Conserving migratory wildlife.
The Athi Kapiti Plains lies in the centre of an annual cyclic event that dominates the ecology of the region. It is part of a much larger area that sees the transitory movement of large ungulates and zebra, but due to its to habitat, rainfall and soils it is perhaps the most important and still intact feeding ground for these migratory animals.
Many species migrate, from birds, reptiles, large mammals to the Blue Whale. Often these are global movements are made to escape the cold of the temperate and polar regions to warmer climes. Large terrestrial mammals are confined by natural barriers such as oceans, rivers, mountains and forests; and today by man. The Arctic Caribou moves each year some 5000km still in large numbers and the Russian Siaga antelope used to cover similar distances, but now in ragged much smaller numbers. The American Bison and pronghorn migrations are long defunct. The Quagga and Springbok migrations of South Africa are a thing of the past with one now extinct, the other in remnant non-migratory sub-populations. The Botswana veterinary fence put an end to a massive Wildebeest migration. The Kob migration into the Gambella region of Ethiopia from Southern Sudan is now imperilled due to the decision of the Ethiopian Government to lease a National Park to foreign agri-businesses. The Tanzanian government has embarked against international furore, on its infamous trans-Serengeti highway, that will threaten the largest migration of wildlife in the world. And we, just outside of Nairobi are naively going ahead with plans that will end another of one of the world’s greatest wildlife migrations; oblivious in our ignorance. So we need to inform and educate if there is a chance to keep one of the few functioning terrestrial mammal migrations intact. As a rule, the more confined movements are, the fewer animals can survive.
Migration is a survival technique that allows an animal to find food that would not be available if it stayed in one place. They can then maintain much higher populations because they avoid drought. Pastoralists drive livestock in the same way and for the same reasons. As governments are about governing and control, they disapprove of disorder and like to confine livestock and wildlife to their designated areas. But this is against nature. While many recognise that Nairobi National park experiences seasonal fluctuations, very few today recognise the wildlife on the Athi Kapiti as part of a dramatic and huge cycle of migratory wildlife. It is a mistake to consider wildlife as belonging to one place, because it is shared between the National Parks. In the process of urbanising and industrialising the greater city environs the voice of concern for its migratory wildlife are barely heard. It is time its importance was put into perspective.
The plains of East Africa are portrayed in many documentaries as vast, gently rolling grasslands with dotted trees and wooded waterways. In this habitat plains “game” such as zebra, wildebeest, gazelles and their big cat predators roam. Few of us are unaware of the migration of these plains game. For example, we all know that millions of Wildebeest and Zebra move through the Serengeti in Tanzania and bottleneck into the very much smaller Maasai Mara each year. Packed to the gunnels to feed on nutritious grasses, they inevitably suffer high mortality from predators, drowning and disease. Here gather vultures in their thousands. Lions, hyena, leopard and cheetah all take their toll whilst the bounty remains. Then it passes as the rains lure the animals to greener more dispersed pastures. The Athi Kapiti and Nairobi National Park was very much like this a decade ago, and still has hope of maintaining these events if proper plans are put in place now.
What does this mean for the predators of migratory animals?
What is generally not portrayed in the documentary is the hard times and those animals that stay behind. Predators are territorial, and when their prey is not, it simply means lean times ahead and a focus on what’s left behind. When thousands of animals enter their territory they feast. When it goes out of their territory they dare not follow as they will enter the territory of others and they will suffer the consequences if they tagged along behind. Equally, they would be foolish to leave their own hard fought-for territory unattended, because should they return they may well find it occupied. Wolves in the Arctic follow Caribou and Polar bears move in search of seals, but in less hostile environments predators stay put, or cautiously investigate unoccupied “new” territory.
Large predators are torn between easy pickings and an inability to follow it when it wanders on through to other areas occupied by fierce competitors of their own species. For lions and leopards the rules are fairly hard and fast. There is minimal movement of these predators in search of their migratory prey. For hyena too the rules are clear. You do not follow these herds, because you’ll get attacked by other clans of hyena. For cheetah the rules are less clear. Most of the research on cheetah is conducted in environments where cyclic large movements of migratory prey species does not (now) occur. Athi Kapiti cannot compare to the arid sparsely populated lands of Namibia where cheetah roam massive loose “territories”. It does not now compare to the Serengeti either and in the coming years we hope to piece together just what they do and if they remain put in defined territories, or go “walk-about” each year.
In order to survive all these predators must be adaptable and be able to subsist during the hard times on less than optimal prey. Lions may turn their attention to Warthogs, Waterbuck and even Aardvarks. Cheetah may turn to hares, springhares and game birds. Leopard may even descend to eating mice and scarab beetles.
Most wildlife species are in fact resident. Those that do not habitually migrate are in the majority, but their numerical abundance may not be that impressive. Impala, Grant’s Gazelle, Gerenuk, Dik dik, Waterbuck, Warthog, Giraffe, Hippo, Buffalo, Reedbuck, Steenbok, Aardvarks and hares are not typically thought of as species that move in vast groups across hundreds of kilometres. It would be incongruous if they did! These stay behind and are adapted to cope with lean times. They form the prey base of predators when the others have checked out. The residents logically set the limit on just how many predators can live in the area.
When resident prey species decrease due to human activity it also lowers the holding capacity of predators. Vast migratory herds moving into this disturbed area from better protected lands may befuddle the casual human observer, who may assume that that all is well when in fact all is not. Such is the probable scenario in the Maasai Mara where resident wildlife has declined. On the Athi Kapiti migratory wildlife still wanders in an out of adjacent Nairobi National Park and far to the south. As it is increasingly confined, an ecological upset is predictable. We need to investigate the dispersal of these animals and just as importantly we need to study the population stability of the ”resident” wildlife.