Amelia Templeton, Earth Fix
It’s the 40th anniversary of the Endangered Species Act. Much of our day to day reporting on endangered species focuses on the political controversies that arise from conservation strategies: wolf predation of livestock, water shutoffs in the Klamath Basin, mill closures after the Northwest Forest Plan.
We also do fair amount of reporting on the strange things people do to try to save individual species in peril: putting fish in trucks, removing a dam, relocating deer, and shooting one kind of owl to save another.
But what interests me the most are the big picture questions. Here are three questions conservation scientists are debating, inspired in part by this excellent conservation literature review.
1) Is It Time To Triage?
Governments and conservation groups have a limited amount of money to spend trying to recover endangered species. Those dollars are typically allocated to species judged to be the most at threat, the most ecologically unique and significant and the most charismatic. Scientists say tigers, pandas and spotted owls all benefit from a disproportionate share of conservation funding.
Researchers with the University of Queensland in Australia and the Department of Conservation in New Zealand have sparked a vigorous debate over the need to include two more criteria: the cost of management and the likelihood that an attempt to save a species will succeed.
The question of whether to stop trying to save some charismatic, highly imperiled species so funding can go to more help conserve more viable populations seems particularly relevant in the Northwest, where scientists are debating a potentially costly and risky campaign to save the spotted owl by shooting barred owls.
It’s also an idea that appears to have influenced local groups like the Wild Salmon Center, which has proposed protecting the Northwest’s strongest salmon runs and healthiest rivers as the most effective approach to salmon recovery.
2) Is There A Universal Minimum Viable Population?
Small populations are particularly vulnerable to extinction due to random catastrophe, variation in birth and death rates, and other factors. The idea of a minimum viable population was first introduced by biologist Mark Shaffer in a paper in 1981.
Getting an accurate population count of an endangered species is surprisingly difficult, and some scientists have argued for universal benchmarks for all species: 50 individuals for short-term survival, 500 individuals for the genetic health of a species, and 5,000 individuals for long-term viability.
However, many researchers have rejected the idea and argue that a species’ life history, size, environment and rate of decline all affect what constitute a viable population size.
In a recent study, authors Curtis Flathers et al, write that while marbled murrelets in the Northwest number in the tens of thousands, the species is still endangered by loss of nesting habitat and depletion of its food sources.
They offer the passenger pigeon as an example of a species that seemed abundant but ended up extinct.
“The extinction of the passenger pigeon (Ectopistes migratorius), perhaps the most abundant land bird in North America during the 1800’s (numbering 3–5 billion individuals ), stands as a sobering reminder that population size alone is noguarantee against extinction.”
3) Should We Be Assisting Migration?
The Oregon Climate Change Research Institute has reported that Humboldt squid from the tropics have moved into Oregon waters, birds are migrating earlier and moving further north, and small mammals in Eastern Oregon are contracting their high-elevation ranges.
Forest ecologists are predicting that climate change could threaten tree species like coastal yellow cedar and alpine whitebark pine.
Some scientists argue that many species will not be able to move or evolve quickly enough to survive climate change, and are calling for human intervention to assist migration of threatened species through the creation of seed banks and other strategies.
Where do you stand on these debates? Let us know the endangered species stories you think we should be covering.