degradation

Global Decline In Wildlife | Earth Wise

October 14, 2020 By EarthWise Leave a Comment

According to a new report released by the World Wildlife Fund, global populations of mammals, birds, amphibians, reptiles, and fish have declined by 68% in less than half a century.

The report presents a comprehensive overview of the state of the natural world based on the tracking of almost 21,000 populations of more than 4,000 vertebrate species between 1970 and 2016.

The report shows that the main cause of the dramatic decline in species populations on land is habitat loss and degradation, which includes deforestation driven by food production. Additional factors include land-use change and the use and trade of wildlife.

Wildlife populations found in freshwater habitats have suffered a decline of 84%, which is the steepest decline in any biome.

Insect populations have declined rapidly in many places, but most of the information about insects comes from a small number of countries in the northern hemisphere. There is very little information from large parts of the world, such as Africa, South America, and Asia, where land-use change and agricultural expansion are happening fast. What happens to insects matters a lot to humanity. Insects play central roles in the world’s ecosystems as waste processors, pollinators, predators, and prey.

The report is clear evidence of the damage human activity is doing to the natural world. Threats to the integrity of ecosystems endanger humans and all of nature. This is especially apparent in the midst of a global pandemic. It is now more important than ever to take coordinated global action to halt and reverse the loss of biodiversity and wildlife populations across the globe.

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Living Planet Report reveals 68% decline in global wildlife populations since 1970

Photo, posted May 7, 2020, courtesy of Bernard Spragg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Beavers And The Warming Arctic | Earth Wise

August 5, 2020 By EarthWise Leave a Comment

Beavers have a remarkable ability to transform landscapes. Using their sharp teeth, they fell trees and shrubs and build dams, which cause small valleys to fill with water and form new lakes. Some of these lakes measure five or ten acres in size, or even more. And beavers are very efficient builders; they often build their dams at precisely those points where can they have the greatest effect with the least effort.

Scientists studying beaver activity in the Arctic regions of Alaska have found that the changing climate is leading to a substantial increase in beaver populations and their effect on the landscape.

In 2018, researchers found that the beavers living in a 7,000 square-mile area in northwest Alaska had created 56 new lakes in just five years. Thanks to rising temperatures, more and more habitats offer the shrubs that beavers need for food and building material. In addition, the lakes, which used to freeze solid, now offer beaver-friendlier conditions. Also, beavers are not hunted as intensively as in the past.

The scientists were surprised that beavers have seized the opportunity so intensively. There is basically an exponential growth in beaver dams. This is actually a worrisome situation. Forming all these new lakes degrades ice-rich permafrost in the area. In the Kotzebue region of Alaska, the overall water area has increased by more than 8% over the past 17 years, and roughly two-thirds of that is due to beavers.

The degradation of the Arctic’s permafrost is a dangerous situation and it appears that anyone who wants to predict its future has to keep the activity of beavers in mind.

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Beavers gnawing away at the permafrost

Photo, posted June 23, 2018, courtesy of Becky Matsubara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Degraded Permafrost In The Arctic

July 11, 2019 By EarthWise Leave a Comment

Permafrost is defined as rock or soil that has been at or below the freezing point of water for two or more years. Most of it is located in high latitudes in and around the Arctic and Antarctic regions. Permafrost covers nearly a quarter of the exposed land in the Northern Hemisphere.

Permafrost can contain many different materials including bedrock, sediment, organic matter, water and ice. Because of the presence of organic matter, permafrost is potentially the source of significant methane emissions if it thaws and the trapped biomass begins to rot.

A recent study looked at the results of 30 years of aerial surveys and extensive ground mapping of an area of Canada’s high Arctic polar desert known as the Eureka Sound Lowlands. This area has an extremely cold climate and the permafrost there is over 1/3 of a mile thick. It has long been assumed that this landscape was stable.

Research led by McGill University in Montreal has found that this is not the case. The increases in summer air temperatures seen in recent years are initiating widespread changes in the landscape.

A particular landform known as a retrogressive thaw slump that forms when ice within permafrost melts and the land slips down is widely occurring in the area. The absence of vegetation and layers of organic soil in these polar deserts make permafrost in the area particularly vulnerable to increases in summer air temperatures.

The research indicates that despite the cold polar desert conditions that characterize much of the high Arctic, the interaction between ice-rich permafrost systems and climate factors is complex and the links between global warming and permafrost degradation are not well understood.

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