Inland Habitats Research Articles

Accelerated differentiation of neo-W nuclear-encoded mitochondrial genes between two climate-associated bird lineages signals potential co-evolution with mitogenomes.

There is considerable evidence for mitochondrial-nuclear co-adaptation as a key evolutionary driver. Hypotheses regarding the roles of sex-linkage have emphasized Z-linked nuclear genes with mitochondrial function (N-mt genes), whereas it remains contentious whether the perfect co-inheritance of W genes with mitogenomes could hinder or facilitate co-adaptation. Young (neo-) sex chromosomes that possess relatively many N-mt genes compared to older chromosomes provide unprecedented hypothesis-testing opportunities. Eastern Yellow Robin (EYR) lineages in coastal and inland habitats with different climates are diverged in mitogenomes, and in a ~ 15.4 Mb nuclear region enriched with N-mt genes, in contrast with otherwise-similar nuclear genomes. This nuclear region maps to passerine chromosome 1A, previously found to be neo-sex in the inland EYR genome. To compare sex-linked Chr1A-derived genes between lineages, we assembled and annotated the coastal EYR genome. We found that: (i) the coastal lineage shares a similar neo-sex system with the inland lineage, (ii) neo-W and neo-Z N-mt genes are not more diverged between lineages than are comparable non-N-mt genes, and showed little evidence for broad positive selection, (iii) however, W-linked N-mt genes are more diverged between lineages than are their Z-linked gametologs. The latter effect was ~7 times stronger for N-mt than non-N-mt genes, suggesting that W-linked N-mt genes might have diverged between lineages under environmental selection through co-evolution with mitogenomes. Finally, we identify a candidate gene driver for divergent selection, NDUFA12. Our data represent a rare example suggesting a possible role for W-associated mitochondrial-nuclear interactions in climate-associated adaptation and lineage differentiation.

Landscape and habitat characteristics jointly drive the urban distribution of a nuisance species

Identifying environmental variables that affect the distribution of pest and/or nuisance species promotes effective management strategies by improving urban planning and the targeted application of direct interventions like population control. Australian white ibis Threskiornis moluccus are considered a nuisance species throughout Australia, having increased significantly in abundance in coastal urban landscapes following declines in their native inland habitats over the past three decades. Few management interventions thus far have successfully reduced conflicts between ibis and humans, necessitating a better understanding of conditions driving ibis distribution and abundance. We surveyed 26 ibis colonies throughout the Moreton Bay region in central eastern Australia and quantified the effects of a range of spatial (e.g. connectivity with waste management facilities, urban land and wetlands) and habitat (e.g. nesting tree species, density and size) variables on ibis and nest abundance. Ibis and their nests were most abundant at sites within 10 km of waste management facilities, and < 60 m from residential or industrial estates. Ibis were also more abundant at sites with tree canopy height < 10 m and lower tree species richness. Nests were most abundant on water bound islands with tree density > 0.5 trees/m2. Urbanisation had contrasting effects, with nest numbers increasing with higher connectivity (i.e. closer proximity) to urban land, while ibis numbers decreased (relative to waste management facilities). Multifaceted approaches are required for controlling ibis populations, including restricting access to anthropogenic food resources, managing the condition of remnant habitats, and considering population control at sites with high connectivity to foraging grounds.

Common‐garden study of introgression at loci associated with traits adaptive to coastal environment from Quercus dentata into Quercus mongolica var. crispula

AbstractAdaptive introgression, which can provide genetic diversity resulting in the expansion to novel habitats and the creation of different ecotypes, has been proposed in oaks (genus Quercus). In northern Japan, Quercus mongolica var. crispula (Qc) is common in inland habitats, and Quercus dentata (Qd) occurs in coastal habitats. At the northern distributional limit of Qd, Quercus × angustilepidota (Qa), a hybrid taxon between Qc and Qd, occurs in coastal habitats. These taxa, Qc, Qa, and Qd, were transplanted to inland and coastal common gardens (sites). Genotypes at 27 495 loci, phenotypes of eight leaf and shoot traits, and the size of 30‐year‐old trees were measured for 224 individuals in both sites. Genotypic variation revealed a hybrid zone between Qc and Qd, including both northern‐edge Qd admixed with Qc and coastal Qa backcrossed to Qc. Phenotypes of Qa trees were intermediate between those of Qc and Qd trees. The size of Qa and Qd trees was smaller than that of Qc trees in the inland site but was larger in the coastal site, suggesting adaptation of Qa and Qd to coastal environment. Local ancestry was estimated from phased genotypes of admixed trees using reference genotypes of 47 Qc and 25 Qd trees, indicating heterogeneous ancestry along chromosomes. Admixture mapping of local ancestry detected loci significantly associated with a leaf trait, which were located in an introgressed genomic region with genes related to stress response. Further studies are necessary to elucidate the genetic basis of adaptive introgression resulting in Qd‐like phenotypes of Qa.

Temporal changes in geographic range and population size of the Santa Cruz Black Salamander

Abstract The Santa Cruz Black Salamander Aneides niger is a priority 3 California species of special concern with a restricted geographic range confined to the Santa Cruz Mountains. Anecdotal observations suggest that the species was relatively abundant in the early 1900’s, but it has become more difficult to find in the past few decades. To better understand if the species has undergone population size fluctuations, we analyzed mitochondrial and nuclear sequence data to examine levels of genetic variation, phylogeographic structure, and test for signatures of population size change. We then reconstructed the climatic suitability for the species to A) determine if past climate fluctuations could have influenced range size and genetic diversity, and B) to estimate the effects of future climate change on geographic range suitability as a proxy for possible future population size change. Genetic analyses detected low levels of genetic variation and a general lack of genetic structuring, suggesting a recent genetic bottleneck. While neutrality tests of individual loci were non-significant, skyline plot and isolation-with-migration analyses detected a relatively recent reduction in population size. These genetic results should be interpreted with consideration of the limited number of localities and individuals that have been sampled for this species. Climatic suitability for Santa Cruz Black Salamanders was much lower during the last glacial maximum, which could be the cause of the detected historical change in population size. Future projections of climatic suitability under a high emission scenario suggest a dramatic geographic range restriction to coastal areas. These projections highlight the need for the protection of coastal habitat patches to preserve existing coastal populations, and to maintain connectivity between coastal and inland habitats to allow the westward movement of populations and genes in response to climate change.

Long‐term (29‐year) spatiotemporal patterns of sea turtle deaths in the southern Gulf of Mexico

Abstract Sea turtles are key imperilled species that interact with numerous threats in their critical in‐water and inland habitats, which they occupy along their complex life cycle. Therefore, analysing these interactions is essential for adapting ongoing conservation and management actions. The long‐term recording of stranded sea turtle individuals and the potential causes of death in their breeding habitats is crucial for defining and adapting conservation actions. Twenty‐nine years of sea turtle stranding and mortality data (1992–2019) at nesting beaches in Campeche, Mexico, were analysed to describe their spatiotemporal patterns per species and possible causes of death. The most impacted species was the hawksbill turtle, followed by green and Kemp's ridley individuals. The most frequent probable causes of death in this region were bycatch, seismic surveys, vehicle strikes and slaughter at nesting beaches. Both immature and breeding individuals were stranded, mostly the former, and the most frequent months were in the summer (June–August). This study establishes a historic reference baseline for the spatiotemporal mortality patterns of imperilled sea turtle species in the southeastern Gulf of Mexico. It shows their interactions with anthropogenic activities and the circumstances jeopardizing their population recovery. It also points out management and conservation actions to implement to improve their long‐term viability in the context of the operationalization of their key attributes and interactions with their seascapes.

Population genomics highlights structural variations in local adaptation to saline coastal environments in woolly grape.

Structural variations (SVs) are a feature of plant genomes that has been largely unexplored despite their significant impact on plant phenotypic traits and local adaptation to abiotic and biotic stress. In this study, we employed woolly grape (Vitis retordii), a species native to the tropical and subtropical regions of East Asia with both coastal and inland habitats, as a valuable model for examining the impact of SVs on local adaptation. We assembled a haplotype-resolved chromosomal reference genome for woolly grape, and conducted population genetic analyses based on whole-genome sequencing (WGS) data from coastal and inland populations. The demographic analyses revealed recent bottlenecks in all populations and asymmetric gene flow from the inland to the coastal population. In total, 1,035 genes associated with plant adaptive regulation for salt stress, radiation, and environmental adaptation were detected underlying local selection by SVs and SNPs in the coastal population, of which 37.29% and 65.26% were detected by SVs and SNPs, respectively. Candidate genes such as FSD2, RGA1, and AAP8 associated with salt tolerance were found to be highly differentiated and selected during the process of local adaptation to coastal habitats in SV regions. Our study highlights the importance of SVs in local adaptation; candidate genes related to salt stress and climatic adaptation to tropical and subtropical environments are important genomic resources for future breeding programs of grapevine and its rootstocks.

Water ecological requirements of Characeae taxa in eastern Spain

Presence of Characeae taxa is limited by the existence of clear and oligotrophic waters. Some other chemical water parameters can also influence the distribution of taxa, which can thus be used as ecological bioindicators. The area of eastern Spain contains a high diversity of water basins in both coastal and inland habitats that allow the study of ecological gradients. This work aimed to identify the most relevant and significant water chemical parameters that determine the distribution of Characeae taxa, and establish their optima and tolerance ranges for each parameter in eastern Spain. Ninety-six records corresponding to unpublished old and recent samplings of the presence of 17 taxa belonging to the genera Chara, Nitella, Tolypella and Lamprothamnium were related to water parameters that included salinity, pH, electric conductivity, total water hardness, alkalinity, concentrations of Na+, Mg2+, Ca2+, Cl-, and SO42-, and Mg2+/Ca2+ ratio. Principal Component Analysis showed that salinity was the major factor that determined the distribution of Characeae taxa, followed by concentration of Mg2+, Mg2+/Ca2+ ratio and alkalinity. When previously published records from the same area were added, non-parametric tests showed significant differences among taxa only for salinity, water hardness, and Mg2+/Ca2+ ratio. These statistical analyses, along with optima and tolerance ranges for each parameter showed that Characeae taxa, especially Lamprothamnium papulosum and Tolypella spp., could be used as bioindicators in eastern Spain, although their ecological differentiation is not clear in many cases.

Habitat-associated genomic variation in a wall lizard from an oceanic island.

The lizard Teira dugesii exhibits morphological divergence between beach and inland habitats in the face of gene flow, within the volcanic island of Madeira, Portugal. Here, we analysed genomic data obtained by genotyping-by-sequencing, which provided 16378 SNPs from 94 individuals sampled from 15 sites across Madeira. Ancient within-island divergence in allopatry appears to have mediated divergence in similar species within other Atlantic islands but this hypothesis was not supported for T. dugesii. Across all samples, a total of 168 SNPs were classified as statistical outliers using pcadapt and OutFLANK. Redundancy analysis revealed that 17 of these outliers were associated with beach/inland habitats. The SNPs were located within 16 sequence tags and 15 of these were homologous with sequences in a 31Mb region on chromosome three of a reference wall lizard genome (the remaining tag could not be associated with any chromosome). We further-investigated outliers through contingency analyses of allele frequencies at each of four pairs of adjacent beach-inland sites. The majority of the outliers detected by the redundancy analysis were confirmed at two pairs of these matched sites. These analyses also suggested some parallel divergence at different localities. Six other outliers were associated with site elevation, four of which were located on chromosome five of the reference genome. Our study lends supports to a previous hypothesis that divergent selection between grey shingle beaches and inland regions overcomes gene flow and leads to the observed morphological divergence between populations in these adjacent habitats.

Long-term responses of Icelandic Arctic foxes to changes in marine and terrestrial ecosystems.

The long-term dynamics of predator populations may be driven by fluctuations in resource availability and reflect ecosystem changes such as those induced by climate change. The Icelandic Arctic fox (Vulpes lagopus) population has known major fluctuations in size since the 1950s. Using stable isotopes analysis of bone collagen over a long-time series (1979-2018), we aimed at identifying the main resources used by Icelandic Arctic foxes during periods of growth and decline to assess if the variations in their population size are linked to fluctuations in the availability of resources. We hypothesized that (1) the decline in Seabird abundance was responsible for the decrease in the fox population; and (2) that the growth in the fox population combined to fluctuations in main resources would lead to an increase in intra-specific competition, ultimately leading to variations in their isotopic niches at the population scale. The isotopic composition of Arctic fox bones differed clearly between inland and coast. Stable isotopes mixing models suggested that marine resources and rock ptarmigans were the most important food source and highlighted a rather stable diet in coastal habitats compared to inland habitats where more fluctuations in dietary composition were observed. Coastal foxes had a broader niche than inland foxes, and there was more variation in niche size in the inland habitat. Our results tend to confirm that a general decline in seabird populations drove the decline in Arctic foxes, especially in coastal habitats. For the inland foxes, our results suggest that the lack of marine resources might have led to an increased use of ptarmigans especially during the most recent period.

Tibetan Artemia (Crustacea: Anostraca) mitogenomic biodiversity and population demographics

Abstract Hypersaline lakes in arid and semi-arid areas are unique ecosystems that harbour unique extremophile organisms such as Artemia, the paradigmatic example of adaptation to harsh living conditions. We assessed the mitogenomic biodiversity of Artemia species from the Tibetan Plateau, China, a remote and yet minimally disturbed ecosystem with a variety of hypersaline lakes. Analysis of ten Tibetan salt lakes demonstrated the occurrence of two regionally endemic species, Artemia tibetiana and Artemia sorgeloosi, with the latter being the dominant species with eight localities. Both species coexist in Jingyu and Jibu lakes, representing the first case of natural distribution overlap between sexual Artemia species. Artemia sorgeloosi exhibits higher genetic diversity and interpopulation differences, a result consistent with the heterogeneity of local salt lakes, local Artemia population demographics, and their adaptive potentials. Significant FST values demonstrate a gene flow barrier between A. sorgeloosi populations that is compatible with an ‘island biogeography’ distribution pattern, making the Tibetan Plateau a sort of natural laboratory to study intraspecific population differences. Artemia sorgeloosi and the exotic Artemia franciscana were found coexisting in Yangnapen Lake, demonstrating the ability of this invasive species to colonize high-altitude inland habitats, and the need to monitor its presence and eventual expansion.

Putative adaptive loci show parallel clinal variation in a California-endemic wildflower.

As the global climate crisis continues, predictions concerning how wild populations will respond to changing climate conditions are informed by an understanding of how populations have responded and/or adapted to climate variables in the past. Changes in the local biotic and abiotic environment can drive differences in phenology, physiology, morphology and demography between populations leading to local adaptation, yet the molecular basis of adaptive evolution in wild non-model organisms is poorly understood. We leverage comparisons between two lineages of Calochortus venustus occurring along parallel transects that allow us to identify loci under selection and measure clinal variation in allele frequencies as evidence of population-specific responses to selection along climatic gradients. We identify targets of selection by distinguishing loci that are outliers to population structure and by using genotype-environment associations across transects to detect loci under selection from each of nine climatic variables. Despite gene flow between individuals of different floral phenotypes and between populations, we find evidence of ecological specialization at the molecular level, including genes associated with key plant functions linked to plant adaptation to California's Mediterranean climate. Single-nucleotide polymorphisms (SNPs) present in both transects show similar trends in allelic similarity across latitudes indicating parallel adaptation to northern climates. Comparisons between eastern and western populations across latitudes indicate divergent genetic evolution between transects, suggesting local adaptation to either coastal or inland habitats. Our study is among the first to show repeated allelic variation across climatic clines in a non-model organism.

Ecophysiology of Endangered Plant Species Saussurea esthonica: Effect of Mineral Nutrient Availability and Soil Moisture

Saussurea esthonica is an endangered plant species typical for wet inland habitats such as calcareous fens. Due to its limited population size and distribution, non-invasive sampling of is important in the research of S. esthonica. The aim of the present study was to assess the effect of mineral nutrient availability and substrate moisture on the growth, physiological status, and mineral nutrition of S. esthonica. The non-destructive measurement of physiological parameters was performed in native habitats during three vegetative seasons, followed by two experiments in controlled conditions. Soil at the two Estonian sites had a relatively larger similarity in the composition of plant-available mineral nutrients in comparison to the two Latvian sites. The chlorophyll a fluorescence parameter Performance Index correlated with the total precipitation in the respective month before measurement, but no significant relationship with other environmental variables was found. For mineral nutrient experiments, plants were grown in four substrates with different mineral nutrient composition, resembling that of soil at different S. esthonica sites. Plant growth and physiological indices were significantly affected by the mineral composition of the substrate. Differences in leaf and root mineral nutrient concentrations of S. esthonica plants in part reflected differences in substrate mineral concentration. To evaluate the effect of soil moisture on growth and photosynthesis-associated parameters of S. esthonica, plants were cultivated in "Pope+" substrate at four different moisture treatments (dry, normal, wet, and waterlodged). The most intense growth of S. esthonica plants was evident in waterlodged conditions, which decreased with a decrease in soil moisture. The biomass of leaves increased by 106% and that of the roots increased by 72% as soil moisture increased from dry to normal. For waterlodged plants, leaf biomass increased by 263% and root biomass increased by 566%, in comparison to that for plants cultivated in dry substrate. Substrate drying had a more negative effect on the growth of S. esthonica plants in comparison to that of waterlodging, and this can be directly linked to prevalent hydrological conditions of an alkaline fen habitat native to the species. Therefore, the preservation of the natural water regime in natural habitats is critical to the conservation of the species.

Diaporthe species associated with the maritime grass Festuca rubra subsp. pruinosa.

Festuca rubra subsp. pruinosa is a perennial grass growing in sea cliffs where plants are highly exposed to salinity and marine winds, and often grow in rock fissures where soil is absent. Diaporthe species are one of the most abundant components of the root microbiome of this grass and several Diaporthe isolates have been found to produce beneficial effects in their host and other plant species of agronomic importance. In this study, 22 strains of Diaporthe isolated as endophytes from roots of Festuca rubra subsp. pruinosa were characterized by molecular, morphological, and biochemical analyses. Sequences of the nuclear ribosomal internal transcribed spacers (ITS), translation elongation factor 1-α (TEF1), beta-tubulin (TUB), histone-3 (HIS), and calmodulin (CAL) genes were analyzed to identify the isolates. A multi-locus phylogenetic analysis of the combined five gene regions led to the identification of two new species named Diaporthe atlantica and Diaporthe iberica. Diaporthe atlantica is the most abundant Diaporthe species in its host plant, and Diaporthe iberica was also isolated from Celtica gigantea, another grass species growing in semiarid inland habitats. An in vitro biochemical characterization showed that all cultures of D. atlantica produced indole-3-acetic acid and ammonium, and the strains of D. iberica produced indole 3-acetic acid, ammonium, siderophores, and cellulase. Diaporthe atlantica is closely related to D. sclerotioides, a pathogen of cucurbits, and caused a growth reduction when inoculated in cucumber, melon, and watermelon.

Partial Migration by Great Egrets Ardea alba in Coastal California

Migratory behavior of California Great Egrets (Ardea alba) is poorly understood. GPS tags were deployed on eleven Great Egrets on Tomales Bay, Marin County, California, USA. Six individuals displayed migratory behavior, four remained resident, and one individual employed both strategies across three winters. Both diurnal and nocturnal migratory movements were observed. Five of the Great Egrets flew through or wintered in the Sacramento-San Joaquin Delta and California's Central Valley, and one Great Egret moved through Nevada, Arizona, and Mexico, indicating use of wintering grounds outside of California. This study provides the first documentation of partial migration by Great Egrets, and the first information on round trip migration of this species on the U.S. west coast. Our results further illustrate the importance of connectivity between coastal and inland habitats for migratory birds.

Life on a beach leads to phenotypic divergence despite gene flow for an island lizard

Limited spatial separation within small islands suggests that observed population divergence may occur due to habitat differences without interruption to gene flow but strong evidence of this is scarce. The wall lizard Teira dugesii lives in starkly contrasting shingle beach and inland habitats on the island of Madeira. We used a matched pairs sampling design to examine morphological and genomic divergence between four beach and adjacent (<1 km) inland areas. Beach populations are significantly darker than corresponding inland populations. Geometric morphometric analyses reveal divergence in head morphology: beach lizards have generally wider snouts. Genotyping-by-sequencing allows the rejection of the hypothesis that beach populations form a distinct lineage. Bayesian analyses provide strong support for models that incorporate gene flow, relative to those that do not, replicated at all pairs of matched sites. Madeiran lizards show morphological divergence between habitats in the face of gene flow, revealing how divergence may originate within small islands.

Type of Anion Largely Determines Salinity Tolerance in Four Rumex Species.

The aim of the present study was to compare the effect of various salts composed of different cations (Na+, K+) and anions (chloride, nitrate, nitrite) on growth, development and ion accumulation in three Rumex species with accessions from sea coast habitats (Rumex hydrolapathum, Rumex longifolius and Rumex maritimus) and Rumex confertus from an inland habitat. Plants were cultivated in soil in an experimental automated greenhouse during the autumn-winter season. Nitrite salts strongly inhibited growth of all Rumex species, but R. maritimus was the least sensitive. Negative effects of chloride salts were rather little-pronounced, but nitrates resulted in significant growth stimulation, plant growth and development. Effects of Na+ and K+ at the morphological level were relatively similar, but treatment with K+ salts resulted in both higher tissue electrolyte levels and proportion of senescent leaves, especially for chloride salts. Increases in tissue water content in leaves were associated with anion type, and were most pronounced in nitrate-treated plants, resulting in dilution of electrolyte concentration. At the morphological level, salinity responses of R. confertus and R. hydrolapathum were similar, but at the developmental and physiological level, R. hydrolapathum and R. maritimus showed more similar salinity effects. In conclusion, the salinity tolerance of all coastal Rumex species was high, but the inland species R. confertus was the least tolerant to salinity. Similarity in effects between Na+ and K+ could be related to the fact that surplus Na+ and K+ has similar fate (including mechanisms of uptake, translocation and compartmentation) in relatively salt-tolerant species. However, differences between various anions are most likely related to differences in physiological functions and metabolic fate of particular ions.

Comparison of Pericarp Functional Traits in Capparis spinosa from Coastal and Inland Mediterranean Habitats.

The caper (Capparis spinosa L.) is a winter deciduous, perennial plant that grows and completes its life cycle entirely during the dry season in the Mediterranean region. Mature caper fruits and their pericarp, collected from the wild shrubs of the Capparis spinosa grown in the inland and coastal sites of Greece during summer, have been studied in order to improve and complete our knowledge of the successful establishment of the C. spinosa in Mediterranean ecosystems. Caper fruits possess substantial nutritional, medicinal and ecological properties that vary according to the developmental stage, agroclimatic and geographical parameters; however, the fruit pericarp and pedicel, unlike the other aboveground plant parts of the caper, have not hitherto been studied. The higher sugar and starch content in the pericarps and fruit pedicels harvested from wild caper plants grown in coastal habitats was investigated in comparison with those from inland habitats, while the higher proline and nitrogen content in pericarps and fruit pedicels harvested from wild caper plants grown in inland habitats was investigated in comparison with those from coastal habitats. The PCA, based on the considered functional traits underlying the constitutional aspects, reveals groupings of fruit pericarp specimens of the C. spinosa collected from coastal and inland habitats that are grounds for adaptive variation.

De novo transcriptome analysis of high-salinity stress-induced antioxidant activity and plant phytohormone alterations in Sesuvium portulacastrum.

Sesuvium portulacastrum has a strong salt tolerance and can grow in saline and alkaline coastal and inland habitats. This study investigated the physiological and molecular responses of S. portulacastrum to high salinity by analyzing the changes in plant phytohormones and antioxidant activity, including their differentially expressed genes (DEGs) under similar high-salinity conditions. High salinity significantly affected proline (Pro) and hydrogen peroxide (H2O2) in S. portulacastrum seedlings, increasing Pro and H2O2 contents by 290.56 and 83.36%, respectively, compared to the control. Antioxidant activities, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), significantly increased by 83.05, 205.14, and 751.87%, respectively, under high salinity. Meanwhile, abscisic acid (ABA) and gibberellic acid (GA3) contents showed the reverse trend of high salt treatment. De novo transcriptome analysis showed that 36,676 unigenes were matched, and 3,622 salt stress-induced DEGs were identified as being associated with the metabolic and biological regulation processes of antioxidant activity and plant phytohormones. POD and SOD were upregulated under high-salinity conditions. In addition, the transcription levels of genes involved in auxin (SAURs and GH3), ethylene (ERF1, ERF3, ERF114, and ABR1), ABA (PP2C), and GA3 (PIF3) transport or signaling were altered. This study identified key metabolic and biological processes and putative genes involved in the high salt tolerance of S. portulacastrum and it is of great significance for identifying new salt-tolerant genes to promote ecological restoration of the coastal strand.

Role of DNA methylation in ecophysiological responses to salinity in natural populations of Phragmites australis from coastal and inland habitats

There are different environmental pressures in coastal and inland wetlands resulting in phenotypic variation among plant populations, which might be related to epigenetic modifications. Phragmites australis is a widespread plant in coastal and inland wetlands, and the phenotype of the population is selected by salinity, but the reasons for the population differences in salt tolerance and phenotype are unclear. We investigated coastal and inland P. australis populations grown under two salinities and two manipulated DNA methylation levels in common gardens. The plants were sprayed with 5-azacytidine (DNA demethylation agent) regularly, and the physiological and morphological traits of reeds were measured. Plant height, density, and basal stem of reeds from different sources were significantly different and correlated with soil conductivity of sampling sites (P &amp;lt; 0.05). Salinity significantly decreased the biomass (37.04%, P &amp;lt; 0.05) and plant height (24.68%, P &amp;lt; 0.05) of inland reeds but had no significant effect on coastal populations (13.48%). P. australis responds to salt stress through phenotypic plasticity, and inland wetland populations exhibit local adaptation to freshwater. Increased salt tolerance in inland populations following DNA demethylation, particularly biomass, plant height, and basal stems (increased 23.62%; 13.08%; 5.35%, respectively), could provide more opportunities in adverse environments. This study will provide important insights into the highly adaptive mechanisms of the large non-model plant.

Artificial sandpit lake as a habitat of brackish diatom species

ABSTRACT During a survey of diatoms in the artificial sandpit lake “Peskara” in the protected zone of the Rusanda Nature Park, a large number of brackish taxa at epipsamic and epiphytic communities were recorded (e.g. Bacillaria paxillifera, Caloneis permagna, Ctenophora pulchella, Entomoneis costata. Haslea duerrenbergiana, Navicula salinarum, Nitzschia agnita, N. filiformis, Staurophora brantii, Seminavis strigosa, Tryblionella apiculata). One new genus Seminavis and 15 diatom species were noted for the first time for the diatom flora of Serbia. Dominant taxa changed over seasons without any regularity. In spring 2021, we have observed an increased abundance of centric species Thalassiosira pseudonana and Stephanodiscus parvus while in other seasons it was difficult to discern a pattern of dominance among benthic diatoms. Metabarcoding analysis of the same sample using 18S rRNA as a gene marker confirmed the dominance of centric diatoms. This study contributes to a better understanding of brackish diatom taxa found in inland habitats, many of which can be utilized as useful tools for the ecological status assessment.