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Soil respiration of karst grasslands subjected to woody‐plant encroachment
Author(s) -
Eler K.,
Plestenjak G.,
Ferlan M.,
Čater M.,
Simončič P.,
Vodnik D.
Publication year - 2013
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.12020
Subject(s) - grassland , soil respiration , environmental science , biogeochemical cycle , vegetation (pathology) , carbon cycle , ecological succession , ecosystem , nutrient cycle , nutrient , cycling , ecosystem respiration , soil carbon , ecology , hydrology (agriculture) , agronomy , soil water , primary production , soil science , forestry , biology , geology , geography , medicine , geotechnical engineering , pathology
Summary The transition of grasslands to forests influences many ecosystem processes, including water and temperature regimes and the cycling of nutrients. Different components of the carbon biogeochemical cycle respond strongly to woody plant encroachment; as a consequence, the carbon balance of the invaded grasslands can change markedly. In our research, we studied the response of soil respiration ( R S ) to natural succession of calcareous grassland. We established two research sites, called grassland and invaded site, at each of which eddy flux measurement were also performed. Within these sites, triplicate plots were fenced for soil flux measurements. At the invaded site, measurements were performed for forest patches and grassy spaces separately. Soil respiration was strongly dependent on temperature and reached 8–12 µmol CO 2 m −2 s −1 in mid‐summer; it was greater at the grassland than at the invaded site. R S dependence on temperature and soil water content was similar between the different vegetation covers (grassland, gaps and forest patches). At a reference temperature of 10°C, the average R S was 2.71 µmol CO 2 m −2 s −1 . The annual sums of R S were also similar between years and sites: 1345 ± 47 (2009) and 1150 ± 37 g C m −2 year −1 (2010) for grassland and 1324 ± 26 (2009) and 1268 ± 26 g C m −2 year −1 (2010) for the invaded site, which is at the upper range of the values reported in the literature. Cumulative R S peaked in July, with about 200 g C m −2 . Large mid‐summer R S rates rely on strong biological activity supported by high, but non‐extreme soil temperatures and by regular summer precipitation. A coupling of photosynthesis and R S was revealed by a 24‐hour measurement, which showed asymmetrical clockwise hysteresis patterns.