@article{fdi:010066956,
  title = {{R}esponse of {CO}2 fluxes and productivity to water availability in two contrasting ecosystems in northern {B}enin ({W}est {A}frica)},
  author = {{A}go, {E}. {E}. and {A}gbossou, {E}. {K}. and {C}ohard, {J}. {M}. and {G}alle, {S}ylvie and {A}ubinet, {M}.},
  editor = {},
  language = {{ENG}},
  abstract = {{CO} (2) fluxes were measured during 18 months in a forest and a savannah in northern {B}enin. {H}igher values of carbon fluxes were found during the wet season at each site. {A} strong dependency of carbon fluxes on water relations was found in two contrasting sites. {T}he forest sequestered 640 +/- 50 and the savannah 190 +/- 40 g {C} m (-2) year (-1) . {I}n {W}est {A}frica, the main mechanisms or factors governing the dynamics of ecosystems, especially the dynamics of the carbon fluxes and productivity, still remain less known. {T}his study reports the carbon fluxes over two contrasting ecosystems, notably a protected forest (lat 9.79{A} degrees {N}, long 1.72{A} degrees {E}, alt 414 m) and a cultivated savannah (lat 9.74{A} degrees {N}, long 1.60{A} degrees {E}, alt 449 m) in northern {B}enin. {T}he two sites were among those equipped by the {AMMA}-{CATCH} observatory and {O}u,m, 2025 project. {F}lux data were analyzed at the daily and seasonal scales in order to understand their controlling variables. {W}e discussed the patterns of {CO}2 fluxes and the characteristics of the two ecosystems. {T}he study also focused on the different water usage strategies developed by the two ecosystems since the alternation between dry and wet seasons highly influenced the seasonal dynamics. {F}inally, the annual carbon sequestration was estimated together with its uncertainty. {T}he carbon fluxes were measured during 18 months ({J}uly 2008-{D}ecember 2009) by an eddy-covariance system over two contrasting sites in northern {B}enin. {F}luxes data were computed following the standard procedure. {T}he responses of {CO}2 fluxes to the principal climatic and edaphic factors, and the canopy conductance were studied. {A} clear {CO}2 fluxes response to main environmental factors was observed, however with difference according to the seasons and vegetation types. {T}he ecosystem respiration showed the highest values during the wet season and a progressive decrease from wet to dry periods. {A}lso, the carbon uptake values were high during the wet period, but low during the dry period. {H}owever, the {CO}2 fluxes for the protected forest were always higher than that for the cultivated savannah within each defined period. {T}his was due to the seasonal changes not only in phenology and physiology but also to the acclimation to environmental conditions, especially to the soil water availability. {T}he water use efficiency was influenced by {VPD} during the day conditions for two ecosystems. {H}owever, the {VPD} response curve of water usage was relatively constant for the protected forest during the transitional and wet seasons. {I}n contrary, for the cultivated savannah the {VPD} response decreased about 46 % from transitional dry-wet to wet seasons and remained relatively constant until transitional wet-dry season. {T}he close relationships between the net {CO}2 assimilation and the canopy conductance were found for the two ecosystems. {T}his suggests a regulation of the stomata by a partial stomatal closure besides the radiation control. {F}inally, the forest sequestered at the annual scale 640 +/- 50 and the savannah 190 +/- 40 g {C} m(-2) year(-1). {W}e conclude with a strong relation between the carbon fluxes and water in the two investigated ecosystems. {A}part from the radiation control, the stomata also play an important role in the regulation of the {CO}2 assimilation in the two ecosystems.},
  keywords = {{E}ddy covariance ; {CO}2 fluxes ; {P}roductivity ; {E}cosystem respiration ; {F}orest ; {S}avannah ; {W}ater usage ; {B}enin ; {W}est {A}frica ; {BENIN}},
  booktitle = {},
  journal = {{A}nnals of {F}orest {S}cience},
  volume = {73},
  numero = {2},
  pages = {483--500},
  ISSN = {1286-4560},
  year = {2016},
  DOI = {10.1007/s13595-016-0542-9},
  URL = {https://www.documentation.ird.fr/hor/fdi:010066956},
}