TY - JOUR
T1 - Age and light effects on seedling growth in two alternative secondary successions in central Amazonia
AU - Jakovac, Ana C.C.
AU - Bentos, Tony V.
AU - Mesquita, Rita C.G.
AU - Williamson, G. Bruce
PY - 2014
Y1 - 2014
N2 - Background: In central Amazonia, previous low intensity land use engenders succession dominated by Cecropia spp. which proceeds at high rates; however, at higher intensity of use succession is arrested and dominated by Vismia spp. over the long-term. Factors driving these two successional pathways are unknown. Aims: We aimed to elucidate seedling growth under the two alternative successional pathways. Methods: We experimentally determined the effects of successional age and photosynthetically active radiation (PAR) on relative height growth (RHG) of nine species of shade-tolerant tree seedlings in secondary forests dominated by Cecropia and Vismia, varying in age from 1-20 years. Results: In Cecropia-dominated successions, seedling RHG decreased with increasing successional age and with associated decreasing PAR. In Vismia-dominated successions, RHG was independent of successional age and PAR, and PAR did not change with successional age, being always higher than in Cecropia stands. The RHG of seedlings was lower in Vismia- than in Cecropia-dominated stands for similar PAR levels. Conclusions: Successional age and light availability affect seedlings growth differently in the two successional pathways. Unlike in Cecropia-dominated successions, in Vismia-dominated secondary forests seedling growth is limited by factors other than light. In a scenario of increasing land use intensity, constraints to seedling development in secondary forests can reduce species diversity in human-altered landscapes.
AB - Background: In central Amazonia, previous low intensity land use engenders succession dominated by Cecropia spp. which proceeds at high rates; however, at higher intensity of use succession is arrested and dominated by Vismia spp. over the long-term. Factors driving these two successional pathways are unknown. Aims: We aimed to elucidate seedling growth under the two alternative successional pathways. Methods: We experimentally determined the effects of successional age and photosynthetically active radiation (PAR) on relative height growth (RHG) of nine species of shade-tolerant tree seedlings in secondary forests dominated by Cecropia and Vismia, varying in age from 1-20 years. Results: In Cecropia-dominated successions, seedling RHG decreased with increasing successional age and with associated decreasing PAR. In Vismia-dominated successions, RHG was independent of successional age and PAR, and PAR did not change with successional age, being always higher than in Cecropia stands. The RHG of seedlings was lower in Vismia- than in Cecropia-dominated stands for similar PAR levels. Conclusions: Successional age and light availability affect seedlings growth differently in the two successional pathways. Unlike in Cecropia-dominated successions, in Vismia-dominated secondary forests seedling growth is limited by factors other than light. In a scenario of increasing land use intensity, constraints to seedling development in secondary forests can reduce species diversity in human-altered landscapes.
KW - Amazon
KW - Vismia
KW - ecosystem degradation
KW - growth rate
KW - photosynthetically active radiation
KW - tropical forest diversity
UR - http://www.scopus.com/inward/record.url?scp=84893244562&partnerID=8YFLogxK
U2 - 10.1080/17550874.2012.716088
DO - 10.1080/17550874.2012.716088
M3 - Article
AN - SCOPUS:84893244562
SN - 1755-0874
VL - 7
SP - 349
EP - 358
JO - Plant Ecology and Diversity
JF - Plant Ecology and Diversity
IS - 1-2
ER -