TY  - JOUR
A1  - Plue, Jan
A1  - De Frenne, Pieter
A1  - Acharya, Kamal
A1  - Brunet, Jörg
A1  - Chabrerie, Olivier
A1  - Decocq, Guillaume
A1  - Diekmann, Martin
A1  - Graae, Bente J.
A1  - Heinken, Thilo
A1  - Hermy, Martin
A1  - Kolb, Annette
A1  - Lemke, Isgard
A1  - Liira, Jaan
A1  - Naaf, Tobias
A1  - Verheyen, Kris
A1  - Wulf, Monika
A1  - Cousins, Sara A. O.
T1  - Where does the community start, and where does it end?
BT  - including the seed bank to reassess forest herb layer responses to the environment
JF  - Journal of vegetation science
N2  - QuestionBelow-ground processes are key determinants of above-ground plant population and community dynamics. Still, our understanding of how environmental drivers shape plant communities is mostly based on above-ground diversity patterns, bypassing below-ground plant diversity stored in seed banks. As seed banks may shape above-ground plant communities, we question whether concurrently analysing the above- and below-ground species assemblages may potentially enhance our understanding of community responses to environmental variation. LocationTemperate deciduous forests along a 2000km latitudinal gradient in NW Europe. MethodsHerb layer, seed bank and local environmental data including soil pH, canopy cover, forest cover continuity and time since last canopy disturbance were collected in 129 temperate deciduous forest plots. We quantified herb layer and seed bank diversity per plot and evaluated how environmental variation structured community diversity in the herb layer, seed bank and the combined herb layer-seed bank community. ResultsSeed banks consistently held more plant species than the herb layer. How local plot diversity was partitioned across the herb layer and seed bank was mediated by environmental variation in drivers serving as proxies of light availability. The herb layer and seed bank contained an ever smaller and ever larger share of local diversity, respectively, as both canopy cover and time since last canopy disturbance decreased. Species richness and -diversity of the combined herb layer-seed bank community responded distinctly differently compared to the separate assemblages in response to environmental variation in, e.g. forest cover continuity and canopy cover. ConclusionsThe seed bank is a below-ground diversity reservoir of the herbaceous forest community, which interacts with the herb layer, although constrained by environmental variation in e.g. light availability. The herb layer and seed bank co-exist as a single community by means of the so-called storage effect, resulting in distinct responses to environmental variation not necessarily recorded in the individual herb layer or seed bank assemblages. Thus, concurrently analysing above- and below-ground diversity will improve our ecological understanding of how understorey plant communities respond to environmental variation.
KW  - Above-ground
KW  - Below-ground
KW  - Canopy
KW  - Disturbance
KW  - Diversity
KW  - Light availability
KW  - NWEurope
KW  - Plant community
KW  - Species co-existence
KW  - Storage effect
Y1  - 2017
U6  - https://doi.org/10.1111/jvs.12493
SN  - 1100-9233
SN  - 1654-1103
VL  - 28
IS  - 2
SP  - 424
EP  - 435
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Caron, Maria Mercedes
A1  - De Frenne, Pieter
A1  - Brunet, J.
A1  - Chabrerie, Olivier
A1  - Cousins, S. A. O.
A1  - De Backer, L.
A1  - Decocq, G.
A1  - Diekmann, M.
A1  - Heinken, Thilo
A1  - Kolb, A.
A1  - Naaf, T.
A1  - Plue, J.
A1  - Selvi, Federico
A1  - Strimbeck, G. R.
A1  - Wulf, Monika
A1  - Verheyen, Kris
T1  - Interacting effects of warming and drought on regeneration and early growth of Acer pseudoplatanus and A. platanoides
JF  - Plant biology
N2  - Climate change is acting on several aspects of plant life cycles, including the sexual reproductive stage, which is considered amongst the most sensitive life-cycle phases. In temperate forests, it is expected that climate change will lead to a compositional change in community structure due to changes in the dominance of currently more abundant forest tree species. Increasing our understanding of the effects of climate change on currently secondary tree species recruitment is therefore important to better understand and forecast population and community dynamics in forests. Here, we analyse the interactive effects of rising temperatures and soil moisture reduction on germination, seedling survival and early growth of two important secondary European tree species, Acer pseudoplatanus and A.platanoides. Additionally, we analyse the effect of the temperature experienced by the mother tree during seed production by collecting seeds of both species along a 2200-km long latitudinal gradient. For most of the responses, A.platanoides showed higher sensitivity to the treatments applied, and especially to its joint manipulation, which for some variables resulted in additive effects while for others only partial compensation. In both species, germination and survival decreased with rising temperatures and/or soil moisture reduction while early growth decreased with declining soil moisture content. We conclude that although A.platanoides germination and survival were more affected after the applied treatments, its initial higher germination and larger seedlings might allow this species to be relatively more successful than A.pseudoplatanus in the face of climate change.
KW  - Acer platanoides
KW  - Acer pseudoplatanus
KW  - climate change
KW  - drought
KW  - reproduction
KW  - seed
KW  - temperature
Y1  - 2015
U6  - https://doi.org/10.1111/plb.12177
SN  - 1435-8603
SN  - 1438-8677
VL  - 17
IS  - 1
SP  - 52
EP  - 62
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Caron, Maria Mercedes
A1  - De Frenne, P.
A1  - Chabrerie, Olivier
A1  - Cousins, S. A. O.
A1  - De Backer, L.
A1  - Decocq, G.
A1  - Diekmann, M.
A1  - Heinken, Thilo
A1  - Kolb, A.
A1  - Naaf, T.
A1  - Plue, J.
A1  - Selvi, F.
A1  - Strimbeck, G. R.
A1  - Wulf, M.
A1  - Verheyen, Kris
T1  - Impacts of warming and changes in precipitation frequency on the regeneration of two Acer species
JF  - Flora : morphology, distribution, functional ecology of plants
KW  - Seed provenance
KW  - Germination
KW  - Climate change
KW  - Interactive effects
Y1  - 2015
U6  - https://doi.org/10.1016/j.flora.2015.05.005
SN  - 0367-2530
SN  - 1618-0585
VL  - 214
SP  - 24
EP  - 33
PB  - Elsevier
CY  - Jena
ER  - 
TY  - JOUR
A1  - Caron, Maria Mercedes
A1  - De Frenne, Pieter
A1  - Brunet, Jörg
A1  - Chabrerie, Olivier
A1  - Cousins, Sara A. O.
A1  - Decocq, Guillaume
A1  - Diekmann, Martin
A1  - Graae, Bente Jessen
A1  - Heinken, Thilo
A1  - Kolb, Annette
A1  - Lenoir, Jonathan
A1  - Naaf, Tobias
A1  - Plue, Jan
A1  - Selvi, Federico
A1  - Wulf, Monika
A1  - Verheyen, Kris
T1  - Divergent regeneration responses of two closely related tree species to direct abiotic and indirect biotic effects of climate change
JF  - Forest ecology and management
N2  - 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.
KW  - Acer
KW  - Regeneration
KW  - Latitudinal gradient
KW  - Temperature
KW  - Precipitation
KW  - Competition
Y1  - 2015
U6  - https://doi.org/10.1016/j.foreco.2015.01.003
SN  - 0378-1127
SN  - 1872-7042
VL  - 342
SP  - 21
EP  - 29
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Lemke, Isgard H.
A1  - Kolb, Annette
A1  - Graae, Bente J.
A1  - De Frenne, Pieter
A1  - Acharya, Kamal P.
A1  - Blandino, Cristina
A1  - Brunet, Jorg
A1  - Chabrerie, Olivier
A1  - Cousins, Sara A. O.
A1  - Decocq, Guillaume
A1  - Heinken, Thilo
A1  - Hermy, Martin
A1  - Liira, Jaan
A1  - Schmucki, Reto
A1  - Shevtsova, Anna
A1  - Verheyen, Kris
A1  - Diekmann, Martin
T1  - Patterns of phenotypic trait variation in two temperate forest herbs along a broad climatic gradient
JF  - Plant ecology : an international journal
N2  - Phenotypic trait variation plays a major role in the response of plants to global environmental change, particularly in species with low migration capabilities and recruitment success. However, little is known about the variation of functional traits within populations and about differences in this variation on larger spatial scales. In a first approach, we therefore related trait expression to climate and local environmental conditions, studying two temperate forest herbs, Milium effusum and Stachys sylvatica, along a similar to 1800-2500 km latitudinal gradient. Within each of 9-10 regions in six European countries, we collected data from six populations of each species and recorded several variables in each region (temperature, precipitation) and population (light availability, soil parameters). For each plant, we measured height, leaf area, specific leaf area, seed mass and the number of seeds and examined environmental effects on within-population trait variation as well as on trait means. Most importantly, trait variation differed both between and within populations. Species, however, differed in their response. Intrapopulation variation in Milium was consistently positively affected by higher mean temperatures and precipitation as well as by more fertile local soil conditions, suggesting that more productive conditions may select for larger phenotypic variation. In Stachys, particularly light availability positively influenced trait variation, whereas local soil conditions had no consistent effects. Generally, our study emphasises that intra-population variation may differ considerably across larger scales-due to phenotypic plasticity and/or underlying genetic diversity-possibly affecting species response to global environmental change.
KW  - Climate change
KW  - Global environmental change
KW  - Milium effusum
KW  - Phenotypic plasticity
KW  - Intraspecific variation
KW  - Stachys sylvatica
Y1  - 2015
U6  - https://doi.org/10.1007/s11258-015-0534-0
SN  - 1385-0237
SN  - 1573-5052
VL  - 216
IS  - 11
SP  - 1523
EP  - 1536
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Caron, Maria Mercedes
A1  - De Frenne, P.
A1  - Brunet, J.
A1  - Chabrerie, Olivier
A1  - Cousins, S. A. O.
A1  - De Backer, L.
A1  - Diekmann, M.
A1  - Graae, B. J.
A1  - Heinken, Thilo
A1  - Kolb, A.
A1  - Naaf, T.
A1  - Plue, J.
A1  - Selvi, F.
A1  - Strimbeck, G. R.
A1  - Wulf, Monika
A1  - Verheyen, Kris
T1  - Latitudinal variation in seeds characteristics of Acer platanoides and A. pseudoplatanus
JF  - Plant ecology : an international journal
N2  - 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.
KW  - Acer platanoides
KW  - Acer pseudoplatanus
KW  - Climate change
KW  - Seed traits
KW  - Latitudinal gradient
Y1  - 2014
U6  - https://doi.org/10.1007/s11258-014-0343-x
SN  - 1385-0237
SN  - 1573-5052
VL  - 215
IS  - 8
SP  - 911
EP  - 925
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - De Frenne, Pieter
A1  - Graae, Bente J.
A1  - Kolb, Annette
A1  - Shevtsova, Anna
A1  - Baeten, Lander
A1  - Brunet, Jörg
A1  - Chabrerie, Olivier
A1  - Cousins, Sara A. O.
A1  - Decocq, Guillaume
A1  - Dhondt, Rob
A1  - Diekmann, Martin
A1  - Gruwez, Robert
A1  - Heinken, Thilo
A1  - Hermy, Martin
A1  - Oster, Mathias
A1  - Saguez, Robert
A1  - Stanton, Sharon
A1  - Tack, Wesley
A1  - Vanhellemont, Margot
A1  - Verheyen, Kris
T1  - An intraspecific application of the leaf-height-seed ecology strategy scheme to forest herbs along a latitudinal gradient
JF  - Ecography : pattern and diversity in ecology ; research papers forum
N2  - We measured LHS traits in 41 Anemone nemorosa and 44 Milium effusum populations along a 1900-2300 km latitudinal gradient from N France to N Sweden. We then applied multilevel models to identify the effects of regional (temperature, latitude) and local (soil fertility and acidity, overstorey canopy cover) environmental factors on LHS traits.
 Both species displayed a significant 4% increase in plant height with every degree northward shift (almost a two-fold plant height difference between the southernmost and northernmost populations). Neither seed mass nor SLA showed a significant latitudinal cline. Temperature had a large effect on the three LHS traits of Anemone. Latitude, canopy cover and soil nutrients were related to the SLA and plant height of Milium. None of the investigated variables appeared to be related to the seed mass of Milium.
 The variation in LHS traits indicates that the ecological strategy determined by the position of each population in this three-factor triangle is not constant along the latitudinal gradient. The significant increase in plant height suggests greater competitive abilities for both species in the northernmost populations. We also found that the studied environmental factors affected the LHS traits of the two species on various scales: spring-flowering Anemone was affected more by temperature, whereas early-summer flowering Milium was affected more by local and other latitude-related factors. Finally, previously reported cross-species correlations between LHS traits and latitude were generally unsupported by our within-species approach.
Y1  - 2011
U6  - https://doi.org/10.1111/j.1600-0587.2010.06399.x
SN  - 0906-7590
VL  - 34
IS  - 1
SP  - 132
EP  - 140
PB  - Wiley-Blackwell
CY  - Malden
ER  - 
TY  - JOUR
A1  - De Frenne, P.
A1  - Kolb, Annette
A1  - Graae, Benete Jessen
A1  - Decocq, Guillaume
A1  - Baltora, S.
A1  - De Schrijver, A.
A1  - Brunet, J.
A1  - Chabrerie, Olivier
A1  - Cousins, Sara A. O.
A1  - Dhondt, Rob
A1  - Diekmann, Martin
A1  - Gruwez, R.
A1  - Heinken, Thilo
A1  - Hermy, Martin
A1  - Liira, J.
A1  - Saguez, R.
A1  - Shevtsova, Anna
A1  - Baskin, Carol C.
A1  - Verheyen, Kris
T1  - A latitudinal gradient in seed nutrients of the forest herb Anemone nemorosa
JF  - Plant biology
N2  - The nutrient concentration in seeds determines many aspects of potential success of the sexual reproductive phase of plants, including the seed predation probability, efficiency of seed dispersal and seedling performance. Despite considerable research interest in latitudinal gradients of foliar nutrients, a similar gradient for seeds remains unexplored. We investigated a potential latitudinal gradient in seed nutrient concentrations within the widespread European understorey forest herb Anemone nemorosa L. We sampled seeds of A. nemorosa in 15 populations along a 1900-km long latitudinal gradient at three to seven seed collection dates post-anthesis and investigated the relative effects of growing degree-hours > 5 degrees C, soil characteristics and latitude on seed nutrient concentrations. Seed nitrogen, nitrogen:phosphorus ratio and calcium concentration decreased towards northern latitudes, while carbon:nitrogen ratios increased. When taking differences in growing degree-hours and measured soil characteristics into account and only considering the most mature seeds, the latitudinal decline remained particularly significant for seed nitrogen concentration. We argue that the decline in seed nitrogen concentration can be attributed to northward decreasing seed provisioning due to lower soil nitrogen availability or greater investment in clonal reproduction. This pattern may have large implications for the reproductive performance of this forest herb as the degree of seed provisioning ultimately co-determines seedling survival and reproductive success.
KW  - Collection date
KW  - latitude
KW  - nutrient stoichiometry
KW  - seed nitrogen
KW  - seed predation
KW  - seed provisioning
KW  - sexual reproduction
KW  - wood anemone
Y1  - 2011
U6  - https://doi.org/10.1111/j.1438-8677.2010.00404.x
SN  - 1435-8603
VL  - 13
IS  - 3
SP  - 493
EP  - 501
PB  - Wiley-Blackwell
CY  - Malden
ER  - 
TY  - JOUR
A1  - De Frenne, Pieter
A1  - Brunet, Jorg
A1  - Shevtsova, Anna
A1  - Kolb, Annette
A1  - Graae, Bente J.
A1  - Chabrerie, Olivier
A1  - Cousins, Sara Ao
A1  - Decocq, Guillaume
A1  - De Schrijver, An
A1  - Diekmann, Martin
A1  - Gruwez, Robert
A1  - Heinken, Thilo
A1  - Hermy, Martin
A1  - Nilsson, Christer
A1  - Stanton, Sharon
A1  - Tack, Wesley
A1  - Willaert, Justin
A1  - Verheyen, Kris
T1  - Temperature effects on forest herbs assessed by warming and transplant experiments along a latitudinal gradient
JF  - Global change biology
N2  - Slow-colonizing forest understorey plants are probably not able to rapidly adjust their distribution range following large-scale climate change. Therefore, the acclimation potential to climate change within their actual occupied habitats will likely be key for their short-and long-term persistence. We combined transplant experiments along a latitudinal gradient with open-top chambers to assess the effects of temperature on phenology, growth and reproductive performance of multiple populations of slow-colonizing understorey plants, using the spring flowering geophytic forb Anemone nemorosa and the early summer flowering grass Milium effusum as study species. In both species, emergence time and start of flowering clearly advanced with increasing temperatures. Vegetative growth (plant height, aboveground biomass) and reproductive success (seed mass, seed germination and germinable seed output) of A. nemorosa benefited from higher temperatures. Climate warming may thus increase future competitive ability and colonization rates of this species. Apart from the effects on phenology, growth and reproductive performance of M. effusum generally decreased when transplanted southwards (e. g., plant size and number of individuals decreased towards the south) and was probably more limited by light availability in the south. Specific leaf area of both species increased when transplanted southwards, but decreased with open-top chamber installation in A. nemorosa. In general, individuals of both species transplanted at the home site performed best, suggesting local adaptation. We conclude that contrasting understorey plants may display divergent plasticity in response to changing temperatures which may alter future understorey community dynamics.
KW  - climate change
KW  - common garden experiment
KW  - forest understorey
KW  - latitude
KW  - local adaptation
KW  - open-top chambers
KW  - phenotypic plasticity
KW  - pot experiment
Y1  - 2011
U6  - https://doi.org/10.1111/j.1365-2486.2011.02449.x
SN  - 1354-1013
VL  - 17
IS  - 10
SP  - 3240
EP  - 3253
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Graae, Bente J.
A1  - De Frenne, Pieter
A1  - Kolb, Annette
A1  - Brunet, Jorg
A1  - Chabrerie, Olivier
A1  - Verheyen, Kris
A1  - Pepin, Nick
A1  - Heinken, Thilo
A1  - Zobel, Martin
A1  - Shevtsova, Anna
A1  - Nijs, Ivan
A1  - Milbau, Ann
T1  - On the use of weather data in ecological studies along altitudinal and latitudinal gradients
JF  - Oikos
N2  - Global warming has created a need for studies along climatic gradients to assess the effects of temperature on ecological processes. Altitudinal and latitudinal gradients are often used as such, usually in combination with air temperature data from the closest weather station recorded at 1.52 m above the ground. However, many ecological processes occur in, at, or right above the soil surface. To evaluate how representative the commonly used weather station data are for the microclimate relevant for soil surface biota, we compared weather station temperatures for an altitudinal (500900 m a.s.l.) and a latitudinal gradient (4968 degrees N) with data obtained by temperature sensors placed right below the soil surface at five sites along these gradients. The mean annual temperatures obtained from weather stations and adjusted using a lapse rate of -5.5 degrees C km-1 were between 3.8 degrees C lower and 1.6 degrees C higher than those recorded by the temperature sensors at the soil surface, depending on the position along the gradients. The monthly mean temperatures were up to 10 degrees C warmer or 5 degrees C colder at the soil surface. The within-site variation in accumulated temperature was as high as would be expected from a 300 m change in altitude or from a 4 degrees change in latitude or a climate change scenario corresponding to warming of 1.63.8 degrees C. Thus, these differences introduced by the decoupling are significant from a climate change perspective, and the results demonstrate the need for incorporating microclimatic variation when conducting studies along altitudinal or latitudinal gradients. We emphasize the need for using relevant temperature data in climate impact studies and further call for more studies describing the soil surface microclimate, which is crucial for much of the biota.
Y1  - 2012
U6  - https://doi.org/10.1111/j.1600-0706.2011.19694.x
SN  - 0030-1299
VL  - 121
IS  - 1
SP  - 3
EP  - 19
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -