Climate Change Effects and Anthropically Induced Wetland Degradation: A Case Study of the Urban Natural Reserve of the Great Niaye of Pikine (Technopole)

Abstract

Senegal, like other coastal African countries, is home to some very important wetlands. These wetlands regulate flooding and help to reduce water deficits during periods of drought, as is the case in the Technopole reserve. In the Dakar region, the Technopole nature reserve plays a crucial role in the ecological balance and is of considerable economic and environmental importance. This study examines the impact of climate variability and human activities on the degradation of wetlands at Technopole. An analysis of precipitation, maximum temperature and evaporation parameters was carried out alongside analyses of climatic indices, including flood and drought risks (SPI analysis), and lake water levels. In addition, field surveys and land use studies (from 1993 to 2023) were carried out, along with water quality analyses to measure levels of degradation. Our studies indicate the influence of rainfall variability on the Technopole's lakes, leading to drought scenarios from the 1970s onwards. These scenarios posed challenges in terms of water renewal, fluctuating water levels, rising salinity levels and the risk of flooding in 2003 and 2013. In addition, the land use results show human pressure on these wetlands through the conversion of natural vegetation and bare land (304.59 Ha and 15.8 Ha, respectively) into buildings, farmland and water bodies, with values of 133 Ha, 109.87 Ha and 77.88 Ha respectively between 1993 and 2023. Agricultural and craft practices continue to pollute the environment and water through the use of chemicals. Water analyses reveal high levels of salinity in the five Technopole lakes and high levels of faecal coliforms in the two Maristes lakes, preventing the normal development of marine flora and fauna. These results were used in the study to propose a sustainable development plan. This plan consists of concrete actions to combat the degradation and regression of the wetlands, such as taking into account land pressure and implementing integrated management of the reserves between political decision-makers and communities.