Balancing The 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. Irrespective of how some people believe in the theory of evolution or others who believe in the wonders of the superb intelligence involved in the creation ecosystems by God, the reality is that all species have a continuous struggle to survive, especially in places where mankind has upset the delicate balances of the ecosystems. Survival is a day by day, season by season process that involves cycles. The seasonal cycles depending on many factors such as rains, soil types, and competition per square kilometer between herbivores.

The total amount of potential food energy available in kilograms per square kilometer is measured, this is 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 5,690kg per sq/km and in the wet peak season, it was as high as 12,775 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 no longer 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. Optimum biomass needs to have seasonal cycles that result in a balanced ecosystem. Due to the negative impact of human development on the natural movement of wildlife to areas outside the area we know today as the Nairobi National Park, the park is now rapidly becoming a “green island in a sea of human development”. Therefore it is important for the Kenya Wildlife Service to manage the park in the best way possible to compensate for the negative factors. Positive actions should include controlled burning of grass to encourage herbivores to remain inside the park. Another important action is to maximize the buffer zone in the form of conservancies adjacent to the southwestern boundary of the park while ensuring that the ancient migration route over the Athi Kapiti plains is kept open to allow wildlife to still continue to migrate.

Herbivores like zebra, eland, wildebeest, coke’s hartebeest, and buffalo 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 sustains larger populations of herbivores and associated predators like lions. Next time you visit the park try focusing on the areas where the herbivores are feeding, and sooner or later you could be rewarded with a predator sighting.