TY - JOUR A1 - De Frenne, Pieter A1 - Graae, Bente J. A1 - Brunet, Jörg A1 - Shevtsova, Anna A1 - De Schrijver, An A1 - Chabrerie, Olivier A1 - Cousins, Sara A. O. A1 - Decocq, Guillaume A1 - Diekmann, Martin A1 - Hermy, Martin A1 - Heinken, Thilo A1 - Kolb, Annette A1 - Nilsson, Christer A1 - Stanton, Sharon A1 - Verheyen, Kris T1 - The response of forest plant regeneration to temperature variation along a latitudinal gradient JF - Annals of botany N2 - The response of forest herb regeneration from seed to temperature variations across latitudes was experimentally assessed in order to forecast the likely response of understorey community dynamics to climate warming. Seeds of two characteristic forest plants (Anemone nemorosa and Milium effusum) were collected in natural populations along a latitudinal gradient from northern France to northern Sweden and exposed to three temperature regimes in growth chambers (first experiment). To test the importance of local adaptation, reciprocal transplants were also made of adult individuals that originated from the same populations in three common gardens located in southern, central and northern sites along the same gradient, and the resulting seeds were germinated (second experiment). Seedling establishment was quantified by measuring the timing and percentage of seedling emergence, and seedling biomass in both experiments. Spring warming increased emergence rates and seedling growth in the early-flowering forb A. nemorosa. Seedlings of the summer-flowering grass M. effusum originating from northern populations responded more strongly in terms of biomass growth to temperature than southern populations. The above-ground biomass of the seedlings of both species decreased with increasing latitude of origin, irrespective of whether seeds were collected from natural populations or from the common gardens. The emergence percentage decreased with increasing home-away distance in seeds from the transplant experiment, suggesting that the maternal plants were locally adapted. Decreasing seedling emergence and growth were found from the centre to the northern edge of the distribution range for both species. Stronger responses to temperature variation in seedling growth of the grass M. effusum in the north may offer a way to cope with environmental change. The results further suggest that climate warming might differentially affect seedling establishment of understorey plants across their distribution range and thus alter future understorey plant dynamics. KW - Anemone nemorosa KW - climate change KW - common garden KW - growth chambers KW - latitudinal gradient KW - local adaptation KW - Milium effusum KW - plant regeneration KW - range edges KW - recruitment KW - seedling establishment KW - temperature Y1 - 2012 U6 - https://doi.org/10.1093/aob/mcs015 SN - 0305-7364 VL - 109 IS - 5 SP - 1037 EP - 1046 PB - Oxford Univ. Press CY - Oxford ER - 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 -