1st Edition

The effect of harvesting and flooding on nutrient cycling and retention in Cyperus papyrus wetlands

By Edwin M.A. Hes Copyright 2022

    African papyrus (Cyperus papyrus L.) wetlands provide water, food and materials to millions of people, and perform important landscape functions such as water and nutrient storage, habitat provision for fish, birds and other wildlife. They are also an integral part of the culture of African wetland communities. With an increasing demand for food, papyrus wetlands are at risk of conversion to agriculture and losing these ecosystem services. Combining increased agricultural production with wetland conservation is urgently needed. The research presented in this book consisted of two parts. First, field experiments investigated nitrogen and phosphorus retention, showing that papyrus grows faster with disturbance from human activities or flooding, but produces less biomass and stores less nutrients. Then, a dynamic simulation model (Papyrus Simulator) based on the hydrological and ecological wetland processes showed that assimilation, mortality, decay, re-translocation, nutrient inflow and soil porosity were the most influential factors. The model demonstrated that controlled harvesting can increase nutrient retention by up to 40%, but overharvesting leads to the release of nutrients. These findings can help determining optimum harvesting strategies for constructed and natural wetlands, and contribute to the quantification of ecosystem services and an evidence-based adaptive management approach for African wetland landscapes.

    General introduction,  The effect of seasonal flooding and livelihood activities on retention of nitrogen and phosphorus in Cyperus papyrus wetlands, the role of aboveground biomass,  Review of wetland models for the development of a model to quantify nutrient retention and the impact of harvesting in Cyperus papyrus wetlands,  A simulation model for nitrogen cycling in natural rooted papyrus wetlands in East Africa,  Modelling nitrogen and phosphorus cycling and retention in Cyperus papyrus dominated natural wetlands,  The effect of harvesting and flooding on nutrient cycling and retention in Cyperus papyrus wetlands – synthesis, conclusions and recommendations


    Edwin Hes obtained an MSc from Wageningen University in 1998, specializing in environmental science and technology. From 1999 to 2002 he worked for the Dutch Ministry of Economic Affairs as a public consultant on European research grants. In 2002, he started at IHE Delft Institute for Water Education and worked for the Liaison Office until 2007. Later that year, he started working as a Lecturer in Environmental Systems Analysis. His main research interests during the past years have been sustainable use of wetlands and modelling nutrient flows in wetland ecosystems, especially in papyrus wetlands in East Africa. He is interested in the use of models to study ecosystem functions and services and to evaluate social-ecological systems. At IHE Delft, he has been coordinating the Environmental Science programme from 2012 to 2016 and the joint degree programme in Limnology and Wetland Management from 2012 until present. Hes has been involved with teaching and training activities in the fields of Environmental Systems Analysis, Environmental Modelling and Wetland Management. In his educational activities he works with partner institutes from Kenya (Egrton University), Austria (BOKU), Mexico (LANCIS-UNAM) and the Netherlands (WUR-CDI). Since 2007 Hes has worked in research and capacity building projects in more than 20 countries in Asia, Africa and Latin America with a focus on sustainable use of wetlands. Mr Hes is an experienced facilitator and moderator in an international (development) setting.