Phalaris Arundinacea Research Articles

Investigation of pyrolysis kinetics and thermal behavior of Invasive Reed Canary (Phalaris arundinacea) for bioenergy potential

The present study investigates the pyrolysis kinetic and thermal behavior of Invasive Reed Canary (Phalaris arundinacea) and evaluate the potential of the biomass as a bioenergy feedstock. The biomass sample was collected from wild areas of Ontario, Canada. Thermal degradation analysis were conducted by exposing the dried and powdered biomass to four heating rates (10, 20, 30 and 40 K min-1) using a Thermogravimetric Analyzer in an inert environment. Thermal data was utilized to explain the reaction chemistry using iso-conversional models of Kissenger-Akahira-Sunose (KSA), Starink and Flynn–Wall–Ozawa (FWO). Evaluation of the kinetic parameters such as the activation energy and the pre-exponential factor illustrates the promising bioenergy potential of the biomass. Fourier-transform infrared spectroscopy and Gas chromatography techniques indicate existence of valuable pyrolysis products such as aliphatic hydrocarbons. Low cost in addition to the abundance of the biomass may facilitates the consumption of the biomass for bioenergy application in cost efficient and environmental friendly manners.

Pioneer plant Phalaris arundinacea and earthworms promote initial soil structure formation despite strong alluvial dynamics in a semi-controlled field experiment

Soil structure formation is among the most important processes in river floodplains which are strongly influenced by alluvial dynamics. In the context of river restoration projects, a better understanding of soil structure formation in habitats adjacent to the river can help to prevent damages caused by riverbank erosion. Ecosystem engineers such as pioneer herbaceous plants and earthworms likely contribute to soil structure formation even despite less favourable environmental conditions. This study aims to assess the capacity of the herbaceous perennial and native species Phalaris arundinacea and earthworm communities to promote a stable soil structure in alluvial sediments, in particular fresh alluvial deposits, in the short term. Delimited plots were set-up in a restored floodplain adjacent to the Thur River in NE Switzerland and exposed to natural alluvial dynamics for 19 months. Four treatments were replicated in a randomised complete block design: (i) plots with Phalaris arundinacea as only vegetation, (ii) plots with all vegetation constantly removed, (iii) and (iv) the earthworm community reduced by mustard treatment, otherwise as (i) and (ii), respectively. Soil structure formation was analysed at the end of the experiment using different indicators: aggregate stability, field-saturated hydraulic conductivity and the porosity calculated from X-ray CT reconstructions of freeze cores. Phalaris arundinacea was capable of improving the porosity and aggregate stability of both alluvial sediments present at the beginning of the experiment but also of sediments freshly deposited during the observation period. The latter indicates a structuring effect within only one vegetation period. Earthworm abundance was as a whole very low, most likely due to the large proportion of sand. There was a small earthworm effect on soil structure formation, and only in combination with Phalaris.arundinacea. Our findings highlight the ability of Phalaris arundinacea in efficiently structuring sandy alluvial sediments in the short term even under strong alluvial dynamics. Phalaris arundinacea can therefore play a key role in the early stage of river restoration projects. Thus, facilitating the colonisation by such native pioneer herbaceous plants is a suitable step to improve the success of river restoration projects.

Co-occurring invasive plant interactions do not predict the impacts of invasion in experimental tallgrass prairie communities

Co-occurring invasive plants are an understudied yet common phenomenon, and likely to become even more frequent with climate change-driven range shifts. Invasive–invasive interactions can be competitive, neutral, or facilitative; symmetric or asymmetric; and their impact on natives can be additive or non-additive. Non-additive impacts, wherein co-occurring invasives either reduce or enhance one another’s effects, have heightened implications for invasive management and native restoration. We investigated interactions among three invasive species—the legume Lotus corniculatus, the forb Cirsium arvense, and the grass Phalaris arundinacea—that co-occur in North American prairie grassland, and impacts on native prairie communities. Employing greenhouse microcosms, we observed invasive–invasive interactions by growing invasive species alone, in pairs, and in three-way combination. To assess impacts of co-occurring invasives, native prairie communities were grown with each single invader, all pairs of invaders, or all three invaders together. For insight into mechanisms of species interactions, measurements of above- and below-ground resources were made. We predicted that the invasive legume would facilitate the other invasive species via nitrogen enrichment, promoting non-additive impacts on native communities. We observed that the legume promoted yields of the other invasive species and was associated with higher soil ammonium content. However, we also observed strongly asymmetric competition between co-occurring invasive species. Impacts of invaders on functionally diverse native communities were similar among invasion treatments and less than expected based on invasive impacts in monoculture. These results warrant future tests of functional group identity and diversity as predictors of co-occurring invasive species interactions and impacts.

Disentangling effects of invasive species and habitat while accounting for observer error in a long‐term amphibian study

AbstractThe invasive American bullfrog (Lithobates catesbeianus) and a variety of non‐native sport fish commonly co‐occur in lowland lentic habitats of the western United States. Both invasive taxa are implicated in declines of native amphibians in this region, but few long‐term studies of communities exist. Further, field studies of invasive–native interactions are complicated by confounding habitat modifications and observation errors. We surveyed amphibians and measured habitat characteristics for 12 yr across 38 wetland sites within the Willamette Valley, Oregon, USA. We assessed the influence of invasive species, habitat, and their interactions on the distributions of five native amphibian species using a multispecies dynamic occupancy model that accounted for false‐negative and false‐positive detections. In general, habitat characteristics—such as within‐pond vegetation cover, surrounding forest, and drought severity—were important for local persistence of native species when bullfrogs co‐occurred. We also found evidence of a cumulative negative effect of bullfrogs and non‐native fish (families Centrarchidae and Ictaluridae) on northern red‐legged frog (Rana aurora) local persistence that was mediated by the dominance of invasive reed canarygrass (Phalaris arundinacea). Non‐native fish and bullfrogs had variable effects on native amphibian species, but neither invasive taxon appears to be causing declines in occupied sites within our study area. Moreover, species relationships with habitat differed when invaders were present, indicating that certain habitats may increase persistence of native amphibians in the invaded landscape.

Uptake of Soil-Derived Carbon into Plants: Implications for Disposal of Nuclear Waste.

Radiocarbon (14C) is potentially significant in terms of release from deep geological disposal of radioactive waste and incorporation into the biosphere. In this study we investigated the transfer of soil-derived C into two plant species by using a novel approach, where the uptake of soil-derived C into newly cultivated plants was studied on 8000-year leftover peat in order to distinguish between soil-derived and atmospheric C. Two-pool isotope mixing model was used to reveal the fraction of soil C in plants. Our results indicated that although the majority of plant C was obtained from atmosphere by photosynthesis, a significant portion (up to 3-5%) of C in plant roots was derived from old soil. We found that uptake of soil C into roots was more pronounced in ectomycorrhizal Scots pine than in endomycorrhizal reed canary grass, but nonetheless, both species showed soil-derived C uptake in their roots. Although plenty of soil-derived C was available in canopy air for reassimilation by photosynthesis, no trace of soil-derived C was detected in aboveground parts, possibly due to the open canopy. The results suggest that the potential for contamination with 14C is higher for roots than for leaves.

Feeding behavior and dry matter digestibility in sheep fed first and second cut reed canary grass (Phalaris arundinacea L.)

We investigated the intake and digestibility of different reed canarygrass (RCG) growth stages by sheep. RCG was cultivated in an experimental field and harvested at the first and second cuts at each pre-blooming stage. Feeding behavior was monitored on adult female sheep, fed 3 kg each of fresh RCG three times daily. While the crude protein content and dry matter digestibility of RCG were significantly higher in leaf than in stem tissue of both first and second cut in harvesting times, neutral and acid detergent fiber contents were higher in stem than in leaf. The dry matter intake of RCG at the second cut (296.1g) was significantly higher than at the first cut (214.1 g). The eating time for consumption of RCG on dry matter at the second cut (54.9 min) was shorter than at the first cut (69.4 min). Consequently, at the second cut, the rate of biting (54.6 bites/min) was lower than at the first cut (64.8 bites/min). Bite size, expressed as dry matter intake per bite, ranged from 0.05 g at first cut to 0.10 g at second cut.

The possibility of using sewage sludge for energy crop cultivation exemplified by reed canary grass and giant miscanthus

Abstract Energy crops, on account of high biomass yields, have high nutrient requirements in relation to macroelements. Municipal sewage sludge can be a potential source of micronutrients for plants with high nutrient requirements. The use of macronutrients from sewage sludge by energy crops is an alternative form of nutrient recycling from organic waste. The aim of the research was to assess the content, uptake and use of N, P, K, Ca, Mg and Na from municipal sewage sludge by reed canary grass (Phalaris arundinacea L.) and giant miscanthus (Miscanthus × giganteus Greef et Deu). The effect of sewage sludge on the ratios between macroelements in the biomass of the tested plants was also assessed. The multi-year field experiment involved four levels of fertilization with sewage sludge at doses of 0, 10, 20, 40, 60 Mg DM·ha−1. Due to the low potassium content in this waste, supplementary potassium fertilization (100 kg K·ha−1 in the form of 40% potassium salt (KCl)) was applied once on all plots. It was established that the increasing doses of sewage sludge had a considerable effect on the increase in the content and uptake of N, P, K, Ca, Mg and Na by the biomass of the tested energy crops. The research shows that, compared to giant miscanthus, reed canary grass had a higher macronutrient content. The largest amount of uptaken N, P, K, Ca and Mg was found in reed canary grass (at a dose of 40 Mg DM·ha−1), whereas Na was detected in giant miscanthus (at a dose o 20 Mg DM·ha−1). It was established that giant miscanthus, on account of its higher yielding, recovers macroelements from sewage sludge applied to soil at a dose of 10 Mg DM·ha−1 to the greatest extent. The increasing doses of sewage sludge considerably decreased the value of K:Mg, Ca:Mg, Ca:P ratios in miscanthus biomass yield. The applied doses of sewage sludge (40–60 Mg DM·ha−1) increased the value of K:Ca, Ca:P, K:Na ratios in miscanthus biomass yield.

Szarvasi-1 and Its Potential to Become a Substitute for Maize Which Is Grown for the Purposes of Biogas Plants in the Czech Republic

The domestic biogas market has been developing rapidly, and legislation (The Act) supporting the use of renewable energy sources has come into force. In light of this act and investment support from national programs co-financed by the European Union (EU), the total number of biogas plants has recently increased from a few to 600. The total capacity of electricity generation of those 600 installed plants exceeds 360 Megawatts (MW) (as of mid-2018). Such dynamic growth is expected to continue, and the targets of the National Renewable Energy Action Plan are projected to be met. The use of waste material, which was urgently needed, was the original aim of biogas plants. However, in certain cases, the original purpose has transformed, and phytomass is very often derived from purpose-grown energy crops. Maize is the most common and widely grown energy crop in the Czech Republic. Nevertheless, maize production raises several environmental issues. One way to potentially reduce maize’s harmful effects is to replace it with other suitable crops. Perennial energy crops, for example, are possible alternatives to maize. A newly introduced species for the conditions of the Czech Republic, Elymus elongatus subsp. ponticus cv. Szarvasi-1, and some other well-known species—Phalaris arundinacea L. and Miscanthus × giganteus—are suitable for Czech Republic climate conditions. This paper presents the findings of the research and evaluation of environmental, energy-related, and economic aspects of growing these crops for use in biogas plants. These findings are based on 5-year small-plot field trials. The energy-related aspects of producing Elymus elongatus subsp. ponticus cv. Szarvasi-1, Phalaris arundinacea L., and Miscanthus x giganteus are reported on the basis of experiments that included measuring the real methane yield from a production unit. The economic analysis is based on a model of every single growing and technological operation and costs. The environmental burden of the individual growing methods was assessed with a simplified life cycle assessment (LCA) using the impact category of Climate Change and the SimaPro 8.5.2.0 software tool, including an integrated method called ReCiPe. The research findings show that Szarvasi-1 produces 5.7–6.7 Euros (EUR) per Gigajoule (GJ) of energy, depending on the growing technology used. Szarvasi-1 generates an average energy profit of 101.4 GJ ha−1, which is half of that produced by maize (214.1 GJ ha−1). The environmental burden per energy unit of maize amounts to 16 kg of carbon dioxide eq GJ−1 compared with the environmental burden per energy unit of Szarvasi-1, which amounts to 7.2–15.6 kg of CO2 eq GJ−1, depending on the yield rate. On the basis of the above-mentioned yield rate of Szarvasi-1, it cannot be definitively recommended for the purpose of biogas plants in the Czech Republic.

Anaerobic digestion of wetland biomass from conservation management for biogas production

In this study, we examined the biogas and methane production of wetland plants species harvested in the Narew River Valley protected as national park, NE Poland. In the experiment, we used the aboveground biomass of five species: reed canary grass (Phalaris arundinacea), common reed (Phragmites australis), reed sweet-grass (Glyceria maxima), tufted sedge (Carex elata) and woollyfruit sedge (Carex lasiocarpa). The plants were harvested in three seasons of the year 2015: mid-summer, late summer, and early fall.The chemical composition of wetland plants was not beneficial for the anaerobic digestion, because of the sub-optimal C:N ratio. Consequently, the wetland species exhibited rather average methane production (102–221 NL kg−1 VS). These values were similar to that observed for grasses collected in extensive grasslands and wetlands by other researchers. They were, however, much lower than those obtained for species harvested in cultivated grasslands. Methane and gross energy yield differed significantly (p < 0.05) depending on the season of the biomass cut. The optimal period for the harvest of wetland biomass for biogas generation was the middle of summer, July–August.Phragmites australis appeared to be the most promising energy species. Despite the low methane yield per kg VS, common reed, due to its high aboveground biomass, achieved quite high methane production per area (1,16·106 NL CH4 ha−1). Our findings suggest that biomass of reed rushes can provide a substantial source of renewable energy used for biogas generation, which will make possible economic exploitation of wetlands combined with the conservation of their natural functions and services.

Trace Element Uptake by Herbaceous Plants from the Soils at a Multiple Trace Element-Contaminated Site.

The uptake of trace elements by wild herbaceous plants in a multiple trace element-contaminated site was investigated. The bioaccumulation factor (BF) of trace elements was markedly variable among the different plant species. On average, the BF for various trace elements was in the following decreasing order: Zn > Cu > Mn > Ni > As > Pb > Cr. The translocation factor among the investigated plant species was also considerably variable and showed the following decreasing order: Mn > Zn > Ni > Cu > Cr > As > Pb. Several hyperaccumulating plants were identified: Artemisia vulgaris for As, Mn and Zn, Phalaris arundinacea for Mn and Ni, Heracleum sphondylium for Cr and Zn, and Bistorta officinalis for Mn and Zn. The marked accumulation of trace elements in the plant tissue suggests that the site may not be suitable for urban agricultural production. The plant tissue-borne trace elements could affect microbial activities and consequently interfere with the ecosystem functioning in the affected areas.

The efficiency and economic aspects of phytoremediation technology using Phalaris arundinacea L. and Brassica napus L. combined with compost and nano SiO2 fertilization for the removal of PAH's from soil

The paper presents an evaluation of efficiency and economic potential of the phytoremediation technology, based on the use of energy crops (P. arundinacea L. and B. Napus L.), combined with the fertilization with compost, supported by the addition of nano SiO2. The experiment was conducted in in-situ conditions, using two experimental blocks, divided according to used plant species. Each block included four types of plots with different fertilization treatments (control plots; treatment with nano SiO2; treatment with compost; treatment with mixture of compost and nano SiO2). During the studied period (three vegetation seasons), a cyclic analysis of 16 PAH's content were conducted. Furthermore, a quantitative determination of biomass production was performed as well as assessment of economic potential of different strategies.Data collected during research, shows that method based on energy crops use, due to the join effect of the dangerous pollutants removal and the production of removable energy resource, can be considered as sustainable and should be recommended for use during heavy polluted soil remediation. Moreover, it should be also noted, that the best results for both PAH's removal efficiency and biomass production, were acquired on plots with P. arundinacea L. cultivation, fertilized with mix of compost and nano SiO2.

Effects of flood inundation, invasion by Phalaris arundinacea, and nitrogen enrichment on extracellular enzyme activity in an Upper Mississippi River floodplain forest

The community structures and ecosystem functions of floodplains are primarily driven by variation in flood inundation. However, global changes, such as invasive species and nutrient enrichment, may alter the effects of flooding in these systems. We added nitrogen (N) to correspond with twice the annual atmospheric deposition rate of the south-west Wisconsin, USA region within mature floodplain forest plots and patches of an invasive grass (reed canarygrass, Phalaris arundinacea) along a floodplain elevation gradient in an Upper Mississippi River floodplain forest. We measured soil physicochemical properties and the activity of six extracellular enzymes during 3 months that varied in flooding conditions. Multivariate analyses (distance-based redundancy analysis) revealed that floodplain elevation, month of sampling, and vegetation type were all significant predictors of variation in soil physicochemical properties, while elevation and month were significant predictors of multivariate extracellular enzyme activity (EEA). The best model for predicting EEA consisted of nitrogen availability, soil porosity, and water filled pore space. Although the categorical fertilization and invasion treatments were not significant predictors of EEA, our results suggest that their effects depend on the degree to which they modify N availability and soil moisture. In this system, spatial and temporal patterns in flooding appear to be the main driver of these properties, but N enrichment and invasion may have the potential to further modify them.

Pilot-scale study on advanced treatment of tail water of urban sewage treatment plant by constructed wetlands with different plants

利用种植不同植物的人工湿地对污水厂尾水进行深度处理以达到更严格的排放标准.利用5块尺寸一致的中试规模人工湿地，以潮汐流作为运行方式，研究不同植物对尾水的处理效果.经过一年的实验，结果表明：5块人工湿地出水各指标均能达到提升标准的排放要求.在不同植物的去污效果对比实验中，种植芦苇（Phragmites communis）的人工湿地对化学需氧量（COD）、氨氮和总氮（TN）的平均去除率均为最高，分别为24.01%、68.15%和92.70%；种植风车草（Cyperus alternifolius）的人工湿地对TP的平均去除率最高，为71.68%.在不同季节的去污效果对比实验中，春季芦苇湿地对COD、氨氮和TN的去除效果最好，平均去除率分别为52.51%、76.06%和92.04%，美人蕉（Canna indica）湿地对TP去除效果最好，平均去除率为66.72%；夏季对COD、氨氮、TP和TN处理效果最好的分别是种植丝带草（Phalaris arundinacea）、菖蒲（Acorus calamus）、风车草和芦苇的人工湿地，平均去除率分别为15.83%、78.11%、67.30%和91.73%；秋季对COD、氨氮、TP、TN处理效果最好的分别是种植芦苇、丝带草、风车草、美人蕉的人工湿地，平均去除率分别为12.19%、58.82%、83.16%和94.01%；冬季对COD去除效果最好的是种植丝带草的人工湿地，平均去除率为33.39%，对氨氮、TP处理效果最好的是种植美人蕉的人工湿地，平均去除率分别为76.33%和79.43%，对TN处理效果最好的是种植芦苇的人工湿地，平均去除率为94.97%.在以后的实际工程中，可以考虑用种植不同季节、不同指标对应的最佳去污植物为主，并且搭配种植其他植物的人工湿地进行污水厂尾水的深度处理.;In order to meet stringent water quality standards, the tail water of the local wastewater treatment plant has been treated by constructed wetlands with different plants. Five pilot-scale constructed wetlands were investigated for the advanced treatment of the tail water of wastewater treatment plant, they had the same size, and were operated with a tidal flow, while they were planted with different plants to compare their treatment effects. After one year's experiment, the results showed that the all indexes of effluent from five constructed wetlands could meet the improved requirements. Among them, the constructed wetland planted with Phragmites communis had the highest average removal rates of chemical oxygen demand (COD), ammonia nitrogen, and total nitrogen (TN), which were 24.01%, 68.15%, and 92.70%, respectively. The constructed wetland planted with Cyperus alternifolius had the highest average removal rate of total phosphorus (TP), which was 71.68%. In the contrast experiment of the performance in different seasons, in the spring, the constructed wetland planted with Phragmites communis had the best removal effect on COD, ammonia nitrogen and TN, the average removal rates were 52.51%, 76.06% and 92.04%, respectively, and the constructed wetland planted with Canna indica had the best removal effect on TP, the average removal rate was 66.72%. In the summer, the constructed wetland respectively planted with Phalaris arundinacea, Acorus calamus, Cyperus alternifolius and Phragmites communis had the best removal effect on COD, ammonia nitrogen, TP and TN, the average removal rates were 15.83%, 78.11%, 67.30% and 91.73%, respectively. In the autumn, the constructed wetland respectively planted with Phragmites communis, Phalaris arundinacea, Cyperus alternifolius and Canna indica had the best removal effect on COD, ammonia nitrogen, TP and TN, respectively, the average removal rates were 12.19%, 58.82%, 83.16% and 94.01%, respectively. In the winter, the constructed wetland planted with Phalaris arundinacea had the best removal effect on COD, the average removal rate was 33.39%, the constructed wetland planted with Canna indica had the best removal effect on ammonia nitrogen and TP, the average removal rates were 76.33% and 79.43%, respectively, and the constructed wetland planted with Phragmites communis had the best removal effect on TN, the average removal rate was 94.97%. It will be of significance to the practical engineering in the future.

Chrastice rákosovitá (Phalaris arundinacea L.) jako slibná energetická plodina

Reed canary grass (Phalaris arundinacea L.) is a perennial fast-growing C3 plant belongs to family Poaceae with an early season growth, a wide physiological tolerance and with large possibilities of utilization. Recently, the use for bioenergy has become very perspective mainly because its high yield (5–10 t dry matter ha/year) and very good properties for combustion. The mean calorific value is about 16–18 MJ/kg dry matter. It can be usually harvested twice a year at lower cultivation inputs and shows the ability to grow in wide range of soil conditions including on land, which is not appropriate for other agricultural purposes. It has also the potential for different industrial applications, for example for biogas, ethanol, pulp and paper production, or for the production of chemical raw materials, too. The cultivation area rapidly increases, mainly in North Europe, where it is cultivated on thousands of hectares. The cultivation for energy or other industrial purposes has also benefits to the environment because of low intensity on agricultural management, supporting biodiversity and soil preservation against erosion.

Testing mechanisms underlying responses of plant functional traits to flooding duration gradient in a lakeshore meadow

Flooding duration is a major factor determining wetland plant growth and community composition. While there have been extensive studies on how direct effects of flooding duration on plant functional traits, very few have tested the indirect effects on these traits, including those arising from competition. We hypothesized that there would be a shift in importance of competition ability and flooding tolerance to functional traits along the flooding duration gradient. We investigated plant functional traits along a flooding duration gradient for two-dominant wetland plant species (Carex cinerascens and Phalaris arundinacea) in a lakeshore meadow of Poyang Lake, China. We found that these two species tended to have different strategies to adapt to flooding stress. P. arundinacea tended to adopt escape strategy with high growth rate (e.g. greater height, specific leaf area, and leaf N and P content) at longer flooding duration, while C. cinerascens tended to adopt more quiescence strategy, with only 5 of 13 of its traits showing a significant response. With shorter flooding duration, both species tended to have lower leaf N and P content, indicating greater nutrient limitation. Meanwhile, relative abundance of C. cinerascens with relatively higher belowground nutrient competition ability (i.e. greater root/shoot biomass ratio) decreased with flooding duration. These results suggest that belowground competition intensifies at shorter flooding duration, because of increased nutrient limitation with increased productivity. Therefore, our study indicates that both flooding stress and nutrient competition could affect plant functional traits along a flooding duration gradient.

Modeling wetland aboveground biomass in the Poyang Lake National Nature Reserve using machine learning algorithms and Landsat-8 imagery

Quantitative estimation of wetland aboveground biomass (AGB) is an essential aspect in evaluating the health and conservation of this valuable ecosystem. We combine AGB field measurements and remote sensing data to establish a suitable model for estimating wetland AGB in the Poyang Lake National Nature Reserve (PLNNR), which is included in the Ramsar Convention’s List of Wetlands of International Importance. All field sampling points cover four dominant vegetation communities (Carex cinerascen, Phalaris arundinacea, Artemisia selengensis, and Miscanthus sacchariflorus) in the PLNNR. Wetland AGB is retrieved from the Landsat-8 OLI image. To improve the accuracy of wetland AGB estimation, we compare the performances of three machine learning algorithms, namely, random forest (RF), back-propagation neural network (BPNN), and support vector regression (SVR), with linear regression (LR) in estimating the AGB in the PLNNR. Results are as follows: (1) the RF model with a root-mean-square error of 0.25 kg m − 2 performs better than BPNN (0.29 kg m − 2), SVR (0.27 kg m − 2), and LR (0.31 kg m − 2) in our testing dataset, and AGB density in the PLNNR is between 0 and 1.973 kg m − 2. (2) The four most important features for AGB modeling are near-infrared, short-wave infrared 1 band, enhanced vegetation index, and red band. Our study presents an effective and operational RF model that estimates wetland AGB from Landsat data, providing a scientific basis for floodplain wetland carbon accounting and possible future studies, such as the linkage between wetland AGB and the great water level fluctuations.

Bioethanol and biomethane potential production of thirteen pluri-annual herbaceous species

The research aimed to study and characterize, in a four-year study, thirteen pluri-annual herbaceous species for their potential bioethanol and biomethane production. The highest biomass yield was obtained with Arundo donax followed by Miscanthus x giganteus. Biomass cellulose content had median values ranging from 23.1% (Symphytum x uplandicum) to 45.4% (Lythrum salicaria), hemicellulose from 9.4% (Iris pseudacorus) to 36.8% (Glyceria maxima) and lignin from 2.6% (G. maxima) to 14.5% (Helianthus tuberosus and L. salicaria). The best ethanol and methane median yields were achieved by A. donax (3.5 Mg ha−1 and 8227 m3 ha−1, respectively) followed by M. x giganteus (3.2 Mg ha−1 and 4446 m3 ha−1, respectively). Methane transformation showed a higher energy output than ethanol with values ranging from 1 GJ ha−1 (Phalaris arundinacea) to 508 GJ ha−1 (A. donax) and from 1 GJ ha−1 (P. arundinacea) to 624 GJ ha−1 (A. donax) for ethanol and methane, respectively. Results showed that A. donax and M. x giganteus are the most interesting species for bioethanol and biomethane production.

The effect of land use change from grassland to bioenergy crops Miscanthus and reed canary grass on nitrous oxide emissions

Bioenergy crop production can enhance greenhouse gas (GHG) mitigation, whilst producing feedstocks for energy generation. However, the GHG balance of these ecosystems is intimately linked to crop selection, previous and current land management and the effects of land conversion. This study aims to quantify nitrous oxide (N2O) emissions from the early stage of land-use change (LUC) from perennial grassland to two perennial rhizomatous grasses in a temperate climate: Miscanthus and reed canary grass (RCG) in the south of Ireland. Emissions of N2O were measured during the first two years of RCG and Miscanthus establishment. Miscanthus stands emitted 7.7 ± 1.6 and 2.3 ± 0.2 kg N2O-N ha−1 yr−1 in the first and the second year, respectively, while RCG produced 1.1 ± 0.2 kg N2O-N ha−1 yr−1 in the first year following LUC. Temporal fluxes of N2O were generally low, however peak emissions observed in the first year contributed approximately 83% of annual N2O in the Miscanthus treatment. This peak occurred in wet (50 mm rainfall in the week preceding the peak) and warm (>18.5 °C in the top 5 cm of soil) weather conditions and was significantly affected (R2 = 0.77) by the soil moisture deficit. However large, annual N2O losses from Miscanthus and RCG found in this study are well within the range of those from grassland soils in temperate climate, drawing conclusions that any short-term increases in N2O production will soon be offset by the reduced future fertilisation, carbon sequestration and produced bioenergy feedstock.

Wetland compensation and its impacts on β-diversity.

The anthropogenic degradation of natural ecological communities can cause biodiversity loss in the form of biotic homogenization (i.e., reduced β-diversity). Biodiversity offsetting practices, such as compensatory wetland mitigation, may inadvertently cause biotic homogenization if they produce locally homogenous or regionally recurring communities. The fact that compensation wetlands often resemble degraded wetlands suggests that potential impacts to β-diversity are likely. Yet, it is unknown how high-quality, low-quality (degraded), and compensation wetlands compare in terms of β-diversity. We compared the β-diversity of high-quality, low-quality, and compensation wetlands at local and regional scales. β-diversity was quantified as the average distance to group centroids in multivariate space based on pairwise comparisons of community composition. The local spatial structure of β-diversity was assessed using species turnover across plots. Indicator species analysis was used to describe compositional differences potentially contributing to differences in β-diversity. Overall, the β-diversity of compensation sites did not differ from high-quality or low-quality natural wetlands. However, compensation wetlands had a high degree of internal turnover along the hydrological gradient, which culminated in homogenous zones in the wettest areas. Compared to high-quality wetlands, low-quality wetlands had significantly lower β-diversity at local scales, but significantly greater β-diversity at regional scales. Indicator species results showed that compensation wetlands were distinguished by low conservation value species typically found in old fields and waste areas. This analysis also indicated that the invasive grass Phalaris arundinacea was indicative of low-quality and compensation wetlands. This species is likely contributing to differing patterns of β-diversity between high-quality and low-quality wetlands. These results indicate that conclusions regarding β-diversity depend on scale and scope of analysis. Particularly, the unique architecture of compensation wetlands makes conclusions regarding within-site β-diversity dependent on the observer's position along the hydrological gradient. Additionally, while we conclude that compensation wetlands are not contributing to biotic homogenization at the regional scale, these wetlands are distinct from both high-quality and low-quality wetlands in their composition and structure. Therefore, assessments of the overall success of wetland mitigation programs should acknowledge the reality of these differences.

Impacts of cattle grazing on seed production in Rainwater Basin Wetlands

The Rainwater Basin region of Nebraska is a critical stopover area for spring migrating waterfowl. Management concerns focus on producing sufficient wetland seed to meet the needs of these waterfowl. Cattle grazing is commonly used both alone and in combination with other management techniques to reduce invasive species such reed canarygrass that suppress seed production, but it was unknown what effect the grazing has on seed production, and how that effect might differ by vegetation type. This project examined the impact that different durations of grazing had on seed production in three sites containing both moist-soil and reed canarygrass dominated areas. We also examined the magnitude of the effect that grazing had on reducing reed canarygrass biomass with differing durations of grazing. The results suggest that cattle grazing impacts seed production differently in moist-soil and reed canarygrass dominated areas. Grazing decreases seed production in moist-soil areas, and longer grazing results in a greater decrease. In contrast, the highest seed production in reed canarygrass dominated areas was in areas grazed until July 15, and the lowest seed production was in areas grazed until September 15. The relationship between grazing and seed production in reed canarygrass areas is complex, but seed production in reed canarygrass areas was universally lower than in moist-soil vegetation at all grazing durations.