Targeted grazing reduces a widespread wetland plant invader with minimal nutrient impacts, yet native community recovery is limited.

Targeted grazing to control undesirable plant species is increasingly of interest across a diversity of ecosystems, particularly as an alternative or complement to widely used herbicides. However, there are limited comprehensive evaluations of targeted grazing that evaluate both invasive species management effectiveness and potential negative effects on the ecosystem. Phragmites australis, a tall-statured, dense perennial invasive grass from Eurasia, is a pervasive problem in wetlands across the North American continent. As with many invasive species where management has historically relied on herbicides and resistance is a growing concern, land managers seek viable alternatives that have minimal negative ecosystem impacts. Grazing has been used for millennia to manage native Phragmites in Europe. Similarly, in its invasive range within North America, small-scale studies suggest Phragmites may be suppressed by grazers. Yet, the effectiveness of grazing at large scales and its effects on broader ecosystem properties remain largely unknown. We evaluated the influence of targeted grazing on vegetation, soil nutrients, and water nutrients over two years in large plots (∼300x the size of previous studies). We also tested the effects of mowing, a treatment that can be used to facilitate grazer access to large, dense Phragmites stands. In line with our predictions, we found that cattle grazing effectively suppressed invasive Phragmites over two years. Mowing reduced litter, and moderately reduced standing dead Phragmites, both of which suppress native plant germination in this system. However, these reductions in Phragmites were not accompanied by indications of native plant community recovery, as we had optimistically predicted. Despite the potential for grazing to reduce nutrient sequestration by plants and fertilize soils, we were surprised to find no clear negative effects of grazing on nutrient mobilization to groundwater or floodwater. Taken together, our findings indicate that targeted grazing, when implemented at broad scales over short time frames, is effective at achieving invasive plant management goals without sizable nutrient impacts. However, additional steps will be needed to achieve the restoration of diverse, robust native plant communities.

Re-watering solution facilitates seed germination and seedling growth of Carex schmidtii: Implication for species re-introduction in degraded semi-arid wetlands.

Water deficiency threatens the health and function of wetlands in semi-arid areas. Optimum re-watering is an effective method for close-to-natural restoration to mitigate wetland degradation. Although the ecological importance of optimal re-watering as a nature-based solution for promoting wetland plant growth has been widely recognized, the response mechanisms of seed germination and seedling growth to re-watering are still poorly understood despite their decisive impact on plant life history. To fill this gap, this study compared the characteristics of seed germination and seedling growth in Carex schmidtii under initial water content with three levels (30%, 50%, and 70%) and five re-watering treatments (maintained at constant water content and re-watering to 100% on 7th, 14th, 21st, and 28th day). Moreover, the degree of reserve mobilization during four germination stages (seed suckering, sprouting, 20% germination, and seedling growth) was investigated. The results showed that water deficiency and re-watering treatments significantly affected C. schmidtii seed germination, seedling growth, and reserve mobilization. Compared with the other treatments, 50% moisture content and re-watering to 100% on the 14th day (50%-RT3) treatment significantly improved germination traits (germination rate, daily germination rate, germination index, and vigor index) and seedling growth characteristics (shoot length, root length, shoot biomass, root biomass, and total biomass). Furthermore, the degree of mobilization of starch, soluble protein, fat, and soluble sugar accumulation in C. schmidtii seeds under 50%-RT3 was higher than that in the other treatments. The structural equation model showed that the characteristics of seed germination and seedling growth of C. schmidtii were directly related to water deficiency and re-watering treatments, whereas reserve mobilization indirectly affected seed germination and seedling growth. These findings demonstrated that water deficiency and re-watering treatments have a crucial regulatory effect on seed germination and seedling growth of wetland plant species through a dual mechanism. This study provides information for the formulation of an optimum re-watering strategy for wetland vegetation restoration in semi-arid areas of the world.

Use of recycled construction and demolition waste as substrate in constructed wetlands for the wastewater treatment of cheese production.

Recycled building debris has recently emerged as a suitable wetland infill substrate due to its low density, exceptional water absorption capabilities, and high porosity. This study investigated, for the first time, the use of construction demolition wastes (CDW), and rock processing residues (RPR) as substrate materials in vertical-horizontal flow hybrid constructed wetlands for the treatment of cheese production wastewater. Results showed that the use of both CDW as well as RPR, as substrate material, provided an equal or even better quality of treated wastewater compared to the conventional use of gravel as a substrate. High removal efficiencies were recorded for turbidity (CDW: 91-92%, RPR: 97%), solids (CDW: 85-88%, RPR: 96-97%), organic matter (CDW: 79-84%, RPR: 96-98%), and total phosphorus (CDW: 72-76%, RPR: 87%) for both examined recycled materials. During the experiment, different loadings rates (HLR) were tested: 25 mm d-1 and 37.5 mm d-1. Radiological measurements indicate that, their use did not cause toxic effects on the environment, as the amounts of radioactivity found in the effluent of the systems are not significant. Increasing the hydraulic loading rate appeared to have no negative effect on pollutant removal, as the systems and plants were fully acclimated and mature. This approach offers several advantages, including the use of readily available and abundant waste material, potential cost savings, and the environmental benefits of recycling CDW and RPR instead of disposing of them in landfills.

Large-scale geographic patterns and environmental and anthropogenic drivers of wetland plant diversity in the Qinghai-Tibet Plateau.

BACKGROUND: The geographic patterns of plant diversity in the Qinghai-Tibet Plateau (QTP) have been widely studied, but few studies have focused on wetland plants. This study quantified the geographic patterns of wetland plant diversity in the QTP through a comprehensive analysis of taxonomic, phylogenetic and functional indices. METHODS: Based on a large number of floras, monographs, specimens and field survey data, we constructed a comprehensive dataset of 1,958 wetland plant species in the QTP. Species richness (SR), phylogenetic diversity (PD), functional diversity (FD), net relatedness index (NRI) and net functional relatedness index (NFRI) were used to assess the taxonomic, phylogenetic and functional diversity of wetland plants. We explored the relationships between the diversity indices and four categories of environmental variables (i.e. energy-water, climate seasonality, topography and human activities). We used four diversity indices, namely endemic species richness, weighted endemism, phylogenetic endemism and functional endemism, together with the categorical analysis of neo- and paleo-endemism (CANAPE), to identify the endemic centers of wetland plants in the QTP. RESULTS: SR, PD and FD were highly consistent and showed a decreasing trend from southeast to northwest, decreasing with increasing elevation. The phylogenetic structure of wetland plant assemblages in most parts of the plateau is mainly clustered. The functional structure of wetland plant assemblages in the southeast of the plateau is overdispersed, while the functional structure of wetland plant assemblages in other areas is clustered. Energy-water and climate seasonality were the two most important categories of variables affecting wetland plant diversity. Environmental variables had a greater effect on the functional structure of wetland plants than on the phylogenetic structure. This study identified seven endemic centres, mainly in the Himalayas and Hengduan Mountains. CONCLUSIONS: Climate and topography are the main factors determining the geographic distribution of wetland plant diversity at large scales. The majority of grid cells in the QTP with significant phylogenetic endemism were mixed and super-endemism. At large scales, compared to climate and topography, human activities may not have a negative impact on wetland plant diversity in the QTP.

Isoptericola haloaureus sp. nov., a dimorphic actinobacterium isolated from mangrove sediments of southeast India, implicating biosaline agricultural significance through nitrogen fixation and salt tolerance genes.

Strain MP-1014T, an obligate halophilic actinobacterium, was isolated from the mangrove soil of Thandavarayancholanganpettai, Tamil Nadu, India. A polyphasic approach was utilized to explore its phylogenetic position completely. The isolate was Gram-positive, filamentous, non-motile, and coccoid in older cultures. Ideal growth conditions were seen at 30 °C and pH 7.0, with 5% NaCl (W/V), and the DNA G + C content was 73.3%. The phylogenic analysis of this strain based upon 16S rRNA gene sequence revealed 97-99.8% similarity to the recognized species of the genus Isoptericola. Strain MP-1014T exhibits the highest similarity to I. sediminis JC619T (99.7%), I. chiayiensis KCTC19740T (98.9%), and subsequently to I. halotolerans KCTC19646T (98.6%), when compared with other members within the Isoptericola genus (< 98%). ANI scores of strain MP-1014T are 86.4%, 84.2%, and 81.5% and dDDH values are 59.7%, 53.6%, and 34.8% with I. sediminis JC619T, I. chiayiensis KCTC19740T and I. halotolerans KCTC19646T respectively. The major polar lipids of the strain MP-1014T were phosphatidylinositol, phosphatidylglycerol, diphosphotidylglycerol, two unknown phospholipids, and glycolipids. The predominant respiratory menaquinones were MK9 (H4) and MK9 (H2). The major fatty acids were anteiso-C15:0, anteiso-C17:0, iso-C14:0, C15:0, and C16:0. Also, initial genome analysis of the organism suggests it as a biostimulant for enhancing agriculture in saline environments. Based on phenotypic and genetic distinctiveness, the strain MP-1014 T represents the novel species of the genus Isoptericola assigned Isoptericola haloaureus sp. nov., is addressed by the strain MP-1014 T, given its phenotypic, phylogenetic, and hereditary uniqueness. The type strain is MP-1014T [(NCBI = OP672482.1 = GCA_036689775.1) ATCC = BAA 2646T; DSMZ = 29325T; MTCC = 13246T].

Changes in above- versus belowground biomass distribution in permafrost regions in response to climate warming.

Permafrost regions contain approximately half of the carbon stored in land ecosystems and have warmed at least twice as much as any other biome. This warming has influenced vegetation activity, leading to changes in plant composition, physiology, and biomass storage in aboveground and belowground components, ultimately impacting ecosystem carbon balance. Yet, little is known about the causes and magnitude of long-term changes in the above- to belowground biomass ratio of plants (η). Here, we analyzed η values using 3,013 plots and 26,337 species-specific measurements across eight sites on the Tibetan Plateau from 1995 to 2021. Our analysis revealed distinct temporal trends in η for three vegetation types: a 17% increase in alpine wetlands, and a decrease of 26% and 48% in alpine meadows and alpine steppes, respectively. These trends were primarily driven by temperature-induced growth preferences rather than shifts in plant species composition. Our findings indicate that in wetter ecosystems, climate warming promotes aboveground plant growth, while in drier ecosystems, such as alpine meadows and alpine steppes, plants allocate more biomass belowground. Furthermore, we observed a threefold strengthening of the warming effect on η over the past 27 y. Soil moisture was found to modulate the sensitivity of η to soil temperature in alpine meadows and alpine steppes, but not in alpine wetlands. Our results contribute to a better understanding of the processes driving the response of biomass distribution to climate warming, which is crucial for predicting the future carbon trajectory of permafrost ecosystems and climate feedback.

[Soil microorganisms and physicochemical properties in marshlands along the Yangtze River basin at different types of land use and their effects on distribution of Oncomelania hupensis snails].

OBJECTIVE: To investigating the microbial communities and physicochemical properties of soil and distribution of Oncomelania hupensis snails in marshlands along the Yangtze River basin at different types of land use, and to examine the effects of soil microorganisms and physicochemical properties on snail distribution, so as to provide insights into snail control and schistosomiasis prevention in marshland along the Yangtze River basin. METHODS: Marshlands with four types of land use were selected along the Yangtze River basin on April 2021, including poplar forest-crops integrated planting, reed areas, agricultural cultivation lands and ditches. The distribution of snails and physicochemical properties of soil were investigated in marshlands with different types of land use, and the V3 to V4 regions of the bacterial 16S ribosomal RNA (16S rRNA) gene, fungal internal transcribed spacer-1 (ITS1) gene and algal ribulose-bisphosphate carboxylase (rbcL) gene in soils were subjected to high-throughput sequencing. The occurrence of frames with living snails and density of living snails were compared in marshland with different types of land use. The associations of soil microorganisms and physicochemical properties with the density of living snails were examined using Pearson correlation analysis, and the contributions of soil microorganisms and physicochemical properties to the density of living snails were evaluated using variance partitioning analysis. RESULTS: In marshlands with four types of land use, the greatest occurrence of frames with living snails [(4.94 ± 2.14)%] and density of living snails [(0.070 ± 0.026) snails/0.1 m2] were seen in ditches, and the lowest were found in [(1.23 ± 1.23)%] agricultural cultivation lands [(0.016 ± 0.019) snails/0.1 m2]. A total of 2 phyla, 5 classes, 8 orders, 9 families and 11 genera of algae were detected in soils at four types of land use, with Chlorophyta as the dominant phylum and Pseudoneochloris as the dominant genus. A total of 44 phyla, 134 classes, 281 orders, 338 families and 516 genera of bacteria were detected in soils at four types of land use, with Proteobacteria and Acidobacteriota as the dominant phyla and uncultured Acidobacterium, MND1, Mitrospira, Haliangium and Sphingomonas as dominant genera. A total of 11 phyla, 41 classes, 108 orders, 223 families and 408 genera of fungi were detected in soils at four types of land use, with phyla Ascomycota, Basidiomycota and Mortierellomycota presenting high relative abundances and genera Cladorrhinum, Mortierella and Humicola presenting high relative abundances. Pearson correlation analysis revealed that the density of living snails correlated negatively with the relative abundance of Proteobacteria (r = -0.965, P < 0.05) and soil electronic conductivity (r = -0.962, P < 0.05) and positively with soil moisture (r = 0.951, P < 0.05). Variance partitioning analysis demonstrated that the physicochemical properties and microorganisms of soil contributed 69% and 10% to the density of living snails, respectively. CONCLUSIONS: The diversity of microbial communities varies in soils at different types of land use in marshland along the Yangtze River basin, and the physicochemical properties and microorganisms of soils may affect the distribution of O. hupensis snails.

Spatio-temporal variation in water quality due to the anthropogenic impact in Rudrasagar Lake, a Ramsar site in India.

Rudrasagar Lake, a vital habitat for diverse flora and fauna, supports over 2000 households to sustain their daily livelihoods. The current study attempts to examine the impact of human activities on spatio-temporal variation in the water quality of the study area. The study integrates extensive field surveys, sample processing, and statistical analysis to assess the recent status of wetland health. Latin Square Matrix (LSM) was employed to select the sampling sites while the Inverse Distance Weighting (IDW) interpolation technique was used for spatial variation mapping. Modified Weighted Arithmetic Water Quality Index (MWAWQI) and Comprehensive Pollution Index (CPI) were utilized for assessing seasonal variation water quality and pollution loads, respectively. The results showed that dissolved oxygen (DO) was strongly influenced by the tributaries, and recreational activities have substantially influenced the highest concentrations of biochemical oxygen demand (BOD), and total suspended solids (TSS). The central portion of the lake is particularly susceptible to pollution from extensive fishing and recreational activities while peripheral sites are strongly influenced by agricultural run-offs, seepages from brick industries, and municipal wastes characterized by high concentrations of pH, total hardness (TH), oxidation-reduction potential (ORP). The findings reveal remarkable spatio-temporal fluctuations and highlight the areas within the lake susceptible to anthropogenic activities. The study proposed a sustainable management model to ameliorate anthropogenic threats. Moreover, the study contributes to the scientific understanding of the challenges and ensures the long-term viability of wetland health as a vital ecological and socio-economic resource.

Mangrovimonas cancribranchiae sp. nov., a novel bacterial species associated with the gills of the fiddler crab Cranuca inversa (Brachyura, Ocypodidae) from Red Sea mangroves.

Two bacteria, UG2_1T and UG2_2, were isolated from the gill tissues of the mangrove fiddler crab Cranuca inversa collected on the east coast of the Red Sea (Thuwal, Saudi Arabia). The cells are Gram-negative, rod-shaped, orange-pigmented, motile by gliding with no flagella, strictly aerobic, and grow at 20-37 °C (optimum, 28-35 °C), at pH 5.0-9.0 (optimum, pH 6.0-7.0), and with 1-11 % (w/v) NaCl (optimum, 2-4 %). They were positive for oxidase and catalase activity. Phylogenetic analysis based on 16S rRNA gene sequences indicated that isolates UG2_1T and UG2_2 belong to the genus Mangrovimonas, showing the highest similarity to Mangrovimonas spongiae HN-E26T (99.4 %). Phylogenomic analysis based on the whole genomes, independently using 49 and 120 concatenated genes, showed that strains UG2_1T and UG2_2 formed a monophyletic lineage in a different cluster from other type strain species within the genus Mangrovimonas. The genome sizes were 3.08 and 3.07 Mbp for UG2_1T and UG2_2, respectively, with a G+C content of 33.8 mol% for both strains. Values of average nucleotide identity and digital DNA-DNA hybridization between the strains and closely related species were 91.0 and 43.5 %, respectively. Chemotaxonomic analysis indicated that both strains had iso-C15 : 0 and iso-C15 : 1 G as dominant fatty acids, and the primary respiratory quinone was identified as MK-6. The major polar lipids comprised phosphatidylethanolamine, one unidentified glycolipid, one unidentified phospholipid, two unidentified aminolipids, and four unidentified lipids. Based on phylogenetic, phylogenomic, genome relatedness, phenotypic, and chemotaxonomical data, the two isolates represent a novel species within the genus Mangrovimonas, with the proposed name Mangrovimonas cancribranchiae sp. nov., and the type strain UG2_1T (=KCTC 102158T=DSM 117025T).

Ecological restoration at pilot-scale employing site-specific rationales for small-patch degraded mangroves in Indian Sundarbans.

To date, degraded mangrove ecosystem restoration accomplished worldwide primarily aligns towards rehabilitation with monotypic plantations, while ecological restoration principles are rarely followed in these interventions. However, researchers admit that most of these initiatives' success rate is not appreciable often. An integrative framework of ecological restoration for degraded mangroves where site-specific observations could be scientifically rationalized, with co-located reference pristine mangroves as the target ecosystem to achieve is currently distinctively lacking. Through this experimental scale study, we studied the suitability of site-specific strategies to ecologically restore degraded mangrove patches vis-à-vis the conventional mono-species plantations in a highly vulnerable mangrove ecosystem in Indian Sundarbans. This comprehensive restoration framework was trialed in small discrete degraded mangrove patches spanning ~ 65 ha. Site-specific key restoration components applied are statistically validated through RDA analyses and Bayesian t-tests. 25 quantifiable metrics evaluate the restoration success of a ~ 3 ha degraded mangrove patch with Ridgeline distribution, Kolmogorov-Smirnov (K-S) tests, and Mahalanobis Distance (D2) measure to prove the site's near-equivalence to pristine reference in multiple ecosystem attributes. This restoration intervention irrevocably establishes the greater potential of this framework in the recovery of ecosystem functions and self-sustenance compared to that of predominant monoculture practices for vulnerable mangroves.

Biomass recovery of coastal young mangrove plantations in Central Thailand.

Around one-third of the world's most carbon-rich ecosystems, mangrove forests, have already been destroyed in Thailand owing to coastal development and aquaculture. Improving these degraded areas through mangrove plantations can restore various coastal ecosystem services, including CO2 absorption and protection against wave action. This study examines the biomass of three coastal mangrove plantations (Avicennia alba) of different ages in Samut Prakarn province, Central Thailand. Our aim was to understand the forest biomass recovery during the early stages of development, particularly fine root biomass expansion. In the chronosequence of the mangrove plantations, woody biomass increased by 40% over four years from 79.7 ± 11.2 Mg C ha-1 to 111.7 ± 12.3 Mg C ha-1. Fine root biomass up to a depth of 100 cm was 4.47 ± 0.33 Mg C ha-1, 4.24 ± 0.63 Mg C ha-1, and 6.92 ± 0.32 Mg C ha-1 at 10, 12, and 14 year-old sites, respectively. Remarkably, the fine root biomass of 14-year-old site was significantly higher than those of the younger sites due to increase of the biomass at 15-30 cm and 30-50 cm depths. Our findings reveal that the biomass recovery in developing mangrove plantations exhibit rapid expansion of fine roots in deeper soil layers.

Augmentation of saline wastewater treatment via functional enrichment of bacteria and optimized distribution in constructed wetlands combined with slag-sponges at different temperatures.

China's aquatic environment continues to face several difficulties. Ecological constructed wetland systems (CWs) can be used to treat polluted saline water to alleviate water shortages regionally and globally. However, the performance is limited by low temperatures. To expand the use of CWs, we introduced a slag-sponge, a flaky material derived from alkaline waste slag, to create a newly constructed wetland system that can operate at both low and high temperatures. We evaluated its effectiveness by placing it at different heights in our devices. The results showed that the treatment was effective for saline wastewater with multiple contaminants. The efficiency was 20% higher than that of traditional CWs. Slag-sponges were found to carry pore structures and exhibit thermal insulation, which led to the enrichment of functional microbial communities (Chryseobacterium and Exiguerium) at low temperatures according to the microbial species analysis. The enhanced CWs offer another option for the treatment of polluted saline water in the environment and provide promising strategies for the utilization of waste slag.

Hydrological variability of middle European peatland during the Holocene, inferred from subfossil bog pine and bog oak dendrochronology and high-resolution peat multiproxy analysis of the Budwity peatland (northern Poland).

Subfossil pine and oak tree trunks were excavated during exploitation of the Budwity peatland in Northern Poland. Based on dendrochronological analysis, the woodland successions in peatland were reconstructed and correlated with moisture dynamics of the peatland ecosystem inferred from the high-resolution multi-proxy analysis of the peatland deposits. From the results of dendrochronological analysis and the 14C wiggle matching methods, four floating pine chronologies (5882-5595; 5250-5089; 3702-3546; and 2222-1979 mod. cal BP) and two oak chronologies (4932-4599 and 4042-3726 mod. cal BP) were developed. The organic sediments of the peatland (6 m thick) were deposited over approximately nine thousand years. The lower complex (525-315 cm) comprises minerogenic peat, while the upper complex (315.0-0.0 cm) is composed of ombrogenic peat. Subfossil tree trunks are distributed across various peat horizons, which suggests multiple stages of tree colonisation followed by subsequent dying-off phases. Multiproxy sediment analyses (lithological, geochemical and δ13C stable isotope, pollen, plant macrofossils, Cladocera, diatom, and Diptera analyses) indicate that the two earliest phases of pine colonisation (5882-5595 and 5250-5089 mod. cal BP) and the two stages of oak colonisation (4932-4599 and 4042-3726 mod. cal BP) were associated with periodic drying of the peatland. Conversely, tree dying-off phases occurred during periods of increased water levels in the peatland, coinciding with stages of increasing climate humidity during the Holocene. The two most recent phases of pine colonisation occurred during the ombrogenic stage of mire development. Remnants of the dead forest from these phases, marked by subfossil trunks still rooted in the ground, were preserved and exposed presently during peat exploitation, approximately 2.5 m below ground level. The identified phases of tree colonisation and subsequent dying-off phases show correlation with analogical phenomena observed in the other investigated European peatlands.

Assessment of parent and alkyl -PAHs in surface sediments of Iranian mangroves on the northern coast of the Persian Gulf: Spatial accumulation distribution, influence factors, and ecotoxicological risks.

Spatial patterns, potential origins, and ecotoxicological risk of alkylated (APAH) -and parent -(PPAH) polycyclic aromatic hydrocarbons (PAHs) were studied in mangrove surface sediments along the northern coasts of the Persian Gulf, Iran. The mean total concentrations (ngg-1dw) ∑32PAH, ∑PPAHs and ∑APAHs in sediments were 3482 (1689-61228), 2642 (1109-4849), and 840 (478-1273), respectively. The spatial variability was similar among these PAH groups, with the highest levels occurring in Nayband National Marine Park (NNMP). Physicochemical environmental factors, such as sediment grain size, and total organic carbon (TOC) contents, are significant factors of PAH distribution. These findings suggest that PAH pollution level is moderate-to-high, supporting the current view that mangrove ecosystems are under intensive anthropogenic impacts, such as petrochemical, oil and gas loads, port activities, and urbanization. Non-parametric multidimensional scaling (NPMDS) ordination demonstrated that NNMP mangrove is the critical site exhibiting high loading of PAH pollutants. Here, for the first time in this region, Soil quality guidelines (SQGs), Toxic equivalency quotient (TEQ), Mutagenic equivalency quotient (MEQ), and composition indices comprising Mean maximum permissible concentration quotient (m-MPC-Q), and Mean effect range median quotient (m-ERM-Q) methods were used to have a comprehensive risk assessment for PAH compounds and confirmed medium-to-high ecological risks of PAHs in the study area, particularly in the western part of the Gulf, highlighting the industrial impacts on the environment.

Salt pollution reduces turbidity, dissolved organic matter, and cyanobacteria in experimental vernal pool communities.

Anthropogenic activities such as the over-application of road deicers are causing an increase in the concentration of salts in historically fresh waters. Experimental and field investigations demonstrate that freshwater salinization disrupts ecosystem functions and services, causing the death of freshwater organisms and changes to nutrient conditions. Wetland habitats are one system negatively affected by salt pollution, including ephemeral wetlands (vernal pools) that fill with salt-polluted water after snowmelt. In urbanized areas, the degradation of these ecosystems could result in irreversible ecological damage including reduced water quality and a reduction in biodiversity. To investigate the effects of freshwater salinization on vernal pool communities, we exposed soils from vernal pools to water containing no salt (control), or four concentrations of three salts standardized by chloride concentration (50 mg Cl- L-1, 100 mg Cl- L-1, 200 mg Cl- L-1, and 400 mg Cl- L-1; magnesium chloride, calcium chloride, and sodium chloride). The results of this experiment suggest that emerging zooplankton communities in vernal pools are sensitive to low concentrations of salt pollution, and that alternative salts such as magnesium chloride and calcium chloride are more toxic than sodium chloride. We did not find positive or negative changes in the abundance of eukaryotic phytoplankton but did find negative effects of salt on cyanobacteria abundance, possibly due to corresponding reductions in turbidity which might be needed as a fixation site for cyanobacteria to form heterocysts. Finally, we found that salt pollution likely caused flocculation of Dissolved Organic Matter (DOM), resulting in reduced concentrations of DOM which could alter the buffering capacity of freshwater systems, light attenuation, and the populations of planktonic heterotrophs.

The inputs of autochthonous organic carbon driven by mangroves reduce metal mobility and bioavailability in intertidal regions.

The significance of mangroves in carbon storage is widely acknowledged. However, the potential role of carbon enhancement driven by mangroves in mitigating the risk of metal exposure remains unclear. In this study, a natural mangrove reserve located in Futian was selected to investigate the potential role of autochthonous organic carbon on metal bioavailability. The presence of mangroves seemed to have little effect on the accumulations of Cu(II), Zn(II), Cr(VI/III), Pb(II), and Ni(II) in surface sediments. Metal mobility and bioavailability, however, were found to be directly influenced by the presence of mangroves. Compared with mudflat, mangrove sediments exhibited an obvious in the bioavailability of Cu(II), Zn(II), Cr(VI/III), Pb(II), and Ni(II) by 19-79 %, with the highest reduction occurring in the interior of mangroves dominated by K. obovata. Mangroves also significantly enhanced the accumulation of organic carbon in sediments, regardless of carbon components. Moreover, the results from random forest analysis further showed that autochthonous organic carbon was the most important carbon component that negatively related to metal bioavailability. In summary, this is the first study to provide a linkage between mangrove cover and increased autochthonous organic carbon input, which decreases metal bioavailability. The present data also suggest that mangroves are an efficient natural barrier to alleviate the risk of metal exposure in intertidal regions.

Permanent areas and changes in forests, grasslands, and wetlands in the North European Plain since the eighteenth century-a case study of the Koscian Plain in Poland.

This study investigates the intricate and enduring interplay of historical events, human activities, and natural processes shaping the landscape of North European Plain in western Poland over 230 years. Topographic maps serve as reliable historical data sources to quantify changes in forest, grassland, and wetland areas, scrutinizing their fragmentation and persistence. The primary objectives are to identify the permanent areas of the landscape and propose a universal cartographic visualization method for effectively mapping these changes. Using topographic maps and historical data, this research quantifies land cover changes, especially in forest, grassland, and wetland areas. With the help of retrogressive method we process raster historical data into vector-based information. Over time, wetlands experienced a substantial reduction, particularly in 1960-1982, attributed to both land reclamation and environmental factors. Grassland areas fluctuated, influenced by wetland and drier habitat dynamics. Fragmentation in grassland areas poses biodiversity and ecosystem health concerns, whereas forested areas showed limited fluctuations, with wetland forests nearly disappearing. These findings highlight wetland ecosystems' sensitivity to human impacts and emphasize the need to balance conservation and sustainable development to preserve ecological integrity. This study advances landscape dynamics understanding, providing insights into historical, demographic, economic, and environmental transformations. It underscores the imperative for sustainable land management and conservation efforts to mitigate human impacts on ecosystems and biodiversity in the North European Plain.

Benefits of tropical peatland rewetting for subsidence reduction and forest regrowth: results from a large-scale restoration trial.

Drainage and deforestation of tropical peat swamp forests (PSF) in Southeast Asia cause carbon emissions and biodiversity loss of global concern. Restoration efforts to mitigate these impacts usually involve peatland rewetting by blocking canals. However, there have been no studies to date of the optimal rewetting approach that will reduce carbon emission whilst also promoting PSF regeneration. Here we present results of a large-scale restoration trial in Sumatra (Indonesia), monitored for 7.5 years. Water levels in a former plantation were raised over an area of 4800 ha by constructing 257 compacted peat dams in canals. We find peat surface subsidence rates in the rewetted restoration area and adjoining PSF to be halved where water tables were raised from ~ - 0.6 m to ~ - 0.3 m, demonstrating the success of rewetting in reducing carbon emission. A total of 57 native PSF tree species were found to spontaneously grow in the most rewetted conditions and in high densities, indicating that forest regrowth is underway. Based on our findings we propose that an effective PSF restoration strategy should follow stepwise rewetting to achieve substantial carbon emission reduction alongside unassisted regrowth of PSF, thereby enabling the peat, forest and canal vegetation to establish a new nature-based ecosystem balance.

Unveiling the landscape predictors of resilient vegetation in coastal wetlands to inform conservation in the face of climate extremes.

Unveiling spatial variation in vegetation resilience to climate extremes can inform effective conservation planning under climate change. Although many conservation efforts are implemented on landscape scales, they often remain blind to landscape variation in vegetation resilience. We explored the distribution of drought-resilient vegetation (i.e., vegetation that could withstand and quickly recover from drought) and its predictors across a heterogeneous coastal landscape under long-term wetland conversion, through a series of high-resolution satellite image interpretations, spatial analyses, and nonlinear modelling. We found that vegetation varied greatly in drought resilience across the coastal wetland landscape and that drought-resilient vegetation could be predicted with distances to coastline and tidal channel. Specifically, drought-resilient vegetation exhibited a nearly bimodal distribution and had a seaward optimum at ~2 km from coastline (corresponding to an inundation frequency of ~30%), a pattern particularly pronounced in areas further away from tidal channels. Furthermore, we found that areas with drought-resilient vegetation were more likely to be eliminated by wetland conversion. Even in protected areas where wetland conversion was slowed, drought-resilient vegetation was increasingly lost to wetland conversion at its landward optimum in combination with rapid plant invasions at its seaward optimum. Our study highlights that the distribution of drought-resilient vegetation can be predicted using landscape features but without incorporating this predictive understanding, conservation efforts may risk failing in the face of climate extremes.

Research on the connectivity of urban river network-wetland and water quality simulation.

The connectivity of urban river networks plays an important role in cities in many aspects, such as urban water safety, water quality (WQ), and aquatic ecological balance. This study focuses on the river network and the Majiawan Wetland in the Chaoyang District of Beijing by establishing a two-dimensional hydrological WQ model employing various water allocation schemes between the river network and the wetland. Water circulation and WQ are the main indexes, and the effects of different scenarios on improving water circulation and WQ are simulated and compared. This study demonstrates that the addition of water replenishment at the intersection of river network and internal slow-water zones of the wetland (Scheme 2) has greater effectiveness in improving both hydrology and WQ compared to two other schemes. The water area of the Majiawan Wetland has expanded, and water velocity has increased. Using chemical oxygen demand, total nitrogen, and total phosphorus as the index values for determining the water class, the WQ of about 20% of the wetland area was reached Water Class II (domestic drinking water), with Water Class III (general industrial water) accounting for the other 80%. This study provides valuable evaluation and reference for similar areas of urban river network connectivity.