Environmental Factors in Peatland Ecosystems
The study of environmental factors in peatland ecosystem and encompasses a broad range of subjects and disciplines. The task of providing a comprehensive overview of such a broad subject is challenging and somewhat daunting, and we undertake this with a good deal of humility. The book is organized into 8 chapters in a logical sequence from biological themes, through environment of peatland and diversity themes, to world distribution and environmental impacts. In the first chapter we introduce the subject of wetland definition and classification of wetlands, with the distribution of the most important wetland over the world .Chapters 2–4 present an overview of the biodiversity of peatlands, and describe the innumerable adaptations of organisms to these peculiar habitats. Particular attention is paid to the biology of one of the most important species groups, the peat mosses of the genus Sphagnum, because of its dominating influence on peatland development in many parts of the world. Peat, the material in which the organisms live, and which they also form themselves. In the chapter 5 is present the materials and methods, general approaches and techniques applied in accomplishing . It starts with a brief description of the study area and site and then progress to present the research design, sample collection, analysis, and gap filling procedure. This is followed by two chapters deal with environmental factors affecting peatland ecosystems.
Peatland ecosystem plays an important role in the global climate change because they act as a pool or sink of the gasses. There are several factors which influence the environmental consequences of peatland especially in relation to climate change. The main influences are: (i) carbon dioxide, (ii) methane flux, (iii) nitrous oxide (N2O) and (iv) others environmental factors. These atmospheric gases concentrates constitute roughly 73 percent of the overall positive energy flux variation. Carbon dioxide is the greenhouse gas considered most consequential in Anthropocene climate change. Methane is a potent greenhouse gas with a global warming potential 34 times greater than carbon dioxide in natural wetlands and the majority of these emissions are from peatlands. Nitrous oxide is one of the main pollutants in the ecosystem of peatlands and can cause eutrophication. The relationship between seasonality effect factors and net ecosystem CO2 exchange (NEE) remains to be clarified, particularly for the non-growing season. Here, based on the eddy covariance technique, NEE in the peatland ecosystem of Central China was examined to measure two years’ (2016 and 2017) accumulation of carbon dioxide emissions with contrasting seasonal distribution of environmental factors. The cumulative net ecosystem CO2 emissions during the two years were in the first non-growing season 2.94 ± 4.83 μmolCO2 m−2 .s−1 with the lowest values in the same year in first growing season was −2.79 ± 4.92 μmolCO2 m−2 .s−1. It’s indicate the effect of seasonal variations of NEE can be directly reflected in daily and seasonal variations in growth and respiration of peatland ecosystem by environmental parameters over different growing stages. At the same time, methane (CH4) flux was measured in two plant growth stages during the one year, growing season and non-growing season. There was clear seasonal and daily variation in CH4 emissions in the different stage of the season. The average of CH4 flux was 0.06 ± 0.27 μmol m-2 s-1. The greatest season of CH4 flux was the non-growing season of 2017 with mean 0.4 ± 0.7 μmol m-2 s-1, and in contrast, the non-growing season of 2016 was the lowest with mean 0.005 ± 0.002 μmol m-2 s-1. Overall, CH4 flux was significantly correlated with environmental factors such as air temperature, soil temperature, photosynthetic photon flux density (PPFD), and rainfall (Rn). The highest value from CH4 fluxes in growing season were measured when air temperature was below 21℃ or when mean of PPFD was 0.4 μmol quanta m-2 s-1. Rainfall was the highest value in growing season from 2017 when the CH4 flux was 0.03 ± 0.01 μmol m-2 s-1 in growing season of 2017. Another interested issue, Precipitation, air temperature, net radiation, sensible heat flux, and vapour pressure deficit are environmental factors that affect evapotranspiration and usually cause a serious loss of water content from wetland ecosystems. Accurate estimation of evapotranspiration is vital to determine the amount of water necessary to preserve wetlands, particularly peatlands in Central China. The period studied was January 2016 through December 2017 (24 months). Evapotranspiration was measured daily to detect diurnal and seasonal variations throughout the year. The highest value (0.157 mm/hr) occurred in summer (first growing season), and the lowest value (0.045 mm/hr) occurred in the non-growing season of 2017. Seasonal differences in evapotranspiration occurred in the active growth seasons June through October. The peak value of net radiation was 369 W.m2 in September 2017. The peak air temperature was 23℃ in August 2016, whilst the coldest air temperature was -1.5℃ in January 2016. There was a clear relationship between evapotranspiration and air temperature but weak correlation with precipitation; annual precipitation was 19 mm. The Bowen ratio showed no correlation with evapotranspiration, but humidity did show a correlation with evapotranspiration. Evapotranspiration increased during the growing season and reached its peak value in August of 2016. The eddy covariance technique was used to determine the effect of certain environmental factors on evapotranspiration in a peatland ecosystem in Central China. These factors correlated well with evapotranspiration because they influence the seasons. The average rate of evapotranspiration throughout the study period was 80–95%.