Analyzing soil charcoals to assess the naturalness of tropical forest Julie Morin-Rivat 1, 2 Anaïs Gorel 1 , Kasso Daïnou 1 , Jean-François Gillet 1 , Nils Bourland 1 , Achille Biwolé 1 , Adeline Fayolle 1 , Olivier Hardy 3 , Alexandre Livingstone Smith 2 , Jason Vleminckx, Jean-Louis Doucet 1 , Hans Beeckman 2 1 University of Liège, Gembloux Agro-Bio Tech, Belgium 2 Royal Museum for Central Africa, Belgium 3 Free University of Brussels (ULB), Belgium ATBC – OTS 50 th Anniversary Meeting 26 th of June 2013
Prologue: On what forest conceals
Chapter 1: On the history that soil reveals
Chapter 1: On the history that soil reveals
Chapter 2: On why, when and where it happened Cameroon FRFC project (FRS/FNRS, Belgium): “Population dynamics of light- demanding trees and herbs in the dense forests of Central Africa in relationship with climatic and anthropogenic disturbances”
Chapter 2: On why, when and where it happened To find evidence for and to characterize past human presence
Chapter 2: On why, when and where it happened Forest company SFID-Mbang (concession) Alongside the transect, 3 sites of 4,8 km each A each site, up to 20 plots of botanical inventory Soil sampling by layers of 10 cm Central transect Plot of botanical inventory Central pits for anthracology (50 x 50 x 60 cm in depth) Soil samples (auger)
Chapter 3: On why soil charcoal is an ideal archive Space Time Botanical inventories Short term evaluation Local signal
Chapter 3: On why soil charcoal is an ideal archive Space Time Long term processes Palaeoecological proxies Regional signal
Chapter 3: On why soil charcoal is an ideal archive Space Time Soil charcoals Local signal Long term processes
Chapter 3: On why soil charcoal is an ideal archive Space Time Pedoanthracology Local signal Long term processes
Chapter 3: On why soil charcoal is an ideal archive - Ubiquitous - Well preserved - Easily extractable - Quantitative - Carbonization conserves wood anatomy
Chapter 4: On the extent to which anthracologists are crazy 53 pits
Chapter 4: On the extent to which anthracologists are crazy ca . 2500 kg (+ ca . 5200 kg from other pedological pits)
Chapter 4: On the extent to which anthracologists are crazy 318 samples (+ ca. 405 from other pedological pits)
Chapter 4: On the extent to which anthracologists are crazy
Chapter 4: On the extent to which anthracologists are crazy
Chapter 4: On the extent to which anthracologists are crazy 823 samples
Chapter 4: On the extent to which anthracologists are crazy
Chapter 4: On the extent to which anthracologists are crazy 10 14C dates
Chapter 4: On the extent to which anthracologists are crazy Weighing Analyzing Selecting Excavating Transporting Sieving Sorting Counting Mapping Dating
Chapter 4: On what soil charcoals taught us Charcoals (g) Charred botanical remains are not correlated - seeds ~ charcoals (R=0.020, p>0,05) - oil palm ~ charcoals (R=-0.012, p>0,05) - seeds ~ oil palm (R=0.027, p>0,05) Other seeds (g) (non identified yet) Oil palm endocarps (g)
Chapter 4: On what soil charcoals taught us Charcoals (g) Charred botanical remains are not correlated - seeds ~ charcoals (R=0.020, p>0,05) - oil palm ~ charcoals (R=-0.012, p>0,05) - seeds ~ oil palm (R=0.027, p>0,05) Other seeds (g) (non identified yet) Represent different signals Oil palm endocarps (g)
Chapter 4: On what soil charcoals taught us Site 3 Site 2 Site 1 Charcoals by site and by depth
Chapter 4: On what soil charcoals taught us Site 3 Site 2 Site 1 Fields Charcoals by site and by depth
Chapter 4: On what soil charcoals taught us Site 3 Site 2 Site 1 Oil palm endocarps by site and by depth
Chapter 4: On what soil charcoals taught us Site 3 Site 2 Site 1 Villages Oil palm endocarps by site and by depth
Chapter 4: On what soil charcoals taught us Orbs of influence of ancient villages (4 th c. BC – 3 th c. AD) Slash-and-burn agriculture
Chapter 5: On the implications for conservation Systematic sampling with simple tools The forest investigated is not natural
Chapter 5: On the implications for conservation Systematic sampling with simple The biggest tools pedoanthracological The forest investigated is not sampling for tropical natural Africa
Chapter 5: On the implications for conservation Human was present long time ago (Bantu initial spread ca. 2000 yr ago) Other results on more recent human activities (last centuries): (Oslisly et al. & Morin-Rivat et al. in press )
Chapter 5: On the implications for conservation Human was present long time ago (Bantu initial spread ca. 2000 yr ago) Secondary forest is Other results on more recent human only about 2 activities (last centuries): centuries old (Oslisly et al. & Morin-Rivat et al. in press )
Chapter 5: On the implications for conservation Study on Pericopsis elata (N. Bourland) Gregarious, endangered species (IUCN) Gaussian structure of population > Problems of regeneration Weak correlation with soil nutrients Strong correlation with charcoal abundance Need of larger gaps to regenerate e.g. slash-and-burn agriculture
Chapter 5: On the implications for conservation Study on Pericopsis elata (N. Bourland) Light-demanding spp. Gregarious, endangered species (IUCN) are closely related to Gaussian structure of population > Problems of regeneration disturbances Weak correlation with soil nutrients Strong correlation with charcoal abundance Need of larger gaps to regenerate e.g. slash-and-burn agriculture
Epilogue: On what will be done next New 14C dates (evidence for more recent human settlements) Relationship with traits (assemblages of traits during the past) Environmental reconstruction (age of the trees, charcoal taxonomical identification)
Epilogue: On what will be done next New 14C dates (evidence for more recent human settlements) Relationship with traits (assemblages of traits during the past) Environmental reconstruction (age of the trees, charcoal taxonomical identification)
Acknowledgements CoForChange project (ERANet BiodivERsA – NERC/UK – ANR/Fr) www.coforchange.eu Nature+ asbl. (Belgium) FRIA (F.R.S./FNRS, Belgium) The forest companies SFID Mbang (Rougier Group) and Pallisco Analyzing soil charcoals to assess the naturalness of tropical forest Julie Morin-Rivat et al. jmorin@doct.ulg.ac.be More information on this platform: ATBC – OTS 50 th Anniversary Meeting 26 th of June 2013
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