title: Present dynamics of the savanna-forest boundary in the Congolese Mayombe: a pedological, botanical and isotopic (13C and14C) study.
abstract: Isolated savannas enclosed by forest are especially abundant in the eastern part of the Congolese Mayombe. They are about 3000 years old, and were more extensive some centuries ago. The boundary between forest and savanna is very abrupt, as a consequence of the numerous savanna fires lit by hunters. Floristic composition and vegetation structure data, organic carbon ratios, Δ14C and δ13C measurements presented here show that forest is spreading over savanna at the present time and suggest that the rate of forest encroachment is is currently between 14 and 75 m per century, and more probably about 20-50 m per century. As most savannas are less than 1 km across, such rates mean, assuming there are no changes in environmental conditions, that enclosed savannas could completely disappear in the Mayombe in about 1000-2000 years.
authors.affiliation: ORSTOM, B.P. 1286, Pointe Noire, Congo.
authors.forename: D
authors.initials: D
authors.lastname: Schwartz
authors.affiliation: ORSTOM, B.P. 1286, Pointe Noire, Congo.
authors.forename: H
authors.initials: H
authors.lastname: de Foresta
authors.affiliation: Biogéochimie Isotopique, Université P et M. Curie-INRA, Case no 120, 4 Place Jussieu, F-75252, Paris 5, France.
authors.forename: A
authors.initials: A
authors.lastname: Mariotti
authors.affiliation: Biogéochimie Isotopique, Université P et M. Curie-INRA, Case no 120, 4 Place Jussieu, F-75252, Paris 5, France.
authors.forename: J
authors.initials: J
authors.lastname: Balesdent
authors.affiliation: ORSTOM, B.P. 1286, Pointe Noire, Congo.
authors.forename: J P
authors.initials: JP
authors.lastname: Massimba
authors.affiliation: Biogéochimie Isotopique, Université P et M. Curie-INRA, Case no 120, 4 Place Jussieu, F-75252, Paris 5, France.
authors.forename: C
authors.initials: C
authors.lastname: Girardin
keywords: 13C natural abundance; Congo; Forest encroachment; Forest-savanna dynamics; Pioneer trees