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Sensitivity of African biomes to changes in the precipitation regime

Hely, C ; Bremond, L ; Alleaume, S ; Smith, Benjamin LU ; Sykes, Martin LU and Guiot, J (2006) In Global Ecology and Biogeography 15(3). p.258-270
Abstract
Aim Africa is identified by the Inter-governmental Panel on Climate Change (IPCC) as the least studied continent in terms of ecosystem dynamics and climate variability. The aim of this study was (1) to adapt the Lund-Postdam-Jena-GUESS (LPJ-GUESS) ecological modelling framework to Africa by providing new parameter values for tropical plant functional types (PFT), and (2) to assess the sensitivity of some African biomes to changes in precipitation regime. Location The study area was a representative transect (0-22 degrees N and 7-18 degrees E) through the transition from equatorial evergreen forests to savannas, steppes and desert northwards. The transect showed large latitudinal variation in precipitation (mean rainfall ranged from 50 to... (More)
Aim Africa is identified by the Inter-governmental Panel on Climate Change (IPCC) as the least studied continent in terms of ecosystem dynamics and climate variability. The aim of this study was (1) to adapt the Lund-Postdam-Jena-GUESS (LPJ-GUESS) ecological modelling framework to Africa by providing new parameter values for tropical plant functional types (PFT), and (2) to assess the sensitivity of some African biomes to changes in precipitation regime. Location The study area was a representative transect (0-22 degrees N and 7-18 degrees E) through the transition from equatorial evergreen forests to savannas, steppes and desert northwards. The transect showed large latitudinal variation in precipitation (mean rainfall ranged from 50 to 2300 mm year(-1)). Methods New PFT parameters used to calibrate LPJ-GUESS were based on modern pollen PFTs and remote sensed leaf area index (LAI). The model was validated using independent modern pollen assemblages, LAI and through comparison with White's modern potential vegetation map. Several scenarios were developed by combining changes in total rainfall amount with variation in the length of the dry season in order to test the sensitivity of African biomes. Results Simulated vegetation compared well to observed data at local and regional scales, in terms of ecosystem functioning (LAI), and composition (pollen and White's vegetation map). The assessment of the sensitivity of biomes to changes in precipitation showed that none of the ecosystems would shift towards a new type under the range of precipitation increases suggested by the IPCC (increases from 5 to 20%). However, deciduous and semi-deciduous forests may be very sensitive to small reductions in both the amount and seasonality of precipitation. Main conclusions This version of LPJ-GUESS parameterized for Africa simulated correctly the vegetation present over a wide precipitation gradient. The biome sensitivity assessment showed that, compared with savannas and grasslands, closed canopy forests may be more sensitive to change in precipitation regime due to the synergetic effects of changed rainfall amounts and seasonality on vegetation functioning. (Less)
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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
White's classification map, vegetation modelling, sensitivity analysis, seasonality, rainfall, pollen, plant functional types, leaf area index, climate change, DGVM
in
Global Ecology and Biogeography
volume
15
issue
3
pages
258 - 270
publisher
Wiley-Blackwell
external identifiers
  • wos:000237116800005
  • scopus:33645776844
ISSN
1466-8238
DOI
10.1111/j.1466-8238.2006.00235.x
language
English
LU publication?
yes
id
b039d4e4-bfee-4260-9d04-7e5bc2673623 (old id 410475)
date added to LUP
2016-04-01 12:36:49
date last changed
2020-11-16 04:30:43
@article{b039d4e4-bfee-4260-9d04-7e5bc2673623,
  abstract     = {Aim Africa is identified by the Inter-governmental Panel on Climate Change (IPCC) as the least studied continent in terms of ecosystem dynamics and climate variability. The aim of this study was (1) to adapt the Lund-Postdam-Jena-GUESS (LPJ-GUESS) ecological modelling framework to Africa by providing new parameter values for tropical plant functional types (PFT), and (2) to assess the sensitivity of some African biomes to changes in precipitation regime. Location The study area was a representative transect (0-22 degrees N and 7-18 degrees E) through the transition from equatorial evergreen forests to savannas, steppes and desert northwards. The transect showed large latitudinal variation in precipitation (mean rainfall ranged from 50 to 2300 mm year(-1)). Methods New PFT parameters used to calibrate LPJ-GUESS were based on modern pollen PFTs and remote sensed leaf area index (LAI). The model was validated using independent modern pollen assemblages, LAI and through comparison with White's modern potential vegetation map. Several scenarios were developed by combining changes in total rainfall amount with variation in the length of the dry season in order to test the sensitivity of African biomes. Results Simulated vegetation compared well to observed data at local and regional scales, in terms of ecosystem functioning (LAI), and composition (pollen and White's vegetation map). The assessment of the sensitivity of biomes to changes in precipitation showed that none of the ecosystems would shift towards a new type under the range of precipitation increases suggested by the IPCC (increases from 5 to 20%). However, deciduous and semi-deciduous forests may be very sensitive to small reductions in both the amount and seasonality of precipitation. Main conclusions This version of LPJ-GUESS parameterized for Africa simulated correctly the vegetation present over a wide precipitation gradient. The biome sensitivity assessment showed that, compared with savannas and grasslands, closed canopy forests may be more sensitive to change in precipitation regime due to the synergetic effects of changed rainfall amounts and seasonality on vegetation functioning.},
  author       = {Hely, C and Bremond, L and Alleaume, S and Smith, Benjamin and Sykes, Martin and Guiot, J},
  issn         = {1466-8238},
  language     = {eng},
  number       = {3},
  pages        = {258--270},
  publisher    = {Wiley-Blackwell},
  series       = {Global Ecology and Biogeography},
  title        = {Sensitivity of African biomes to changes in the precipitation regime},
  url          = {http://dx.doi.org/10.1111/j.1466-8238.2006.00235.x},
  doi          = {10.1111/j.1466-8238.2006.00235.x},
  volume       = {15},
  year         = {2006},
}