The distribution of C3 and C4 plants in a successional sequence in the Okavango Delta

Carbon isotope techniques were used to determine the photosynthetic pathway of a number of wetland plant species. The relative cover abundances of C3 and C4 plants were compared along a successional sequence of the Maunachira River system of the Okavango Delta. Plants with a C3 photosynthetic pathway were dominant in early successional stages and C4 plants were dominant in late successional stages. It is proposed that nutrient availability, particularly nitrogen limitation, could be a determinant of the change from C3 to C4 plant dominance during succession. Die fotosintetiese verloop in ’n aantal moerasplante is deur middel van koolstof-isotooptegnieke vasgestel. Die relatiewe dekkingsdigthede van C3 en C4 plante in opeenvolgende seksies van die Maunachira riviersisteem van die Okavango Delta is met mekaar vergelyk. In die aanvanklike seksies was plante met ’n C3 fotosintetiese verloop dominant, terwyl C4 plante in die daaropvolgende seksies dominant was. Daar word voorgestel dat die beskikbaarheid van voedingstowwe, veral stikstof, ’n rol speel in die verandering van C3 dominansie na C4 dominansie.