Tenaw Geremew, A. Gonsamo, Worku Zewdie, P. Pellikka
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引用次数: 1
Abstract
Abstract Global environmental changes have implications for the terrestrial ecosystem functioning, but disentangling individual effects remains elusive. The impact of vegetation responses to increasing atmospheric CO2 concentrations is particularly poorly understood. As the atmospheric CO2 concentration increases, the CO2 acts as a fertilizer for plant growth. An increase in atmospheric CO2 reduces the amount of water needed to produce an equivalent amount of biomass due to closing or a narrowing of the stomata that reduces the amount of water that is transpired by plants. To study the impacts of climate change and CO2 fertilization on plant growth, we analyzed the growing season sensitivity of plant growth to climatic forcing from alpine to semi-desert eco-climatic zones of Ethiopia for various plant functional types over the period of 1982–2011. Growing season 3rd generation Normalized Difference Vegetation Index of Global Inventory Modeling and Mapping Studies (NDVI) was used as a proxy of plant growth, while mean growing season precipitation (prec), temperature (temp), and solar radiation (sr) as the climate forcing. The sensitivities of plant growth are calculated as a partial correlation, and a derivative of NDVI with respect to prec, temp and sr for earliest and recent 15-year periods of the satellite records, and using a moving window of 15-year. Our results show increasing trends of plant growth that are not explained by any climate variables. We also find that an equivalent increase in prec leads to a larger increase in NDVI since the 1980s. This result implies a given amount of prec has sustained greater amounts of plant foliage materials over time due to decreasing transpiration with increasing CO2 concentration as expected from the CO2 fertilization effect on water use efficiency and plant growth. Increasing trends of growth in shallow-rooted vegetation tend to be associated with woody vegetation encroachment.
期刊介绍:
Journal of Landscape Ecology is a fully reviewed scientific journal published by Czech National Chapter of the Association for Landscape Ecology (CZ-IALE). Our international editorial board has ambition to fill up a gap in the ecological field scope covered by the European scientific journals and mainly those among them which are produced in the Czech Republic. Subjects of papers are not limited teritorially, however, emphasis is given to the Middle-European landscape-ecological themes. The journal is not preferentially theoretical or applied, it is prepared to serve as a bridge between both levels of knowledge. The effort will be developed to increase gradually its quality level and to reach for acceptation by databases of scientific journals with IF. The first issue of JLE was published in 2008. Recently, three issues of JLE are published per year.