Linking small-scale topography with microclimate, plant species diversity and intra-specific trait variation in an alpine landscape

Abstract

Background: Small-scale topographic complexity is a characteristic feature of alpine landscapes, with important effects on alpine plant distribution.

Aims: We investigated the links between small-scale topographic complexity and resultant microclimatic heterogeneity, vascular-plant species richness and beta diversity, and realised niche width and trait variation of some target species.

Methods: We recorded temperature and soil moisture within 10 sites (40 m × 40 m) of differing topographic complexity in alpine terrain at Finse, Norway (N 60° 36ʹ, E 7° 33ʹ). Plant species occurrence and traits of target species were recorded in 16 sample plots at each site.

Results: Sites differed significantly in microclimatic heterogeneity, and topographically rough sites were always more heterogeneous than flatter ones. Greater species richness and turnover was associated with greater microclimatic heterogeneity, and rough sites contained 15–55% more species than flatter ones. Plant species had on average wider realised niches when growing at rough sites. Individuals of Bistorta vivipara, but not those of Luzula spicata, tended to exhibit greater phenotypic variation at rough sites.

Conclusions: Rough alpine terrains create small-scale variation in microclimate, promoting species richness and beta diversity. In the event of climate change, small-scale microclimatic heterogeneity might allow plant species to escape from regional climate change by short-distance migration to local micro-refugia. This study suggests that the opportunity for such responses would be greater in topographically complex terrains.

Keywords:

• alpine plants
• beta diversity
• Bistorta vivipara
• climate change
• Luzula spicata
• microclimatic heterogeneity
• phenotypic variation
• topography

Acknowledgements

The authors would like to thank the staff at Finse Alpine Research Center for their hospitality during field work and E. Gardiner for help in the field. We thank V. Vandvik, B. Blonder, J. Stöcklin, C. Randin, two anonymous reviewers and the editor for valuable comments and discussion on previous versions of this manuscript.

Additional information

Funding

This study was supported by the ‘Stay or Go’ network funded by Nordforsk (Project number 29662 to BJG).

Notes on contributors

Øystein H. Opedal

Øystein H. Opedal is a Ph.D. candidate in Evolutionary Biology and is interested in global change biology, community ecology and plant evolutionary ecology.

W. Scott Armbruster

Scott Armbruster is a Professor of Ecology and Evolution, with an interest in floral morphological evolution and the evolution of plant–animal interactions.

Bente J. Graae

Bente Jessen Graae is Professor in Plant Ecology. Her research mainly focuses on climate change impacts on vegetation in arctic, alpine and forest ecosystems.