Cyperus papyrus (papyrus) is a large herbaceous sedge commonly found in waterlogged environments in the African tropics. These wetland ecosystems provide ecological and socio-economic services related to the harvesting of aerial biomass, wastewater treatment, hydrological functions and climate modification [1] . It has been suggested that removal of large quantities of nutrients associated with papyrus harvesting results in reduced production rates in subsequent re-growth periods [2] . In addition, negative influences of frequent and indiscriminant harvesting on growth of aerial biomass have been reported [3] -[5] . Therefore, in order to achieve sustainable production, there should be a suitable management program to regulate harvesting [3] [5] . This could maximize wetlands potential as carbon sink [1] .

For sound management, there is need to understand the growth and development which form the basic components of plant population dynamics [6] . In papyrus wetlands, the aerial structure (shoot) consists of sheath, culm and umbel (Figure 1).

During development, the vegetative shoot grows out from the rhizome with the umbel fully enclosed in a sheath. The sheath surrounds the base of the culm in later growth stages. The developing papyrus goes through different growth stages starting as young elongating culms with closed umbels, then elongating culms with umbels just opening, fully elongated culms and fully expanded umbels, senescent culms (≤ 40% achlorophyllous) and finally dead culms (≥60% achlorophyllous).

Tropical wetlands are often unstable environments and in particular they are subject to substantial water level fluctuation [8] -[10] . However, the loose structure of the floating papyrus rhizomes allows a free exchange of water and dissolved matter from underneath into the rhizome mat [11] . The effect of these fluctuations in water level on the natural regeneration of papyrus is unknown, although natural regenerative capacity is known to be influenced by water depth [12] .

The potential economic importance of papyrus wetlands has stimulated many studies on growth and development of the vegetation. These studies have shown that papyrus wetlands are characterized as having regular turnover of individual plant units [3] . However, estimates of growth rate of single shoots in terms of relative growth rate (RGR) [13] have not been made although measures of absolute growth rates of unit area have been a common comparison tool for performance in different wetlands [14] -[17] . Growth rates can be determined using culm-girth biomass relationships [3] [18] . An effort in understanding how RGR of the papyrus depends partly on the umbels and how actual value of RGR at an instant of time depends on the amount of foliage which presented at that time is an important aspect of their physiology.

RGR or growth efficiency index expresses growth in terms of a rate increase in size per unit of size and is an important parameter in plant growth models [19] [20] . This study is a growth analysis using biomass data of aerial shoot of C. papyrus. Mathematical equations in the form of fitted functions have been employed to analyze time series of dry weight [21] -[23] . The objective of this investigation was to estimate the temporal changes in growth and development in a papyrus wetlands. This involved determining the pattern of individual papyrus shoot relative growth rates. In addition, measurement of leafiness was made by determining the LWR over time. The effect of some environmental variables on culm recruitment and senescence, and total culm density was also investigated. It was hypothesized that growth rate of shoots and their total culm density, recruitment and senescence are dependent on water level and water temperature variation in the wetland.