@article{CaronDeFrenneBrunetetal.2014, author = {Caron, Maria Mercedes and De Frenne, P. and Brunet, J. and Chabrerie, Olivier and Cousins, S. A. O. and De Backer, L. and Diekmann, M. and Graae, B. J. and Heinken, Thilo and Kolb, A. and Naaf, T. and Plue, J. and Selvi, F. and Strimbeck, G. R. and Wulf, Monika and Verheyen, Kris}, title = {Latitudinal variation in seeds characteristics of Acer platanoides and A. pseudoplatanus}, series = {Plant ecology : an international journal}, volume = {215}, journal = {Plant ecology : an international journal}, number = {8}, publisher = {Springer}, address = {Dordrecht}, issn = {1385-0237}, doi = {10.1007/s11258-014-0343-x}, pages = {911 -- 925}, year = {2014}, abstract = {Climate change will likely affect population dynamics of numerous plant species by modifying several aspects of the life cycle. Because plant regeneration from seeds may be particularly vulnerable, here we assess the possible effects of climate change on seed characteristics and present an integrated analysis of seven seed traits (nutrient concentrations, samara mass, seed mass, wing length, seed viability, germination percentage, and seedling biomass) of Acer platanoides and A. pseudoplatanus seeds collected along a wide latitudinal gradient from Italy to Norway. Seed traits were analyzed in relation to the environmental conditions experienced by the mother trees along the latitudinal gradient. We found that seed traits of A. platanoides were more influenced by the climatic conditions than those of A. pseudoplatanus. Additionally, seed viability, germination percentage, and seedling biomass of A. platanoides were strongly related to the seed mass and nutrient concentration. While A. platanoides seeds were more influenced by the environmental conditions (generally negatively affected by rising temperatures), compared to A. pseudoplatanus, A. platanoides still showed higher germination percentage and seedling biomass than A. pseudoplatanus. Thus, further research on subsequent life-history stages of both species is needed. The variation in seed quality observed along the climatic gradient highlights the importance of studying the possible impact of climate change on seed production and species demography.}, language = {en} } @article{CaronDeFrenneBrunetetal.2015, author = {Caron, Maria Mercedes and De Frenne, Pieter and Brunet, J{\"o}rg and Chabrerie, Olivier and Cousins, Sara A. O. and Decocq, Guillaume and Diekmann, Martin and Graae, Bente Jessen and Heinken, Thilo and Kolb, Annette and Lenoir, Jonathan and Naaf, Tobias and Plue, Jan and Selvi, Federico and Wulf, Monika and Verheyen, Kris}, title = {Divergent regeneration responses of two closely related tree species to direct abiotic and indirect biotic effects of climate change}, series = {Forest ecology and management}, volume = {342}, journal = {Forest ecology and management}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0378-1127}, doi = {10.1016/j.foreco.2015.01.003}, pages = {21 -- 29}, year = {2015}, abstract = {Changing temperature and precipitation can strongly influence plant reproduction. However, also biotic interactions might indirectly affect the reproduction and recruitment success of plants in the context of climate change. Information about the interactive effects of changes in abiotic and biotic factors is essential, but still largely lacking, to better understand the potential effects of a changing climate on plant populations. Here we analyze the regeneration from seeds of Acer platanoides and Acer pseudoplatanus, two currently secondary forest tree species from seven regions along a 2200 km-wide latitudinal gradient in Europe. We assessed the germination, seedling survival and growth during two years in a common garden experiment where temperature, precipitation and competition with the understory vegetation were manipulated. A. platanoides was more sensitive to changes in biotic conditions while A. pseudoplatanus was affected by both abiotic and biotic changes. In general, competition reduced (in A. platanoides) and warming enhanced (in A. pseudoplatanus) germination and survival, respectively. Reduced competition strongly increased the growth of A. platanoides seedlings. Seedling responses were independent of the conditions experienced by the mother tree during seed production and maturation. Our results indicate that, due to the negative effects of competition on the regeneration of A. platanoides, it is likely that under stronger competition (projected under future climatic conditions) this species will be negatively affected in terms of germination, survival and seedling biomass. Climate-change experiments including both abiotic and biotic factors constitute a key step forward to better understand the response of tree species' regeneration to climate change. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{DeFrenneBlondeelBrunetetal.2018, author = {De Frenne, Pieter and Blondeel, H. and Brunet, J. and Caron, M. M. and Chabrerie, O. and Cougnon, M. and Cousins, S. A. O. and Decocq, G. and Diekmann, M. and Graae, B. J. and Hanley, M. E. and Heinken, Thilo and Hermy, M. and Kolb, A. and Lenoir, J. and Liira, J. and Orczewska, A. and Shevtsova, A. and Vanneste, T. and Verheyen, K.}, title = {Atmospheric nitrogen deposition on petals enhances seed quality of the forest herb Anemone nemorosa}, series = {Plant biology}, volume = {20}, journal = {Plant biology}, number = {3}, publisher = {Wiley}, address = {Hoboken}, issn = {1435-8603}, doi = {10.1111/plb.12688}, pages = {619 -- 626}, year = {2018}, abstract = {Elevated atmospheric input of nitrogen (N) is currently affecting plant biodiversity and ecosystem functioning. The growth and survival of numerous plant species is known to respond strongly to N fertilisation. Yet, few studies have assessed the effects of N deposition on seed quality and reproductive performance, which is an important life-history stage of plants. Here we address this knowledge gap by assessing the effects of atmospheric N deposition on seed quality of the ancient forest herb Anemone nemorosa using two complementary approaches. By taking advantage of the wide spatiotemporal variation in N deposition rates in pan-European temperate and boreal forests over 2years, we detected positive effects of N deposition on the N concentration (percentage N per unit seed mass, increased from 2.8\% to 4.1\%) and N content (total N mass per seed more than doubled) of A.nemorosa seeds. In a complementary experiment, we applied ammonium nitrate to aboveground plant tissues and the soil surface to determine whether dissolved N sources in precipitation could be incorporated into seeds. Although the addition of N to leaves and the soil surface had no effect, a concentrated N solution applied to petals during anthesis resulted in increased seed mass, seed N concentration and N content. Our results demonstrate that N deposition on the petals enhances bioaccumulation of N in the seeds of A.nemorosa. Enhanced atmospheric inputs of N can thus not only affect growth and population dynamics via root or canopy uptake, but can also influence seed quality and reproduction via intake through the inflorescences.}, language = {en} }