Changes Versus Homeostasis in Alpine and Sub-Alpine Vegetation Over Three Decades in the Sub-Arctic

Abstract

Plant species distributions are expected to shift and diversity is expected to decline as a result of global climate change, particularly in the Arctic where climate warming is amplified. We have recorded the changes in richness and abundance of vascular plants at Abisko, subArctic Sweden, by re-sampling five studies consisting of seven datasets; one in the mountain birch forest and six at open sites. The oldest study was initiated in 1977-1979 and the latest in 1992. Total species number increased at all sites except for the birch forest site where richness decreased. We found no general pattern in how composition of vascular plants has changed over time. Three species, Calamagrostis lapponica, Carex vaginata and Salix reticulata, showed an overall increase in cover/frequency, while two Equisetum taxa decreased. Instead, we showed that the magnitude and direction of changes in species richness and composition differ among sites.

Ecosystem change and stability over multiple decades in the Swedish subarctic: complex processes and multiple drivers

“…At the Carlsson & Callaghan [108] Overall, and including an open meadow site (see §4a(iv)), total species number increased over the sampling period and substantially at some sites. This contrasts with the overall decrease expected from warming experiments [99] although observations on species changes in cold region open vegetation vary between increases and decreases [95]. Although an increase in thermophilic species would be expected, no overall increase was observed [95].…”

“…At fine-scale resolution (50 m grid cells), modelled summer degree-day temperature change [28] ranges between 598C and 658C (see figure 2 and electronic supplementary material, [84] heaths evergreen shrub expansion 1995-2006 (factor of change) [38] heaths shrub expansion 1999-2008 (factor of change) [100] heaths biomass change 1998-2011 (factor of change) [13] shrubs expansion 1976-2010 (% change min/mean/max) [83] no. vascular understorey species (annual increase/decrease) [95] ground cover bedrock and blocks birch forest bog, fen, and mire built-up area heath meadow snow-bed and glacier water willow wetland vegetation change 1970-2007 (factor of shrub/grass/others) [53] no. vascular meadow species (annual increase/decrease) [95] no.…”

“…vascular meadow species (annual increase/decrease) [95] no. vascular heath species (annual increase/decrease) [95] f o r e s t birch tree-line change 1912-2009 (metre elevation shift) [16] understorey shrub change 1991-2009 (evergreens versus deciduous) [95,96] understorey change 1991-2009 (factor of change, shrubs versus others) [57] birch forestation 1906-1986 (degree of change 0-1) [58] aspen versus birch 1900-2007 (factor of change) [74] aspen species line 1904-2009 (dotted versus solid lines) [33] biomass change 1997-2010 (t ha -1 min/mean/max) [81] mountain and vegetation maps with courtesy of Lantmäteriet, Sweden rstb.royalsocietypublishing.org Phil Trans R Soc B 368: 20120488 from 26.8 to þ0.68C across the study area (see figure 4 and electronic supplementary material, table 1). There is a notable diminishing of differences in the rate of warming between north-and south-facing slopes (see figure 2 and electronic supplementary material, table S1).…”

“…The re-sampling of PMK plots established in a meadow at Påtjujaure in 1983 by Hedenås et al [95] in 2008 showed a significant increase in 11 species and a decrease in seven. Equisetum arvense and E. scirpoides/ variegatum decreased in cover [95], perhaps in response to recent decreases in snow depth (see [112] which describes this effect for the area surrounding Wellington Bay on southeastern Victoria Island, Canada). At Latnjajaure also, the species turnover in alpine meadow vegetation has been very significant over the past 20 years [10].…”

The Man, the Myth, the Legend: Professor Terry V. Callaghan and His 3M Concept

“…Hence, this special issue presents papers on monitoring Hedenås et al 2012;Körner 2012;Christensen et al 2012), on manipulations (Michelsen et al 2012;Cornelissen et al 2012;Bokhorst et al 2012;Gwynn-Jones et al 2012;Keuper et al 2012), and finally, papers on modeling (Miller and Smith 2012;Yang et al 2012;Hein et al 2012). Fig.…”