What Effect Does Climate Have on Wildlife?

There are many examples of animal species already severely affected by climate change. Here are just a few:

Butterflies – In North America and Europe, over 35 species of butterflies have been expanding their ranges northward by up to 200 km. In the western U.S., Edith’s Checker spot butterfly has not only shifted its range 92 km northward since the early 20th century, but has also shifted its range in elevation (approximately 124 m in elevation).

Foxes – In Canada, general warming is allowing red foxes to expand their range northward. Unfortunately for arctic foxes, red foxes are better suited to living in a warmer environment. Arctic foxes are retreating further north as their habitat shrinks.

Frogs, Toads & Salamanders – In Costa Rica and North America, frogs, toads and salamanders are disappearing due to climate change. With less winter precipitation, breeding pools aren’t deep enough to protect eggs and tadpoles from damaging ultraviolet rays. Weakened by UV-B radiation, they become susceptible to fungal infection, dying at epidemic rates. With inadequate water, over 50% of western toads succumb to fungal infection.

Grizzlies and Pines – Nutritious whitebark pine seeds are a major food source for grizzly bears in western North America. The ability of a female grizzly to successfully bear young is linked to pine seed abundance – more seeds mean healthier bear families. Unfortunately, whitebark pine is vulnerable to the impacts of climate change. Warm temperatures allow pine blister rust – a deadly fungus – to thrive and spread, killing up to 90% of whitebark pine in a given area. Less trees, less seeds, less bears.

Newts – In Britain, earlier winter warming has thrown off the timing of amphibian reproduction. Newts have started breeding earlier, but frogs haven’t. With a head start, the large, hungry newts feast on frog spawn, reducing frog numbers dramatically. Before climate change tipped the scales, frogs hatched first, thus avoiding being eaten by the newts.

Penguins – In four years of unprecedented warm winters Adelie and Chinstrap penguin populations on King George Island have declined by 40 and 35 percent, respectively. Sea ice cannot form on Antarctic seas warmed by climate change. The krill that typically feed on the algae are the primary food source of the penguins. As krill becomes scarce, penguins starve.

Polar Bears – In the last two decades, polar bears living in the western Hudson Bay area have undergone a change for the worse. The polar bear feeds primarily on ringed seals. Bears rely heavily on the predictable spring abundance of ringed seal pups to provide energy and nourishment for survival throughout the year – particularly for raising and nursing cubs. They need stable sea ice as a solid surface on which to hunt ringed seals. Anything that affects the distribution and annual duration of sea ice has a profound effect on the health and well-being of polar bear populations. Since 1981, ice break-up on Hudson Bay has occurred earlier and earlier, forcing bears to come ashore in progressively poorer condition. Their hunting season cut short, they do not have enough time to regain their energy stores. Increased temperatures – caused by human-made greenhouse gas emissions – are responsible for melting the arctic ice out from under the bears’ feet.

Reptiles – In many reptiles, temperature determines the sex of offspring. Increased global temperatures could seriously skew sex ratios. A shortage of either sex could undermine a species’ ability to replace itself from generation to generation. In painted turtles, offspring sex ratio is correlated with mean July temperature. Even a modest temperature increase (2–4°C), could dramatically reduce the number of male turtles produced.

Salmon – Usually restricted by cold water temperatures, Pacific salmon species such as sockeye, pink salmon and coho salmon have been found far outside their normal ranges. A coho salmon was found almost 2000 km further into northern waters than usual. Temperature increases in the Arctic as a result of climate change have allowed these temperate-water salmon to expand their ranges.

Trout – Trout are a cold-water fish, thriving in spring- and glacier-fed water. Already struggling under the burden of pollution, erosion and diversion projects, trout are now – literally – in hot water. As climate change raises temperatures in North America, streams, rivers and lakes are becoming too warm for trout to survive. Brook, brown and rainbow trout will lose up to 76% of their habitat if greenhouse gases continue to build up and trap heat in the atmosphere .

Wolves, Moose and Trees – With increased winter snowfall in the North Atlantic region of North America, wolves are hunting in larger packs. Triple the numbers of moose are killed per day, compared to less snowy years when wolves hunt in smaller packs. With fewer moose feeding on their lower branches, fir trees quickly fill in the forest’s understory.