Marsh deer

The marsh deer (Blastocerus dichotomus) is the largest of the South American cervids. Its body is almost 2 meters long and its tail can measure up to 16 cm, weighing between 100 and 150 kg. Males have branched antlers that are used to compete with other males for females and resources. Its fur is woolly, the body color is auburn and reddish brown, the belly is white and the legs are black. The black snout is also notable. The marsh deer has one offspring per birth, but can occasionally have twins. The offspring stays with the mother until its first year.

It inhabits open areas of the lowlands, preferring the flooded savannah ecosystems and water bodies where it finds food consisting mainly of aquatic grasses and herbs. Its distribution in Bolivia includes the Departments of La Paz, Beni and Santa Cruz, in the ecoregions of the flooded savannas of northern La Paz, the Moxos plains, the Pantanal,the Chaco and Cerrado, between 100 and 400 masl. It is an endangered species described as vulnerable (VU) in the Bolivian Red Book for Vertebrates due to habitat loss associated with livestock productionand hunting. The protected areas of Madidi, Noel Kempff Mercado and Otuquis support populations of the species.

Since 2004 WCS has collected information for Blastocerus dichotomus in northern La Paz, at first by overflights in limited areas to count populations in Pampas del Heath, within the Madidi National Park and its area of influence estimating high densities for the species: 0.84 individuals/km2. Later, in 2005, deer counts by terrestrial transects were made in the savannahs of Tacana I Indigenous Territory, obtaining a relative abundance of 0.48 individuals/km.

In 2007, studies continued by conducting over flights in the savannas of northern La Paz and the savannas bordering the Mamore and Itenez Rivers in the Department of Beni, as part of Boris Ríos-Uzeda master’s thesis, supported by WCS. The results of this study demonstrated the density of the species in these broad regions: 0.24 individuals/km2 in La Paz and 0.12 to 0.15 individuals/km2 in Beni.

These studies established the presence of significant populations of marsh deer, around 2.500 individuals, in the northern plains of La Paz representing a critical area for the conservation of this species in Bolivia.