Responses of a subarctic dwarf shrub heath community to simulated environmental change

• Published in: Journal of Ecology
• Main Authors: Press, M.C., Potter, J.A., Burke, M.J.W., Callaghan, T.V., Lee, J.A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1998
• Subjects: Subarctic
• Online Access: http://dx.doi.org/10.1046/j.1365-2745.1998.00261.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-2745.1998.00261.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2745.1998.00261.x; https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2745.1998.00261.x

1 A dwarf shrub heath in subarctic Sweden was subjected to factorial manipulation of air temperature, water and nutrient supply for 5 years. The responses of the vegetation to the perturbations were then assessed by point intercept (quadrat) analysis followed by determination of above‐ground biomass. 2 Nineteen vascular and 23 non‐vascular species (or species groups) were recorded and the most dramatic response was that of the grass Calamagrostis lapponica to nutrient addition, with abundance being stimulated by a factor of more than 18 compared with plots not subjected to nutrient addition. Calamagrostis lapponica did not show any significant responses to temperature or water alone but there was a synergistic interaction between all three variables. 3 The abundance of the dominant dwarf shrubs ( Empetrum hermaphroditum , Vaccinium vitis‐idaea , V. myrtillus and V. uliginosum ) was unaffected by the perturbations but elevated temperature stimulated the biomass of V. uliginosum by 125% and total shrub biomass by 16%. The low ratio of current year's growth to standing biomass may have concealed other responses of the dwarf shrub group to the perturbations. 4 The response of the non‐vascular flora to the perturbations was either neutral or negative, with lichens showing the most dramatic responses. Lichen biomass on temperature‐ and nutrient‐amended plots was 56% and 18%, respectively, of that on unperturbed plots. Nutrients also exerted a negative effect on the biomass of bryophytes, and the combined biomass of lichens and bryophytes on nutrient‐treated plots was almost a third of that on plots which did not receive additional nutrients. 5 Total above‐ground biomass was not affected by the perturbations but the total number of interceptions determined by point quadrat analysis was greater on the elevated temperature and nutrient‐treated plots. Point quadrat analysis also revealed an accumulation of litter and standing dead material in response to the nutrient and temperature perturbations, both singly and in ...