Category: Natural resources

Parts of the Amazon go from absorbing carbon dioxide to emitting it

Read the full story in the New York Times.

A new study analyzing hundreds of aerial readings of emissions above the forest canopy found that forest regions in the southeast were most affected.

Don’t hike so close to me: How the presence of humans can disturb wildlife up to half a mile away

What are you looking at? Greg Shine, BLM/Flickr, CC BY

by Jeremy Dertien (Clemson University); Courtney Larson (University of Wyoming); and Sarah Reed, (Colorado State University)

Millions of Americans are traveling this summer as pandemic restrictions wind down. Rental bookings and crowds in national parks show that many people are headed for the great outdoors.

Seeing animals and birds is one of the main draws of spending time in nature. But as researchers who study conservation, wildlife and human impacts on wild places, we believe it’s important to know that you can have major effects on wildlife just by being nearby.

In a recent review of hundreds of studies covering many species, we found that the presence of humans can alter wild animal and bird behavior patterns at much greater distances than most people may think. Small mammals and birds may change their behavior when hikers or birders come within 300 feet (100 meters) – the length of a football field. Large birds like eagles and hawks can be affected when humans are over 1,300 feet (400 meters) away – roughly a quarter of a mile. And large mammals like elk and moose can be affected by humans up to 3,300 feet (1,000 meters) away – more than half a mile.

Elk viewed over a hiker's shoulder.
A hiker about 75 feet from a bull elk in Yellowstone National Park. Jacob W. Frank, NPS/Flickr

Many recent studies and reports have shown that the world is facing a biodiversity crisis. Over the past 50 years, Earth has lost so many species that many scientists believe the planet is experiencing its sixth mass extinction – due mainly to human activities.

Protected areas, from local open spaces to national parks, are vital for conserving plants and animals. They also are places where people like to spend time in nature. We believe that everyone who uses the outdoors should understand and respect this balance between outdoor recreation, sustainable use and conservation.

How human presence affects wildlife

Pandemic lockdowns in 2020 confined many people indoors – and wildlife responded. In Istanbul, dolphins ventured much closer to shore than usual. Penguins explored quiet South African Streets. Nubian ibex grazed on Israeli playgrounds. The fact that animals moved so freely without people present shows how wild species change their behavior in response to human activities.

Decades of research have shown that outdoor recreation, whether it’s hiking, cross-country skiing or riding all-terrain vehicles, has negative effects on wildlife. The most obvious signs are behavioral changes: Animals may flee from nearby people, decrease the time they feed and abandon nests or dens.

Other effects are harder to see, but can have serious consequences for animals’ health and survival. Wild animals that detect humans can experience physiological changes, such as increased heart rates and elevated levels of stress hormones.

And humans’ outdoor activities can degrade habitat that wild species depend on for food, shelter and reproduction. Human voices, off-leash dogs and campsite overuse all have harmful effects that make habitat unusable for many wild species.

Disturbing shorebirds can cause them to stop eating, stop feeding their young or flee their nests, leaving chicks vulnerable.

Effects of human presence vary for different species

For our study we examined 330 peer-reviewed articles spanning 38 years to locate thresholds at which recreation activities negatively affected wild animals and birds. The main thresholds we found were related to distances between wildlife and people or trails. But we also found other important factors, including the number of daily park visitors and the decibel levels of people’s conversations.

The studies that we reviewed covered over a dozen different types of motorized and nonmotorized recreation. While it might seem that motorized activities would have a bigger impact, some studies have found that dispersed “quiet” activities, such as day hiking, biking and wildlife viewing, can also affect which wild species will use a protected area.

Put another way, many species may be disturbed by humans nearby, even if those people are not using motorboats or all-terrain vehicles. It’s harder for animals to detect quiet humans, so there’s a better chance that they’ll be surprised by a cross-country skier than a snowmobile, for instance. In addition, some species that have been historically hunted are more likely to recognize – and flee from – a person walking than a person in a motorized vehicle.

Generally, larger animals need more distance, though the relationship is clearer for birds than mammals. We found that for birds, as bird size increased, so did the threshold distance. The smallest birds could tolerate humans within 65 feet (20 meters), while the largest birds had thresholds of roughly 2,000 feet (600 meters). Previous research has found a similar relationship. We did not find that this relationship existed as clearly for mammals.

We found little research on impact thresholds for amphibians and reptiles, such as lizards, frogs, turtles and snakes. A growing body of evidence shows that amphibians and reptiles are disturbed and negatively affected by recreation. So far, however, it’s unclear whether those effects reflect mainly the distance to people, the number of visitors or other factors.

Graphic showing distances at which human presence affects animals' behavior.
Human recreation starts to affect wild creatures’ behavior and physical state at different distances. Small mammals and birds tolerate closer recreation than do larger birds of prey and large mammals. Sarah Markes, CC BY-ND

How to reduce your impact on wildlife

While there’s much still to learn, we know enough to identify some simple actions people can take to minimize their impacts on wildlife. First, keep your distance. Although some species or individual animals will become used to human presence at close range, many others won’t. And it can be hard to tell when you are stressing an animal and potentially endangering both it and yourself.

Second, respect closed areas and stay on trails. For example, in Jackson Hole, Wyoming, wildlife managers seasonally close some backcountry ski areas to protect critical habitat for bighorn sheep and reduce stress on other species like moose, elk and mule deer. And rangers in Maine’s Acadia National Park close several trails annually near peregrine falcon nests. This reduces stress to nesting birds and has helped this formerly endangered species recover.

Getting involved with educational or volunteer programs is a great way to learn about wildlife and help maintain undisturbed areas. As our research shows, balancing recreation with conservation means opening some areas to human use and keeping others entirely or mostly undisturbed.

As development fragments wild habitat and climate change forces many species to shift their ranges, movement corridors between protected areas become even more important. Our research suggests that creating recreation-free wildlife corridors of at least 3,300 feet (1,000 meters) wide can enable most species to move between protected areas without disturbance. Seeing wildlife can be part of a fun outdoor experience – but for the animals’ sake, you may need binoculars or a zoom lens for your camera.

Jeremy Dertien, PhD Candidate in Forestry and Environmental Conservation, Clemson University ; Courtney Larson, Adjunct Assistant Professor, University of Wyoming; and Sarah Reed, Affiliate Faculty in Fish, Wildlife and Conservation Biology, Colorado State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Lax pesticide policies are putting wildlife health at risk, experts warn

Read the full story in Audubon Magazine.

Scientists and advocates say neonicotinoids—shown to harm bees, birds, and other wildlife—need tougher regulation. The U.S. EPA has a key window to take action in the next year.

Salmon going nuts at a fish farm possibly high on cocaine, officials say

Read the full story at Motherboard.

Salmon frantically jumping around on a fish farm in Germany may have been on cocaine, according to a report released by German environmental officials. 

Officials from the State Environmental Agency of North Rhine-Westphalia (also known as Lanuv) noticed the strange and erratic behavior from the Atlantic Salmon in June of 2020 while overseeing a species conservation project. 

Genetic study in giant evergreens reveals clues to pest resistance

Read the full story from North Carolina State University.

Recent research into a group of giant evergreens is helping scientists better understand why some trees are able to survive in the face of insect pests, and could help foresters breed trees with the resistance necessary to survive in the face of new and emerging challenges to forest health.

Sharks that hunted near Antarctica millions of years ago recorded Earth’s climate history in their teeth

Sharks’ teeth carry clues about the oceans they swam in. Christina Spence Morgan

This story is part of Oceans 21
The Conversation’s series on the global ocean opened with five in depth profiles. Look out for new articles on the state of oceans in the lead up to the UN’s next climate conference, COP26. The series is brought to you by The Conversation’s international network.

by Sora Kim (University of California, Merced)

Tens of million years ago, sand tiger sharks hunted in the waters off the Antarctic Peninsula, gliding over a thriving marine ecosystem on the seafloor below.

All that remains of them today is their sharp pointed teeth, but those teeth tell a story.

They’re helping solve the mystery of why the Earth, some 50 million years ago, began shifting from a “greenhouse” climate that was warmer than today toward cooler “icehouse” conditions.

Many theories about this climate shift focus on Antarctica. There is geologic evidence that both the Drake Passage, which is the water between South America and the Antarctic Peninsula, and the Tasman Gateway, between Australia and East Antarctica, widened and deepened during this time as Earth’s tectonic plates moved. The wider, deeper passages would have been necessary for the waters of the major oceans to come together and the Antarctic Circumpolar Current to form. That current, which flows around Antarctica today, traps cold waters in the Southern Ocean, keeping Antarctica cold and frozen.

Map showing temperature differences from very cold around Antarctica to warming beyond the current.
A map of the ocean surface temperature as measured by satellites shows the Antarctic Circumpolar Current, marked by dark lines. Antarctica’s sea ice appears in light blue. Copernicus Marine Services/European Union

The now-extinct sand tiger shark species Striatolamia macrota was once a constant in the waters around the Antarctic Peninsula, and it left exquisitely preserved fossil teeth on what is now Seymour Island near the tip of the peninsula.

By studying the chemistry preserved in these shark teeth, my colleagues and I found evidence of when the Drake Passage opened, which allowed the waters of the Pacific and Atlantic oceans to mix, and what the water felt like at the time. The temperatures recorded in shark teeth are some of the warmest for Antarctic waters and verify climate simulations with high atmospheric carbon dioxide concentrations.

Oxygen captured in very sharp teeth

Sand tiger sharks have sharp teeth that protrude from their jaw to grasp prey. A single shark has hundreds of teeth in multiple rows. Over a lifetime, it sheds thousands of teeth as new ones grow.

Important environmental information is encoded within the chemistry of each tooth and preserved there over millions of years.

For example, the outer layer of a shark’s tooth is composed of an enameloid hydroxyapatite, similar to enamel in human teeth. It contains oxygen atoms from the water the shark lived in. By analyzing the oxygen, we can determine the temperature and salinity of the surrounding water during the shark’s life.

The teeth from Seymour Island show that the Antarctic waters – at least where the sharks lived – stayed warmer longer than scientists had estimated.

Five sizes of shark teeth
Illustrations of sand tiger shark teeth used by the scientists. Christina Spence Morgan

Another clue comes from the element neodymium, which adsorbs and replaces other elements in the outer enameloid of the tooth during early fossilization. Each ocean basin has a distinct ratio of two different neodymium isotopes based on the age of its rocks. Looking at the ratio in the shark teeth allows us to detect the sources of the water where the shark died.

If conditions are stable, the neodymium composition would not change. However, if neodymium composition does change in fossil teeth over time, that indicates changes in oceanography.

Big sharks, warm water

We studied 400 teeth from Seymour Island, from all ages of shark, juvenile to adult, from individuals living between 45 million to 37 million years ago. The combination of tooth size and chemistry yielded some surprising clues to the past.

Some of the teeth were extremely large, suggesting these ancient Antarctic sand tigers were larger than today’s sand tiger shark, Carcharias taurus, which can grow to about 10 feet long.

In addition, water temperatures the sharks lived in were warmer than previous studies involving Antarctic clam shells suggested. It’s possible the difference was between waters closer to the surface and deeper on the sea floor, or the sharks whose teeth we found may have spent part of their lives in South America. Today’s sand tiger sharks track warm waters. They spend summer and early fall between coastal Massachusetts and Delaware, but when waters cool off, they migrate to coastal North Carolina and Florida. Because their teeth continuously form and move forward almost like a conveyor belt, there are some teeth within the jaw that represent a different habitat than where a shark is living. It is possible that the ancient sand tiger sharks also migrated, and when Antarctic waters cooled off, they headed north to warmer waters at lower latitudes.

A shark showing its teeth
A modern sand tiger shark, also known as a grey nurse shark, shows its rows of teeth. Jlencion/Wikimedia, CC BY-SA

The teeth suggested that the sharks’ water temperature then was similar to the water temperatures where modern sand tiger sharks can be found today. Carbon dioxide concentrations were also three to six times higher than today, so scientists would expect amplified temperatures in the regions.

Finally, the neodymium in the fossil sand tiger shark teeth provides the earliest chemical evidence of water flowing through the Drake Passage that aligns with tectonic evidence. The early timing of the Drake Passage opening, but the delayed cooling effect, indicates there are complex interactions between Earth’s systems that affect climate change.

What about their northern cousins?

Sand tiger sharks were found around the world during the Eocene, suggesting they survived in a wide range of environments. In the Arctic Ocean, for example, they lived in brackish waters that are less salty than the open ocean 53 million to 38 million years ago and were much smaller than their southern cousins off Antarctica.

Differences in the saltiness of the tiger sharks’ habitat and size of the sharks also show up in the Gulf of Mexico during this time. That range of environmental tolerance bodes well for the modern sand tiger sharks’ survival as the planet warms once again. Unfortunately, the pace of warming today is faster and may be beyond the sand tiger shark’s ability to adapt.

Sora Kim, Assistant Professor of Paleoecology, University of California, Merced

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Coastal ecosystems worldwide: Billion-dollar carbon reservoirs

Read the full story from the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig.

Australia’s coastal ecosystems alone save the rest of the world costs of around 23 billion US dollar a year by absorbing CO2 from the atmosphere. Coastal ecosystems such as seagrass meadows, salt marshes and mangrove forests make an important contribution to mitigating climate change.

Male dragonflies get less flashy in hotter climates

Read the full post at Treehugger.

When temperatures rise, male dragonflies have come up with a decidedly drab but clever way to stay cool. They lose some of the showy pigmentation on their wings, a new study finds. Shedding the dark patches helps regulate their body temperature, but it could make it harder to attract mates and fend off rivals.

Wolf wars: As Michigan packs grow, a battle brews over killing the predators

Read the full story at Bridge Michigan.

While the governor-appointed Michigan Natural Resources Council prepares to decide whether to allow wolf hunting in Michigan, advocates and foes of the iconic and deeply divisive canid are locked in a struggle for influence over the next era of Michigan’s wolf management program.

Balloon releases have deadly consequences – we’re helping citizen scientists map them

A mylar balloon at Presqu’ile Provincial Park in Ontario, Canada. Lara O’Brien, CC BY-ND

by Lara O’Brien and Shannon Brines (University of Michigan)

Balloons are often seen as fun, harmless decorations. But they become deadly litter as soon as they are released into the air and forgotten.

Plastic pollution is one of today’s biggest environmental challenges. Microplastics have been found in our drinking water, food and even the air we breathe. While many people are trying to reduce their use of single-use plastic bags, bottles, utensils and straws, balloons are often overlooked.

To help bring attention to the environmental dangers of released balloons, one of us (Lara O’Brien) created a citizen science survey to track and map balloon debris. This work is designed to raise awareness about the dangers of balloons, while also gathering data to help influence policies regulating celebratory balloon releases.

Balloons cause many kinds of damage

Deliberate releases of tens, hundreds or sometimes thousands of balloons are common sights at weddings, graduations, memorials, sporting events and other celebrations. These fleeting feel-good acts inflict long-lasting and potentially deadly consequences on the environment and wildlife.

Balloons filled with helium – a finite and rapidly dwindling resource – travel hundreds or even thousands of miles. They land as litter on beaches, rivers, lakes, oceans, forests and other natural areas.

The two most common types of balloons are Mylar and latex. Mylar balloons, also called foil balloons, are made from plastic nylon sheets with a metallic coating and will never biodegrade. They also cause thousands of power outages every year when they come into contact with power lines or circuit breakers.

While some manufacturers claim that natural latex balloons made from liquid rubber are biodegradable, they still take years to break down because they are mixed with plasticizers and other chemical additives that hinder the biodegradation process. Other latex balloons are synthetic, made from a petroleum derivative called neoprene – the same material used to make scuba diving wetsuits – and will remain in the environment indefinitely, breaking down into smaller and smaller pieces over time.

Both Mylar and latex balloons are a significant threat to wildlife, livestock and pets, which can be injured or killed from eating balloon fragments, getting tangled in long balloon ribbons or strings, or being spooked by the falling debris.

More than 100 balloons collected at the Edwin B. Forsythe National Wildlife Refuge in New Jersey. USFWS/Flickr, CC BY

Latex shreds: A deadly meal

Unlike Mylar balloons, latex balloons burst in the atmosphere, shredding into small pieces that, when floating on the surface of water, resemble jellyfish or squid. Plastic debris in the ocean can also become coated with algae and other marine microbes that produce a chemical scent, which sea turtles, seabirds, fish and other marine life associate with food. Because they are soft and malleable, latex balloons easily conform to an animal’s stomach cavity or digestive tract and can cause obstruction, starvation and death.

As a result, latex balloons are the deadliest form of marine debris for seabirds. They are 32 times more likely to kill than hard plastics when ingested. Balloons tied with ribbons and strings also rank just behind discarded fishing gear and plastic bags and utensils due to the high risk of entanglement and death that they pose to marine life.

This juvenile Kemps Ridley sea turtle has ingested balloon debris. Blair Witherington, Florida FWC/NOAA, CC BY

Volunteers track debris in real time

Environmental organizations are working to both clean up and record data on plastic pollution and marine debris, including balloons. Between 2016 and 2018, volunteers with the Alliance for the Great Lakes picked up and recorded more than 18,000 pieces of balloon debris. In 2019 the International Coastal Cleanup, an annual event organized by the Ocean Conservancy, recorded over 104,150 balloons found around the world, with almost half in the United States.

Utilizing citizen science as a way to collect more data and help raise awareness in the Great Lakes region and beyond, Lara O’Brien created an online survey in June 2019 that people can use to record the date, location, condition and photo of balloon debris. The survey is completely anonymous and can be easily accessed on a smartphone, so users can document balloon debris they find while walking the dog, hiking or participating in a beach cleanup.

Since the survey began, citizen scientists have helped record more than 1,580 pieces of balloon debris found in an area stretching from remote Isle Royale National Park in Lake Superior to Sandbanks Provincial Park in Lake Ontario. Surveys and photos have also been submitted from Washington state, Oregon, Montana, Nevada, Kansas, Florida, Iceland and the United Kingdom. (View an interactive map of balloon debris sightings submitted since June 2019 at Balloondebris.org).

The most important feature of this survey allows volunteers to pinpoint and submit the exact GPS coordinates of balloon debris in real time. This geospatial data is immediately uploaded onto an interactive map that clearly and powerfully shows where released balloons end up, and how prevalent and widespread balloon waste is. It helps researchers see emerging patterns or trends that might be present, including potential hotspots where higher concentrations of balloon debris may occur.

In the United States, balloons float eastward with prevailing west-to-east winds. In the Great Lakes region, higher concentrations of balloon debris have been reported along the eastern shores of Lakes Michigan and Huron. This includes the Indiana Dunes National Park southeast of Chicago, where volunteers regularly come across balloons. One person reported finding 84 balloons in a single morning along a two-mile stretch of beach. (View an interactive heat map showing where the greatest concentrations of balloon debris in the Great Lakes region have been found since June 2019 at Balloondebris.org.)

Ending balloon pollution

Thanks to research like this and work by organizations such as Balloons Blow, the Alliance for the Great Lakes and the NOAA Marine Debris Program, awareness of balloon pollution is growing. More people are choosing to use alternatives and urging schools, businesses and other organizations to stop balloon releases.

A growing movement across the United States is calling for more policies and laws restricting or eliminating single-use plastics, including balloons. California, Connecticut, Florida, Tennessee and Virginia have all passed laws prohibiting the deliberate release of balloons in order to protect the environment and wildlife. Others, including Maryland, Kentucky and Arizona, are considering similar bans.

Volunteers who want to collect data and map the location of balloon debris in their communities may visit the project’s page on the citizen science site SciStarter or at balloondebris.org. There they can find links to the survey, interactive maps, photos, suggestions for eco-friendly alternatives and more. By helping people visualize and understand balloon pollution, we hope to prevent future balloon releases.

Lara O’Brien, Master of Science in Conservation Ecology and Environmental Informatics, University of Michigan and Shannon Brines, Applied Geographer, Lecturer and Manager, Environmental Spatial Analysis Laboratory, University of Michigan

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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