Increasing Precipitation Interval Has More Impacts on Litter Mass Loss Than Decreasing Precipitation Amount in Desert Steppe

Hao Qu,Xia Tang,Eduardo Medina-Roldán,Xueyong Zhao,Xinyuan Wang,Jie Lian

doi:10.3389/fenvs.2020.00088

Abstract

Litter mass loss and nutrient release are key links in the material cycling and energy flowing in ecosystems and of special ecological significance in maintaining ecosystem stability, improving soil structure and promoting vegetation restoration in the arid and semi-arid regions. Furthermore, litter mass loss could be affected by the change in precipitation patterns. However, currently, most studies on the response of litter mass loss to precipitation pattern change focus on the precipitation amount much more than the precipitation frequency. Therefore, we conducted a three-year manipulative research in a desert steppe to assess the effects of decreasing precipitation amount and increasing precipitation interval on the litter mass loss of Stipa klemenzii, and their relationships with litter chemical traits (contents of carbon (C), nitrogen (N), phosphorus (P), potassium (K), lignin and ash, C/N ratio and lignin/N ratio) and abiotic factors (light intensity and temperature and humidity of soil and air). The results showed that (1) both the treatments have negative effects on litter mass loss; (2) for abiotic factors, both the treatments only affected soil moisture; for biotic factors, both the treatments decreased the litter lignin contents, the increased precipitation interval treatment decreased the litter N and K contents while increased the litter C/N ratio and lignin/N ratio; (3) the main control of litter mass loss was due to our manipulation of drought regime and its effects on the soil decomposition environment, rather to other factors such as litter quality or light intensity; (4) compare to decreased precipitation amount, increased precipitation interval has more impact on litter mass loss, and this was caused by the increased litter C/N ratio in increased precipitation interval treatment. We speculated that increased precipitation interval was a harsher abiotic factor for the decomposer, and more research on this should be conducted in the future.

Highlights

Global climate change has altered precipitation pattern and extended time intervals between precipitation events (Easterling et al, 2000; Intergovernmental Panel on Climate Change [IPCC], 2014)
We conclude that the main control of litter mass loss was due to our manipulation of drought regime and its effects on the soil decomposition environment, rather than to other factors such as litter quality or light intensity
We found that as two of the most common phenomena in precipitation patterns under global climate change, both increased precipitation interval and decreased precipitation amount have negative effects on litter mass loss in the desert steppe because of the reduced soil and litter humidity

Summary

Introduction

Global climate change has altered precipitation pattern and extended time intervals between precipitation events (Easterling et al, 2000; Intergovernmental Panel on Climate Change [IPCC], 2014). In arid and semi-arid regions, precipitation is the most important source of water (Easterling et al, 2000), and its spatial and temporal distribution determines plant colonization and growth, biomass production and distribution, litter mass loss, and nutrient release (Hobbie et al, 2001; Salinas et al, 2011). Among the biogeochemical cycles affected by precipitation, litter mass loss and nutrient release are key links in the material and energy cycle within an ecosystem and play a decisive role in soil properties and plant productivity (Zhang et al, 2013). In the arid and semi-arid regions, there is a special ecological significance of litter decomposition in maintaining ecosystem stability, improving soil structure, and promoting vegetation restoration (Cornwell et al, 2008)

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Results

Discussion

Conclusion