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- Elmendorf, Sarah C., et al.
(author)
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Global assessment of experimental climate warming on tundra vegetation : heterogeneity over space and time
- 2012
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In: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 15:2, s. 164-175
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Research review (peer-reviewed)abstract
- Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20 years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation and associated ecosystem consequences have the potential to be much greater than we have observed to date.
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| 2. |
- Lazaro, Amparo, et al.
(author)
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How do pollinator visitation rate and seed set relate to species' floral traits and community context?
- 2013
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In: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 173:3, s. 881-893
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Journal article (peer-reviewed)abstract
- Differences among plant species in visitation rate and seed set within a community may be explained both by the species' floral traits and the community context. Additionally, the importance of species' floral traits vs. community context on visitation rate and seed set may vary among communities. In communities where the pollinator-to-flower ratio is low, floral traits may be more important than community context, as pollinators may have the opportunity to be choosier when visiting plant species. In this study we investigated whether species' floral traits (flower shape, size and number, and flowering duration) and community context (conspecific and heterospecific flower density, and pollinator abundance) could explain among-species variation in visitation rate and seed set. For this, we used data on 47 plant species from two Norwegian plant communities differing in pollinator-to-flower ratio. Differences among species in visitation rate and seed set within a community could be explained by similar variables as those explaining visitation rate and seed set within species. As expected, we found floral traits to be more important than community context in the community with a lower pollinator-to-flower ratio; whereas in the community with a higher pollinator-to-flower ratio, community context played a bigger role. Our study gives significant insights into the relative importance of floral traits on species' visitation rate and seed set, and contributes to our understanding of the role of the community context on the fitness of plant species.
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