TY  - JOUR
A1  - Wieczorek, Mareike
A1  - Kruse, Stefan
A1  - Epp, Laura Saskia
A1  - Kolmogorov, Alexei
A1  - Nikolaev, Anatoly N.
A1  - Heinrich, Ingo
A1  - Jeltsch, Florian
A1  - Pestryakova, Luidmila Agafyevna
A1  - Zibulski, Romy
A1  - Herzschuh, Ulrike
T1  - Dissimilar responses of larch stands in northern Siberia to increasing temperatures-a field and simulation based study
JF  - Ecology : a publication of the Ecological Society of America
N2  - Arctic and alpine treelines worldwide differ in their reactions to climate change. A northward advance of or densification within the treeline ecotone will likely influence climate-vegetation feedback mechanisms. In our study, which was conducted in the Taimyr Depression in the North Siberian Lowlands, w present a combined field-and model-based approach helping us to better understand the population processes involved in the responses of the whole treeline ecotone, spanning from closed forest to single-tree tundra, to climate warming. Using information on stand structure, tree age, and seed quality and quantity from seven sites, we investigate effects of intra-specific competition and seed availability on the specific impact of recent climate warming on larch stands. Field data show that tree density is highest in the forest-tundra, and average tree size decreases from closed forest to single-tree tundra. Age-structure analyses indicate that the trees in the closed forest and forest-tundra have been present for at least similar to 240 yr. At all sites except the most southerly ones, past establishment is positively correlated with regional temperature increase. In the single-tree tundra, however, a change in growth form from krummholz to erect trees, beginning similar to 130 yr ago, rather than establishment date has been recorded. Seed mass decreases from south to north, while seed quantity increases. Simulations with LAVESI (Larix Vegetation Simulator) further suggest that relative density changes strongly in response to a warming signal in the forest-tundra while intra-specific competition limits densification in the closed forest and seed limitation hinders densification in the single-tree tundra. We find striking differences in strength and timing of responses to recent climate warming. While forest-tundra stands recently densified, recruitment is almost non-existent at the southern and northern end of the ecotone due to autecological processes. Palaeo-treelines may therefore be inappropriate to infer past temperature changes at a fine scale. Moreover, a lagged treeline response to past warming will, via feedback mechanisms, influence climate change in the future.
KW  - climate change
KW  - closed forest
KW  - dendroecology
KW  - forest change
KW  - latitude
KW  - recruitment
KW  - tundra
KW  - vegetation model
Y1  - 2017
U6  - https://doi.org/10.1002/ecy.1887
SN  - 0012-9658
SN  - 1939-9170
VL  - 98
SP  - 2343
EP  - 2355
PB  - Wiley
CY  - Hoboken
ER  -