Conservation biologists Paul Ehrlich and Gerardo Ceballos have raised the alarm about the impending human driven sixth extinction in their book, The Annihilation of Nature: Human Extinction of Birds and Nature, a must read for anyone concerned about the loss of biodiversity, and in a formal paper in the journal Science. In the latter article Ceballos, Ehrlich, et al conclude that “The evidence is incontrovertible that recent extinction rates are unprecedented in human history and highly unusual in Earth’s history. Our analysis emphasizes that our global society has started to destroy species of other organisms at an accelerating rate, initiating a mass extinction episode unparalleled for 65 million years.”
I agree that the impending loss of biodiversity is the most serious aspect of the current ecological crisis and the most neglected by those in power. The loss of biodiversity is easy to overlook because populations die out slowly in in the human time frame, although quickly in the geological time frame. The loss of breeding populations is barely noticeable but as each population is lost, the species edges closer to extinction. Those of us who have been observing birds for decades notice a loss of numbers and of species but today’s diminished biodiversity seems normal to the young. Most ecosystems are resilient enough to adjust to the loss of a few species but as losses build up or a critical keystone species is lost, a point of no return is reached and ecosystems collapse, go through a period of chaotic instability, and reestablish themselves as less complex ecosystems with fewer species and interconnections. While no major terrestrial ecosystem has yet collapsed, several regional marine ecosystems have experienced ecosystem collapses resulting in a loss of vertebrate dominated ecosystems and their replacement with jellyfish dominated ecosystems, a simplified marine ecosystem that ruled the oceans over 300 million years ago.
Habitat loss and fragmentation is the prime driver of species extinction accounting for the unsustainable decline of more than seventy percent of the species at risk for extinction. Climate change and pollution exacerbate the problem by degrading habitats. The loss of biodiversity is universal. Tropical regions with their greater biodiversity are experiencing the greatest loss of numbers of individuals and species but temperate regions are suffering a higher percentage of loss. Migratory birds that rely upon temperate breeding grounds, tropical wintering grounds, and refueling and resting stops in-between are especially vulnerable. An astonishing thirty-seven percent of North American birds are at risk of extinction in the immediate future according to the 2016 State of North American Birds.
To reverse this loss, Dr. Ehrlich thinks that we should concentrate on populations, not species. By the time the species is threatened with extinction, only an expensive and time consuming sustained effort can reverse the decline and for many species heroic efforts are too late. Instead local populations should be identified and their habitats preserved to maintain a critical number of populations. This is where we can all help. Citizen Scientists are essential to identifying and monitoring local populations. The need is too great and the number of conservation biologists are too few to leave this job to professionals alone. EBird is an accessible way to contribute to the conservation effort, as is participating in the Christmas Bird Count, Bioblitzes, and other biosurveys. Once the relevant habitats are identified, conservation efforts can preserve and protect them. We are in a crisis but it is not hopeless. If each and every one of us does her or his part, we can still save many of the remarkable species with whom we share this planet. If enough species are saved, ecosystems remain intact.
~ Sharyn Magee