survival

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.

**********

Web Links

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.

Mangrove Trees And Climate Change | Earth Wise

July 7, 2020 By EarthWise Leave a Comment

Mangrove trees are small trees that grow in coastal saline or brackish water at tropical and subtropical latitudes. Many mangrove trees can be identified by their dense tangle of prop roots. These roots make the trees appear as if they are standing on stilts above the water. The tangle of roots allows mangrove trees to handle the daily rise and fall of tides and to slow the movement of tidal waters.

Mangrove forests provide many ecosystem services, including stabilizing the coastline by reducing erosion from storm surges, waves, and tides. The intricate root system of mangrove trees are attractive to fish and other species seeking food and shelter from predators. Mangrove forests also store large amounts of carbon.

But according to a new study recently published in the journal Science, mangrove trees won’t survive sea level rise by 2050 if greenhouse gas emissions aren’t reduced.

Using sediment data from 78 locations over the last 10,000 years, an international team of scientists led by Macquarie University in Australia estimated the chances of mangrove trees survival based on the projected rates of future sea-level rise.

When sea level rise rates exceeded 6 millimeters per year, which is similar to estimates under high-emissions scenarios for 2050, researchers found that mangrove trees were unlikely to keep pace with the rising water levels. But when the annual increase was 5 millimeters or less – which is the projected low-emissions scenario this century – mangrove trees are much more likely to survive.

These findings underscore the importance of reducing greenhouse gas emissions to mitigate rapid sea level rise. The future of mangrove trees may depend on it.

**********

Web Links

Mangrove trees won’t survive sea-level rise by 2050 if emissions aren’t cut

Photo, posted December 17, 2012, courtesy of Edward Stojakovic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Dolphins

May 27, 2019 By EarthWise Leave a Comment

We don’t think of heatwaves as something that affects the ocean, but increasingly, as the planet warms, there have been instances where ocean water temperatures become much higher than normal for extended periods of time. There has been much discussion of this phenomenon with regard to coral reefs where the catastrophic rise in coral bleaching events has been the result.

Recently, a study at the University of Zurich looked at the effects of ocean heatwaves on marine life higher in the food chain. They studied the well-known dolphin population in Shark Bay, Western Australia.

In early 2011, a heatwave caused water temperatures in Shark Bay to rise more than 4 degrees above the annual average for an extended period. This led to a substantial loss of seagrass, which is a driving factor in the Shark Bay ecosystem.

The researchers investigated how this environmental damage affected survival and reproduction of dolphins, using long-term data on hundreds of animals collected over a ten-year period from 2007 to 2017.

Their analysis showed that dolphins’ survival rate dropped by 12% and female dolphins were giving birth to fewer calves. That phenomenon that began in 2011 lasted at least until 2017.

The researchers were surprised by the extent and the duration of the influence of the heatwave, especially the fact that the reproductive rate of dolphins had not returned to normal even after 6 years.

This study shows for the first time that marine heatwaves not only affect organisms at the lower levels of the food chain, but also might have considerable long-term consequences for the animals at the top, such as dolphins.

**********

Web Links

Climate change is a threat to dolphins’ survival

Photo, posted December 14, 2014, courtesy of Ed Dunens via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Frogs Are In Big Trouble

May 22, 2019 By EarthWise Leave a Comment

Scientists first noticed in the 1970s that some frog populations were declining rapidly. By the 1980s, some species appeared to be extinct. The loss of frog species was mysterious because many were actually living in pristine habitats that did not face pollution or deforestation.

By the late 1990s, researchers had identified that frogs in widely different places around the world were infected with a deadly fungus called Batrachochytrium dendrobatidis – or Bd for short. The fungus originated on the Korean peninsula, but the pathogen spread throughout the world, probably via the international trade in pet amphibians. By 2007, researchers speculated that Bd might be responsible for all known declines of frogs that had no other apparent cause – about 200 species.

Recently, a group of 41 scientists published the first worldwide analysis of the fungal outbreak and the devastation turns out to be far worse than anyone had previously realized. Populations of more than 500 species of amphibians have declined significantly because of the outbreak, including at least 90 species presumed to have gone extinct. These figures are more than twice as large as earlier estimates.

According to biologists, Bd is now considered to be the deadliest pathogen known to science. But the decimation of frogs peaked in the 1980s. Today, although 39% of the species that suffered population declines in the past are still declining, 12% are showing signs of recovery, possibly because natural selection is favoring resistant animals.

There is cautious optimism for the surviving amphibian species, but scientists worry that another strain of Bd or some different species of fungus altogether may prove even deadlier. The best we can do is not participate in moving pathogens around the world.

**********

Web Links

The Plague Killing Frogs Everywhere Is Far Worse Than Scientists Thought

Photo, posted June 19, 2010, courtesy of Chris Luczkow via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Is There Hope For Coral Reefs?

January 16, 2019 By EarthWise Leave a Comment

News about the world’s coral reefs has been relentlessly bad for a number of years. Warming, acidifying oceans have wreaked havoc with coral reefs leading to enormous losses. Nowhere have things been more dire than in Australia’s Great Barrier Reef. Coral bleaching events have been increasingly common and severe over the past two decades. In fact, only 7% of the Great Barrier Reef has escaped bleaching entirely since 1998.

While the future of the world’s coral reefs is very much uncertain as global heating continues, there is a recent bit of hopeful news. According to a study published in Nature Climate Change, the response of the Great Barrier Reef to the extreme temperatures in 2017 was quite different from that of the previous year in the aftermath of back-to-back bouts of coral bleaching.

Surprisingly, corals that bleached in 2016 but managed to survive were more resistant to the recurrence of hot conditions in 2017.

Many corals don’t survive bleaching events at all and, of course,those corals don’t bleach for a second time. But the surviving corals from the 2016 bleaching event were tougher species. As a result of bleaching, the mix of coral species on the reef is changing very rapidly. The net result was that there was less bleaching in 2017 even though the temperatures that year were even more extreme than in 2016.

There have now been four mass bleaching events on the Great Barrier Reef over the past 20 years and it is only a matter of time before another one occurs triggered by the next marine heatwave. Almost half of the corals on the northern two-thirds of the reef have been killed. But at least some of the reef is showing impressive survival skills.

**********

Web Links

A glimmer of hope for the world’s coral reefs

Photo, posted November 29, 2012, courtesy of Robert Linsdell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Value Of Biodiversity

July 16, 2018 By EarthWise Leave a Comment

It is often said that biodiversity is crucial for staving off extinctions. Ecosystems are complex and are essentially defined by the interdependencies among the various animals and plants. It stands to reason that removing species from an ecosystem can have significant effects up and down the food chain. Extinctions are much more likely when biodiversity diminishes.

Polar Bears Are Struggling To Find Food

March 9, 2018 By EarthWise Leave a Comment

Climate change continues to pose a major threat to polar bear survival. Polar bears, whose native range largely lies within the Arctic Circle, depend on sea ice for nearly all of their life cycle functions. And rising global temperatures are causing that sea ice to disappear.

Can Polar Bears Be Saved?

January 30, 2017 By EarthWise

Climate change is posing a major threat to polar bear survival. The polar bear, whose native range lies largely within the Arctic Circle, depends on sea ice for nearly all of its life cycle functions. And rising temperatures are causing that sea ice to disappear.

Can Cheetahs Survive?

January 24, 2017 By EarthWise

A new study has revealed that the global population of the world’s fastest land animal – the cheetah – is down to only 7,100, a drop of 50% over the past 40 years. The dramatic decline in cheetah population could soon lead to the extinction of the species unless urgent conservation efforts are made.

Climate Change And Reindeer

December 23, 2016 By EarthWise

Hundreds of thousands of reindeer roam Russia’s Yamal Peninsula, which is located in northwestern Siberia, and are herded by the indigenous Nenets people, reportedly among the Arctic’s last truly nomadic reindeer herders. Reindeer provide these indigenous people with transportation, food, clothes, and even tools made from their bones. Reindeer are well suited for the freezing temperatures and thick snow of this climate. But they are not well suited for climate change.

The Zombieless Apocalypse

November 29, 2016 By WAMC WEB

Post-apocalyptic fiction is all the rage these days. There are numerous stories featuring an endless list of civilization-ending disasters: asteroid collisions, cataclysmic earthquakes, nuclear wars, supervolcanoes, pandemics… the list goes on and on. Most of the time, humanity either perishes entirely, is reduced to a handful of heroic and astonishingly resourceful souls, or ends up inexplicably as zombies staggering around the landscape in search of brains.

Ecotourism And Endangered Species

March 24, 2016 By WAMC WEB

Ecotourism is increasing on a global scale. Ecotourism is generally defined as responsible travel to natural areas that conserves the environment, sustains the well-being of the local people, and involves interpretation and education. Visitor numbers to many protected areas around the world are expanding every year. Ecotourism provides rich experiences for the traveler and often has great benefits to local communities fighting poverty and seeking sustainable development.