Earth surface processes drive the richness, composition and occurrence of plant species in an arctic–alpine environment

• Published in: Journal of Vegetation Science
• Main Authors: le Roux, Peter C., Luoto, Miska
• Other Authors: Michalet, Richard, Academy of Finland
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2013
• Subjects: Tundra
• Online Access: http://dx.doi.org/10.1111/jvs.12059; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjvs.12059; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jvs.12059

Abstract Questions Are earth surface processes ( ESP s) important determinants of species richness, composition and fine‐scale distributions? Do different ESP s have similar effects on these vegetation characteristics? Location Saana massif, northwest Finland (69 °N). Methods Vascular plant species occurrences, five environmental variables (related to soil conditions and topography) and five ESP s were surveyed across 960 1‐m 2 quadrats in arctic–alpine tundra. Community composition was examined using non‐metric multi‐dimensional scaling ( NMDS ), while species richness and individual species occurrence were modelled using GLM s, GAM s and boosted regression trees. Results Three ESP s (solifluction, fluvial activity and nivation) were strongly related to community composition, with only soil moisture and mesotopography exhibiting stronger correlations with NMDS scores. ESP s significantly improved the accuracy of species richness models based on soil conditions and topography, with solifluction and fluvial processes having the largest individual contributions. Solifluction and fluvial activity also increased the predictive power of species distribution models, with these processes often being as influential on occurrence patterns as some of the traditionally utilized direct and resource variables. Arctic–alpine species generally responded positively to ESP s, with boreal species showing the opposite trend. Conclusions This study, the first to examine the impacts of several independent ESP s on multiple vegetation characteristics, demonstrates that ESP s are primary drivers of species fine‐scale distributions, species richness and community composition in arctic–alpine plant communities. ESP s varied in their effect and relative influence, and thus several ESP s need to be considered when examining species‐ and community‐level properties of vegetation.