10.5061/DRYAD.1154F
Saccone, Patrick
University of Oulu
Pyykkonen, Tuija
University of Oulu
Eskelinen, Anu
University of Oulu
University of California, Davis
Virtanen, Risto
University of Oulu
Data from: Environmental perturbation, grazing pressure and soil wetness
jointly drive mountain tundra toward divergent alternative states
Dryad
dataset
2015
alternative states
long-term experiment
species abundance distribution
multiple drivers
Joint effects
Tundra shrubification
2015-08-13T00:00:00Z
2015-08-13T00:00:00Z
en
https://doi.org/10.1111/1365-2745.12316
13244 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
1. Plant communities are structured by complex interactions between
multiple factors, which veil our understanding of the effects of
environmental changes on communities and ecosystems. Besides the relative
role of biotic and abiotic factors as community-structuring processes,
addressing how they jointly affect the ecological resilience and
resistance of plant communities is crucial to understand better the
long-term response of communities facing global changes. 2. Here, we used
the results from a long-term (23 years) perturbation experiment set up in
Fennoscandian mountain tundra to test these mechanisms. The experiment
consisted of a transplantation of twenty blocks of Vaccinium myrtillus
heath vegetation including upper soil layer from a lower elevation tundra
heath habitat to a snowbed habitat 150 m higher in elevation where V.
myrtillus lies at its upper limit. In the snowbed with contrasting levels
of soil wetness, half of the transplanted blocks were protected from
mammalian herbivores. 3. Our results revealed that in addition to the
important role of environmental conditions as a structuring force, the
joint effects of multiple drivers resulted in divergent patterns in both
plant functional composition and species diversity among transplanted
communities. Under environmental perturbation (i.e. transplantation to
snowbed), the heath vegetation was altered by grazing pressure that
reduced the cover of shrubs (especially V. myrtillus). In grazed dry
snowbed, a species rich community with high functional type evenness and
diversity developed. Reversely, in dry exclosures, V. myrtillus gained
high dominance associated with only few graminoids and forbs. In wet
snowbed conditions, shrubs tended to decline both in grazed plots and
exclosures whereas bryophytes attained high abundance. Grazing promoted
species richness while soil waterlogging tended to promote among-plot
heterogeneity (β-diversity) which was highest in wet exclosures. 4.
Synthesis Our long-term experiment reveals that environmental
perturbation, grazing and soil wetness exhibit joint effects that induce
divergent trajectories of tundra plant communities. We suggest that a
strong environmental perturbation triggers mountain tundra heath community
to move away from its equilibrium state. The outcome of this shift depends
on the interplay between grazing pressure and soil wetness that drive
tundra plant communities toward divergent alternative states.
Plot CompositionPlant cover visually estimated in percentage in the plots
of the transplant experiment and associated soil water content in % of dry
soil
mass.Saccone-JEcol-2014-0186-Plot-composition.txtSaccone-JEcol-2014-0186-species-namesThe complete species names of species and their abbreviated names (used as column names of the Plot composition file)
Fennoscandian tundra