摘要:Sustainability of tundra vegetation under changing climate on the Yamal Peninsula,
northwestern Siberia, home to the world's largest area of reindeer husbandry, is of crucial
importance to the local native community. An integrated investigation is needed for better
understanding of the effects of soils, climate change and grazing on tundra vegetation in
the Yamal region. In this study we applied a nutrient-based plant community
model—ArcVeg—to evaluate how two factors (soil organic nitrogen (SON) levels and
grazing) interact to affect tundra responses to climate warming across a latitudinal climatic
gradient on the Yamal Peninsula. Model simulations were driven by field-collected soil data
and expected grazing patterns along the Yamal Arctic Transect (YAT), within bioclimate
subzones C (high arctic), D (northern low arctic) and E (southern low arctic). Plant
biomass and NPP (net primary productivity) were significantly increased with warmer
bioclimate subzones, greater soil nutrient levels and temporal climate warming,
while they declined with higher grazing frequency. Temporal climate warming of
2 °C caused an
increase of 665 g m−2 in total biomass at the high SON site in subzone E, but only
298 g m−2 at the low SON site. When grazing frequency was also increased, total biomass increased by only
369 g m−2 at the high SON
site in contrast to 184 g m−2 at the low SON site in subzone E. Our results suggest that high SON can support greater
plant biomass and plant responses to climate warming, while low SON and grazing may
limit plant response to climate change. In addition to the first order factors (SON,
bioclimate subzones, grazing and temporal climate warming), interactions among these
significantly affect plant biomass and productivity in the arctic tundra and should not be
ignored in regional scale studies.