Population and distribution of Wattled Crane Bugeranus carunculatus, Gmelin, 1989 at lake Tana area, Ethiopia

Abstract

The Wattled Crane is listed as Vulnerable on the IUCN Red List, and isolated population occurs in Ethiopia. This study was conducted in Chimba wetlands, Lake Tana area from October–2013 to December–2014. The objectives were to understand the distribution and population status of the Wattled crane and assess the vegetation characteristics and threats of the ecological units. The population size and density of cranes in the study area was determined from weekly counts carried out in equal-sized sampling units. The total survey area was divided into square grids, and each of them was 1.23 square km wide/size. A total of 10 grid squares, which have an area of 12.32 square km were considered for density analysis. Although the total area of the study was 208.2 km2, unsuitable habitats, such as forest or farmlands were excluded. Counts of cranes were made at known sites. The density was calculated as the average number of cranes counted per unit area. A total of 32 cranes were recorded. The density of cranes in the study area is 2.6 per km2. Cranes were located in Addis Amba, Dehena Mesenta, Latamba, and Legdia local administrative areas. The number recorded in each area varied, the largest (17) was recorded in Latamba Kebele and the fewest (2) in Legdia. The dominant vegetation type of Chimba wetlands is emergent macrophyte. However, the papyrus bed represents about 10% of the wetland. Species of vegetation other than papyrus bed is represented by a 20 quadrat study. A total of 26 macrophyte species belonging to 10 families were recorded. Intensive cultivation, draining of the wetland, habitat degradation, overgrazing of the wetland, overharvesting of papyrus, invasive species, and over-flooding are the major threats of wetlands.