It is not news that human activities have an effect on wildlife populations. As data has been reported and analyzed over the past several decades, some trends have emerged.

It is interesting to note that the human population of earth has ballooned from 1 billion or less in 1900, to 6.5 billion in 2006. The altered wildlife habitat just from this increased human existence is drastic. The impact comes not just from cities and towns, but from all the combined human activity such as transportation systems, and deforestation for mining and agricultural purposes. We must also remember the effects of oceanic activities on sea life.

It is easy to think of encroachment on a local level, where the main problem is human land development and local wildlife wandering into residential areas or small towns. News reports tell us that since 1990, there has been a substantial increase in the number of attacks on humans by large predatory animals.

The problem of human encroachment is much greater than that. Worldwide, there are diseases that are hosted or spread by contact with wild animals. As contact increases, the incidence of these diseases also increases. An example of this in the US is the spread of tick-borne Lyme Disease, which has spread from the east coast to the west in less than a decade. And SARS is a prominent global threat, as is avian flu, both of which are transmitted to humans by animal hosts. The crossover of pathogens can also work from human to animal. The possibility of spreading diseases that could hasten the demise of endangered species is very real. Domestic animal production could also be affected.