Thriving in a diminishing world: waders of the Songhor Wetland in Ghana

Yaa Ntiamoa-Baidu 1, 2, Jones K. Quartey1,, Emanuel N. A Taye 2  and Alfred A. Nuoh1

 1Centre for African Wetlands, University of Ghana, P.O. Box LG 67, Legon, Accra

2Department of Animal Biology and Conservation Science, University of Ghana, P.O. Box LG 67, Legon, Accra

A number of taxa including plants, invertebrates, fish and birds have been used as indicators of changes in the environment in which they live. For example, the common Yellowthroat and Sandhill crane have been shown to be indicators of low disturbance, while the European Starling and the Common Grackle are considered as indicators of coastal wetlands highly disturbed by agricultural and urban land-use. The Songhor Lagoon, associated with the Volta River estuary, is the key feature of the Songhor wetland, designated as a Ramsar site in 1992 on the basis of its international importance for waterbirds. The Ramsar designation requires monitoring and reporting on changes in the ecological character of listed sites. Key parameters used to describe the ecological character include ecosystem components, comprising physical, chemical and biological attributes. This paper presents trends in the population of shorebirds, a key biological feature of the Soghor Ramsar site, over a 28 year period and compares the bird population trends with the changes in the chemical (water quality) and physical(lagoon area) attributes of the wetland. Teams of two persons carried out monthly counts of waterbirds between 1986 and 2015; water quality measurements were taken at two separate time periods during the study and land use changes were derived from satellite imagery at ten-year intervals. The results show a clear reduction in the size of the water body (83.12 km2 to 72.47 km2 from 2000 to 2015) and more than doubling of built-up areas within the catchment (from 87.57 km2-180.85 km2), while the water quality measurements indicated a decreasing wetland health. Despite these changes, the Songhor Lagoon continues to hold internationally important populations of five species (Curlew sandpiper, Ringed plover, Greenshank and Black-winged stilt). Peak numbers recorded at any one time in any year varied from 7,690 to 35,500. The status of individual species varied from total collapse (e.g. Avocet) to stable (e.g. Ringed plover) or increasing (e.g. Curlew sandpiper). The findings support earlier assertions that waterbird populations may be affected significantly only when their wetland environment is completely destroyed. A number of taxa including plants, invertebrates, fish and birds have been used as indicators of changes in the environment in which they live. For example the European Starling and the Common grackle are reported to be indicators of coastal wetlands highly disturbed by agricultural and urban land-use. The Songhor Lagoon is the key feature of the Songhor Ramsar site, designated on the basis of its international importance for waterbirds. The Ramsar designation requires monitoring and reporting on changes in the ecological character of listed sites. Key parameters used to describe the ecological character include ecosystem components and processes. This paper presents trends in the population of shorebirds, a key biological feature of the Soghor Ramsar site, over a 28 year period and compares the bird population trends with the changes in the chemical and physical attributes of the wetland. Teams of two persons carried out monthly counts of waterbirds from 1986 to 2015; water quality measurements were taken at two separate time periods during the study and land use changes were derived from satellite imagery. The results show a clear reduction in the size of the water body (83.12 km2 to 72.47 km2 from 2000 to 2015) and more than doubling of built-up areas within the catchment (from 87.57 km2-180.85 km2), while the water quality measurements indicated a decreasing wetland health. Despite these changes, the Songhor Lagoon continues to hold internationally important populations of five species (Curlew sandpiper, Ringed plover, Greenshank and Black-winged stilt). Peak numbers recorded at any one time in any year varied from 7,690 to 35,500. The status of individual species varied from total collapse (e.g. Avocet) to stable (e.g. Ringed plover) or increasing (e.g. Curlew sandpiper). The findings support earlier assertions that waterbird populations may be affected significantly only when their wetland environment is completely destroyed.