Parsimonious modelling of nutrient fluxes for a terrestrial ecosystem on Svalbard

• Published in: Biogeochemistry
• Main Authors: Stapleton, LM, Laybourn-Parry, J, Poulton, PR, Tye, AM, West, HM, Young, SD, Crout, NMJ
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Netherlands 2006
• Subjects: Biological Sciences; Microbiology; Microbial ecology; Arctic; Brandalpynten; Svalbard
• Online Access: http://www.springerlink.com; https://doi.org/10.1007/s10533-006-6253-9; http://ecite.utas.edu.au/49092

Abstract. MBL-MEL, a simple model of ecosystem biogeochemistry, is amended and applied to plant and soil C, 14N and 15N data forthe summers of 2001-2003 from Brandalpynten, a maritime high Arctic site on Svalbard following the application of 15N (99 atom%) as15NO3-N at or 15NH4-N at concentrations of 1 or 5 kg N ha1. Variants of this Parent model are also developed to incorporate:temperature dependence into equations describing nutrient fluxes (Temp model); cryptogams (Cryp model); both features combined(CrypTemp model). Goodness-of-fit (GOF) statistics suggest that the addition of temperature-dependence improves the utility ofmodels with and without cryptogams: the residual weighted sums of squares per data point were 5.69, 3.91, 4.31 and 3.93 for the Parent,Temp, Cryp and CrypTemp models respectively. The application of model selection criteria confirm that the addition of temperaturedependencealso improves model generalisability. Across all models, the principal discrepancies between observation and prediction areassociated with the inorganic soil 15N pool. We conclude that models in which fluxes are described using simple equations that can beaugmented to include additional complexity, are an ideal starting point from which the relationship between GOF and model generalisabilitycan be assessed.