Our aim was to test whether allopatric and sympatric populations of N. melanospilus differ morphologically from each other and from N. eggersi and examine whether these differences are consistent with the predictions of ECD. We find that sympatric N. melanospilus differ from allopatric N. melanospilus and differ from N. eggersi more strongly than the latter. Our data satisfy four criteria for demonstrating ECD: Differences in phenotypes between allopatric and sympatric N. melanospilus are greater than expected by chance; the divergence pattern between allopatric and sympatric N. melanospilus results from an evolutionary shift rather than from ecological sorting; morphological differences observed reflect differences in resource use; and, lastly, sites of allopatry and sympatry do not differ in food resource availability or other ecological conditions. Our results suggest that competition is the main driver of the observed divergence between two N. melanospilus populations.

Trait divergence and opposite above- and below-ground strategies facilitate moso bamboo invasion into subtropical evergreen broadleaf forest.

Understanding the invasion of moso bamboo (Phyllostachys edulis) into adjacent evergreen broadleaf forest based on functional traits is crucial due to its significant influence on ecosystem processes. However, existing research has primarily focused on above- or below-ground traits in isolation, lacking a comprehensive integration of both. In this study, we conducted a trait-based analysis including 23 leaf traits and 11 root traits in three forest types - bamboo forest, mixed bamboo and broadleaf forest, and evergreen broadleaf forest - to investigate trait differences, phenotypic integration, and above- and below-ground resource strategies in bamboo and broadleaf species. Our findings demonstrated significant differences in leaf and root key traits between bamboo and broadleaf species, strongly supporting the "phenotypic divergence hypothesis". Bamboo exhibited stronger trait correlations compared to broadleaf species, indicating higher phenotypic integration. Above- and below-ground strategies were characterized by trade-offs rather than coordination, resulting in a multi-dimensional trait syndrome. Specifically, a unidimensional leaf economics spectrum revealed that bamboo with higher leaf N concentrations (LNC), P concentrations (LPC), and specific leaf area (SLA) adopted a "fast acquisitive" above-ground strategy, while broadleaf species with thicker leaves employed a "slow conservative" above-ground strategy. A two-dimensional root trait syndrome indicated a "conservation" gradient with bamboo adopting a "slow conservative" below-ground strategy associated with higher root tissue density (RTD), and broadleaf species exhibiting a "fast acquisitive" below-ground strategy linked to higher root N concentrations (RNC) and P concentrations (RPC), and a "collaboration" gradient probably ranging from broadleaf species with a "do-it-yourself" strategy characterized by high specific root length (SRL), to bamboo adopting an "outsourcing" strategy with thicker roots. In conclusion, key trait divergence from coexisting broadleaf species, higher phenotypic integration, and multi-dimensional opposite above- and below-ground resource strategies confer competitive advantages to moso bamboo, shedding light on the mechanistic understanding of its invasion into subtropical evergreen broadleaf forest and providing theoretical guidance for maintaining the stability of subtropical forest ecosystem.

Exploring CRY1 Protein Residue Associations with Diurnal and Nocturnal Behaviors Across Vertebrate Species

Background/Aim: Core clock genes exert influence over a spectrum of behavioral consequences and physiological processes. In mammals, distinct transcription-translation feedback loops oscillate approximately every 24 hours, aligning peripheral tissues with the dark-light cycle. Consequently, species manifest diverse activity patterns in their daily routines; for instance, diurnal species exhibit sleep during dark periods and heightened activity during light periods. Over the course of evolution, subtle changes in protein sequences can lead to divergent phenotypic traits. This study aims to scrutinize core clock protein residues to identify significant amino acid sites that might underlie diurnal or non-diurnal tendencies from an evolutionary standpoint. Methods: We performed multiple sequence alignment on coding sequences of vertebrate core clock protein, CRY1, orthologs obtained from the NCBI database. This was achieved using the Constraint-based Multiple Alignment Tool (COBALT). Vertebrate species were classified into diurnal (n=127) and nocturnal (n=92) categories. Statistical methods were applied to analyze the non-random distribution of amino acid residues between the two groups. Results: Our analysis of the CRY1 protein provides initial insights into specific amino acid residues exhibiting non-random associations with both nocturnal and diurnal behaviors. Notably, we identified five residues subject to purifying selection and 21 residues under positive selection within CRY1 orthologs. These residues span across exons 1, 4, and 9-12, predominantly concentrated in the tail region. Conclusion: This preliminary investigation highlights the importance of particular amino acids within core clock proteins, offering valuable insights into their functional significance. The observed discrepancies in conservation patterns between diurnal and nocturnal groups underscore the potential disruption of essential folding processes or post-translational mechanisms by mutations in these regions. This research marks a pioneering advancement in understanding the phenotypic outcomes of core clock proteins and their direct correlation with behavioral traits within evolutionary contexts, potentially linking to sleep disorders.

Elementary and Advanced Mechanisms for Genetic Engineering in Crops

Presently, the field of plant breeding is in the genomics era, where innovative techniques are being integrated to accelerate and enhance the efficiency of breeding. Traditional plant breeding methods rely on maintaining plant germplasm with desirable agronomic traits from distinct plants produced through crosses or mutagenesis. However, advancements in genetic engineering encompass all forms of genetic modification through recombinant DNA technology (RDT) and cell fusion mechanisms. These approaches shed light on areas involving mutant organisms, DNA replication, genetic linkage resolution, genetically modified organisms (GMOs), protein sequencing, functional genomics, and computational genomics alterations in genetic engineering. The integration of structural genomics into breeding and eugenics analysis has resulted in a vast knowledge base on crop genetics, species divergence, and molecular origin of traits, as well as the evolutionary history of crop lineage from ancient ancestral species. The genomic data and advancements have proven essential in identifying rare genes, alleles, or local lesions crucial to significant agronomic traits, thereby expediting breeding cycles. This article aims to explore the potential of emerging genetic engineering technologies, including synthetic biology and genome editing, to further advance crop genetics and plant breeding.

Bird‐flower colour on islands supports the bee‐avoidance hypothesis

Abstract Many insular plant species inhabiting different archipelagos worldwide present typical ornithophilous floral traits (e.g. copious nectar, red‐orange colours), but most of them are visited by insectivorous/granivorous birds and lizards, which act as generalist pollinators. Oceanic islands promote these ecological interactions mainly due to the scarcity of arthropods. Our goal is to understand how these generalist interactions contribute to the shift of floral traits from entomophily (mainland) to ornithophily or saurophily (island), where specialist nectar‐feeding birds have not inhabited. We used the well‐known pollination interactions occurring in the Canary Islands to evaluate two proposed ecological hypotheses, bee‐avoidance or bird‐attraction, explaining evolutionary transitions of floral traits. Specifically, we studied the flower colour conspicuousness of bird‐pollinated Canarian species visited by birds and lizards with their closest relatives from the mainland mainly visited by bees. We analysed the chromatic contrast of flower colours using visual models of bees, birds and lizards and the achromatic contrast in visual models of bees. We also compared reflectance spectra marker points of flowers with available spectral discrimination sensitivities of bees and birds. Using a phylogenetically corrected framework of independent plant lineages, our results revealed that bird‐pollinated Canarian species showed lower chromatic contrast according to bees and lizard visual models than their mainland relatives, but similar chromatic contrast for bird vision. In addition, reflectance spectra marker points of the Canarian species were displaced to the longest wavelengths, far from the wavelengths of maximum discrimination of bees, but close to birds. We conclude that the avoidance of bees would be a primary ecological strategy explaining the evolutionary transitions of flower colours from melittophily to ornithophily. The lower conspicuousness of bird‐pollinated Canarian flowers in lizards is perhaps a side effect of the bee‐avoidance strategy rather than an independent evolutionary strategy. Together, these findings provide insights into how vertebrate generalist pollinators can also lead to divergence of floral traits in insular habitats, but also in other arthropod‐poor habitats. Read the free Plain Language Summary for this article on the Journal blog.

Plastic and genomic change of a newly established lizard population following a founder event.

Understanding how phenotypic divergence arises among natural populations remains one of the major goals in evolutionary biology. As part of competitive exclusion experiment conducted in 1971, 10 individuals of Italian wall lizard (Podarcis siculus (Rafinesque-Schmaltz, 1810)) were transplanted from Pod Kopište Island to the nearby island of Pod Mrčaru (Adriatic Sea). Merely 35 years after the introduction, the newly established population on Pod Mrčaru Island had shifted their diet from predominantly insectivorous towards omnivorous and changed significantly in a range of morphological, behavioural, physiological and ecological characteristics. Here, we combine genomic and quantitative genetic approaches to determine the relative roles of genetic adaptation and phenotypic plasticity in driving this rapid phenotypic shift. Our results show genome-wide genetic differentiation between ancestral and transplanted population, with weak genetic erosion on Pod Mrčaru Island. Adaptive processes following the founder event are indicated by highly differentiated genomic loci associating with ecologically relevant phenotypic traits, and/or having a putatively adaptive role across multiple lizard populations. Diverged traits related to head size and shape or bite force showed moderate heritability in a crossing experiment, but between-population differences in these traits did not persist in a common garden environment. Our results confirm the existence of sufficient additive genetic variance for traits to evolve under selection while also demonstrating that phenotypic plasticity and/or genotype by environment interactions are the main drivers of population differentiation at this early evolutionary stage.

Morphological and functional trait divergence in endemic fish populations along the small-scale karstic stream

BackgroundOrganisms with broad distribution ranges, such as fish, often exhibit local ecological specializations based on their utilization of food and habitat. Populations of species that live in different habitat types (lotic vs. lentic) show morphological variations. However, the phenotypic differences of endemic fish populations in a small karst river basin under anthropogenic pressure are still not fully understood. In this study, the functional traits and morphological variations of the populations of endemic Pseudophoxinus antalyae Bogutskaya, 1992, in the Düden Stream basin, which is subjected to various anthropogenic disturbances and habitat types in southwestern Anatolia of Türkiye, were examined using linear measurements and geometric morphometric analysis.ResultsDifferences have been identified in functional traits, particularly those related to food acquisition between populations. Results of both univariate and multivariate analyses revealed significant differences in body shape and size among populations living at sites along the stream with different habitat and environmental characteristics.ConclusionsThe reason for these differences determined in the morphology and traits of the populations may depend on habitat types, ecological, or environmental, and obstruction of gene flow. More detailed studies are needed to explain the mechanisms (genetic and ecological) that cause these differences.

Climate warming has divergent physiological impacts on sympatric lizards

Climate warming is expected to affect the vulnerability of sympatric species differentially due to their divergent traits, but the underlying physiological mechanisms of those impacts are poorly understood. We conducted field warming experiments (present climate vs. warm climate) using open-top chambers to determine the effects of climate warming on active body temperature, oxidative damage, immune competence, growth and survival in two sympatric desert-dwelling lizards, Eremias multiocellata and Eremias argus from May 2019 to September 2020. Our climate warming treatment did not affect survival of the two species, but it did increase active body temperatures and growth rate in E. multiocellata compared to E. argus. Climate warming also induced greater oxidative damage (higher malondialdehyde content and catalase activity) in E. multiocellata, but not in E. argus. Further, climate warming increased immune competence in E. multiocellata, but decreased immune competence in E. argus, with regards to white blood cell counts, bacteria killing ability and relative expression of immunoglobulin M. Our results suggest that climate warming enhances body temperature, and thereby oxidative stress, immune competence and growth in E. multiocellata, but decreases immune competence of E. argus, perhaps as a cost of thermoregulation to maintain body temperatures under climate warming. The divergent physiological effects of climate warming on sympatric species may have profound ecological consequences if it eventually leads to changes in reproductive activities, population dynamics and community structure. Our study highlights the importance of considering interspecific differences in physiological traits when we evaluate the impact of climate warming on organisms, even for those closely-related species coexisting within the same geographical area.

Habitat fragmentation affects climate adaptation in a forest herb

Abstract Climate change and the resulting increased drought frequencies pose considerable threats to forest herb populations, particularly where additional environmental challenges jeopardize responses to selection. Specifically, habitat fragmentation may hamper climate adaptation by altering the distribution of adaptive genetic variation and may also induce evolutionary changes in mating systems. To assess how habitat fragmentation disrupts climate adaptation, we conducted a common garden experiment with Primula elatior offspring originating from 24 populations sampled along a latitudinal gradient with varying climate and landscape characteristics. We then quantified a range of vegetative, regulatory and reproductive traits under distinct soil moisture regimes to evaluate imprints of local adaptation and phenotypic plasticity. Additionally, we conducted a more extensive field campaign in 60 populations along the same latitudinal gradient to evaluate the potential evolutionary breakdown of reciprocal herkogamy. For large, connected populations, our results demonstrated an evolutionary shift from a strategy in southern populations that seems aligned with drought avoidance—where plants minimize their exposure to dry conditions and optimize photosynthesis—to a drought tolerance strategy in northern populations, where plants are adapted to function despite water scarcity. However, habitat fragmentation disrupted climate clines and the adaptive responses to drought stress in key traits related to growth, biomass allocation and water regulation. Additionally, our findings indicate the onset of evolutionary breakdown in reciprocal herkogamy and divergence in other key flower traits. The disruption of climate clines, drought responses and adaptations in mating systems contributed to a substantially diminished flowering investment across the distribution range, with the most pronounced effects observed in southern fragmented populations. Synthesis. We present novel empirical evidence of how habitat fragmentation disrupts climate adaptation and drought tolerance in a wide range of traits along the range of the forest herb Primula elatior. These findings emphasize the need to account for habitat fragmentation while designing effective conservation strategies in order to preserve and restore resilient meta‐populations of forest herbs amidst ongoing global changes.

Within- and between-population comparisons suggest independently acting selection maintaining parallel clines in Scots pine (Pinus sylvestris).

Parallel clines in traits related to adaptation in a species can be due to independent selection on a pair of traits, or due to selection in one trait resulting in a parallel cline in a correlated trait. To distinguish between the mechanisms giving rise to parallel adaptive population divergence of multiple traits along an environmental gradient we need to study variation, correlations, and selective forces within individual populations along the gradient. In many tree species, budset timing (BST) forms a latitudinal cline, and parallel clinal variation is also found in other seedling traits, such as first-year height (FYH) and fall frost injury (FFI). In this study, we set up a common garden experiment with open pollinated progeny from natural populations of Scots pine (Pinus sylvestris), with one large sample from single population (500 families) and smaller samples from across a latitudinal gradient. BST, FYH and induced FFI were first measured in a greenhouse. The seedlings were then planted in the field, where survival and height were measured at the age of 9 years as fitness proxies. We compared between- and within-population variation and genetic correlations of these three seedling traits, and estimated selection gradients at the family level in our main population, taking into account the potential effects of seed weight. Between-population genetic correlations between seedling traits were high (0.76-0.95). Within-population genetic correlations in the main population were lower (0.14-0.35), as in other populations (0.10-0.39). Within population, extensive adaptive variation persists in the seedling traits, in line with rather weak selection gradients, yet maintaining the clines. Although our sampling does not cover the whole cline equally, the results suggest that the individual clines in these traits are maintained by largely independently acting selection, which results in fewer constraints in adaptation under changing climate.

Urbanization and a green corridor do not impact genetic divergence in common milkweed (Asclepias syriaca L.)

Urbanization is altering landscapes globally at an unprecedented rate. While ecological differences between urban and rural environments often promote phenotypic divergence among populations, it is unclear to what degree these trait differences arise from genetic divergence as opposed to phenotypic plasticity. Furthermore, little is known about how specific landscape elements, such as green corridors, impact genetic divergence in urban environments. We tested the hypotheses that: (1) urbanization, and (2) proximity to an urban green corridor influence genetic divergence in common milkweed (Asclepias syriaca) populations for phenotypic traits. Using seeds from 52 populations along three urban-to-rural subtransects in the Greater Toronto Area, Canada, one of which followed a green corridor, we grew ~ 1000 plants in a common garden setup and measured > 20 ecologically-important traits associated with plant defense/damage, reproduction, and growth over four years. We found significant heritable variation for nine traits within common milkweed populations and weak phenotypic divergence among populations. However, neither urbanization nor an urban green corridor influenced genetic divergence in individual traits or multivariate phenotype. These findings contrast with the expanding literature demonstrating that urbanization promotes rapid evolutionary change and offer preliminary insights into the eco-evolutionary role of green corridors in urban environments.

Divergence of Seed Mass in Riparian Plant Communities Dominated by Filtering and Random Processes

Restoration of degraded riparian zones is the primary challenge for ensuring the sustainability of watershed ecosystems. An essential aspect of this endeavor is gaining a deep understanding of how riparian plant communities are assembled. The main focus of this study was to investigate how riparian plant communities respond to varying levels of flooding stress along the Three Gorges Reservoir (TGR) in China’s Yangtze River. To accomplish this, we calculated the diversity of plant taxonomy, traits and phylogeny, and used a null model to reflect the plant community assembly rules within the riparian zones along the TGR. The riparian zones were divided into four regions based on water regime: the fluctuating backwater area, the permanent backwater area, mainstream and tributaries of the TGR, covering the reservoir area of 1084 km2 with 180 sampling sites surveyed. Our results showed that within the permanent backwater area of the tributaries, the gradient variation in taxonomic and trait diversity of the riparian community was strongly aligned with the varying levels of flooding stress, which suggests that strong environmental selection plays a significant role in this section. Furthermore, through analysis of phylogenetic and trait structures based on the null model, we found that environmental filtering and random processes were the primary mechanisms shaping plant communities in the riparian zones across the entire study area. However, by further examining single traits, we found that seed mass was the sole trait displaying noteworthy divergence in the riparian communities throughout the study area. This finding highlights that seed mass appears as a pivotal divergent trait in the herb succession stage of the riparian communities that is strongly governed by filtering and random processes. In conclusion, we recommend prioritizing seed mass differences in ecological restoration efforts for herb succession in flooding-stressed riparian communities. This approach is crucial for enhancing source utilization, facilitating community assembly, and improving overall recovery outcomes.