TY - JOUR
T1 - Ecophysiological responses of Terminalia sericea to fire history in a semi-arid woodland savanna, central Namibia
AU - Daniels, Quanita Farrah
AU - Throop, Heather L.
N1 - Publisher Copyright:
© 2021 SAAB
PY - 2022/5
Y1 - 2022/5
N2 - Woody vegetation is increasing in savanna ecosystems worldwide. Fire is frequently used as a management tool to decrease bush encroachment, but knowledge regarding the underlying leaf-level ecophysiological responses to fire history is lacking. In southern Africa, Terminalia sericea is a dominant encroaching species that resprouts readily following fires. The impact of fire on leaf-level photosynthesis, transpiration, conductance and water use efficiency was investigated using infrared gas analysis. Data were collected in three areas on the Waterberg Plateau with different fire histories (fire occurring 2, 3 and 15 years prior to sampling). Leaf-level photosynthetic rates were comparable to the relatively high rates shown by other encroaching bush species. In contrast to expectations, ecophysiological variables did not differ among plants in areas with different fire histories. However, photosynthetic rates were highly sensitive to variation in light level, suggesting that canopy structural differences may affect carbon fixation and growth rates at the whole-plant level. Encroachment by T. sericea may be facilitated, at least in part, by high leaf-level photosynthetic rates that are insensitive to long-term fire history on sandy, low-nutrient soils.
AB - Woody vegetation is increasing in savanna ecosystems worldwide. Fire is frequently used as a management tool to decrease bush encroachment, but knowledge regarding the underlying leaf-level ecophysiological responses to fire history is lacking. In southern Africa, Terminalia sericea is a dominant encroaching species that resprouts readily following fires. The impact of fire on leaf-level photosynthesis, transpiration, conductance and water use efficiency was investigated using infrared gas analysis. Data were collected in three areas on the Waterberg Plateau with different fire histories (fire occurring 2, 3 and 15 years prior to sampling). Leaf-level photosynthetic rates were comparable to the relatively high rates shown by other encroaching bush species. In contrast to expectations, ecophysiological variables did not differ among plants in areas with different fire histories. However, photosynthetic rates were highly sensitive to variation in light level, suggesting that canopy structural differences may affect carbon fixation and growth rates at the whole-plant level. Encroachment by T. sericea may be facilitated, at least in part, by high leaf-level photosynthetic rates that are insensitive to long-term fire history on sandy, low-nutrient soils.
KW - Bush encroachment
KW - Photosynthesis
KW - Regrowth
KW - Transpiration
KW - Water use efficiency
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U2 - 10.1016/j.sajb.2021.10.023
DO - 10.1016/j.sajb.2021.10.023
M3 - Article
AN - SCOPUS:85118559137
SN - 0254-6299
VL - 146
SP - 205
EP - 212
JO - South African Journal of Botany
JF - South African Journal of Botany
ER -