A cross-continental comparison of phenology, leaf dynamics and dry matter allocation in arctic and temperate zone herbaceous plants from contrasting altitudes

摘要

Here we investigate, across a wide range of latitudes and altitudes, the commonness of and differences in a number of key features related to growth and development of herbaceous plants of cold climates in comparison to warmer climates. In order to separate genotypic from phenotypic characteristics, we made reciprocal transplants of populations of the same or closely related species. We used plants from high and low altitude in the Tyrolian Alps (47°N, 2600 m and 600 m altitude) and the northern Scandes near Abisko (68°N, 1150 m and 380 m) plus a low altitude site in Spitzbergen (79°N, 50 m). The most important genera in this comparison were Ranunculus and Geum. In situ, our results show relatively small altitudinal and latitudinal differences in parameters like leaf weight ratio and leaf life span (except Spitzbergen), whereas differences in specific leaf area and fine root weight ratio were pronounced. Reciprocal latitudinal transplants within the alpine or lowland life zone revealed strong but species-specific phenorhythmic disorder related to photoperiod. We conclude that in a warming climate temperature-opportunistic species (e.g. Geum spp.) will profit in terms of biomass production and reproduction, while strongly photoperiod-controlled species (e.g. Ranunculus glacialis) will benefit little or not. These findings re-emphasize the need for considering phenology in predictive models of vegetation changes.