Query: Suaeda heteroptera  Phragmites australis reed Suaeda salsa

title: Dynamic Response to Climate Change by Phragmites australis and Suaeda salsa in Liaohe Delta Wetland
abstract: Because of its unique geographical location and its ecological function, the Liaohe Delta wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating change in the wetland are therefore of great importance. We used medium and high resolution satellite data, meteorological station data and site measurement data to analyze changes in the area and spatial distribution of Phragmites australis and Suaeda salsa in the Liaohe Delta wetland from 1998 to 2017, as well as their growth response to climate change. The results showed that during the period 1998 2017, the area of both P. australis and S. salsa wetlands alternated through periods of decreasing, then increasing and then decreasing trends. The annual change in area and spatial distribution range of S. salsa fluctuated more than that of P. australis. The annual variation of normalized difference vegetation index (NDVI) in P. australis wetland showed an upward trend from 1998 to 2017. The area of P. australis cover that was improved, unchanged or decreased accounted for 81.8% 12.3% and 5.9% respectively, of the total area. Evaporation and wind speed were the main meteorological factors affecting NDVI. The contribution rates of climate change and human activities to NDVI were 73.2% and 26.8% respectively. The area where vegetation cover was mainly S. salsa and that was improved, unchanged or decreased accounted for 63.3% 18.3% and 18.4% respectively, of the total area. No meteorological factors significantly affected NDVI in the region. The interaction between vegetation growth and meteorological factors may help to explain the increasing trend in vegetation cover. The improvement in wetland vegetation also led to carbon sequestration and an increase in sequestration capacity.

title: Phragmites australis meets Suaeda salsa on the "red beach" Effects of an ecosystem engineer on salt marsh litter decomposition.
abstract: Suaeda salsa is a pioneer species in coastal wetlands of East Asia and recently an ecosystem engineer species, Phragmites australis, has started to enter into S. salsa communities owing to either autogenic or external drivers. The consequences of this phenomenon on the ecosystem functions of coastal wetlands are still unclear, especially for decomposition processes. Here we compared the decomposition rate of S. salsa litter, and associated litter chemistry dynamics, between sites with and without P. australis encroachment. We conducted a litter transplantation experiment to tease apart the effects of litter quality and decomposing environment or decomposer community composition. Our results showed that P. australis encroachment led to higher carbon and phosphorus losses of S. salsa litter, but equal losses of total mass, lignin, hemicellulose and nitrogen. Phragmites australis encroachment might affect decomposition rate indirectly by making S. salsa produce litter with higher lignin concentrations or via increasing the fungal diversity for decomposition. Moreover, P. australis as an ecosystem engineer might also alter the allocation of total phosphorus between the plants and the soils in coastal wetlands. Our findings indicate that P. australis could impact aboveground and belowground carbon and nutrient dynamics in coastal wetlands, and highlight the important consequences that encroaching plant species, especially ecosystem engineers, can have on ecosystem functions and services of coastal wetlands, not only in East Asia but probably also elsewhere in the world.

title: Dynamic Response of Phragmites australis and Suaeda salsa to Climate Change in the Liaohe Delta Wetland
abstract: Because of its unique geographical location and ecological function, the Liaohe Delta Wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating changes in the wetland are therefore of great importance. We used medium and high resolution satellite data, meteorological station data, and site measurement data to analyze changes in the area and spatial distribution of Phragmites australis and Suaeda salsa in the Liaohe Delta Wetland from 1998 to 2017, as well as their growth response to the climate change. The results showed that during 1998 2017, the areas of both P. australis and S. salsa wetlands alternated through periods of decreasing, increasing, and then decreasing trends. The annual change in the area and spatial distribution range of S. salsa fluctuated more than that of P. australis. The annual variation of normalized difference vegetation index (NDVI) in P. australis wetland showed an upward trend from 1998 to 2017. The area of P. australis cover that was improved, unchanged, and decreased accounted for 81.8% 12.3% and 5.9% respectively, of the total area; evaporation and wind speed were the main meteorological factors affecting the NDVI; and contribution rates of the climate change and human activities to the NDVI were 73.2% and 26.8% respectively. The area with vegetation cover being mainly S. salsa that was improved, unchanged, and decreased accounted for 63.3% 18.3% and 18.4% respectively, of the total area; and no meteorological factors significantly affected the NDVI of S. salsa in the region. The interaction between vegetation growth and meteorological factors may help to explain the increasing trend in vegetation cover. The improvement in wetland vegetation also led to carbon sequestration and an increase in sequestration capacity.

title: Heavy metal contents and transfer capacities of Phragmites australis and Suaeda salsa in the Yellow River Delta, China
abstract: Plant samples including roots, stems and leaves of Phragmites australis and Suaeda salsa were collected in the short term flooding and tidal flooding wetlands of the Yellow River Delta of China. Six heavy metals (e.g. As, Cd, Cr, Cu, Pb, and Zn) were measured in roots, stems and leaves of each plant species using inductively coupled plasma atomic absorption spectrometry (ICP AAS) to investigate the levels, and transfer capabilities of heavy metals in these two plant species. Our results showed that in the tidal flooding wetlands, the contents of As, Cr and Cd in roots of Phragmites australis and Suaeda salsa were higher than those in their stems and leaves. Suaeda salsa showed higher contents of Pb and Zn in leaves than those in roots and stems, whereas lower levels of Pb and Zn were observed in Phragmites australis In the short term flooding wetlands, heavy metal contents exhibited a big difference between different tissues of Phragmites australis and Suaeda salsa and both plant species showed higher levels of Pb and Zn in leaves. Suaeda salsa roots enriched more As and Cd, whereas higher enrichment levels were observed in Phragmites australis leaves, which indicated different transfer capacities of these two wetland plants. The transfer factors for stems and leaves of Phragmites australis in the tidal flooding wetlands significantly differed from those in the short term flooding wetlands, however, no significant differences in transfer factors for stems and leaves of Suaeda salsa were observed between these two types of wetlands.

title: Changes of Biogenic Elements in Phragmites australis and Suaeda salsa from Salt Marshes in Yellow River Delta, China
abstract: Little information is available on biogenic elements (carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nitrogen, phosphorus and sulfur of plants, and their ecological stoichiometric characteristics in the Yellow (Huanghe) River Delta, plant samples were collected from two typical salt marshes (Suaeda salsa and Phragmites australis wetlands) during the period of from August to October in 2007, and the ratios of C/N, C/P, N/P, C/N/P and C/N/P/S were calculated. Results showed that during the studying period, plant C, N and P were lower than the global average values, and plant N and P were lower than the China's average values. Leaf C and S in Suaeda salsa were significantly lower than those in Phragmites australis (P 0.05) and leaf N and P in Suaeda salsa and Phragmites australis showed no significant differences (P 0.05) Average C/N ratios were 23.75 in leaf, 73.36 in stem, 65.67 in root of Suaeda salsa, and 33.77 in leaf, 121.68 in stem, 97.13 in root of Phragmites australis. Average C/N ratios of Suaeda salsa and Phragmites australis were all great than 25, indicating the salt marsh in the Yellow River Delta is an N limitation system. Average C/P ratios were 276.78 in leaf, 709.28 in stem and 1031.32 in root of Suaeda salsa, and 536.94 in leaf, 768.13 in stem and 875.22 in root of Phragmites australis. The average N/P ratios of Suaeda salsa were 12.92 in leaf, 10.77 in stem and 10.91 in root, and the average N/P ratios of Phragmites australis were 16.40 in leaf, 7.40 in stem and 6.92 in root, indicating the Suaeda salsa wetlands were N limited and Phragmites australis wetlands were N limited in August and P limited in October in 2007. The average C/N, C/P and C/N/P ratios in Suaeda salsa and Pragmites australis were higher than the global average values, indicating the lower quality of organic matter provided by wetland plants in the Yellow River delta.

title: Belowground responses of Phragmites australis and Suaeda salsa to salinity and water depth changes.

title: Release and Microbial Degradation of Dissolved Organic Carbon and Nitrogen from Phragmites australis and Suaeda salsa in the Wetland of the Yellow River Estuary
abstract: Release of dissolved organic matter (DOM) and chromophoric dissolved organic matter (CDOM) from two dominant plants Phragmites australis and Suaeda salsa in the Yellow River Estuarine wetlands was studied in laboratory incubation experiments. The release dynamic of dissolved organic carbon (DOC) dissolved nitrogen (DN) and CDOM from the plants was rapid process and hydrolysis played an important role in the initial leaching stage of the organic compounds from the plants. Bacterial activities enhanced the release processes of DOM during degradation of the plants and utilization of the released organic compounds. The fluorescence characteristics of the CDOM indicate that the proteinlike organic substances are the major components released from P. australis and S. salsa in the initial stage and these compounds are labile and highly biodegradable. Our study suggests that leaching of DOM from P. australis and S. salsa provide not only major sources of DOC, DN, and CDOM that affect many biogeochemical processes, but also as important food sources supporting microbial communities in the Yellow River wetlands and adjacent coastal waters.

title: Potential effects of tidal flat variations on decomposition and nutrient dynamics of Phragmites australis, Suaeda salsa and Suaeda glauca litter in newly created marshes of the Yellow River estuary, China
abstract: Salinity gradient and tidal flooding are two key factors in the newly created marshes of the Yellow River estuary as they are closely correlated with the accretion or erosion of tidal flat. To investigate the potential effects of tidal flat variations on decomposition and nutrient dynamics of Phragmites australis Suaeda salsa and Suaeda glauca litters in the Yellow River estuary, the natural salinity and flooding gradients in the newly created tidal flat [high marsh (river bank) middle marsh and low marsh] were applied to simulate the variations of salinity and tidal flooding in the three typical halophyte communities. Results showed that the mass losses and decomposition rates of the three halophyte litters differed significantly along salinity and flooding gradients p p P australis S glauca S salsa while in low salinity and moisture, the order demonstrated S glauca S salsa P australis The C and N concentrations in the three halophytes along salinity and flooding gradients showed different variations, and, with the increasing of salinity and moisture, there was a tendency that the N in P australis and S salsa shifted from accumulation to release while those in S glauca demonstrated strong release at all times. This study also indicated that salinity, tidal inundation and C/N ratios were three important factors affecting the differences in decomposition rates and C and N release patterns of the three halophytes. If the salinity and flooding frequency in P australis and S salsa communities were greatly increased, the decomposition rates would increase by 61.88 205.48% and 103.93% and the C release after 571 days would increase by 40.23 83.49% and 30.12% respectively; if the salinity and flooding frequency in S glauca community were significantly decreased, the decomposition rates would decrease by 42.79 44.78% and the C release would decrease by 23.78 27.93% Differently, if the salinity and flooding frequency in S glauca community were greatly decreased, the N release would at least decrease by 67.46% if the salinity and flooding frequency in P australis and S salsa communities were significantly increased, the N release only would occur in high salinity and flooding frequency. In recent years, the coastal marsh in the Yellow River estuary has shifted from erosion to accretion with the long term implementation of "Flow sediment Regulation Project" and our results provided valuable information for predicting the possible influences of tidal flat variations on decomposition and nutrient dynamics of the three halophytes in future.

title: Simulative Study on Effects of Petroleum Contamination on Seedling Growth of Phragmites australis and Suaeda salsa in Coastal Wetland of Yellow River Delta
abstract: The Yellow River Delta is a typical and representative coastal wetland in China.As the Shengli Oil Field,which is the second largest oil field in China,locates in the region,the crude oil contamination has become a key reason which causes deterioration of coastal wetland ecological system in this area.A simulative study was conducted to explain the effects of different concentration of petroleum(0.5% 2.0% contaminated wetland soils on growth of reed(Phragmites australis)and seepweed(Suaeda salsa) seedling in the greenhouse.The soil samples without oil pollution were collected in coastal wetlands in the Yellow River Delta of soils in May 2010.The soil oil pollution levels was controlled by three oil concentration(0%,0.5%,2.0% in the simulative experiment in greenhouse,four replicates for each treatment.The crude oil in experiments collected from the Shengli Oil Field production wells.The typical representative plants of reed and seepweed in coastal wetlands in the Yellow River Delta were cultivated in the different soil treatments,respectively.The reed was planted with root with same buds and the seepweed seed was sowed(0.5 g per pot).During experiment period,the seedling height of both reed and seepweeed,tillering number of reed,leaf number and branch number of seepweed were recorded.The soluble protein content,Catalase activity(CAT) activities,peroxidase activity(POD) activities,malondialdehyde(MDA) content,Chlorophyll(Chl) content of seedling leaves were determined,then the ratio of chl a/ chl b was calculated.The results showed that,with increasing petroleum concentration,the inhibitory effects of petroleum for plant height of reed and seepweed were increased.The inhibitory effects of petroleum contamination on reed tillering number were weakened with time,while that functions on seepweed branch number were strengthened.With increasing oil concentration in soils,the soluble protein content in seedling leaves of seepweed was decline after increase,while the opposite regulars were observed for MDA content and POD activities,and the CAT activities was decreased obviously.Compared to seepweed seedling,the reed seedling appeared high oil contamination tolerance.The Chl content in reed seedling leaves shows a trend of increase after decline with time under different condition of oil contamination.In generally,the inhibitory effects of soil oil contamination for seepweed seedling were higher than that for reed seedling.It indicated that the reed was much more suitable for restoration of oil contaminated soil than seepweed.Our results suggested that both reed and seepweed with high salt tolerance properties could be extensively applied in soil restoration of oil contamination regions in the coastal wetland of Yellow River Delta.

title: Soil As Levels and Bioaccumulation in Suaeda salsa and Phragmites australis Wetlands of the Yellow River Estuary, China
abstract: Little information is available on As contamination dynamics in the soil plant systems of wetlands. Total arsenic (As) in soil and plant samples from Suaeda salsa and Phragmites australis wetlands was measured in the Yellow River Estuary (YRE) in summer and autumn of 2007 to investigate the seasonal changes in As concentrations in different wetlands. The results showed that soil As levels greatly exceeded the global and regional background values. As levels in soil and the roots and stems of both types of plants were much higher in summer than in autumn, whereas leaf As showed higher level in autumn. Soil sulfur was the main factor influencing As levels in Suaeda salsa wetlands, whereas soil porosity was the most important factor for Phragmites australis wetlands. The contamination factor (CF) showed moderately to considerably polluted levels of As in both wetland soils. Plant roots and leaves of Suaeda salsa had higher As concentrations and biological concentration factors (BCFs) than stems, while the leaves and stems of Phragmites australis showed higher As levels and BCFs than roots. Compared to Phragmites australis, Suaeda salsa generally showed higher translocation factor (TF) while TF values for both plant species were higher in summer than in autumn.