Disentangling climate from soil nutrient effects on plant biomass production using a multispecies phytometer

Peter A Wilfahrt,Michael Bierbaumer,Marleen Van Dusseldorp,David Reinthaler,Pia Eibes,Otmar Urban,Ildikó Orbán,Michael Bahn,Inger Kappel Schmidt,Karel Klem,Josep Peñuelas,Julienne M.‐I Schweiger,Petr Holub,Marc Estiarte,Pille Mänd,György Kröel‐Dulay,Dajana Radujković,Sara Vicca,Anke Jentsch,Bernd J Berauer,Johannes Ingrisch,Ika Djukic,Nélson Abrantes ,Lazar Kesić ,Krista Lõhmus ,Albert Tietema ,Andreas Von Heßberg ,Andreas Schweiger ,Mohammed Abu Sayed Arfin Khan ,Saša Orlović ,Klaus Steenberg Larsen ,Srdjan Stojnić ,Max A Schuchardt

doi:10.1002/ecs2.3719

Abstract

AbstractPlant community biomass production is co‐dependent on climatic and edaphic factors that are often covarying and non‐independent. Disentangling how these factors act in isolation is challenging, especially along large climatic gradients that can mask soil effects. As anthropogenic pressure increasingly alters local climate and soil resource supply unevenly across landscapes, our ability to predict concurrent changes in plant community processes requires clearer understandings of independent and interactive effects of climate and soil. To address this, we developed a multispecies phytometer (i.e., standardized plant community) for separating key drivers underlying plant productivity across gradients. Phytometers were composed of three globally cosmopolitan herbaceous perennials, Dactylis glomerata, Plantago lanceolata, and Trifolium pratense. In 2017, we grew phytometer communities in 18 sites across a pan‐European aridity gradient in local site soils and a standardized substrate and compared biomass production. Standard substrate phytometers succeeded in providing a standardized climate biomass response independent of local soil effects. This allowed us to factor out climate effects in local soil phytometers, establishing that nitrogen availability did not predict biomass production, while phosphorus availability exerted a strong, positive effect independent of climate. Additionally, we identified a negative relationship between biomass production and potassium and magnesium availability. Species‐specific biomass responses to the environment in the climate‐corrected biomass were asynchronous, demonstrating the importance of species interactions in vegetation responses to global change. Biomass production was co‐limited by climatic and soil drivers, with each species experiencing its own unique set of co‐limitations. Our study demonstrates the potential of phytometers for disentangling effects of climate and soil on plant biomass production and suggests an increasing role of P limitation in the temperate regions of Europe.

Highlights

Understanding vegetation responses to multiple global change factors is a central goal in ecology (Franklin et al 2016)
We expand on the traditional definition of a phytometer as a model plant community used within a single study (Clements and Goldsmith 1924) by introducing a standardized protocol and plant community grown in both local soil and a standardized substrate under different climate regimes. By testing this approach across a pan-European climate gradient, we address the following hypotheses: (1) Biomass production will decrease with aridity and increase with N and P availability, (2) biomass production in standard substrate will decrease with aridity but be unrelated to nutrient availability, (3) factoring out the biomass production from standard substrate in local soils will clarify soil relationships and potentially allow new relationships to biomass to emerge in local soils, and (4) species will have asynchronous responses to climate and soil drivers and the nature of these responses will be clearer using standard substrate and climate-corrected biomass
Empirical data Linear regression of the principle biomass–environment relationships revealed that aboveground community biomass production in the local soil phytometers decreased with increasing aridity, increased with P availability, and had no relationship with N availability (P = 0.84)

Summary

Introduction

Understanding vegetation responses to multiple global change factors is a central goal in ecology (Franklin et al 2016). Key to addressing this challenge is disentangling the co-occurring and covarying environmental factors that drive responses such as primary production (Dormann et al 2013). An additional challenge emerges as these drivers often have non-linear effects (Knapp et al 2017) and non-additive interactions (Wang et al 2017). Isolating drivers of primary production can improve our understanding of vegetation dynamics in the face of global change. Controlling for multiple influential factors while allowing for natural variation in others is a challenging task, along environmental gradients at continental scales

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Conclusion