Some wild animals thrive near humans, but only up to a point.
- A recent study used motion-triggered cameras to study mammal behavior at 61 sites across North America.
- The results showed that large, carnivorous mammals with slow life histories are most negatively impacted by human presence and development.
- The researchers noted that although some mammals are able to tolerate or even benefit from humans, there might be a threshold to how much human disturbance mammals can tolerate.
The proliferation of human civilization has impacted nearly every animal species on Earth. Since the 16th century, humans have driven about 700 vertebrate species to extinction, while our presence and activities threaten to kill off more than one million plant and animal species over the coming decades.
But it's not always a zero-sum game. Amid the chaos of the Anthropocene — the term some geologists use to refer to the current geological age in which human activity is the dominant force on the environment — some animals are doing fine. It's not just pet labradoodles and cockapoos: Deer, squirrels, mosquitoes, and cephalopods are a few of the species that have been surviving or even thriving among us in recent decades.
So, why do some species suffer amidst human civilization while others adapt?
A new study published in Global Change Biology explores that question by analyzing which North American mammal species live most successfully among humans. The researchers hypothesized that North American mammals with certain traits and life strategies are more likely to suffer outsized consequences from humans.
"Specifically, we hypothesized that larger, more carnivorous species and those with slower life history strategies (i.e., longer maturation periods, slower reproductive rates) are more negatively affected by both human presence and human footprint, given that these species are typically more likely to come into conflict with humans."
Human development vs. human presence
To find out, the researchers used data from "camera traps" to monitor the behavior of 24 mammal species. These motion-triggered cameras were set up at 61 locations across the U.S., Canada, and Mexico, and they captured photos of animals representing three trophic guilds: herbivores, omnivores, and carnivores. A few of the species analyzed in the study included black bears, white-tailed deer, wolves, coyotes, grizzly bears, and raccoons.
The goal was to see how animal populations responded to two different types of human disturbance: human development (buildings, roads, agricultural fields) and human presence (hunting, hiking, other recreation).
The results showed that one-third of mammal species were less likely to appear in areas with high human presence or development. Specifically, the results supported one part of the original hypothesis, which stated that larger, more carnivorous, and slower reproducing species (like wolves and grizzly bears) are more negatively affected by human development and its accompanying threats, like noise and light pollution and vehicle strikes.
However, these animals weren't significantly affected by human presence, a finding that highlights "the importance of considering these two forms of human disturbance separately when estimating anthropogenic impacts on wildlife," the researchers wrote.
Raccoons love you...
Smaller mammals and those that reproduce quickly responded more positively to human disturbance. Raccoons and white-tailed deer, for example, tended to appear more frequently in areas with both higher human presence and development. Meanwhile, mammals like elk, bobcats, coyotes, and pumas appeared more frequently in areas with only higher human presence.
Why do smaller, quickly reproducing animals fare better among us and our infrastructure? The researchers suggested it may be that they are better able to tolerate threats like sensory pollution and vehicle strikes or have a more generalist diet. Alternatively, areas near humans tend to have fewer predators.
...up to a point
But the results might be a bit misleading. For example, the cameras might have captured a certain species showing up frequently near human disturbances not because the animals prefer it there but because humans are destroying their natural habitat.
The study noted another caveat: Once human disturbances become too intense, even once-tolerant mammals start responding negatively. In other words, there seems to be a threshold of human disturbances beyond which co-existence with other mammals becomes difficult or impossible.
"We suggest that such thresholds are critical to consider when attempting to promote 'landscapes of coexistence' (i.e., ecological conditions that allow the long-term persistence of sensitive mammal species in human-dominated landscapes) and functional connectivity between populations, particularly as several large mammal species continue recolonizing modified landscapes in North America and globally," the researchers wrote.
The unique light signatures of nautical beacons translate into hypnotic cartography.
- Many of the world's 23,000 lighthouses feature a distinct combination of color, frequency, and range.
- These unique light signatures help ships verify their positions and safeguard maritime traffic.
- But they also translate into this map, visualizing the ingenuity and courage of lighthouse builders and keepers.
Land and sea are both shaded dark, so it's a bit hard at first to make out that this collection of merrily blinking lights is actually a map. Once the coastal contours pop, though, all becomes clear: these are lighthouses!
The Age of Big Data
The map not only shows where they are, but how they are: static or blinking in various colors with the size of the circles corresponding to the range of their lights.
Up until the 20th century, a map of lighthouses would have been a subdued affair: just a string of dots strung along lines of coast. But this is the 21st century! We're in the Age of Big Data, ruled by the clever boffins who know how to stitch one dataset to another. Zap it with electricity and presto: it's alive!
That's what the folks did over at Geodienst, the spatial expertise center of the University of Groningen (Netherlands). Back in 2018, student/assistant Jelmer van der Linde (currently with the University of Edinburgh) came across OpenSeaMap, an open-source resource for nautical information similar to its more famous landlubber cousin, OpenStreetMap.
OpenSeaMap contained a database with detailed information on nautical beacons and lighthouses, which included not just their location, but also the frequency, range, and even the color of their signals. Would it be possible to visualize all those data points on a map? Yes, it would!
The result is this riot of a map. It's important that ships don't mistake one lighthouse for another. That's why they come in various colors and their lights flicker with a distinct frequency. Norway in particular is lit up with beacons and lighthouses, as its fjord-indented coast warrants. And the rest of Europe is well provided with nautical warning lights.
However, while the map is reminiscent of other global traffic trackers for flights (like Flightradar24 or FlightAware) or shipping (such as VesselFinder or MarineTraffic), it is neither live nor global. The flickering lights aren't a real-time report; they merely repeat the code in the original database. And that database is incomplete.
Zoom out, and the map gets a bit too dark. According to the Lighthouse Directory, there are at least 23,000 lighthouses in the world. And even though the United States has more lighthouses than any other nation – 700 by some counts – the map only shows a handful of lights in North America.
Like its parent, the lighthouse map is open source too, so if anyone out there is capable of filling in the gaps, they can. Lighthouse enthusiasts, get to it!
Not one yet yourself? Below are 10 lighthouse facts to help you come over to the light side.
Trapped in a giant phallus and other true facts about lighthouses
- The world's smallest lighthouse is the North Queensferry Light Tower, near the Forth Bridge in Scotland. A mere 16 feet (5 m) tall, it was built in 1817 by Robert Stevenson, famous builder of lighthouses, as was his son Thomas, who was the father of the famous novelist Robert Louis Stevenson.
- Reaching a height of 436 ft (133 m), Jeddah Light in Saudi Arabia is the world's tallest lighthouse.
- The 2019 movie The Lighthouse, starring Willem Dafoe and Robert Pattinson, was based on a true incident, known as the Smalls Lighthouse Tragedy. In 1801, a storm trapped two Welsh lighthouse keepers, both named Thomas, in their lighthouse. One died, the other went mad. Asked to summarize his film, writer/director Robert Eggers said, "Nothing good can happen when two men are trapped alone in a giant phallus."
- From its inauguration in 1886 until 1901, the Statue of Liberty also served as a lighthouse. Its nine electric arc lamps, located in the torch, could be seen 24 miles out to sea.
- All U.S. lighthouses are now automated – save for Boston Light, the oldest continually used lighthouse in the country. For historical reasons, Congress has decided it shall remain staffed year-round.
- Hook Lighthouse, on Hook Head in Ireland's County Wexford, claims to be the world's oldest lighthouse still in use. It was first built by a medieval lord in the early decades of the 13th century.
- The Tower of Hercules in La Coruña, Spain has a slightly better claim. It was built by the Romans in the 1st century AD and still functions as a lighthouse.
- Stannard Rock Lighthouse is also known as "the loneliest place in the world." It is located in Lake Superior, Michigan. At 24 miles (39 km) from shore, it is the most remote lighthouse in the U.S. and one of the most remote in the world. It opened in 1883 and was staffed for parts of the year until 1962.
- A lighthouse on Märket is the reason for the weird border on the island, divided between Sweden and Finland. In 1885, the Finns built a lighthouse on the highest part of the island – on the Swedish half. Thanks to a complicated land swap, the lighthouse is back on the Finnish side.
- In the United States, August 7 is National Lighthouse Day.
Strange Maps #1082
Many thanks to Toon Wassenberg for sending in this map. Got a strange map? Let me know at firstname.lastname@example.org.
First drawn in 1935, Hu Line illustrates persistent demographic split – how Beijing deals with it will determine the country's future.
- In 1935, demographer Hu Huanyong drew a line across a map of China.
- The 'Hu Line' illustrated a remarkable divide in China's population distribution.
- That divide remains relevant, not just for China's present but also for its future.
A bather in Blagoveshchensk, on the Russian bank of the Amur. Across the river: the Chinese city of Heihe.
Credit: Dimitar Dilkoff/AFP via Getty Images
The Hu Line is arguably the most consequential feature of China's geography, with demographic, economic, cultural, and political implications for the country's past, present, and future. Yet you won't find it on any official map of China, nor on the actual terrain of the People's Republic itself.
There are no monuments at its endpoints: not in Heihe in the north, just an icy swim across the Amur from Blagoveshchensk, in Russia's Far East; nor in Tengchong, the subtropical southern city set among the hills rolling into Myanmar. Nor indeed anywhere on the 2,330-mile (3,750-km) diagonal that connects both dots. The Hu Line is as invisible as it is imaginary.
Yet the point that the Hu Line makes is as relevant as when it was first imagined. Back in 1935, a Chinese demographer called Hu Huanyong used a hand-drawn map of the line to illustrate his article on 'The Distribution of China's Population' in the Chinese Journal of Geography.
The point of the article, and of the map: China's population is distributed unevenly, and not just a little, but a lot. Like, a lot.
- The area to the west of the line comprised 64 percent of China's territory but contained only 4 percent of the country's population.
- Inversely, 96 percent of the Chinese lived east of the 'geo-demographic demarcation line', as Hu called it, on just 36 percent of the land.
Much has changed in China in the intervening near-century. The weak post-imperial republic is now a highly centralized world power. Its population has nearly tripled, from around 500 million to almost 1.4 billion. But the fundamentals of the imbalance have remained virtually the same.
Even if China's territory has not: in 1946, China recognized the independence of Mongolia, shrinking the area west of the Hu Line. Still, in 2015, the distribution was as follows:
- West of the line, 6 percent of the population on 57 percent of the territory (average population density: 39.6 inhabitants per square mile (15.3/km2).
- East of the line, 94 percent of the population on 43 percent of the territory (average population density: 815.3 inhabitants per square mile (314.8/km2).
Hu Huanyong's original hand-drawn map of China, showing population density and the now-famous line (enhanced for visibility).
Credit: Chinese Journal of Geography (1935) – public domain.
Why is this demographic dichotomy so persistent? In two words: climate and terrain. East of the line, the land is flatter and wetter, meaning it's easier to farm, hence easier to produce enough food for an ever-larger population. West of the line: deserts, mountains, and plateaus. Much harsher terrain with a drier climate to boot, making it much harder to sustain large amounts of people.
And where the people are, all the rest follows. East of the line is virtually all of China's infrastructure and economy. At night, satellites see the area to the east twinkle with lantern-like strings of light, while the west is a blanket of near total darkness, only occasionally pierced by signs of life. In China's 'Wild West', per-capita GDP is 15 percent lower on average than in the industrious east.
An additional factor typifies China's population divide: while the country overall is ethnically very homogenous – 92 percent are Han Chinese – most of the 8 percent that make up China's ethnic minorities live west of the line. This is notably the case in Tibet and Xinjiang, two nominally autonomous regions with non-Han ethnic majorities.
This combination of economic and ethnic imbalances means the Hu Line is not just a persistent quirk, but a potential problem – at least from Beijing's perspective. Culturally and geographically distant from the country's east, Tibetans and Uyghurs have registered strong opposition to China's centralizing tendencies, often resulting in heavy-handed repression.
Street view in Tengchong, on China's border with Myanmar.
Credit: China Photos/Getty Images
But repression is not the central government's long-term strategy. Its plan is to pacify by progress. China's 'Manifest Destiny' has a name. In 1999, Jiang Zemin, then Secretary-General of the Chinese Communist Party, launched the 'Develop the West' campaign. The idea behind the slogan retains its political currency. In the last decade, Chinese Premier Li Keqiang has repeatedly urged the country to "break through" the Hu Line, in order to modernize China's western half.
The development strategy has an economic angle – adding industry and infrastructure to raise the region's per-capita GDP to the nation's average. But the locals fear that progress will bring population change: an influx of enough internal migrants from the east to tip the local ethnic balance to their disadvantage.
China's ethnic minorities are officially recognized and enjoy certain rights; however, if they become minorities in their own regions, those will mean little more than the right to perform folklore songs and dances. The Soviets were past masters in this technique.
Will China follow the same path? That question will be answered if and when the Hu Line fades from relevance, by how much of the west's ethnic diversity will have been sacrificed for economic progress.
Strange Maps #1071
Got a strange map? Let me know at email@example.com.
Humans churn out about 30 gigatons (30,000,000,000 tons) of material every year.
- The study compared estimates of the planet's total biomass (the mass of all living things) with anthropogenic mass, which includes all human-made materials.
- Every year, humans are bringing materials into the world at a higher rate.
- Concrete is the single biggest contributor to anthropogenic mass and it's a major source of greenhouse-gas emissions, suggesting that finding more sustainable alternatives could help curb climate change.
What's the weight of all human-made stuff—products, infrastructure, buildings—created each week? According to a new study published in Nature, the answer is roughly equivalent to the body weight of all people on Earth.
The study marks 2020 as a tipping point: This year, human-made mass (or anthropogenic mass) will exceed the planet's total biomass, which is the mass of all living things. Currently, humans are churning out about 30 gigatons (30,000,000,000 tons) of material a year, and for decades that rate has been growing at a fast clip.
In 1900, for example, anthropogenic mass was just 3 percent of biomass. But every 20 years since, that ratio has at least doubled, gaining pace in more recent decades as industries have been using more geological materials like metals, minerals and rocks.
To measure anthropogenic mass and biomass, the researchers combined previous estimates generated through computer modeling, field surveys and stock-flow modeling, an approach commonly used in macroeconomics research.
It's hard to determine precise figures; imagine trying to weigh all the cars, trees, whales, butterflies, and bacteria across the planet. Making matters more complicated are water and waste.
The researchers didn't include waste in anthropogenic mass estimates, nor did they include water in biomass estimates. Without waste and water included in estimates, anthropogenic mass probably won't exceed biomass for another two decades.
These ballpark estimates highlight humanity's heavy-handed impact on the planet. Our influence is so great that some scientists think we've entered a new epoch: the Anthropocene.
In 2000, the atmospheric chemist Paul J. Crutzen proposed that human activity has ushered us into a new geological epoch.
An epoch is a subdivision of geologic timescale. These broad categories help scientists think about changes on Earth over long periods of time. Currently, Earth is considered to be in the:
- Cenozoic Era — 66 million years ago
- Quaternary Period — 2.6 million years ago
- Holocene Epoch — 11,650 years ago
The Holocene Epoch began at about the time when the planet was warming, glaciers were melting, and humans were beginning the agricultural revolution. Scientists like Crutzen argue that it's worth distinguishing the Holocene from our present human-driven epoch, the Anthropocene. (Anthro meaning "human", cene meaning "new".)
Proponents of the concept note that human activity has caused marked changes and damage to the planet, including the sixth mass extinction, the pollution of oceans and the atmosphere, and large-scale changes to the planet's terrain through agriculture, dwellings and industry, which currently cover 70 percent of land.
Elhacham et al.
Not all scientists agree with the idea, and it hasn't been officially accepted by the geological community. These critics generally argue that while humans have left a mark on the planet, it's not significant or observable enough to warrant the creation of a new epoch. And some take issue with the political motivations that may underlie the concept.
"The proliferation of this concept can mainly be traced back to the fact that, under the guise of scientific neutrality, it conveys a message of almost unparalleled moral-political urgency," wrote the German philosopher Peter Sloterdijk.
Still, the researchers behind the recent study said the findings give "a mass-based quantitative and symbolic characterization of the human-induced epoch of the Anthropocene."
But never mind the Anthropocene or Holocene debate: It's clear that humans are producing a ton of stuff, and that stuff eventually becomes waste. So, what are policymakers and scientists supposed to do with this information?
The recent findings don't necessarily hold an answer, but they do highlight the single largest contributor to total human-made stuff: concrete. It's the most widely used material on Earth, and also one of the main culprits in emissions of greenhouse gas.
A 2020 study published in Nature found that, in terms of total emissions contributions, concrete production is responsible for "7.8% of nitrogen oxide emissions, 4.8% of sulfur oxide emissions, 5.2% of particulate matter emissions smaller than 10 microns and 6.4% of particulate emissions smaller than 2.5 microns."
"If we invented concrete today, nobody would think it was a good idea," said architectural engineer and panel member Michael Ramage, an architectural engineer and member of Architecture of Emergency, at a 2019 summit. "We've got this liquid and you need special trucks, and it takes two weeks to get hard. And it doesn't even work if you don't put steel in it."
In 2018, the Global Cement and Concrete Association issued six Sustainability Guidelines to encourage better practices for the 30 percent of the cement and concrete production companies it represents. Still, it's unclear the extent to which the industry could make itself more sustainable.
One sustainable alternative building material to concrete is cross-laminated timber, which is as strong as concrete, but is able to store carbon, which could help lower the carbon footprint of buildings.
Of course, it's all about where you move. The authors argue that it needs to be less populous regions.
- Moving from densely-populated urban regions is more effective in stopping the spreading of disease than closing borders.
- Two researchers from Spain and Italy ran 10,000 simulations to discover that travel bans are ultimately ineffective.
- Smaller cities might suffer high rates of infection, but the nation overall could benefit from this model.
As the holiday season approaches, tens of millions of Americans will not be seeing their families or loved ones this year. On the flip side, tens of millions will travel locally, nationally, and even internationally (where they can get in). The reality of "two Americas" has wedged itself into the conversation of coronavirus dangers, which we can see clearly in our travel patterns.
Few questions have inflamed the national consciousness this year as "Are lockdowns necessary?" and "Should we close our borders?" A new study, published in the appropriately named journal Chaos, dissects this issue by looking at migration patterns.
In a simulation study that included 10,000 iterations, Spanish researcher Massimiliano Zanin and Italian researcher David Papo argue that moving away from densely-populated urban regions is far more effective in stopping the spreading of disease than closing borders.
The authors wanted to know if banning travel is the ideal way of stopping the spread of disease. While it seems to be a commonsense approach to some—stop mobility patterns and the virus won't spread—the authors point to research that suggests allowing for some travel actually hinders infection rates. Of course, it depends on where people travel—or, in this case, move.
Regardless, a smart flow of traffic turns out to be a better solution than an outright ban on travel.
"Our results confirm that, under certain conditions, allowing individuals to move from regions of high to low infection rates may turn out to have a positive effect on aggregate; such positive effect is nevertheless reduced if a directional flow is allowed."
Naturally, when we think of restrictions, we consider international travel bans. This pandemic played out differently, however, with regional bans enforced as well. Of course, putting restrictions on regions with low infection rates—this happened in the United States, Italy, and Spain, for example—has the potential of increasing the spread of the virus there, but the authors were more interested in how the entire system operates.
Credit: Alexander Ozerov / Adobe Stock
The author realizes this model has limitations. Their focus was purely on population densities. Ideally, mobility during a pandemic coincides with public health measures, such as wearing a mask, washing your hands, and self-quaranting—factors that differ radically depending on what region you happen to be in.
While their modeling is hypothetical, it does track with real-world migration patterns. A mass exodus has been occurring from New York City, for example. The reasons for so many people fleeing are manifold, but the pandemic certainly catalyzed the migration. Similar trends are occurring in Los Angeles and San Francisco.
In their paper, Zanin and Papo wonder if forced relocation, from high-density to low-density regions, could be proactively enforced. Of course, there would be political pushback for initiating such measures, though it appears it could impact the spread of disease as well.
The authors also note that their model does not take into account the impact on regional health care systems, which, at least in America, are often not equipped to handle population increases. And they recognize the political concern—hypothetical modeling does not necessarily take ethical considerations into question.
That said, this is and will remain a political issue. As Zanin says, the success of any pandemic response lies in the cooperation between national and regional governments looking at their country as a whole, as well as considering the impact of their actions on the rest of the planet.
"Collaboration between different governments and administrations is an essential ingredient towards controlling a pandemic, and one should consider the possibility of small-scale sacrifices to reach a global benefit."
Stay in touch with Derek on Twitter and Facebook. His new book is "Hero's Dose: The Case For Psychedelics in Ritual and Therapy."