Why have Nature conservation corridors?

"Wildlife" means different things to different people. From conversations with a host of people it is obvious that most people only regard the larger animals and birds as “wildlife” and that they exclude the myriad of other living creatures and organisms from their “definition”.
In reality, wildlife includes all naturally occurring organisms and plants. The organisms range in size from the smallest microbes to the largest mammals; from the smallest mosses and fungi to the largest trees; and from the tiniest midges to the vultures and eagles.

For wildlife, in its broadest sense, to be sustainable it must occur in a biome that contains sufficient food resources, suitable habitat with natural cover and suitable clean unpolluted water.

In any biome there are specific niches containing specific resources which specific species can fit into. No two species can fit into the same niche (This is an important thing to consider when introducing a new species into an area!), and if two species that occupy the same niche are introduced to an area the dominant species will drive the other one out. A typical example of this is when Bushbuck occur in an area and Nyala are then introduced or they migrate in from somewhere else. In almost all cases the Bushbuck numbers become drastically reduced as the Nyala numbers increase. The reason for this is that the two closely related species, Bushbuck and Nyala, rely on the same browse vegetation and the bigger Nyala soon deplete the browse that is within the Bushbuck’s reach forcing them to go elsewhere in search of food. The same thing happens throughout the animal kingdom. If there are no corridors for the displaced species to move through, in their search for new territory, or if the natural area is not large enough for them to move to another area they starve and die out. It’s as simple as that!
Where wildlife habitats consist of relatively small areas – such as we have in the Mpushini and Mkhondeni Valleys – there is also the ever-present danger of inbreeding occurring among all wildlife species. This situation results in the dominance of recessive genes in the wildlife population resulting in reduced fertility, increased genetic disorders, lower birth rates, higher infant mortality, slower growth rates, smaller adult size, a loss of immune system function. All of these factors can lead to the local extinction of the species.

Unfortunately, due to increasing human populations and the resulting expansion of the urban sprawl, many natural areas are becoming more and more isolated from each other, effectively preventing any interbreeding of individuals and thus increasing the risk of inbreeding with its harmful effects on wildlife populations. Human destruction of the natural habitat also results in those animal and bird species that are mobile retreating into the remaining fragmented and isolated natural areas. This can lead to overcrowding and increased competition for food and shelter.

Urban development inevitably leads to rapid habitat fragmentation when indigenous vegetation is destroyed for housing, industries, roads and parks. Habitats that were once continuous become divided into separate fragments. This also occurs in rural developments when farmers clear land for crops, pastures and buildings.

Habitat destruction can also result from the injudicious burning or mowing of natural veld where all of the palatable plants die out and only the hardiest of grasses may survive after a few years. These fires also kill any young tree and shrub saplings leading to the degradation of the flora. This effectively converts these areas into grassed deserts with very little biodiversity.
A possible solution to these problems is the establishment of a network of wildlife migration corridors linking natural preserved areas, and this becomes absolutely essential if wildlife biodiversity is to be preserved and strengthened.

There are some individuals living in the Mpushini-Mkhondeni catchment area who are opposed to the establishment of any form of wildlife corridors because they feel that they will provide the hunting fraternity with increased ranges on which to carry out their pastime. However, they are misguided and if the migration corridors are not established it will lead to the eventual extinction – or at least genetic degeneration of all species that we hold so dear to us. In order to attempt to dispel their fears I will now explain what the wildlife corridor concept entails.

A wildlife corridor (sometimes called a green corridor) is an area of mainly natural habitat connecting wildlife populations that are separated by human activities such as roads, township developments or industry. They allow an exchange of individuals between populations, resulting in the reduction of inbreeding in populations, so increasing effective population size. They also enable the re-establishment of wildlife populations that have been decimated or eliminated due to random events such as disease or poaching. They therefore help to alleviate some of the effects of habitat fragmentation.

If corridors are too narrow they are susceptible to what is known as “edge effects” where the habitat quality along the edge of habitat fragments is much lower than in areas further away from the edge. Wildlife corridors are especially important for the larger species which require ranges of a significant size. However, they are also important as connection corridors for smaller animals, birds, invertebrates and plants, as well as ecological connectors to provide a rescue effect for small isolated species. Here one should bear in mind that the width of wildlife corridors should be sufficient to preserve the habitat in which the wildlife species exist without the habitat inside the corridor being appreciably degraded due to the edge effect.

An argument that has been advanced by some of the residents of our area is that it would be useless to provide wildlife migration corridors where the area is dissected by barriers such as the National Road (N3) and the railway line. These detractors are inclined to forget that bridges have been built across the rivers where they are crossed by these “barriers”. Large and small animals soon learn that these bridges provide an easy access to the corridors on the other side of the barrier. Besides this, birds and flying insects (which are also wildlife) merely fly over the barrier. When the concept of migration corridors becomes more widely accepted road and rail designers can make allowances for animal migration by providing more under- or over-passes or even viaducts across the corridor for animal migration.

Mr AP Austen Smith, a well-known attorney, and the owner of a game ranch in the Upper Mpushini area, has proposed an extensive conservation corridor system stretching from the source of the Umlaas River on Trewergie Farm, through the Mpushini and Mkhondeni catchment areas, the Msunduzi and uMngeni River systems to the Karkloof and Blinkwater ranges. This is a vast area and it will take a lot of lobbying of municipal counsellors and officials, KZN Wildlife officials, DEAT officials and local residents to get it off the ground – but, it can be done!

There can be no doubt that a lot of hard work and planning needs to be done in order to get the corridor concept off the ground. But, with the assistance of a few dedicated conservationists and wildlife experts it can be done! An upside to the whole conservation issue is that a large number of income-earning opportunities will become available as the area develops into a form of “Midlands Meander”. This is something else that residents will have to consider; what will we call this new tourist route?