Energy extraction and accidents like an oil spill can compromise stopover habitat, migratory corridors, and breeding and wintering areas that are critical to animal survival and breeding success. Connectivity information is essential to understand and minimize impacts to threatened populations.
Dams & hydroelectric power
Dams are a source of energy, water, and flood control. But they are also impassable barriers to migratory fish, and their turbines can kill small fry as they swim downstream. Massive dams such as the Three Gorges Dam have already wreaked havoc on fish migrations.
Restoration, however, is possible. The largest dam removal project in the history of the United States will remove two dams on the Elwha River in Washington. Researchers are currently working to understand whether restoring salmon runs will introduce marine-derived nutrients and affect the ecosystem above the old dams.
Gas & oil drilling
As gas and oil reserves are depleted and demand heightens, exploratory and active drilling will continue to increase. To understand the affects of drilling on migratory species, regulators need knowledge of which populations are affected and their migratory connectivity. Carry-over effects can have repercussions beyond the area of energy extraction.
- Seabirds that congregate around offshore oil drilling platforms can be killed by collisions, oiling, and incineration by the flare
- Fish and birds that feed that forage near oil rigs ingest toxic heavy metals that bio-accumulate and reduce the ability to survive and reproduce
Drilling on land can also have lasting effects on both migratory and sedentary populations. Exploratory drilling causes habitat fragmentation and can affect migration and other animal behaviors.
- In Appalachia, coal mining is contributing to the rapid decline of the cerulean warbler
- Natural gas drilling alters breeding behavior and productivity of sage grouse
- Mule deer avoid drilling pads and roads, even when alternative habitat is of poor quality
Wind turbines & wind power
For wind farms to be successful, turbines must be placed where there are frequent and strong winds. Unfortunately, these sites are also favored by migratory birds and bats, and fatal collisions are common (¼ – ½ million birds are killed each year).
- Raptors, which can travel at 180 mph, do not see the blades
- Bats are often sucked into the turning blade
- August 2011, turbines kill 6 golden eagles at the Pine Tree Wind Farm Project, CA
- 2004, turbines kill 4,000 bats on Backbone Mountain, WV
- Altamont Pass Wind Farm, CA, kills more raptors per megawatt than any other USA wind farm (10,000 birds per year)
Although wind turbine mortality is believed to be significant, estimating impacts is not trivial. Consideration of migratory timing, location of migratory routes, elevation of migratory flight, and blade height would go a long way towards preventing fatalities.
Oil is moved via pipeline or tanker, and spills can have devastating repercussions that persist for decades. Connectivity data are important for knowing long-term consequences of oil spills on migratory populations, and they are vital to understanding both direct and indirect effects.
In addition to the toxicity of ingesting oil, a small spot of oil on a bird, seal, or sea lion can compromise an animal’s ability to keep warm. Poisoning and hypothermia are real risks of oil transportation.
- RENA, Astrolabe Reef, New Zealand (October, 2011): 93,000 gallons
- DEEPWATER HORIZON, Gulf of Mexico, USA (April, 2010): largest spill in the history of the petroleum industry, official estimates place it at >206 million gallons
- Alaska Pipeline, Prudhoe Bay, USA (March, 2006): a terrestrial spill in Alaska’s pristine North Slope spilled >200,000 gallons
- PRESTIGE, Galicia, Spain (November, 2002): >20 million gallons
- JESSICA, Galapagos, Ecuador (January, 2001): 150,000 gallons
- EXXON VALDEZ, Prince William Sound, USA (March, 1989): 11 million gallons, 20 years later wildlife are still coming into contact with oil
Above-ground power lines are also hazardous to migratory birds. They fragment habitat, contain herbicide-treated grass, and are a collision and electrocution hazard to birds.
- Ten million birds per year are killed by power line collision or electrocution
- Wyoming (2007-2009): 232 eagles were illegally electrocuted by improperly grounded power lines
- California (2011): bird collision starts brush fire that burned 23 acres
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