TY - JOUR
T1 - The firewall between Cerrado and Amazonia
T2 - Interaction of temperature and fire govern seed recruitment in a Neotropical savanna
AU - Borghetti, Fabian
AU - de Oliveira Caetano, Gabriel Henrique
AU - Colli, Guarino Rinaldi
AU - Françoso, Renata
AU - Sinervo, Barry Raymond
N1 - Publisher Copyright:
© 2021 International Association for Vegetation Science
PY - 2021/1/1
Y1 - 2021/1/1
N2 - Questions: Models predicting the distribution of savannas worldwide have identified rainfall and fire as their primary determinants. However, most of them have relied upon adult traits, while juvenile traits, at the bottleneck of the plant's life cycle, have been largely overlooked. We developed a novel mechanistic model based on the effects of temperature and fire on germination traits to predict the distribution of Cerrado, i.e., the largest neotropical savanna. Location: Cerrado and neighboring biomes. Methods: We compiled data on the germination of seeds subjected to temperature and heat shock treatments and used generalized additive mixed models to predict germination potential as a function of temperature, species, physiognomy (forest/savanna), habits (herbs/shrubs/trees), and fire frequency. Results: The best model showed that seasonal temperatures set the germination limits for seeds of both savanna and forest physiognomies. Forest seeds presented a higher germinability in the optimum temperature range, but savanna seeds had higher survival rates after heat shocks. The model revealed that the southern limit of Cerrado is determined by low winter temperatures, while the western and eastern boundaries are set by high summer temperatures. The model also predicted an area of high germination potential that coincides with high biodiversity and climate stability in the Cerrado. Conclusions: Germination traits are highly valuable to predict vegetation responses to climate. Seasonal temperatures are primary determinants of the Cerrado’s extent, while fire favors the recruitment of savanna species over the Cerrado–Amazonia ecotone. Global warming may significantly impact the germination potential of native species.
AB - Questions: Models predicting the distribution of savannas worldwide have identified rainfall and fire as their primary determinants. However, most of them have relied upon adult traits, while juvenile traits, at the bottleneck of the plant's life cycle, have been largely overlooked. We developed a novel mechanistic model based on the effects of temperature and fire on germination traits to predict the distribution of Cerrado, i.e., the largest neotropical savanna. Location: Cerrado and neighboring biomes. Methods: We compiled data on the germination of seeds subjected to temperature and heat shock treatments and used generalized additive mixed models to predict germination potential as a function of temperature, species, physiognomy (forest/savanna), habits (herbs/shrubs/trees), and fire frequency. Results: The best model showed that seasonal temperatures set the germination limits for seeds of both savanna and forest physiognomies. Forest seeds presented a higher germinability in the optimum temperature range, but savanna seeds had higher survival rates after heat shocks. The model revealed that the southern limit of Cerrado is determined by low winter temperatures, while the western and eastern boundaries are set by high summer temperatures. The model also predicted an area of high germination potential that coincides with high biodiversity and climate stability in the Cerrado. Conclusions: Germination traits are highly valuable to predict vegetation responses to climate. Seasonal temperatures are primary determinants of the Cerrado’s extent, while fire favors the recruitment of savanna species over the Cerrado–Amazonia ecotone. Global warming may significantly impact the germination potential of native species.
KW - alternative stable states
KW - climate change
KW - forest
KW - modeling
KW - recruitment
KW - savanna
KW - temperature seasonality
UR - http://www.scopus.com/inward/record.url?scp=85101775206&partnerID=8YFLogxK
U2 - 10.1111/jvs.12988
DO - 10.1111/jvs.12988
M3 - Article
AN - SCOPUS:85101775206
SN - 1100-9233
VL - 32
JO - Journal of Vegetation Science
JF - Journal of Vegetation Science
IS - 1
M1 - e12988
ER -