Effects of water level on plant characteristics in a restored wetland and referenced natural wetland in Wakiso, Uganda

Abstract

Wetland restoration success is dependent on the likeness of both structure and function of the restored wetland systems comparable to reference sites. Assessing the success of restoration is reliant on the monitoring and evaluation of the restored system overtime as was done with Nakyesanja, a restored wetland, and Kiryagonja, a referenced natural wetland in Wakiso District, Uganda. The objectives of this study were to determine plant characteristics (species abundance, diversity, height and phytomass) in the wetlands and evaluate the effect of water level on plants establishment and phytomass accumulation. Two transects were established in each wetland with five plots measuring 1×1 m 2 on each transect. Plant species were identified in the plots while papyrus was measured and harvested. The water level was also measured in each plot. No significant difference was detected in the above ground phytomass of Cyperus papyrus L. in the restored and the natural wetlands (p = 0.202). The restoration process has caused papyrus plants to accumulate productivity similar to the natural level. No significant difference was also observed in the heights of papyrus (p = 0.232). This indicated that the restoration methodology was effective on plants growth; making plants acquiring heights as their counterparts in the natural wetland. Uneven water distribution affected the growth and distribution of plants in the restored wetland. Areas of high water level got colonized with typical wetland species while areas with low water level got colonized by opportunistic plants. However, the water level was positively correlated (R 2 = 0.485, p = 0.042) with species diversity in the natural wetland making waterlogging the key determinant of macrophytic plants establishment in a natural environment. Periodic study is therefore recommended to monitor the success of the wetland restoration overtime.