Warming decreases desert ecosystem functioning by altering biocrusts in drylands

Journal Article · Fri Nov 10 04:00:00 EST 2023 · Journal of Applied Ecology

DOI:https://doi.org/10.1111/1365-2664.14528· OSTI ID:2331441

Li, Xinrong ^[1]; Sun, Jingyao ^[2]; Zhang, Hongxia ^[2]; Tan, Huijuan ^[2]; Hui, Rong ^[2]; Qi, Jinghua ^[2]; Zhang, Peng ^[2]; Ward, Nicholas D. ^[3]

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1. Chinese Academy of Sciences (CAS), Lanzhou (China); Ningxia University, Yinchuan (China)
2. Chinese Academy of Sciences (CAS), Lanzhou (China)
3. Pacific Northwest National Laboratory (PNNL), Sequim, WA (United States). Marine Sciences Laboratory; University of Washington, Seattle, WA (United States)

Warming and precipitation fluctuations are changing desert ecosystems in global drylands. However, the effects of climate change on keystone species such as cryptogamic biocrust in drylands remain relatively under-investigated, even though biocrusts play a vital role in desert ecosystems. Here we conducted a long-term experiment (14 years) to simulate the responses of two main types of biocrusts to warming coupled with reduction in precipitation that was achieved by open-top chambers (OTCs) to simulate the predicted warming and precipitation decreasing under climate change scenario. We also conduct a structural analysis to evaluate the resulting changes in desert ecosystem functioning (carbon and nitrogen cycling). Neither warming and corresponding rainfall reduction treatments had a negative effect on lichen species richness, but both treatments reduced lichen cover and biomass. The negative effects of warming on moss-dominated crusts were much greater than those on lichen-dominated crusts. Although mosses and lichens had varying degree responses to warming, the loss of mosses and decreased lichen cover and biomass, as well as the shortening of the wet time, resulted in a reduction in carbon and nitrogen fixation, soil enzyme activity and water-holding capacity of biocrusts and topsoil. These impacts collectively change the water balance of drylands and weaken the hydrological and biogeochemical function of biocrusts. Synthesis and applications: Results from this long-term experiment suggest that the ecosystem C and N cycling and water balance of global drylands may be highly impacted by climate change, in part because of the response of biocrusts, which contribute an important implication for both dryland restoration and earth system dynamics.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Science (SC); National Natural Science Foundation of China; Gansu Provincial Major Science and Technology
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 2331441
• Report Number(s): PNNL-SA--176642
• Journal Information: Journal of Applied Ecology, Journal Name: Journal of Applied Ecology Journal Issue: 12 Vol. 60; ISSN 0021-8901
• Publisher: British Ecological Society
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
biocrust keystone species
carbon and nitrogen fixation
climate change
ecosystem functioning