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Climate change manipulations alter biodiversity and biogeochemistry of a temperate grassland community

Kerstin Grant1, Juergen Kreyling2, Carl Beierkuhnlein2, Julia Walter1, Anke Jentsch1
1 Disturbance Ecology, University of Bayreuth
2 Biogeography, University of Bayreuth

O 5.7 in Linking biodiversity and biogeochemistry

15.07.2014, 15:50-16:10, H19

Increasing temperatures and more extreme precipitation regimes are likely to alter plant productivity and community composition, with potential consequences for biogeochemical processes such as decomposition or ecosystem services such as forage quantity and quality of grasslands.

Here, we present the responses of aboveground production and community composition to altered intra-annual precipitation variability (including spring or summer drought combined with heavy rain pulses as well as regular irrigation) interacting with winter versus summer warming over five years in a temperate grassland. We further show how increased intra-annual precipitation variability altered nutritive values and decomposition of the grassland.

Both, winter warming and high precipitation variability with spring drought events, favored forbs over grasses. Species evenness decreased when summer warming coincided with increased precipitation variability. Thus, less variable precipitation regimes during warmer summer favoured an even distribution of species. Increased crude protein content and reduced fiber content with increasing precipitation variability improved the forage quality. Decomposition was reduced by increasing precipitation variability and unaffected by warming.

Alterations in the plant community composition and plant senescence seem to be the main drivers of forage quality change. Furthermore, seasonality of climatic factors, here early vs. late drought events in the high precipitation variability treatments, was decisive for shifts in community composition but not for decreases in ANPP. Decomposition, however, was mainly driven by reduced soil biotic activity rather than by altered litter quality. Timing of chronic warming, here winter vs. summer, affected the direction of response of both, community composition and ANPP. Taken together, these results imply that biodiversity and biogeochemistry are both altered by increased precipitation variability and seasonal warming, with no clear cause-and-effect chain among each other despite manifold potential links. Furthermore, the seasonality of climate change might indirectly affect ecosystem processes and species interactions and should receive more attention in climate change research.

References:

Grant K, Kreyling J, Dienstbach L, Beierkuhnlein C, Jentsch A (2014) Water stress due to increased intra-annual precipitation variability reduced forage yield but raised forage quality of a temperate grassland. Agriculture, Ecosystems and Environment 186:11-22
Grant K, Kreyling J, Beierkuhnlein C, Jentsch A (in review) Importance of seasonality for response to precipitation variability and warming in a temperate grassland, Journal of Ecology
Walter J, Hein R, Beierkuhnlein C, Hammerl V, Jentsch A, Schaedler M, Schuerings J, Kreyling J (2013) Combined effects of multifactor climate change and land-use on decomposition in temperate grassland. Soil Biology & Biochemistry 60: 10-18

 



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last modified 2014-06-19