New Hampshire Nature Notes
by Eric Orff

GAME CHANGERS

Tuesday 04/05/2011

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Air pollution, a warming climate, and the troubled future for America’s hunting and fishing heritage

For American hunters and anglers, healthy populations of fish and game are considered a birthright. But woods and waters teeming with bass, trout, ducks, and deer, didn’t happen by accident. For more than 150 years, countless individuals have spoken up on behalf of the conservation of our fish and wildlife. Hunters and anglers have contributed more than $10 billion to fish and wildlife conservation, and in a typical year pump $75 billion into the economy. And in a future increasingly characterized by urban sprawl and the demands of modern life, retreating to wild places with a rod or gun in hand is a cherished means of reconnecting with those sportsmen conservationists who came before us and re-invigorating ourselves to step up to the conservation challenges of our time.

America’s remarkable storehouse of wildlife is threatened by assaults unknown until modern times. Toxic air pollution and a warming climate are a double whammy for wildlife, and some of our most popular and beloved game species are paying a heavy price. Fish are disappearing from lakes and streams. Birds are taking to wing with heavy metals and other contaminants in their bodies. Big game populations are being pushed out of their historic ranges by a warming climate.

In a single generation, the future for game and fish is changing. It’s time for this generation of American hunters and anglers to continue the legacy of speaking up for wildlife.

INVISIBLE VILLIANS

There are four specific threats that are endangering the air and habitats of these wildlife species. Each affects wildlife in places as diverse as urban parks and remote wilderness regions, but they come from the same sources: the smokestacks of power plants and refineries as well as America’s fleet of automobiles.

Mercury Pollution
Mercury pollution has long been identified as a major issue for many fish species. As predator fish eat smaller prey, mercury accumulates in their tissue. Top-level predator fish such as brown trout, pickerel and bass are also favorite fish for the frying pan, but more and more regions are issuing strict warnings about the human consumption of mercury-laced fish. Emerging research is showing how mercury harms terrestrial mammals and even migrating songbirds, prompting scientists to reconsider how mercury negatively impacts larger ecosystems.

Acid Rain
Even in remote, wild regions, acid rain has long been identified as a killer of lakes and streams. Scientists are now learning that acidification of aquatic habitats may even alter the ability for some fish species to recognize threats such as predators—ushering in new questions about how chemical pollutants might affect not only the health of wildlife, but the intricacies of wildlife behavior. In New Hampshire the spring melting of acid snow has curtailed the natural reproduction of trout in several remote ponds.

Ground-Level Ozone
Ground-level ozone is only beginning to be identified as a game-changer for game and fish species. Long known to exacerbate respiratory and cardiopulmonary difficulties in humans, ozone is emerging as a threat not only to specific animal species, but to forest ecosystems on a vast scale

Climate Change
A warming climate will lead to direct habitat loss as well as more insidious changes, such as decreases in snowpack that result in a massive loss of fish spawning sites and increased summertime temperatures that are lethal to trout. Many fishery scientists predict more than half of all trout habitat will be eliminated from the lower 48 states by the year 2100 due to warming temperatures. Rising temperatures will shift the ranges and displace game species as varied as ruffed grouse and mountain goats.

This report puts a spotlight on 13 species of American wildlife that hold a special place in the hearts of sportsmen and women, and that are battling some of most difficult challenges in the natural world. These fish, birds, and mammals are not alone, however. Behind each of these icons are many more that face a troubling future due to toxic air pollution and rising temperatures. Those modern threats will change the game for American hunters and anglers—unless the sporting public stands up to fight for clean air and an end to the pollutants that lead to a warming climate.

WILDLIFE ICONS AT RISK

Bass-Perch-Pickerel

The vicious surface strikes and head-shaking leaps of the largemouth bass make it America’s favorite gamefish—but those predatory behaviors also make the largemouth and, other predators like perch and pickerel, highly susceptible to America’s serious water quality issues. Bioaccumulation of mercury in largemouth bass is an issue in states from California to New York to Massachusetts. In many New Hampshire waters consumption of largemouth bass, perch and pickerel is strictly curtailed due to mercury concentrations. In fact the NH Department of Fish and Game and Environmental Service have jointly released a health alert on the consumption of these freshwater fish. Depending on the area, nearly all of the mercury can be attributed to local sources. ( http://www.wildlife.state.nh.us/Fishing/fish_consumption.htm)

Climate change is also an issue for largemouth bass. Some anglers are heartened with news that a warming climate might bring faster growth rates for bass. But scientists warn that warming waters threatens to alter entire aquatic food webs, and could destabilize entire ecosystems. A warming climate could lead to a greater number and greater intensity of hurricanes, and as rising seas inundate freshwater marshes along the coast, more largemouth habitat could be lost.

Threats: Mercury. Climate change.

Moose

Massive and majestic, moose are a symbol of the North Woods and a cherished icon of North American hunting for both Native Americans and modern hunters alike. These big mammals are tied to wetlands and require cool climates, and those aspects of moose biology place the animals in difficult straits. When it comes to rising temperatures, heat affects moose directly, leading to a fall in pregnancy rates. A warming climate will also devastate moose habitat as the preferred habitat of aspen and birch retreats northward. In northwestern Minnesota, moose numbers fell from more than 4,000 animals to fewer than 100 over the last two decades. In northeastern Minnesota, habitat loss due to warming temperatures threatens a climatic refuge for moose exists , , And there are more insidious effects of climate change on moose. Moose also may have evolved to bear young when climate conditions are most favorable, and some scientists are concerned that they could have a difficult time adapting to climatic variability. Higher temperatures also may promote higher winter tick infestations, which have impacted the moose herds in Isle Royale National Park. and in New Hampshire. A single moose can host as many as 120,000 ticks.

Ground-level ozone might add to these ills. Birch, beech, and aspen have been shown to be sensitive to high levels of ozone, and these trees are an important part of much moose habitat. And there is the possibility that acid rain might be helping whittle moose populations to a fraction of their historic numbers. The potential for acid rain to leach cadmium from watersheds could be a problem for moose. In Norway, moose with high cadmium levels in their kidneys and livers were shown to have lower body weights and diminished reproductive success. In Maine and New Hampshire, high cadmium levels have led to advisories for human consumption of moose liver and kidneys. White tailed deer liver and kidneys are also contaminated with cadmium and are unfit for human consumption.

Threats: Climate change. Acid rain. Ground-level ozone.

Striped bass

The comeback of the striped bass has been heralded as one of the great conservation success stories of the last 100 years. Stripers, also known as “rockfish,” live as adults in the open ocean, and migrate up coastal rivers to spawn in the spring. Few gamefish require such vastly different habitats. But there could be rocky times ahead for rockfish populations. A warming climate could lead to sea-level rise that would decimate the coastal marshes that serve as nurseries for juvenile striped bass. In the Chesapeake Bay, warming waters could lead to increased incidence of toxic algal blooms, which could have profound impacts on fish resources, and an increased incidence of hypoxia, which could reduce the amount of deep, cool waters favored by striped bass. And warmer waters can have a cascade of ill effects on fish. Fish can bioaccumulate toxins more quickly at higher temperatures, and research has shown that striped bass with higher loads of organochlorines produced fewer viable offspring than control fish.

As top predators, striped bass are known for high levels of mercury. Mercury bioaccumulation has been found in striped bass populations in a wide range of waters, from the open marine environments of Rhode Island’s Narragansett Bay to Georgia’s Savannah River .

Threats: Global warming. Mercury.

Brook trout

Dappled with color and quick to take a fly, brook trout are a cherished part of our national fishing heritage. The only trout native to eastern America, they are sought in tiny headwater brooks, remote wilderness ponds, and fast-flowing rivers. The very fact that they require clear, cold, healthy waters is proof that the brook trout lives up to its scientific name, which means “dweller near springs.” Unfortunately, that requirement also puts brookies in peril from a host of air pollution problems. In the Northeast, many high-elevation brook trout streams and ponds have suffered from high rates of acidification, which studies have shown causes decreased growth rates in brook trout, plus lower survival rates of smaller trout and a drop in egg-to-larva survival rates. Farther south, in the Great Smoky Mountain National Park along the Tennessee-North Carolina state line, a study of caged brook trout in three mountain streams showed measurable signs of physiological stress during periods of artificially induced acidification.

And it’s not just acid rain stressing out native brook trout. In a recent survey of data from the northeastern United States and southeastern Canada, 75 percent of brook trout samples showed mercury concentrations higher than accepted levels of concern. A warming climate is expected to decimate populations. Across the Appalachian mountain range, some scientists estimate that up to 90 percent of brook trout habitat could be lost due to climate change, and what suitable habitat remains could be fragmented and scattered, making natural recolonization improbable.

Threats: Acid rain. Mercury. Climate change.

Lesser scaup

From their boreal forest and prairie pothole breeding grounds, lesser scaup wing southward across all four North American flyways. Migrating in large flocks, these swift fliers are a favorite quarry for big-water duck hunters. Fewer of these ducks are making it to hunters’ decoys, however. According to the U.S. Fish and Wildlife Service, the continental population for lesser scaup has fallen to a record low, and the future presents enormous challenges. In the prairie pothole region, a warming climate could impact 90 percent of the small wetlands vital for breeding ducks. Breeding range for lesser scaup on National Wildlife Refuges alone has been predicted to contract by nearly 37 percent due to climate change. And it’s not just a warming climate that’s turning up the heat on lesser scaup. The primary breeding range for scaup is the boreal forest of Canada, where declining snowpack could lead to an erosion in breeding habitat quality. Acid rain in Midwest wetlands used by scaup on their spring migrations southward could reduce the quality of invertebrate foods in the critical weeks prior to breeding. In the boreal forests of northern Alberta, acid rain caused by emissions from the massive tar sands development projects in northern Alberta could affect birds in a highly productive portion of their breeding grounds. And lesser scaup from areas as geographically diverse as the Great Lakes, Florida, and San Francisco Bay have shown relatively high levels of mercury, prompting further scientific study.

Threats: Climate change. Acid rain. Mercury.

Black duck

American black ducks hold a special place in the hearts of duck hunters. Big, brawny, and revered as one of the craftiest of all ducks, black ducks are considered a true trophy on the wing.
But even its legendary wariness won’t protect the black duck from a double whammy threat of climate change and acid rain. One-third of the 165 species of wetlands breeding birds show medium or high vulnerability to climate change, and black ducks have been identified as particularly susceptible to sea-level rise associated with a warming climate. And acid rain affects black ducks in insidious ways. Young broods of black ducks have shown a tendency to avoid wetlands with high acidity, and no wonder: Acidification of wetlands used by black ducks decreases the quality of forage foods, and has been shown to stunt the growth and development of black duck chicks , even potentially reducing bone mass and strength.

Threats: Climate change. Acid rain.

Salmon

From their storied migrations to their wild, remote habitats, few other fish can compare to the salmon for a majestic expression of the marvels of natural history. And few other fish are as imperiled by a world quickly changing. In addition to the well-known challenges salmon face from human-caused factors such as dams, the fish must confront a warming climate. Healthy stocks of salmon in the Pacific Northwest are dependent on sufficient water supplies in their headwater spawning streams. But the region has warmed over the last century, with snowpack volumes dropping more than 10 percent. The timing of peak stream flows from melted snow water are coming earlier and earlier, and with warming waters and lower flows, available spawning habitat will plummet. Some scientists predict that Oregon and Idaho could lose more than 40 percent of salmon habitat by 2090. It’s also possible that a warming climate could fast-forward the timetable when juvenile salmon enter the ocean. If they arrive before the flush of oceanic plankton fully matures, feeding could be difficult.

Across the continent, acid rain threatens Atlantic salmon populations from southeastern Canada and into Maine. Acidic waters impair the ability of a salmon’s gills to absorb oxygen, leading to circulatory failure. Research on Atlantic salmon has shown that acidification in the fish’s small nursery streams may disrupt the efficiency of its biophysical alarm system based on chemical cues in the water. If salmon can’t process threats that might translate into increased predation. According to the Atlantic Salmon Foundation, acid rain has decimated salmon in Nova Scotia’s southern upland region, with populations in 50 rivers threatened.

Threats: Climate change. Acid rain.

Other Affected Species

• River otters and mink are the frequent companions of anglers on streams and creeks. Feeding heavily on fish, otters and mink accumulate mercury from their prey. The New Hampshire Trappers Association assisted the Fish and Game Department in the collection of mink carcasses to be tested for mercury. All twenty mink tested had high levels of mercury. At high levels mercury is suspected to negatively impact the reproductive health in otters; mercury levels in the tissue of one Ontario river otter suspected of dying of mercury poison were among the highest ever recorded for a free-living terrestrial mammal.

• The upward flute-like trill of the wood thrush signals the end of the day for hunters and anglers in Eastern forests. But wood thrush numbers are falling, in part because of acid rain that depletes the soil of much-needed calcium. Without the needed nutrient, the birds lay thin, brittle eggs. Mercury also has been found in the wood thrush, and studies have shown that a related species, Bicknell’s thrush, bioaccumulates mercury not from aquatic sources but in high-elevation forests.

• Few bird songs are as recognizable as the tremulous call of the common loon. Northern lakes are getting quieter, however. High levels of mercury in loons has been shown to cut loon egg production by more than 40 percents.

TAKING ACTION FOR WILDLIFE

Throughout American history, hunters and anglers have fought to protect and preserve wildlife and wild places. Once upon a time, those threats were as visible as a cleared forest—unchecked logging, unregulated water pollution, unrelenting development. Now, some of the most challenging threats to the future of our iconic game species are invisible, silent, and progress over long periods of time. But they are no less real. And they require no less action on the part of America’s hunters and anglers.

It is becoming increasingly clear that the wildlife and wild places that Americans have held dear for generations are undoubtedly being affected by the 21st century pollution challenges that we now face. Thankfully, there are solutions to these toxic, invisible villains. Strong environmental laws like the Clean Air Act can clean up the air which affects our waters and woodlands, and keep America’s wild places safe and sound for wildlife. But since moose, brook trout, black ducks, salmon and other species have no voices of their own then each of us have a responsibility to help fight off the pollution that is affecting them.

For forty years, Americans and wildlife have benefitted tremendously from the Clean Air Act:

• Clean Air Act programs protect our streams and rivers from acid rain, our lakes from toxic mercury pollution, and our forests from tree killing smog.
• The economic benefits of the Clean Air Act updates of 1990 will exceed $2 trillion by 2020 compared to only $65 billion for implementation costs: a cost-to-benefit ratio of 30:1.
• Adult deaths were reduced by 160,000 in 2010 due to the Clean Air Act updates; in 2020, this number will increase to more than 230,000

The first forty years of the Clean Air Act have just been a starting point for continued work. Now, more than ever, the Clean Air Act is an important tool for significantly reducing the pollution that is wreaking havoc on wildlife.

We must all speak up in support of the Clean Air Act and encourage the Environmental Protection Agency (EPA) to update its pollution standards for pollutants like mercury, ozone, acid rain, and climate changing carbon dioxide – all of which directly threaten our wildlife heritage. The EPA is poised to take action on our country’s biggest polluters, which include coal plants, refineries, and vehicles, but we must demand that Congress not interfere but instead let EPA do its job. We cannot afford to let the special interests of big polluters to come before healthy wildlife, clean air, and clean water if we want to pass along our wildlife heritage to future generations.

For more information and how to get involved please visit www.nwf.org/cleanair


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Ibid