Habitat, abundance, strongholds, Sudd, climate preferences, Hydrology, C4
Cyperus papyrus L. grows in full sun, in wet swamps, river mouths and on freshwater lake margins in many parts of Africa where it is native, and will persist in sub-tropical and tropical climates where introduced. It requires annual rainfall of 10-420 cm, annual temperatures of 20-30°C, and pH of 6.0-8.5, (Duke 1996), but is reputed to tolerate frost, in the Highveld of South Africa regenerating if above ground parts are killed, providing that the rhizomes do not freeze, Archer, 2004. It grows from sea level, up to circa 2335, e.g. Thompson, 1976, but N.B. the type location for C. papyrus ssp. hadidii in Wadi Natrun, Egypt, is up to 24m below sea level. Growing as a tall, emergent marginal it forms dense often near single-species-dominated stands, with 10-22 culms m2 commonly with climbers such as Ipomoea spp. Van Dam et al., 2011
It is most abundant and can cover vast areas in the east African swamp lands, river basins and lake margins of Uganda, Chad, Kenya, and Sudan, extending south through Rwanda, Kenya, Malawi and Zimbabwe along the lakes and major river basins, so far as the Zambesi delta in Mozambique. In Uganda, the largest Papyrus swamps are recorded along lake margins of Lake Albert, George, Kioga and Victoria, as well as other small lakes (Beadle, 1981). The bulk of permanent swamps along the Nile lie within the Sudd region of southern Sudan (Migahed, 1948, Serag, 2003). In Kenya and Tanzania, lake, river and valley swamps are common and pure populations of Papyrus are recorded (Muthuri et al., 1989). Large swamps also occur in Zaire where Papyrus swamps are best developed in the Upemba region (Thompson et al., 1979).
The wetlands of East and Central Africa where it is the commonest type of vegetation, comprise ± 10% of the land cover (Maclean 2011), Thompson and Hamilton (1983) estimated its coverage at ± 4000 km2, however a review by Maclean et al., in 2013 reported decline to 1532 km2.
Papyrus is very widely reported to grow in deeper water where it is the chief component of floating, detached, masses of vegetation known as “Sudd”, after the Sudd area of the Sudanese White Nile. These vegetation islands are moved by the wind.
Its dominance and abundance is widely reported to result in the blockage of waterways and channels on rivers (e.g. Serag, 2003) to either navigation and or water flow, and has been studied in areas such as the Okovango Delta where as well as the cause, it may also encroach following sedimentation to the same effect, e.g. Ellery et al., 1995. It is, therefore, widely considered an invasive species where introduced, and conditions are suitable e.g. Dugan ,1992 (not seen).
A recognised community zonation has been observed in the Lake Victoria basin, from Cyperus papyrus marginal, to Vossia cuspidata then Eichornia crassipes in open water (reported in Van Dam et al., 2011, Maclean, 2011).
Hydrology, C4 photosynthesis
Given its prominence and abundance, Papyrus’ hydrological, ecological, and economic roles in aquatic systems are significant and have been widely studied, see for example Adam & Mutanga, 2009, Gaudet, 1980, Mafabi, 2000. Papyrus uses the C4 photosynthetic pathway, as do several other species of tropical wetlands, and the efficient use of light, water and nutrients characteristic of this phytochemistry affect in particular the carbon fixing capacities of these habitats and their water loss through evapotranspiration (Saunders et al., 2007). There is considerable debate about whether Papyrus swamps exacerbate wetlands water loss, or decrease it, although there is evidence that C4 plants have lower transpiration rates than C3 plants. Jones and Humphries, 2002.
Reproduction, rhizomes, seed
Terer et al., 2012 (p. 136) report that Papyrus reproduces predominantly vegetatively by extension of its rhizomes, but that seed production, normally sporadic, can increase in certain conditions, notably associated with water level changes. See also Gaudet, 1977, Harper, 1992, Terer, 2011.
Cyperus; Cyperus papyrus
Cyperus; Cyperus papyrus
Cyperus; Cyperus papyrus
Cyperus; Cyperus papyrus