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Abstract Detail



Ecology

Ronk, Argo [1], Liancourt, Pierre [2], Petraitis, Peter [1], Casper, Brenda [1].

In the Mongolian steppe, plant community response to warming depends on precipitation, grazing and landscape location.

Global climate change in concert with other anthropogenic drivers is affecting biodiversity by causing shifts in species ranges and abundances. Continuing climate change will shape local plant community compositions, but the magnitude of change may well vary with location, even within the same region, and depend on interactions among climate change factors and with land use. We set up a four-year field experiment to examine how climate change will affect the semiarid, northern Mongolian steppe, which supports pastoral nomads as it has for millennia. This region is predicted to experience an above average temperature increase, but it is not certain how the precipitation regime will change. We first wanted to determine if passive warming created by open top chambers (OTCs) had similar consequences at two locations within the landscape that differ in aspect, ambient conditions, and species composition. Then, on the warmer, more arid, upper slope location we crossed the OTC treatment with a supplemental watering treatment. On the cooler, more productive, lower slope location, we crossed the OTC with grazing. We examined changes to the community composition as a whole and also changes to particular plant groups: generalist species found at both slope locations, specialists found at one location only, graminoids, and forbs. OTCs affected plant community composition, but the magnitude differed at the two slope locations as shown by Canonical Analysis of Principal Coordinates (CAP). At the community level, the response to warming was greater at the more productive lower slope compared to drier upper slope and was especially pronounced in the last year of the experiment. On the upper slope, the warming effect was increased by water addition; plots with warming and watering showed a greater difference from controls than plots with warming only. Generalists and forbs decreased with warming on the upper slope; graminoids decreased and forbs increased with watering. On the lower slope, both warming and grazing affected community composition, but the effect of warming was greater. Generalists increased and specialists decreased with grazing. Warming by itself did not affect any particular plant group, but warming and grazing interacted to affect the abundance of specialists. Our results show the importance of taking landscape-scale variation into account in climate change studies and that warming will interact with changes in precipitation and land use to affect the relative abundance of species, and hence community composition.


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1 - University of Pennsylvania, Biology, Philadelphia, PA, 19104-6018, USA
2 - Academy of Sciences of the Czech Republic, Institute of Botany, Trebon, Czech Republic

Keywords:
warming
climate
grazing
precipitation
steppe
Mongolia.

Presentation Type: Oral Paper
Session: 11, Ecology Section - Population Biology
Location: Sundance 5/Omni Hotel
Date: Monday, June 26th, 2017
Time: 2:00 PM
Number: 11003
Abstract ID:251
Candidate for Awards:None


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