In order to fulfil their purpose of giving a place for large mammals to live naturally, many national parks and nature reserves are very large. Often this is a great draw for tourism, and when done right can create a healthy income for many people living in the area around the park.
However, this area is also a something that often takes a great deal of time to drive around, adding cost for the rest of the economy and so often the road is built across the park. In the short term this can often appear like a good idea, but can have serious problems.
One of the oldest examples is the road and railway that splits the national parks of Tsavo east from Tsavo west in Kenya. This railway is 50 years older than the national parks that lie either side. When this railway was built, workers slept in tents near where they were working, and some of the local lions turned to eating some of these unfortunate men. There is a book “The Maneaters of Tsavo”, it is a very interesting book, and has been made into several films. While birds can easily pass between the two parks and, they are both pretty large, mammals are not able to act as one larger population. I have been unable to find any evidence of under or overpasses to connect these parks, though there may be some.
A road I have experienced that passes through the middle of a national park is the A7, which passes through the centre of Mikumi national park in Tanzania. When I first saw this, I was sad to see this area spoilt by this road, and certainly more means for animals to cross without the risk of being hit would be good, however without the road this national park would not exist. This was simply a road that was built through a wilderness area, from the capital of Tanzania Dodoma east to the coastal city of Dar es Salam. It was noticed after the road was completed that the wildlife of the area was being rapidly depleted by hunting and poaching, so the area was protected. It is a nature reserve of 2500 square miles, which while large is relatively small compared to other protected areas in the area, but it runs alongside a huge nature reserve called the Selous. The Selous is vast, however it is rarely entered as 95% of it is set aside as a hunting reserve. This reserve supports a huge population of around 5000 lions.
Another famous recent case was in the Serengeti national park in Tanzania. The proposal was to build a road across the northern Serengeti to connect different parts of the country. However, one of the biggest problems with this proposal was that it would have cut the Serengeti off from the Masaii Mara. While originally it was proposed that this would be a two lane mud road, it was then upgraded to being paved and widened. The Serengeti supports vast herds of wildebeast among other grazers, because of the ability for the herbivores to follow the rains around the transfrontier park. Without this ability, it is thought that the park would likely support perhaps only a tenth of the wildlife that it currently does. Furthermore, Kenya would have found that the income from the Masaii Mara would have dropped precipitously due to the loss of the the annual spectacle of the wildebeasts arrival.
Katavi national park in Tanzania also had a proposed road building scheme cancelled for similar reasons. What was particularly odd about the Tanzanian governments blinkered determination with this road, was that people had proposed a route that would pass around the south of the park. While this would make the route (which was wanted to transfer goods and people from Dar es Salam, west into Uganda and beyond) longer, it would give good transport links to millions of extra people. Furthermore, the world bank among others had agreed to fund the study into the southern route.
There are many other examples around the world and it is likely to be a subject that I return to. Large animals need to be able to roam large areas to survive, and populations of these animals need vast areas, but by allowing them to thrive large amounts of money in tourism can be generated. The environmental good of reserves like this (such as water catchment) is not realised with many smaller reserves.