Effects of the 2018 drought on mire productivity in Skogaryd - Evaluation of ground sensors, satellite data and meteorological data

• Main Author: Júlio Alfredo, Ines
• Format: Other/Unknown Material
• Language: English
• Published: Lunds universitet/Institutionen för naturgeografi och ekosystemvetenskap 2021
• Subjects: Sentinel 2; Vegetation Indices; Ground Sensors; Drought and Mire; Earth and Environmental Sciences; Arctic; Climate change; Global warming
• Online Access: http://lup.lub.lu.se/student-papers/record/9042163

The drought is a complex meteorological phenomenon associated with low precipitation and low water saturation in atmosphere, soils and plants and can has a great effect on aboveground biomass and change the structure and function of the ecosystems. The droughts also are known to reduce the primary and secondary productivity of vegetation. The Climate has high influence on vegetation productivity. The global increases of mean temperature mainly caused by emissions of greenhouse gases are widely acknowledged by the scientific community. The summer of 2018, Europe experienced an exceptional drought and heatwave, also affecting the vegetation productivity in ecosystems. The frequency of droughts in Europe in the last years and particularly in Northern ecosystems, has motivated the interest in studying the impact of 2018 drought in Skogaryd using satellite data, ground sensor and meteorological data such as air temperature, precipitation and relative humidity. The work in this thesis was to examine how drought affected the mire ecosystem in southwest Sweden located in Skogaryd. Satellite-based remote sensing was used to calculate Normalized Difference Vegetation Index and Two-band version of Enhanced Vegetation Index derived from ground sensors and Sentinel 2 over the months of growing season, for the years 2017 to 2020. The climate data for the same period were used to examine the relation between vegetation indices and meteorological variables. The studied remote sensing parameters indicates that the values of vegetation indices were generally lower during the summer of 2018 in dry mire and wet mire. The Air temperature and relative humidity are the meteorological variables that affected mire productivity in Skogaryd. The study of the dynamic and evolution of ecosystems presented are important due the frequent change that ecosystem presents. The results could help in identification through remote sensing the increases and decreases of vegetation productivity and as well as planning of development activities in Skogaryd (Mycklemossen). Mire ecosystems provide many benefits to society and economy because they are source of important natural resources such as fuel, peat, berries. In addition, they are important carbon storage, and play important roles in climate regulation and water quality. The mire ecosystem also give opportunities for tourism and recreation because of their unique species and habitats with high conservation value. However, mire ecosystems are highly integrated ecosystems which are vulnerable natural and human induced perturbations in addition with direct and indirect effects of climate change arising from global warming, which has multiple implications for Arctic peatlands. This thesis focused on a dry mire where the vegetation is quite homogenous across the ecosystem, composed of a mosaic of drier hummocks and dry mire composed with wetter hollows. The aim was to investigate how the change in meteorological variables such as air temperature, relative humidity and precipitation affected the vegetation productivity in mire ecosystem in Skogaryd (Southwestern Sweden). This was done by making use of remote sensing to study the effects of climate on ecosystems with vegetation indices, which capture spectral changes caused by changes in vegetation physiology. Specific aims were to investigate how the vegetation indices were correlated with meteorological variables and, in addition, to investigate if the mire ecosystem showed resilience during the drought episodes. The air temperature and relative humidity were the meteorological variables that affected mire productivity in Skogaryd, but no significant correlation was observed between precipitation and productivity. The dry parts of the mire show more resistance to limited water availability due to their plant species either being tolerant to drought, or are able to reestablish when wet conditions return.