@article{fdi:010058796,
  title = {{P}alynological evidence for gradual vegetation and climate changes during the african humid period termination at 13°{N} from a {M}ega-{L}ake {C}had sedimentary sequence},
  author = {{A}maral, {P}.{G}.{C}. and {V}incens, {A}. and {G}uiot, {J}. and {B}uchet, {G}. and {D}eschamps, {P}ierre and {D}oumnang, {J}.{C}. and {S}ylvestre, {F}lorence},
  editor = {},
  language = {{ENG}},
  abstract = {{L}ocated at the transition between the {S}aharan and {S}ahelian zones, at the center of one of the largest endorheic basins, {L}ake {C}had is ideally located to record regional environmental changes that occurred in the past. {H}owever, until now, no {H}olocene archive was directly cored in this lake. {I}n this paper, we present pollen data from the first sedimentary sequence collected in {L}ake {C}had (13 degrees {N}; 14 degrees {E}; {S}ahel region). {D}ated between ca. 6700 and ca. 5000 cal yr {BP}, this record is continuous and encompasses part of the termination of the {A}frican {H}umid {P}eriod ({AHP}). {V}egetation reconstructions are based on standard analyses of pollen diagrams and are strengthened by quantitative approaches. {P}otential biomes are reconstructed using the biomization method and mean annual precipitation ({P}-ann) is estimated using the modern analogues technique. {R}esults show that, between ca. 6700 and ca. 6050 cal yr {BP}, a vegetation close to humid woodland or humid savanna, including elements currently found further southward, thrived in the vicinity of the {M}ega-{L}ake {C}had in place of the modern dry woodland, steppe and desert vegetation. {A}t the same time, montane forest populations extended further southward on the {A}damawa {P}lateau. {T}he high abundance of lowland humid pollen taxa, particularly of {U}apaca, is interpreted as the result of a northward migration of the corresponding plants during the {AHP}. {T}his preferential zonal occurrence of these taxa in {L}ake {C}had {B}asin ({LCB}) (rather than extrazonal) is driven by more humid local and regional climate conditions at this latitude, as shown by mean {P}-ann estimated values of ca. 800 (-400/+700) mm during this period. {H}owever, we cannot rule out that an increase of the {C}hari-{L}ogone inputs into the {M}ega-{L}ake {C}had might have also contributed to control the abundance of these taxa. {C}hanges in the structure and floristic composition of the vegetation towards more open and drier formations occurred after ca. 6050 cal yr {BP}, following a decrease in mean {P}-ann estimates to approximately 600 (-230/+600) mm. {B}ut, the constant significant presence of lowland humid taxa until ca. 5000 cal yr {BP}, contemporaneous with a slight increase in steppic taxa, demonstrates that at this date, the modern vegetation was not yet established in the vicinity of {L}ake {C}had. {O}ur data indicate that between ca. 6700 and ca. 5000 cal yr {BP} vegetation and climate changes must have occurred progressively, but that century-scale climate variability was superimposed on this long-term mid-{H}olocene drying trend as observed around ca. 6300 cal yr {BP}, where pollen data indicate more humid conditions.},
  keywords = {{PALEOCLIMAT} ; {HOLOCENE} ; {PALYNOLOGIE} ; {SEDIMENTATION} {LACUSTRE} ; {PALEOENVIRONNEMENT} ; {VEGETATION} ; {RELATION} {CLIMAT} {COUVERT} {VEGETAL} ; {TCHAD} {LAC}},
  booktitle = {},
  journal = {{C}limate of the {P}ast},
  volume = {9},
  numero = {1},
  pages = {223--241},
  ISSN = {1814-9324},
  year = {2013},
  DOI = {10.5194/cp-9-223-2013},
  URL = {https://www.documentation.ird.fr/hor/fdi:010058796},
}