Vulture Extinction Could Cause Trouble For Ecosystem
Utah’s native turkey vulture is considered abundant in cities along the Wasatch Front but the vast majority of vultures are either critically endangered or near threatened.
Vulture decline is the subject of a study published in the peer-reviewed science journal Biological Conservation. Researchers are concerned that if vulture populations wane, animals that fill their place and perform their function will ultimately cause an ecosystem collapse.
“When vultures are absent, first thing is that carcasses will stay out in the environment much longer. When they do, then other animals are [going to] start taking advantage of that resource,” said Evan Buechley, a PhD candidate in the biology department at the University of Utah and one of the authors of The Avian Scavenger Crisis: Looming Extinction, Trophic Cascades, and Loss of Critical Ecosystem Functions, published in Biological Conservation.
“For example, you’ll have many more flies that reproduce in carcasses by laying maggots, so you’ll have a lot more flies, which from a human perspective is not good. You’ll also have other species of facultative scavengers like dogs, crows and ravens. Their populations will increase because there is all this increased availability of food. When those populations increase, they can cause trophic cascades in ecosystems.”
Scavengers replacing vultures, such as rats and feral dogs, are vectors of disease.
The main reason for vulture decline, Buechley said is human influences. One example is Utah’s California Condor is dying from lead poisoning after ingesting bullet fragments found in mule deer and elk. Çağan Şekercioğlu, a University of Utah biology professor and co-author of the study said as vultures die, facultative scavengers work to fill the void.
The disadvantage to this is the scavengers replacing vultures, such as rats and feral dogs, are vectors of disease. Vultures can quickly find and consume a carcass and they eradicate any traces of bacteria. Facultative scavengers, however, take longer to find carcasses and their digestive systems do not fully eradicate bacteria from the carcass the way a vulture's digestive system can. Şekercioğlu said this will ultimately result in the spread of pathogens wherever these animals go.
“We are very worried that this decline will lead to an increase in feral dogs which will lead to an increase in rabies and human deaths from rabies, so that’s why birds matter,” Şekercioğlu said.
Since vultures aren’t always perceived in the most positive light, one solution for stopping their decline is changing the human perception and helping people to understand their value, Buechley said. After all, they play a crucial role in environmental cleanup.