Yes, the survival of the fittest species is ensured whereas, others are ultimately discarded by nature. Man not only tops the animal kindom but also influences every species in most of the cases negatively. Man has taken the role of many species and thus, influencing them negatively and leading them towards their extinction.

For example, The population of Gyps vultures has declined in South Asian region from 80 to 95 % in the recent years. Current evidences suggest that populations of these species are continuing to fall rapidly, to the extent that White-rumped Vulture has now declined in numbers by 99.9% since 1992. White-rumped Vulture has almost reached at the verge of extinction and this decline in its population is attributed to a non-steroidal anti-inflammatory drug (NSAID) known with the generic name of diclofenac.

There are four basic components of a habitat; (i) food (ii) water (iii) shelter & refuge (iv) space & home range. If habitat components (ii), (iii) and (iv) are not in good condition and component (i) (food) is plentiful, the animal will still manage to live in the same habitat even that it will be vulnerable to certain threats in that habitat. But if the component (i) food is not available in a habitat then there is no surety of the animal to live there. Thus, food is the most important component of a habitat and a limiting factor for the species.

Six causes for decline in population of Gyps vultures has been given including; Electrocution, Food shortage, Diclofenac, Avian malaria, Pesticides and Loss of habitats. No doubt Diclofenac is the major culprit in vultures’ decline but food scarcity is another main reason for the decline of vultures. Certain evolutions in socioeconomic sectors have caused to an insidious shortage but permanent changes which reduced the food of vultures in general such as; burying of carcass as advised by the veterinary departments for disease prevention and environmental cleanliness and emergence of poultry industry as uniquely growing sector in livestock. Any kind of flesh is used to make the most costly ingredient of poultry feed or meat meal and bone meal. A number of poor people are involved in providing raw material for poultry industry. These people collect wasted flesh, bones etc. from slaughter houses as well as from nature thus leaving no carcass in nature for these scavengers. So, carcasses are instantly removed and used in the poultry feed industry. Thus, in Pakistan poultry industry is a potent etiological factor after diclofenac and a positive factor in this food shortage, which contributed in dinosaur death phenomenon in case of vultures.

The role of vultures to remove carcasses from nature has been taken by man and the helpless vultures are either deprived of food or forced to take the food infected with Diclofenac.

Agreed, man has seemingly destroyed the niche of vulture. Household sparrow is also rare. Thanks!

It depends on how you define the niche, whether it is the habitat that species lives, or the functional relationship of species to the environment, but in any case humans definitely is increasing its niche breadth resulting on niche overlap with many organisms and ultimately exterminating other species.