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Coral Reefs And Ecosystem Services

October 18, 2021 By EarthWise Leave a Comment

A new study led by the University of British Columbia provides the first comprehensive look at what climate change, overfishing, and habitat destruction of coral reefs mean for their ecosystem services. For humans, this means how the global decline in coral reefs has affected their ability to provide essential benefits including food, livelihoods, and protection from storms.

The study found that global coverage of living corals has declined by about half since the 1950s and the diversity of reef species has declined by more than 60%. So, it is no surprise that there has been a significant loss in the ability of reefs to provide ecosystem services.

The study analyzed data from coral reef surveys around the world, fisheries catches, indigenous consumption, and more. Apart from the declines in reef coverage and biodiversity, the study found that fish catches on coral reefs peaked in 2002 and has steadily declined since then, despite increased fishing efforts.

The findings of the study led the researchers to conclude that continued degradation of coral reefs in the years to come threaten the well-being and sustainable development of millions of people in communities on the coast that depend on coral reefs. Fish and fisheries provide essential nutrients in places with few alternative sources of nutrition. Coral reef biodiversity and fisheries have added importance for indigenous communities, where important cultural relationships exist with reefs.

The study’s authors say that the results are a call to action. The level of destruction happening all over the world’s coral reefs is threatening people’s culture, their daily food, and their history. It is not just an environmental issue; it is a human rights issue.

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Photo, posted September 22, 2010, courtesy of David Burdick / NOAA Photo Library via Flickr.

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Carbon From 25 Cities | Earth Wise

September 10, 2021 By EarthWise Leave a Comment

There are roughly 10,000 cities in the world, defined as places with at least 50,000 inhabitants with a sufficient population density. Roughly half the world’s population lives in cities.

Urban carbon emissions are one of the world’s biggest problems with respect to the climate. A new study has determined that just 25 cities globally are responsible for 52% of urban greenhouse gas emissions.

The study gathered data on greenhouse gas emissions in 167 cities in 53 countries. The results were that megacities in Asia, such as Shanghai and Tokyo, were among the biggest total emitters, and that major cities in Europe, the US, and Australia tended to have larger per capita emissions. Several Chinese cities, however, matched levels seen in developed countries. Researchers tracked emissions over time in 42 of the cities studied. Some cities saw declining emissions in the period between 2005 and 2016. These included Oslo, Houston, Seattle, and Bogota. Others saw large increases, including Rio de Janeiro, Johannesburg, and Venice.

The largest sources of emissions are power generation, industry, and transportation. In a third of the cities, road transportation alone accounted for over 30% of emissions. (Railways, waterways, and aviation combined only accounted for less than 15% of total emissions).

Half of the world’s population lives in cities, but cities are responsible for more than 70% of greenhouse gas emissions. Thus, cities have a big responsibility for the decarbonization of the global economy. Of the 167 cities in the study, 113 have set emission-reduction targets. But as the study shows, cities have much more work to do to meet the goals of the Paris Climate Agreement.

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Two Dozen Large Cities Produce 52 Percent of Urban Carbon Emissions

Photo, posted December 1, 2017, courtesy of Hector Galbis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A New Fishway Technology | Earth Wise

February 5, 2021 By EarthWise Leave a Comment

Freshwater fish populations have declined by more than 80% over the past forty years across the globe. This is in part due to hundreds of thousands of dams, weirs, and barriers stopping their movements. These river barriers have disrupted fish reproduction cycles the world over by preventing river fish from migrating to spawn.

Fishways or fish ladders are waterways constructed on or around obstructions in order to provide passageways for fish and other aquatic species. Often, they consist of a series of small overflow weirs and pools constructed in the form of steps. Fish need to jump from one pool to another to migrate to the upstream. Such fish ladders require a large space to construct. These and several other types of fishways tend to be expensive to install and maintain and are not always successful in allowing fish to get to where they need to go.

Researchers at the University of New South Wales in Australia have come up with an ingenious new type of fishway. Called a “tube fishway”, it is a low-cost and low-energy installation that works by pumping fish at high velocity – protected by a cushion of bubbly water – through a tube running over the obstructing barrier to deliver them safely into the water on the other side.

They successfully demonstrated a prototype system on a rugged slope behind a campus building that transported fish from one tank to another about 25 feet up the slope.

Fish are attracted into the chamber by suitable geometry and the system uses the energy available from the upper reservoir to lift the fish. Modeling shows that the system will work for pipes as large as three feet in diameter and could lift fish more than 300 feet vertically.

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New fishway technology to get fish up and over those dam walls

Photo, posted October 19, 2019, courtesy of Andrew Harvey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change and Komodo Dragons | Earth Wise

October 12, 2020 By EarthWise Leave a Comment

The Komodo dragon is the world’s largest and most iconic lizard. Growing up to 10 feet long and weighing up to 360 pounds, Komodo dragons are endemic to five islands in southeast Indonesia, four of which are part of Komodo National Park, as well as a fifth that has three nature reserves. Komodo dragons have existed on earth for at least four million years, and it’s estimated that 4,000 of them survive in the wild today.

But according to a new study by researchers from the University of Adelaide and Deakin University in Australia, Komodo dragons could soon be driven to extinction. The research team found that the impacts of both global warming and sea level rise are likely to cause a sharp decline in available habitat for Komodo dragons. Current conservation strategies are not enough to avoid climate-driven Komodo dragon population declines.

The study, which was recently published in the journal Ecology and Evolution, involved close collaboration with Komodo National Park and the Eastern Lesser Sunda Central Bureau for Conservation of Natural Resources.

Climate-change-informed decisions should be a common part of conservation practice. According to the research team’s conservation model, Komodo dragons on two of the five Indonesian islands are less vulnerable to climate change. But those two islands might not be enough for the survival of the species. Conservation managers may need to translocate Komodo dragons in the future – to sites where these animals have not been found for decades – in order to protect the species from extinction.

Without taking immediate action to mitigate climate change, the research team says many range-restricted species like Komodo dragons are at risk of extinction.

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Climate change threatens Komodo dragons

Photo, posted August 6, 2016, courtesy of Tony Alter via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sharks On The Decline | Earth Wise

September 4, 2020 By EarthWise Leave a Comment

During the past 70 years, global shark populations have been on the decline. Many species have become threatened or endangered. Conservation efforts have been underway in many places, but shark populations continue to be at risk because of over-fishing and habitat loss.

A comprehensive study by marine biologists at Texas A&M University deployed more than 15,000 baited remote underwater video stations on 371 coral reefs in 58 countries. The study included 59 different shark species in the Atlantic, Pacific and Indian Oceans. The researchers were surprised to find that no sharks at all were detected in almost 20% of the locations surveyed and were almost completely absent from coral reefs in several nations.

Scientists believe that demand for shark products, such as fins and meat, and bycatch (that is, sharks captured in nets by fisherman trapping other kinds of fish) are strong contributors to the widespread declines in shark numbers around the world.

The study shows that if corrective steps are not taken in regions where marine management is still ineffective, continued depletion of shark populations is highly likely.

Sharks have important roles in marine ecosystems. When their habitats deteriorate and their populations decrease, ecosystem stability and health is degraded because sharks help regulate prey populations.

Some countries, notably the Bahamas, are combating the problem by providing sanctuaries for sharks where fishing and harvesting is prohibited. Such places support some of the healthiest shark populations in the world. However, the decline of coral reefs is just another challenge facing shark populations around the world.

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Study Shows Alarming Decline In Shark Numbers Around The World

Photo, posted January 9, 2017, courtesy of Kris-Mikael Krister via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wildlife Rediscoveries

March 30, 2017 By EarthWise

We recently brought you the rediscovery story of cave squeakers. These tiny frogs, known for their high-pitched whistling calls, were native to the mountainous region of eastern Zimbabwe but had not been seen since 1962. That all changed in late 2016, when researchers found four cave squeakers, confirming that after 58 years the species was not extinct. Cave squeakers remain critically endangered according to the IUCN’s Red List of Endangered Species.

Squeaking By

March 14, 2017 By EarthWise

Amphibians are one of the most threatened groups of animals on the planet. Since the late 1980s, scientists have measured dramatic population declines from locations all over the world. The plummeting amphibian populations are perceived to be one of the most critical threats to global biodiversity. According to the IUCN, about 1 of every 3 amphibian species is facing extinction. Some of the greatest threats facing amphibians include climate change, disease, and habitat destruction.

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The Great Salt Lake Is Shrinking

January 9, 2017 By EarthWise

Utah’s Great Salt Lake is the largest salt water lake in the Western Hemisphere and is the largest body of water in the United States after the five Great Lakes. When the pioneers first arrived in the area back in the middle of the 19th century, the lake spread across about 1,600 square miles. Now, the lake covers an area of only about 1,050 square miles, a reduction of about 35%.