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Categories: Archaeology: General, Environmental: Ecosystems

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This study, conducted from 2015-19 in the Thunder Basin National Grassland, may be the first to specifically examine the multispecies impacts of a wide-scale plague outbreak, which reduced the area covered by prairie dog colonies from nearly 25,000 acres to only about 125 acres in the study area. The 2017 outbreak was followed by abnormally high precipitation in 2018, which caused vegetation to grow quickly and taller without the presence of prairie dogs. The researchers found that the mountain plover, birds that thrive when vegetation is kept shorter by prairie dogs, almost disappeared from the study area, while migrant songbirds such as the lark bunting, which prefer taller vegetation, increased in number. Meanwhile, species including ferruginous hawks, badgers and swift foxes declined dramatically as their prey base crashed.

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The severity of marine heatwaves (MHWs) that are increasingly impacting ocean ecosystems, including vulnerable coral reefs, has primarily been assessed using remotely sensed sea-surface temperatures (SSTs), without information relevant to heating across ecosystem depths. Here, using a rare combination of SST, high-resolution in-situ temperatures, and sea level anomalies observed over 15 years near Moorea, French Polynesia, we document subsurface MHWs that have been paradoxical in comparison to SST metrics and associated with unexpected coral bleaching across depths. Variations in the depth range and severity of MHWs was driven by mesoscale (10s to 100s of km) eddies that altered sea levels and thermocline depths and decreased (2007, 2017 and 2019) or increased (2012, 2015, 2016) internal-wave cooling.

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Scientists have discovered for the first time that invasive rats on tropical islands are affecting the territorial behavior of fish on surrounding coral reefs. The new study shows that the presence of invasive black rats on tropical islands is causing changes in the territorial behavior of the jewel damselfish -- a herbivorous species of tropical reef fish that 'farm' algae in the branches of corals.

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A new study based on 297 ancient Scandinavian genomes analysed together with the genomic data of 16,638 present day Scandinavians resolve the complex relations between geography, ancestry, and gene flow in Scandinavia -- encompassing the Roman Age, the Viking Age and later periods. A surprising increase of variation during the Viking period indicates that gene flow into Scandinavia was especially intense during this period.

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What genetic changes are responsible for the evolution of phenotypic traits? This question is not always easy to answer. A newly developed method now makes the search much easier.

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A study of vegetation across New York City and some densely populated adjoining areas has found that on many summer days, photosynthesis by trees and grasses absorbs all the carbon emissions produced by cars, trucks and buses, and then some. The surprising result, based on new hyper-local vegetation maps, points to the underappreciated importance of urban greenery in the carbon cycle.

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More than 500 years ago in the midwestern Guatemalan highlands, Maya people bought and sold goods with far less oversight from their rulers than many archeologists previously thought. Overtime, the availability of obsidian resources and the prevalence of craftsmen to shape it resulted in a system that is in many ways suggestive of contemporary market-based economies.

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Mass coral bleaching events are making it harder for some species of reef fish to identify competitors, new research reveals. Scientists studying reefs across five Indo-Pacific regions found that the ability of butterflyfish individuals to identify competitor species and respond appropriately was compromised after widespread loss of coral caused by bleaching. This change means they make poorer decisions that leave them less able to avoid unnecessary fights, using up precious limited energy.

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Brown algae take up large amounts of carbon dioxide from the air and release parts of the carbon contained therein back into the environment in mucous form. This mucus is hard to break down for other ocean inhabitants, thus the carbon is removed from the atmosphere for a long time, as researchers now show. They reveal that the algal mucus called fucoidan is particularly responsible for this carbon removal and estimate that brown algae could thus remove up to 550 million tons of carbon dioxide from the air every year -- almost the amount of Germany's entire annual greenhouse gas emissions.

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A new study that reconstructs the history of sea level at the Bering Strait shows that the Bering Land Bridge connecting Asia to North America did not emerge until around 35,700 years ago, less than 10,000 years before the height of the last ice age (known as the Last Glacial Maximum). The findings indicate that the growth of the ice sheets -- and the resulting drop in sea level -- occurred surprisingly quickly and much later in the glacial cycle than previous studies had suggested.

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Archaeologists have uncovered projectile points in Idaho that are thousands of years older than any previously found in the Americas, helping to fill in the history of how early humans crafted and used stone weapons.

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Researchers have developed accurate nation-wide mapping of the carbon content of trees based on aerial images.

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A new study found bird diversity increased in North Carolina mountain forest areas severely burned by wildfire in 2016, reinforcing that while wildfire can pose risks to safety and property, it can be beneficial to wildlife. The study results could help forest managers better predict bird responses to wildfire, and manage forests to benefit birds.

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Ocean warming is driving an increase in the frequency and severity of marine heatwaves, causing untold damage to coral reefs. Tropical corals, which live in symbiosis with tiny single celled algae, are sensitive to high temperatures, and exhibit a stress response called bleaching when the ocean gets too hot. In the last 4 decades, marine heatwaves have caused widespread bleaching, and killed millions of corals. Because of this, a global search is underway for reefs that can withstand the heat stress, survive future warming, and act as sources of heat-tolerant coral larvae to replenish affected areas both naturally and through restoration.

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New research shows that disproportionately large amounts of carbon accumulate at the bottom of deep-sea trenches. The trenches may thus play an important role for deep-sea storage of organic material -- and thus for the atmospheric Co2 balance.

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Using satellite monitoring data, researchers have developed a deep learning algorithm that could provide real-time monthly land use and land cover maps for parts of India.

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UK forests could store almost double the amount of carbon than previous calculations suggest, with consequences for our understanding of carbon stocks and humanity's response to climate change, according to a new study.

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Spread across vast distances, the islands of the tropical Pacific Ocean are thought to have been populated by humans in two distinct migrations beginning approximately 3,330 years ago. The first followed a northern route out of what is today the Philippines and the second followed a southern route from Taiwan and New Guinea. People arrived on the islands between these routes -- now making up the Federated States of Micronesia -- about 1,000 years later. But a new finding by sea-level researchers suggests that the islands in Micronesia were possibly settled much earlier than supposed and that voyagers on the two routes may have interacted with one another.

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Traction is important. Humans have been continually interested in discovering how to better move across wet or frozen surfaces safely -- whether to improve shoes for walking on sidewalks or tires to maneuver the roadways. But what makes it possible for some Arctic animals to walk and run across the ice so effortlessly and gracefully without slipping and falling? Researchers took a deep dive into the paws of polar bears to find out. What the team discovered was that all bears (except sun bears) have papillae on their paw pads, but that the papillae on polar bears were taller -- up to 1.5 times. And, that the taller papillae of polar bears help to increase traction on snow relative to shorter ones. Even though polar bears have smaller paw pads compared to the other species (likely because of greater fur coverage for heat conservation), the taller papillae of polar bears compensate for their smaller paw pads, giving them a 30-50% increase in frictional shear stress.

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Hunnic peoples migrated westward across Eurasia, switched between farming and herding, and became violent raiders in response to severe drought in the Danube frontier provinces of the Roman empire, a new study argues.