Precipitation variability does not affect soil respiration and nitrogen dynamics in the understorey of a Mediterranean o
- PDF / 807,474 Bytes
- 17 Pages / 547.087 x 737.008 pts Page_size
- 48 Downloads / 169 Views
REGULAR ARTICLE
Precipitation variability does not affect soil respiration and nitrogen dynamics in the understorey of a Mediterranean oak woodland Marjan Jongen & Xavier Lecomte & Stephan Unger & David Fangueiro & João Santos Pereira
Received: 24 January 2013 / Accepted: 11 April 2013 # Springer Science+Business Media Dordrecht 2013
Abstract Background and aims Future climate scenarios for the Mediterranean imply increasing precipitation variability. This study presents a large-scale water manipulation experiment simulating changes in precipitation variability, aiming at a better understanding of the effects of rainfall patterns on soil C and N cycling and understorey productivity in a Mediterranean oak woodland. Methods We used rain-out shelters to achieve (1) a normal dry period (7 days), and (2) a dry period increased three-fold (21 days), without altering total annual precipitation inputs. Results The temporal patterns of soil respiration (Rs) and soil inorganic N were not affected by treatment. However, water infiltration and N leaching increased with large infrequent watering events. Rs and soil NH4+-N correlated with soil temperature, with soil NO3−-N being influenced by leaching. Conclusions The lack of significant treatment effects on either Rs or soil inorganic N can be explained by (1) Responsible Editor: Stefano Manzoni. M. Jongen (*) : X. Lecomte : D. Fangueiro : J. S. Pereira Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisbon, Portugal e-mail: [email protected] S. Unger Department of Experimental and Systems Ecology, University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
minor differences in plant productivity between the treatments, suggesting equal plant N demand, and (2) the absence of moisture dependence of Rs and soil NH4+-N. Increased N leaching with large infrequent precipitation events may have longer-term consequences for ecosystem functioning. Our results contribute to an improved understanding of possible climate change effects on key ecosystem processes in Mediterranean ecosystems. Keywords Soil CO2 flux . Soil inorganic N . Understorey vegetation . Mediterranean ecosystem . Precipitation manipulation . Climate change
Introduction Anthropogenic activities continue to change atmospheric greenhouse gas concentrations, thereby exerting strong impacts on climate and biogeochemical cycles (Raupach and Canadell 2010). Future climate scenarios for the Iberian Peninsula predict increasing temperatures and an overall decrease in precipitation (IPCC 2007). In addition, scenarios predict an increased temporal variability of precipitation regimes (Luterbacher et al. 2006), with a lower frequency of rainfall days and longer intervening dry periods (Easterling et al. 2000). The increase in precipitation variability is expected to extend the periods of soil moisture deficit (Jackson et al. 2001), which might have important consequences for productivity, biodiversity and the matter cycles of many
Plant Soil
terrestrial ecosystem
Data Loading...
