Community carbon and water exchange responses to warming and precipitation enhancement in sandy grassland along a restoration gradient.

Juanli Chen,Xueyong Zhao,Xiaoan Zuo,Yayong Luo,Rui Zhang,Yulin Li,Peng Lv,Tonghui Zhang

doi:10.1002/ece3.5490

Juanli Chen, Xueyong Zhao + Show 6 more

Open Access

https://doi.org/10.1002/ece3.5490

Copy DOI

Abstract

Temperature increasing and precipitation alteration are predicted to occur in arid and semiarid lands; however, the response mechanism of carbon and water exchange at community level is still unclear in semiarid sandy land. We investigated the responses of carbon and water exchanges to warming and precipitation enhancement along a sand dune restoration gradient: mobile sand dunes (MD), semifixed sand dunes (SFD), and fixed sand dunes (FD). The average net ecosystem productivity (NEP) and evapotranspiration (ET) between May and August increased by 98% and 59%, respectively, from MD to SFD, while they had no significant differences between FD and the other two habitats. Warming inhibited ecosystem NEP, ET, and water use efficiency (WUE) by 69%, 49% (p < .001), and 80%, respectively, in SFD, while it nearly had no significant effects in MD and FD. However, precipitation addition by 30% nearly had no significant effects on community NEP, ET, and WUE, except for warming treatment in FD. In general, precipitation addition of 30% may still not be enough to prevent drought stress for growth of plants, due to with low water holding capacity and high evaporation rates in sandy land. Temperature increase magnified drought stress as it increased evapotranspiration rates especially in summer. In addition, community NEP, ET, and WUE were usually influenced by interactions between habitats and temperature, as well as the interactions among habitats, temperature, and precipitation. Species differences in each habitat along the restoration gradient may alter climate sensitivity of sandy land. These results will support in understanding and the prediction of the impacts of warming and precipitation change in semiarid sandy grassland.

Highlights

Sandy land ecosystems play a significant role in carbon sequestra‐ tion (Zuo et al, 2015) due to their large area in many parts of the world, especially in China
The average community net ecosystem productivity (NEP) and ET between May and August increased by 98% (p = .006) and 59%
The results showed smaller differences in community NEP among the three habitats, and even higher NEP in semifixed dunes (SFD) than fixed sand dunes (FD), were found in July

Summary

| INTRODUCTION

Sandy land ecosystems play a significant role in carbon sequestra‐ tion (Zuo et al, 2015) due to their large area in many parts of the world, especially in China. Results showed that sandy land has large carbon (C) sequestration potential under beneficial conditions (Miao et al, 2015), but may turn into a large C source under unfavorable conditions such as overgrazing (Brunet & Larson‐ Rabin, 2012) These areas are vulnerable to climate and land use change, leading to uncertainty in their contributions to regional and global carbon budgets (Brunet & Larson‐Rabin, 2012). Altered precipitation regimes represent a sensitive and dramatic impact on plant photosynthesis, growth, and productivity (Salazar‐ Parra et al, 2015), especially in arid and semiarid regions (Yue, Zhang, Zhao, Liu, & Ma, 2016). In order to understand the impacts of projected changes in both warming and precipitation enhancement on the community carbon and water exchange of sandy grassland ecosystems, we conducted a warming and water addition experiment in sand dunes along a res‐ toration gradient in northeastern China. We hypothesized that (a) NEP would increase along a sand dunes restoration gradient; (b) warming would inhibit NEP; and (c) water addition would enhance NEP in temperate semiarid sand dunes

| MATERIALS AND METHODS

| DISCUSSION

Findings

| CONCLUSION

CONFLICT OF INTEREST