The impacts of changing habitats and climates for many endangered species are playing a significant role in lowering threatened populations, pushing some near the brink of extinction.
Food scarcity, loss of livable habitat and shifts to crucial migration patterns are just some of the ways that climate changes are laying a heavy blow to struggling species.
Scientists have noted drastic changes in the populations of migrating monarch butterflies. Extreme drought conditions and herbicides have heavily damaged milkweed populations, which the butterflies use to feed, lay eggs and my even hatch from their chrysalides. The butterflies migrate from as far north as Canada down to Mexico for the winter, and this past year saw the lowest population numbers in 20 years; a 59 percent decrease in occupied areas.
A butterfly feeds on milkweed, a valuable life source for the insect, which is threatened by droughts and herbicides. Photo by Terry Reimink.
Monarch butterflies are susceptible to fluctuations in their environment. Higher temperatures kill off eggs, pupae and larvae and an arid atmosphere can dry them out. Though there is a significant decrease in the central U.S. drought this year compared to last, cattle farmers also continue to kill off milkweed plants, which are toxic to cows, decreasing a vital food supply for the butterflies as they make their long journeys.
Estimates put current snow leopard populations only at 4,000 to 6,500. An in-depth study conducted by the World Wildlife Fund (WWF) on the effects of climate changes to snow leopard habitats found that snow leopards are facing a large habitat loss in the Himalayan Mountains, where glaciers are melting faster than in other parts of the world, two to three times quicker than polar ice.
An endangered snow leopard perches in its preferred habitat. High-speed glacial melt in the Himalayans are threatening their habitats. Photo by Tom Brakefield.
The biggest threat to their habitat is a shift in the tree line. Snow leopards hunt in the high alpine areas above the tree line, but it is estimated that as much as 30 percent of their habitat could be lost as the tree line shifts. The group looks at rising temperatures and an increase in greenhouse gas emissions as causes for this change, as warmer temperatures at higher elevations are allowing trees to grow in new areas. The leopards try to avoid the forests and are not able to travel much higher in altitude, so as the tree line moves up, the area for the snow leopards to thrive shrinks.
According to Sarah Fogel, director of media relations with WWF, "Glaciers are receding and treeline and non-frozen habitat is moving up, meaning there is far more human-wildlife conflict with herders and potentially with tourism."
Contributing to the threat for snow leopards are the ways that humans directly impact their lands with hunting and livestock grazing. The study found that the snow leopards can be adaptive to the changes in their environment if the area is able to be conserved and protected from these additional threats.
The massive North American right whales have been considered an endangered species since the 1970s with a habitat ranging from Nova Scotia to the southeastern United States. Now only about 500 of the whales remain in the world. Changes in water temperature and currents are having massive effects on how well these whale populations are able to sustain their already fragile numbers.
A North American right whale's tail emerges from the water. Warmer water temperatures are affecting the populations of its primary food source, which is affecting their ability to reproduce. Photo by Wim Stolwerk.
The biggest threat to the whales has been direct human activities, such as hunting and fishing. Now they face an additional threat in the form of zooplankton population fluctuations. Zooplankton are a vital food source for the whales, especially for pregnant or nursing mothers. Warming waters in the North Atlantic are shifting the habitats of zooplankton to areas that make them more susceptible to some predators, which could affect their populations for the animals that already rely on them, such as the right whale.
A whale research scientist and Dr. Scott Kraus, vice president of research for the New England Aquarium stated that, "Strong correlations have been made between C. finmarchicus [zooplankton] abundance and right whale reproductive success, so reduction in prey abundance could lead to a decline in the number of calves. Reduced food can also lead to malnourishment, increased susceptibility to disease and increased mortality."
Whale monitors have noted a relationship between the zooplankton populations and whale births. After a drop in zooplankton in 1998, only one new whale was born the following year. That same year the zooplankton levels began to rise again, and in 2001 30 of the whale calves were born, the most born in a year since 1982.
With only an estimated 3,200 tigers left in the wild, many wildlife conservationists are worried about further habitat loss for the species. Rising sea levels along the Bangladesh coast are swallowing valuable lands for tigers and may outpace their ability to adapt, according to Colby Loucks, WWF-US deputy director of conservation science and the lead author of the study Sea Level Rise and Tigers: Predicted Impacts to Bangladesh's Sundarbans Mangroves.
Tigers are incredible adaptable, able to live in the mangrove forests of Bangladesh or in the icy tundra of Siberia. Sea level rise is threatening their mangrove forests, however, and experts fear the forest destruction will move faster than they can adapt. Photo by Tom Brakefield.
This area occupied by the tigers, the Sundarbans, is the world's largest block of mangrove forest. A 2007 report by the Intergovernmental Panel on Climate Change estimates that sea levels could rise by 28 cm by the year 2070, which wildlife experts say would eliminate the Sundarbans as a habitat for tigers.
As the mangrove forests shrink, the tigers are forced to more open areas where they are more vulnerable to illegal poaching and will have increased difficulties hunting for food. Wildlife groups are calling for better conservation efforts and for increased environmental awareness and energy conservation to help protect the species and their crucial habitats.
Polar bears are facing a series of macabre threats to their existence because of the loss of sea ice in their areas. According to Tammy Schmidt, curator of carnivores and ungulates at the Philadelphia Zoo, though polar bears are able to feed on a number of arctic animals, they rely on seals to fatten themselves up sufficiently to survive the winters. This is especially true for mother bears who may go for months without eating when tending to her cubs.
But as sea ice melts in the Arctic, seal populations are going down, leading to food scarcities for the polar bears.
A polar bear sits with her cub. Sea ice loss is making it difficult for polar bears to get an adequate supply of seals, which is creating a series of feeding problems for the bears. Photo by John Pitcher.
The results of food shortages are grim; cubs not able to survive, adults starving to death or turning to cannibalism, an increase in aggression among competitive adult males. Schmidt said that although polar bears are swimmers, they are not equipped to swim long distances, especially if a mother bear is carrying two or three cubs on her back. The loss of ice has led to some bears drowning as they try to go longer distances between places to land.
"It's not pretty, but that's what's happening," Schmidt told AccuWeather.com. "It's happening and they are dying."
Of the 19 subspecies of polar bears, eight were confirmed to be declining in 2009, compared to five in decline in 2005. It's estimated that two-thirds of the world's polar bears could die in the next four years if this path continues. The Philadelphia Zoo and Polar Bears International are working on advocacy programs to help educate children and the public at large on ways to conserve energy and improve the ways we recycle to create an overall better environment to help protect the planet's animal populations.
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