The Importance Of Biomass At The NNP – Written by Gareth Jones

We all need the energy to survive in the world, wild animals who eat plant species can only survive and thrive if there is enough plant material, like grasses, leaves and stems to give them enough nutrition and energy to sustain them throughout the annual cycles of dry and wet seasons.

The total amount of potential food energy available in kilograms per square kilometre is measured, this known as the biomass. In the Nairobi National Park, scientific studies have been conducted by people like (JB Voster and MJ Coe from 1960-1966) to determine the estimated sustainable biomass of the Nairobi National Park. In the dry season, the biomass was estimated to be about 5690kg per sq/km and in the wet peak season, it was as high as 12775 kg per sq/km.

Optimum biomass is also known as the carrying capacity or the number of species that can live in the park without downgrading the ecosystem. This is very important for the park as the total area is only 117 sq/km and the herds are not able to migrate as before due to blocked seasonal routes. Certain species also have a preference for particular plant species in their diet, so there are some parts of the park that have higher herbivore populations at times. It is also very important that wildlife be able to seasonally move outside the park and feed on alternative biomass south of the park. It is also important to note that apart from the relative size of an area, soil type and annual rainfall patterns combined with a temperate climate are all key factors that either result in lush vegetation and very sparse growth.

Herbivores like zebra, eland, wildebeest, coke’s hartebeest, impala and buffalo also attract predators when they prefer to feed in certain parts of the park.

In my experience, the Kingfisher area plains, Eland valley and the Athi basin are typical areas where the soil type is more fertile and able to sustain larger populations of herbivores and associated predators like lions, leopards and hyenas… Biomass is very important as it supports the entire ecosystem, predators would not survive without herbivores and herbivores would not survive without sufficient plant vegetation to sustain them through the seasons. As the Nairobi National Park has effectively become a green island surrounded by a sea on human developments, it is important that the Kenya Wildlife Service (KWS) continue to monitor wildlife populations. Both herbivores & predators need to be in balance, if there is overgrazing this could result in species starving, therefore predators also have an important role in reducing herbivore populations.

So next time you decide to visit the park try focusing on the areas where the herbivores are feeding and spent some time observing the herbivores, and hopefully sooner or later you could be rewarded with a predator sighting.