Studying the Influence of Nitrogen Deposition, Precipitation, Temperature, and Sunshine in Remotely Sensed Gross Primary Production Response in Switzerland

Marta Gómez Giménez,Armin Keller,Rogier De Jong,Michael E Schaepman,Beat Rihm

doi:10.3390/rs11091135

Abstract

Climate, soil type, and management practices have been reported as primary limiting factors of gross primary production (GPP). However, the extent to which these factors predict GPP response varies according to scales and land cover classes. Nitrogen (N) deposition has been highlighted as an important driver of primary production in N-limited ecosystems that also have an impact on biodiversity in alpine grasslands. However, the effect of N deposition on GPP response in alpine grasslands hasn’t been studied much at a large scale. These remote areas are characterized by complex topography and extensive management practices with high species richness. Remotely sensed GPP products, weather datasets, and available N deposition maps bring along the opportunity of analyzing how those factors predict GPP in alpine grasslands and compare these results with those obtained in other land cover classes with intensive and mixed management practices. This study aims at (i) analyzing the impact of N deposition and climatic variables (precipitation, sunshine, and temperature) on carbon (C) fixation response in alpine grasslands and (ii) comparing the results obtained in alpine grasslands with those from other land cover classes with different management practices. We stratified the analysis using three land cover classes: Grasslands, croplands, and croplands/natural vegetation mosaic and built multiple linear regression models. In addition, we analyzed the soil characteristics, such as aptitude for croplands, stone content, and water and nutrient storage capacity for each class to interpret the results. In alpine grasslands, explanatory variables explained up to 80% of the GPP response. However, the explanatory performance of the covariates decreased to maximums of 47% in croplands and 19% in croplands/natural vegetation mosaic. Further information will improve our understanding of how N deposition affects GPP response in ecosystems with high and mixed intensity of use management practices, and high species richness. Nevertheless, this study helps to characterize large patterns of GPP response in regions affected by local climatic conditions and different land management patterns. Finally, we highlight the importance of including N deposition in C budget models, while accounting for N dynamics.

Highlights

Organic carbon (C), which is fixed through photosynthesis, provides agricultural soils with the quality required to obtain high yields [1]
The objectives of this study are (i) to analyze the impact of N deposition and climatic variables on C fixation response in alpine grasslands, and (ii) to compare the results obtained in alpine grasslands with those from other land cover classes with different management practices
We showed the role of N deposition in explaining gross primary production (GPP) variance in soils with low nutrient storage capacity and how these areas present plant N saturation

Summary

Introduction

Organic carbon (C), which is fixed through photosynthesis, provides agricultural soils with the quality required to obtain high yields [1]. The most substantial fluxes of C fixed per unit of ground and time (gross primary production (GPP)) [2] occur in the tropics, subtropics, and humid temperate regions, e.g., Eastern North America and Western and Central Europe [3]. Western Europe has one of the highest cultivated net primary productions in the world (>1 Kg C/m2) [4]. Climatic variables have been widely used to monitor C fixation [5,6,7]. Temperature analyses have traditionally dominated C budget studies [8]. Controlling factors, scale, and the ecosystem’s complexity vary among studies and, the extent to which limiting factors influence C fixation response

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