TY - JOUR
T1 - Seedling emergence and growth of Quercus spp. following severe drought effects on a Pinus sylvestris canopy
AU - Galiano, Lucía
AU - Martínez-Vilalta, Jordi
AU - Eugenio, Màrcia
AU - Granzow-de la Cerda, Íñigo
AU - Lloret, Francisco
PY - 2013/5/1
Y1 - 2013/5/1
N2 - Questions: We addressed the following questions: (1) did defoliation and die-off of the dominant Pinus sylvestris, induced by an extreme drought episode, favour emergence of other tree species; (2) did the defoliated canopies of P. sylvestris resulting from drought promote radial growth among other pre-existing tree species seedlings under them? Location: P. sylvestris forest in Central Pyrenees (NE Spain) affected by a severe drought in 2004-2005. Methods: Despite increased focus on climate-related forest die-off, studies of the effects on regeneration processes following extreme drought remain scarce. We analysed whether an episode of drought-induced mortality on the dominant P. sylvestris L. may act as a driver of vegetation shift. Seedlings of Quercus humilis Mill. and Q. ilex L. from 27 plots were sampled under P. sylvestris canopies with <50% and ≥50% defoliation (standing dead trees included) to determine age distribution and radial growth using a retrospective, dendrochronological approach. Results: Drought-induced canopy losses appear not to be compensated by regeneration of P. sylvestris. Recruitment of below-canopy tree species (specifically Q. humilis and Q. ilex) that could potentially become dominant was high in the entire studied area. However, the spatial patterns of Quercus spp. regeneration following the 2004-2005 drought were complex. While the emergence of new Quercus spp. seedlings was reduced under open, drought-induced canopies, growth of seedlings already established was favoured in open-canopy conditions. Conclusions: Although the effects of extreme drought events may disfavour the establishment of new recruits, enhanced growth responses of a pre-established seedling bank could still contribute to accelerate forest dynamics under drier conditions. Because of the predicted increases in intensity and frequency of extreme droughts, monitoring studies are key to elucidate whether the initial patterns observed will be maintained in the long term, eventually leading to a vegetation shift. © 2012 International Association for Vegetation Science.
AB - Questions: We addressed the following questions: (1) did defoliation and die-off of the dominant Pinus sylvestris, induced by an extreme drought episode, favour emergence of other tree species; (2) did the defoliated canopies of P. sylvestris resulting from drought promote radial growth among other pre-existing tree species seedlings under them? Location: P. sylvestris forest in Central Pyrenees (NE Spain) affected by a severe drought in 2004-2005. Methods: Despite increased focus on climate-related forest die-off, studies of the effects on regeneration processes following extreme drought remain scarce. We analysed whether an episode of drought-induced mortality on the dominant P. sylvestris L. may act as a driver of vegetation shift. Seedlings of Quercus humilis Mill. and Q. ilex L. from 27 plots were sampled under P. sylvestris canopies with <50% and ≥50% defoliation (standing dead trees included) to determine age distribution and radial growth using a retrospective, dendrochronological approach. Results: Drought-induced canopy losses appear not to be compensated by regeneration of P. sylvestris. Recruitment of below-canopy tree species (specifically Q. humilis and Q. ilex) that could potentially become dominant was high in the entire studied area. However, the spatial patterns of Quercus spp. regeneration following the 2004-2005 drought were complex. While the emergence of new Quercus spp. seedlings was reduced under open, drought-induced canopies, growth of seedlings already established was favoured in open-canopy conditions. Conclusions: Although the effects of extreme drought events may disfavour the establishment of new recruits, enhanced growth responses of a pre-established seedling bank could still contribute to accelerate forest dynamics under drier conditions. Because of the predicted increases in intensity and frequency of extreme droughts, monitoring studies are key to elucidate whether the initial patterns observed will be maintained in the long term, eventually leading to a vegetation shift. © 2012 International Association for Vegetation Science.
KW - Canopy gap
KW - Extreme climatic episode
KW - Pinus sylvestris
KW - Quercus humilis
KW - Quercus ilex
KW - Seedling growth
KW - Seedling recruitment
KW - Tree mortality
KW - Vegetation shift
U2 - 10.1111/j.1654-1103.2012.01485.x
DO - 10.1111/j.1654-1103.2012.01485.x
M3 - Article
SN - 1100-9233
VL - 24
SP - 580
EP - 588
JO - Journal of Vegetation Science
JF - Journal of Vegetation Science
ER -