Summer warming and increased winter snow cover affect Sphagnum fuscum growth, structure and production in a sub-arctic bog

Sphagnum mosses form a major component of northern peatlands, which are expected to experience substantially higher increases in temperature and winter precipitation than the global average. Sphagnum may play an important role in the responses of the global carbon cycle to climate change. We investi...

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Vydané v:Global change biology Ročník 10; číslo 1; s. 93 - 104
Hlavní autori: Dorrepaal, Ellen, Aerts, Rien, Cornelissen, Johannes H. C., Callaghan, Terry V., Van Logtestijn, Richard S. P.
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: Oxford, UK Blackwell Science Ltd 01.01.2004
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ISSN:1354-1013, 1365-2486
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Shrnutí:Sphagnum mosses form a major component of northern peatlands, which are expected to experience substantially higher increases in temperature and winter precipitation than the global average. Sphagnum may play an important role in the responses of the global carbon cycle to climate change. We investigated the responses of summer length growth, carpet structure and production in Sphagnum fuscum to experimentally induced changes in climate in a sub‐arctic bog. Thereto, we used open‐top chambers (OTCs) to create six climate scenarios including changes in summer temperatures, and changes in winter snow cover and spring temperatures. In winter, the OTCs doubled the snow thickness, resulting in 0.5–2.8°C higher average air temperatures. Spring air temperatures in OTCs increased by 1.0°C. Summer warming had a maximum effect of 0.9°C, while vapor pressure deficit was not affected. The climate manipulations had strong effects on S. fuscum. Summer warming enhanced the length increment by 42–62%, whereas bulk density decreased. This resulted in a trend (P<0.10) of enhanced biomass production. Winter snow addition enhanced dry matter production by 33%, despite the fact that the length growth and bulk density did not change significantly. The addition of spring warming to snow addition alone did not significantly enhance this effect, but we may have missed part of the early spring growth. There were no interactions between the manipulations in summer and those in winter/spring, indicating that the effects were additive. Summer warming may in the long term negatively affect productivity through the adverse effects of changes in Sphagnum structure on moisture holding and transporting capacity. Moreover, the strong length growth enhancement may affect interactions with other mosses and vascular plants. Because winter snow addition enhanced the production of S. fuscum without affecting its structure, it may increase the carbon balance of northern peatlands.
Bibliografia:ark:/67375/WNG-NFWS4DQB-1
ArticleID:GCB718
istex:2789B38A5C802D8242798C88427A4DC924D8768E
ObjectType-Article-2
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ISSN:1354-1013
1365-2486
DOI:10.1111/j.1365-2486.2003.00718.x