Above‐belowground linkages of functionally dissimilar plant communities and soil properties in a grassland experiment

Katja Steinauer,Minggang Wang,T Martijn Bezemer,S Emilia Hannula,Martine Huberty,Jonathan R De Long,Renske Jongen,Robin Heinen

doi:10.1002/ecs2.3246

Abstract

AbstractChanges in plant community composition can have long‐lasting consequences for ecosystem functioning. However, how the duration of plant growth of functionally distinct grassland plant communities influences abiotic and biotic soil properties and thus ecosystem functions is poorly known. In a field experiment, we established identical experimental subplots in two successive years comprising of fast‐ or slow‐growing grass and forb community mixtures with different forb:grass ratios. After one and two years of plant growth, we measured above‐ and belowground biomass, soil abiotic characteristics (pH, organic matter, soil nutrients), soil microbial properties (respiration, biomass, community composition), and nematode abundance. Fast‐ and slow‐growing plant communities did not differ in above‐ and belowground biomass. However, fast‐ and slow‐growing plant communities created distinct soil bacterial communities, whereas soil fungal communities differed most in 100% forb communities compared to other forb:grass ratio mixtures. Moreover, soil nitrate availability was higher after two years of plant growth, whereas the opposite was true for soil ammonium concentrations. Furthermore, total nematodes and especially bacterial‐feeding nematodes were more abundant after two years of plant growth. Our results show that plant community composition is a driving factor in soil microbial community assembly and that the duration of plant growth plays a crucial role in the establishment of plant community and functional group composition effects on abiotic and biotic soil ecosystem functioning under natural field conditions.

Highlights

Variations in climate and land use are leading to worldwide changes in plant communities, resulting in profound impacts on ecosystem functions and services (Sala et al 2000, Wardle et al 2011)
Root biomass decreased with increasing forb dominance after one year (Fig. 1D), whereas root biomass was similar across all plant community mixtures after 2 yr of plant growth (Appendix S1: Table S1; time 9 forb:grass ratio F3,88 = 3.71, P = 0.014)
Other soil extractable elements (K, P, S, Fe, Zn, and Mg) as well as pH and soil organic matter showed no differences between the duration of plant growth or any of the plant community treatments (Appendix S1: Table S2)

Summary

Introduction

Variations in climate and land use are leading to worldwide changes in plant communities, resulting in profound impacts on ecosystem functions and services (Sala et al 2000, Wardle et al 2011). This, in turn, has a major effect on soil microbial communities mineralizing organic matter and enhancing the release of nutrients by mineral weathering (Van der Krift and Berendse 2001, Lange et al 2014) Such plant-induced changes in substrate availability affect other parts of the soil community, comprising, for example, bacteria, fungi, and nematodes which all act as mutualists, decomposers, herbivores, or pathogens (Wardle et al 2003, De Deyn et al 2004, Wardle 2006). Plant species can be assigned to specific functional groups (such as grasses and forbs) differing in their functional trait compositions related to plant growth and resource acquisition Those can drive differences in above- and belowground community functioning (Finke and Snyder 2008, Cadotte et al 2009), which can alter both abiotic and biotic soil conditions (Ehrenfeld 2010, Lange et al 2014, Heinen et al 2018). Both forb and grass species are associated with distinctly different plant-feeding nematode communities (De Deyn et al 2004)

Methods

Results

Conclusion