Pleuroploca clava

Honey bees fly out of the hive each day in search of flowers with nectar and pollen. Once they have loaded up with these delicacies, they head back to the hive to make a deposit and inform other workers where the successful foraging locations are. All of this relies on a bee’s ability to process wide-field visual motion information, to navigate using environmental queues and to fly directly back home. Research now shows that certain common <a href="https://www.earth.com/news/neonicotinoids-kill-bees-and-threaten-hundreds-of-species/">pesticides</a> interfere with a bee’s brain in such a way that it may no longer be able to navigate its way around or fly home successfully.



“Here we show that commonly used insecticides like sulfoxaflor and the neonicotinoid imidacloprid can profoundly impair the visually guided behavior of honeybees. Our results are reason for concern because the ability of bees to respond appropriately to visual information is crucial for their flight and navigation, and thus their survival,” said study lead author Dr. Rachel H Parkinson, an expert in the Department of Zoology at the <a href="https://www.ox.ac.uk/">University of Oxford</a>.&nbsp;



Insects show an innate&nbsp;<a href="https://en.wikipedia.org/wiki/Orienting_response">orienting</a>&nbsp;behavior whereby they correct their body position in order for them to continue moving in a straight trajectory if they have gone off course by mistake. Known as the optomotor response, this position-stabilizing behavior is switched on by whole-field visual motion on the left and right of the flying or walking insect. The response is crucial for insects to adjust to unexpected perturbations in their flight path, such as a breeze blowing them to one side, so that they can continue to move in a straight line.&nbsp;



Dr. Parkinson and colleagues worked with four groups of wild-caught worker honey bees, with between 22 and 28 bees in each group. They exposed the bees to videos of vertical bars that moved from left to right, or vice versa, across two screens placed in front of the bees and watched their walking response. Variations in the speeds of the bars on the two screens “trick” the bee into thinking that it has suddenly been pushed off-course and is turning to one side. A healthy optomotor response will instruct the bee’s motor system to perform a corrective adjustment in the form of a turn that takes the bee back to an illusory straight line mid-way between the optic flow from the right and from the left.&nbsp;



Prior to testing the optomotor response in the experimental honey bees, the researchers allowed them to drink unlimited 1.5 molar sucrose solution over five days. However, although one group received pure sucrose solution, the other groups received sucrose contaminated with either 50 ppb (parts per billion) imidacloprid (a neonicotinoid insecticide), 50 ppb sulfoxaflor, or 25 ppb imidacloprid and 25 ppb sulfoxaflor simultaneously.&nbsp;



Neonicotinoid insecticides disrupt visual motion detection in locusts, resulting in impaired escape behaviors, but it had not been shown previously whether these insecticides disrupt wide-field motion detection in honeybees.&nbsp;When the researchers compared the efficiency of the optomotor responses in the four groups of bees, they found that the bees were nowhere near as efficient at making the expected adjustments if they had ingested pesticides.&nbsp;



All bees responded less efficiently to the simulated optic flow when the bars were narrow or moving slowly (i.e., seemed far away) than when they were wide or moving fast (i.e., seemed close by). But for any width and speed of bars, the bees that had ingested pesticides performed poorly compared to the control bees. For example, they turned quickly in one direction only and didn’t respond to changes in the direction of movement of the bars, or failed to show any turning response at all. The asymmetry between left and right turns was at least 2.4 times greater for pesticide-exposed bees than for control bees.



The poor optomotor responses in pesticide-exposed honey bees were accompanied by alterations in the expression of genes in their brains, particularly genes related to detoxification and the presence of stress. But these genetic changes were relatively weak and highly variable across bees, and unlikely to be the sole explanation for the observed strong impairment of the optomotor response. Exposure to sulfoxaflor led to small but noticeable increases in dead brain cells, primarily in the optic lobes which are important for processing visual information. 



“Neonicotinoid and sulfoximine insecticides activate neurons in the insect brain and are not always recycled fast enough to prevent toxicity. The effects we observed could be due to a type of rewiring in the brain: to prevent neural damage by reducing the sensitivity of neurons to these compounds,” said Dr. Parkinson.



“To fully understand the risk of these insecticides to bees, we need to explore whether the effects we observed in walking bees occur in freely flying bees as well. The major concern is that, if bees are unable to overcome any impairment while flying, there could be profound negative effects on their ability to forage, navigate, and pollinate wildflowers and crops."



"The results add to what the Food and Agriculture Organization of the United Nations, and the World Health Organization, have identified as&nbsp;the “rapidly growing body of evidence [which] strongly suggests that the existing levels of environmental contamination [from neonicotinoid pesticides] are causing large-scale adverse effects on bees and other beneficial insects.”



The research is published in the journal <a href="https://www.frontiersin.org/articles/10.3389/finsc.2022.936826/full">Frontiers in Insect Science</a>.



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By <a href="mailto:bosman@truewan.co.za">Alison Bosman</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Honey bees cannot fly straight after ingesting pesticides

Honey bees fly out of the hive each day in...

A large variety of animal species eat fruit – from toucans and fruit bats to maned wolves and humans. However, most fruit-bearing plants evolved relatively recent in our planet’s history, during the Cretaceous Period (145.5 to 65.5 million years ago). Now, by comparing the skull shapes and stomach contents of fossil birds, a research team led by the <a href="https://www.ox.ac.uk/">University of Oxford</a> has tracked down the first fossil evidence of fruit consumption. They found that the earliest-known fruit-eating animal was a long-tailed, raven-sized <a href="https://www.earth.com/news/climate-change-will-severely-impact-birds-by-2080/">bird</a> called Jeholornis, which lived 120 million years ago. According to the experts, this bird may have helped contribute to the spread of plants that dominate the world today.



“This is the oldest evidence of fruit-eating in any animal,” said study co-author Jingmai O’Connor, an associate curator of fossil reptiles at the <a href="https://www.fieldmuseum.org/">Field Museum</a> in Chicago. “Fruits are an incredible resource that everybody’s familiar with, and the plants that produce them are everywhere, but it wasn’t always that way. This discovery about how and when birds started exploiting this resource could help explain why these kinds of plants are so dominant in our landscape today.”



According to O’Connor, the fist Jeholornis fossil – described in 2002 – had plant remains scattered around it, as if they exploded out of its stomach cavity. At the beginning, researchers thought these were only seed and argued that the bird was feeding on seeds, rather than whole fruits. However, by examining dozens of Jeholornis specimens preserved at the <a href="http://www.tynhm.com/">Shandong Tianyu Museum of Nature</a> in China, the scientists discovered that, although the birds had more traits similar to dinosaurs than to modern birds, some features of their mouths and beaks – such as reduced teeth – could potentially hint at a “modern” diet including fruit.



Moreover, since birds which eat seeds have a “gastric mill” consisting of gizzard stones in their stomachs – which they ingest to help them crush seeds - the researchers examined also the stomach cavities of the fossils. The analysis revealed that, while some Jeholornis had gizzard stones, and others preserved seed in their stomachs, no specimen with both of these features was found. This suggests that the bird was eating different types of foods at different times of the year, including fruits when available. “Birds can drastically change the proportions of their digestive system to adapt to whatever their diet is for a particular season,” O’Connor explained. “This is the first evidence of that plasticity in dinosaurs.”&nbsp;



Thus, not only was Jeholornis the first known fruit-eating animal, but it may also have contributed to the evolution of the first fruit-producing plants. “Birds may have been recruited for seed dispersal during their earliest evolutionary stages,” said study lead author Han Hu, an expert in Paleobiology at Oxford. “As highly-mobile seed dispersers, early frugivorous birds might therefore indicate a potential role of bird-plant interactions during the Cretaceous Terrestrial Revolution.”



“Our research will hopefully inspire the research of paleontologists, ecologists, zoologists, and botanists who are interested in bird ecology, trophic interactions, and the Cretaceous Terrestrial Revolution,” she concluded.



The study is published in the journal <a href="http://dx.doi.org/10.7554/eLife.74751">eLife</a>.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer&nbsp;&nbsp;

First fruit-eating animal in Earth’s history identified

A large variety of animal species eat fruit – from...

A new study led by the <a href="https://www.izw-berlin.de/en/home.html">Leibniz Institute for Zoo and Wildlife Research</a> (Leibniz-IZW) has investigated the influence of maternal, social, and ecological factors during early life on the survival and reproductive fitness of female adult <a href="https://www.earth.com/news/spotted-hyenas-change-their-foraging-behavior-to-adapt/">spotted hyenas</a> (Crocuta crocuta). The analysis revealed that the social status of the mother had a positive effect on the reproductive success of the next generation, while being born to an elderly mother or growing up during a period of environmental stresses such as massive rainfall reduced survival and longevity. 



However, the experts suggest that the combination of specific conditions during early life may matter more than just the simple accumulation of either beneficial or adverse conditions in predicting life prospects in hyena populations.



The scientists analyzed data from the life histories of 666 female spotted hyenas from the Serengeti National Park in Tanzania from 1987 to 2020 to assess how a variety of maternal, social, demographic, and ecological factors affected their evolutionary fitness (how many of an individual’s offspring reach reproductive age and manage to pass their genes to the next generation).



“Through careful analyses of the long-term data we were able to show clearly, for example, that female offspring of elder mothers have a significantly shorter lifespan and raise fewer young than those of mothers in their prime age,” said study lead author Morgane Gicquel, an expert in Ecological Dynamics at Leibniz-IZW. The investigation also revealed that daughters benefited if they did not have siblings, if were the dominant rather than the subordinate cubs in twin litters, or if their mothers had a high social status.



“We were surprised to find that maternal social status, litter size, and offspring dominance status only mattered to hyena offspring in the first few years, namely for survival to adulthood and for age at first reproduction, but that they did not influence longevity or lifetime reproductive success,” Gicquel explained.



“In contrast, we found both short-term and long-term effects for the number of lactating&nbsp;adult females&nbsp;in a clan,” said study senior author Sarah Benhaiem, a behavioral ecologist at Leibniz-IZW. “As the number of lactating female clan members increased, growth rate, survival to adulthood, and lifetime reproductive success of the offspring decreased. This could be related to more frequent conflicts and increased competition among breeding females.”



The scientists also discovered that ecological factors, such as increases in rainfall in the first six months of their lives, reduced the changes of female hyenas of surviving to adulthood, possibly due to increased parasite load and transmission of pathogens, or the flooding of communal dens, leading to cubs drowning at an early age. “In terms of climate change, it now rains more in the Serengeti than ever before - quite in contrast to many other areas in Africa. In the light of these insights, this might have a long-term negative effect on the population,” concluded Leibniz-IZW director Heribert Hofer.



The study is published in the <a href="https://dx.doi.org/10.1111/1365-2656.13785">Journal of Animal Ecology</a>.&nbsp;&nbsp;



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer&nbsp;&nbsp;

Early life has long-term effects on the health of hyenas

A new study led by the Leibniz Institute for Zoo...

Spring,Single,Daisy,Flower,And,Bee

Pesticides known as neonicotinoids, or neonics, have become increasingly prevalent in the agricultural industry since they were first introduced in the early 1990s. According to a report in the journal <a href="https://www.pnas.org/">PNAS</a>, neonicotinoids are now the most widely used <a href="https://www.earth.com/news/common-insecticide-can-kill-bees-in-very-small-doses/">insecticides</a> in the world.



Neonics are chemically similar to nicotine, attacking the central nervous system of insects. Ben Williamson, the U.S. Executive Director of the animal welfare organization <a href="http://www.ciwf.com/">Compassion in World Farming</a> (CIWF), has written a report to raise awareness about the dangerous effects of neonicotinoids. These effects, says Williamson, extend far beyond the insects for which they were intended.



"Despite being touted as less toxic than previously used pesticides, neonicotinoids are wreaking havoc on bees and other pollinators who are critical to our food system, harming animals and threatening human health. Factory farming is significantly adding to their widespread use," writes Williamson.



"About one-third of all corn grown in the U.S., spanning <a href="https://www.ers.usda.gov/topics/crops/corn-and-other-feedgrains/feedgrains-sector-at-a-glance/">30 million acres</a>, is used directly for livestock feed. Another third is grown for ethanol production, the byproducts of which are also turned into feed. Corn feed is typically used in industrialized operations where the animals live intensively confined (either indoors or on feedlots) and are not allowed to feed naturally by grazing or foraging."



"Most breeds of intensively farmed chickens and cattle are also bred to require high-energy diets to reach market weight quickly, making their once natural diets from foraging and grazing unsustainable for their bodies. Nearly all corn seeds used to grow ethanol and livestock feed are coated with either clothianidin or thiamethoxam, two neonic pesticides. About half of all soy, another crop often used in livestock feed, is also treated with neonics."



In his report, Williamson breaks down how neonicotinoids affect humans, bees, and other wildlife:



Bees



Numerous studies have linked neonics to mass bee die-offs and colony collapse. The amount of active ingredient on one corn seed is enough to <a href="https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2013.3067">kill a quarter of a million bees</a>. Over the last several years, U.S. beekeepers have lost over <a href="https://insights.osu.edu/sustainability/bee-population">30% of their colonies annually</a>, and several wild bee populations have become endangered. When combined with other stressors such as habitat loss, disease, and climate change, the excessive use of neonics on feed crops is putting bees at critical risk.&nbsp;



Bees are crucial to our food system, pollinating over $15 billion worth of U.S. crops each year. Dozens of key crops across the world, including cacao, coffee, peaches, almonds, tomatoes, blueberries, strawberries, apples, and pumpkins, require bees to reproduce. Thus, the health of our bee population directly impacts the health of our food system. Fewer bees means lower crop yields, less food availability, and higher prices for consumers. These effects disproportionately impact low-income consumers, who already struggle to access and afford nutritious foods.&nbsp;



Wildlife



Mounting evidence shows that neonicotinoids are harming vastly more species than previously thought. Their negative impacts on unintended insects, birds, fish, and mammals are having ripple effects across ecosystems and food webs.&nbsp;



Neonics have added <a href="https://www.nature.com/articles/s41893-020-0582-x">further pressures on the bird population</a>, particularly seed and insect-eating birds. Eating just one neonic-coated seed is enough to kill some songbirds. Ingesting contaminated seeds or insects can also harm birds’ reproductive systems, immune systems, and navigation ability, reducing their chance of survival. North America has <a href="https://www.science.org/doi/10.1126/science.aaw1313">lost 29% of its bird population</a>—over 3 billion birds—over the last 50 years due in large part to neonics. The pesticides have also been found in waterways across the United States, harming aquatic insects and invertebrates. This is especially concerning with the recent outbreak of avian flu, which has been most deadly to predatory birds and aquatic birds. Feeding on contaminated fish, amphibians, insects, and invertebrates like snails and mollusks could lessen their chance of survival.&nbsp;



According to the Environmental Protection Agency’s (EPA) own assessment, <a href="https://www.epa.gov/endangered-species/draft-national-level-listed-species-biological-evaluation-clothianidin">clothianidin</a> and <a href="https://www.epa.gov/endangered-species/draft-national-level-listed-species-biological-evaluation-thiamethoxam">thiamethoxam</a> alone are likely to adversely affect over 75% of all endangered species—more than 1,300 plants and animals. These include the San Joaquin kit fox, gray wolf, and dozens of endangered insects, fish, crustaceans, and birds. Many of the species on the list are prey animals that serve as the foundation of the food web. Chinook salmon, for instance, an endangered species and the primary food source for the also endangered Southern Resident killer whales, are among the species likely to be adversely affected.



Humans



Neonics are of particular concern to human health because they are the most widely used pesticide on the market. Neonics are also persistent, meaning they do not readily decompose in soil, water, or air. Even more disturbing, once applied to a plant or seed surface, neonics are designed absorb into and throughout the plant’s tissues so they cannot be washed off.&nbsp;



All humans may be exposed to pesticides through ingestion of contaminated water or food. Still, the <a href="https://pollinator.cals.cornell.edu/sites/pollinator.cals.cornell.edu/files/shared/documents/0727%20Accessible%20Neonicotinoid%20Assessment%20compressed.pdf">risks from pesticides are greater for pesticide applicators</a> and those who work and live near application areas. An overwhelming majority of America’s farmworkers are Black, Hispanic, and people of the global majority, <a href="https://amp-theguardian-com.cdn.ampproject.org/c/s/amp.theguardian.com/us-news/2022/apr/18/us-people-of-color-pesticides-study">disproportionately exposing </a>these groups. Structural injustices, regulation loopholes, and weak farmworker protections have exacerbated the problem. Exposure to various pesticides has been linked to neurological disorders, brain tumors, childhood leukemia, and other solid tumors in children.&nbsp;



One study published earlier this year found <a href="https://ehjournal.biomedcentral.com/articles/10.1186/s12940-021-00821-z">multiple neonicotinoids in children’s spinal fluid, plasma, and urine</a>. This is especially concerning because neonics attack the brain receptors responsible for proper brain organization and are involved in motor, emotional, and cognitive functions. Other studies suggest that neonics are associated with congenital malformations, autism spectrum disorder, and memory loss and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0041008X19303850">could impact the human nervous system</a>.



While some of the active ingredients are absorbed into the seed, much of the neonic seed coatings wash off into local waterways, which make their way into drinking water treatment plants. When mixed with chlorine or chloramine, however, which are used in treatment plants to kill bacteria, it can create <a href="https://pubs.er.usgs.gov/publication/70201737">compounds that are even more toxic</a> to humans than the pesticide itself.&nbsp;



Better farming for all



The widespread use of pesticides in feed production is just another book in the library of reasons why factory farming must end. Industrialized food production has created a world of compartmentalization—with monocropped fields, CAFOs, and feedlots that operate separately. These methods undermine nature’s synergistic structure, in which plants and animals thrive without pesticides. To produce food sustainably, we must implement regenerative practices that nurture ecosystems instead of saturating them in chemicals that harm pollinators, wildlife, and people.&nbsp;



To do this, we must:



<ul><li>Produce and consume more organic, plant-based foods (hop over to our <a href="https://www.ciwf.com/sustainable-food/eat-plants-for-a-change/">Eat Plants. For a Change.</a> page for a host of recipes and tips).</li><li>Support whole-farm systems where animals graze and forage naturally and any supplemental nutrition is grown organically on the same farm.&nbsp;</li><li>Support a just transition where farmworkers are treated with respect and kept safe from potential health hazards.</li></ul>



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Credit: Ben Williamson, U.S. Executive Director of Compassion in World Farming

Neonicotinoids kill bees and threaten hundreds of species

Pesticides known as neonicotinoids, or neonics, have become increasingly prevalent...

At 29,032 feet (8,849 m), Mt. Everest is the world's highest mountain. Although many people go to Everest to climb, very little is known about its <a href="https://www.earth.com/news/vanilla-cultivation-can-boost-biodiversity-in-madagascar/">biodiversity</a>.



In 2019, National Geographic and Rolex came together for the <a href="https://www.nationalgeographic.com/environment/topic/perpetual-planet">Perpetual Planet Everest Expedition</a>, the most comprehensive scientific expedition in Everest's history. Scientists from The Wildlife Conservation Society (WCS) and Appalachian State University led the research team.&nbsp;



The experts collected environmental DNA (eDNA) samples for various water sources between 14,763 feet and 18,044 feet. Environmental DNA can be used to search for small amounts of genetic material left by organisms and is known to be more efficient than traditional surveys. This technique has previously helped scientists to study elusive marine animals such as humpback whales and Swinhoe's softshell turtle. Samples were collected in the field using sealed cartridges and analyzed in a lab.&nbsp;



The scientific team analyzed 20 liters of water and found organisms representing 187 taxonomic orders, or one-sixth of all known orders. The team was also able to identify some samples to the species level. They found DNA from microorganisms, rotifers and tardigrades, as well as from Tibetan snow cock, domestic dogs, and domestic chickens. Several sites contained mayfly DNA, an indicator species of environmental change.&nbsp;



"High-alpine and aeolian environments, which have often been thought of as barren and mostly devoid of life, in fact have abundant biodiversity," said Dr. Tracie Seimon, co-leader of the Everest biology field team. "High mountain environments including Mount Everest should be recognized as a target for sustained long-term biodiversity monitoring of high-alpine taxa to complement bioclimatic monitoring and climate change impact assessments."



Dr. Marisa Lim of the Wildlife Conservation Society is excited about what is left to discover. "We went in search for life on the roof of the world. This is what we found. However, the story does not end here. There is more to be discovered and we hope our findings help to inform future exploration," said Dr. Lim.



The team hopes that the eDNA inventory gathered in this study will help future scientists monitor high alpine regions in the Himalaya and inform past studies so that we may better understand how the region's biodiversity is responding to human pressure and a changing climate.



This study is published in the journal <a href="https://www.cell.com/iscience/fulltext/S2589-0042(22)01120-8?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2589004222011208%3Fshowall%3Dtrue">iScience</a>.



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By <a href="mailto:nire518@gmail.com">Erin Moody </a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Environmental DNA reveals the diversity of Mount Everest

At 29,032 feet (8,849 m), Mt. Everest is the world's...

In learning to communicate, a good teacher is essential not only in the case of humans, but also for other animals. For instance, juvenile <a href="https://www.earth.com/news/zebra-finches-use-both-calls-and-vision-to-coordinate-flight/">zebra finches</a> learn songs directly from a “tutor” – usually their father – through social interactions which keep them focused and motivated. The physical presence of the tutor seems to be essential – young birds that only hear the songs through a speaker don’t manage to learn so well. A research team led by the <a href="https://www.oist.jp/">Okinawa Institute of Science and Technology</a> (OIST) has now managed to identify for the first time the brain circuitry which controls such learning.&nbsp;



“This study is the first demonstration of the neural circuitry that is telling these animals what incoming information they need to pay attention to,” said study senior author Yoko Yazaki-Sugiyama, an associate professor of Neuroscience at OIST. Since in the wild, zebra finches are surrounded by many sounds, including the songs of other birds, this specific neural circuit is activated to signal that the song coming from the tutor is important and has to be memorized.



Two decades ago, scientists discovered that human babies also need a personal tutor to teach them how to recognize phonemes in language by engaging the learner’s attention. “That is pretty logical – if we are attentive, we are learning better,” said study lead author Jelena Katic, a postdoctoral fellow in Neuroscience at OIST. “We wanted to understand, is the same true for juvenile birds?”



Dr. Katic and her colleagues found that during the learning process, neurons from a brain area called locus coeruleus (LC) project to a higher order auditory region in the brain called the caudomedial nidopallium (NCM), which is where the young birds’ memories of a tutor’s song are formed. Both of these brain regions responded more strongly when the tutor sang than when the youngsters heard a recording of the song, and the firing of the NCM neurons was time-locked to specific syllables of the tutor’s song, suggesting that they are registering the incoming auditory information.&nbsp;



However, since the LC neurons were active constantly while the tutor sang, they were likely responding to vocal communication itself rather than the specific notes that were emitted. Moreover, if the scientists deactivated the neurons projecting from the LC to the NCM while the tutor sang, the juveniles were unable to accurately copy the song.&nbsp;



“Imagine that the NCM neurons are receiving multiple inputs from different regions of the brain, including some from auditory areas that convey the notes and prosodic patterns of the song,” explained Dr. Katic. “But LC is conveying another type of information – the social context identifying that the song is important.”



Further research is needed to clarify what cues juveniles use to capture this social context, which chemicals in the brain structure the functioning of the LC-NCM circuitry, and what kinds of cues the juveniles emit that might encourage the tutor to teach them.



The study is published in the journal <a href="http://dx.doi.org/10.1038/s41467-022-32207-1">Nature Communications</a>.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer&nbsp;&nbsp;

What brain circuitry drives social learning in birds?

In learning to communicate, a good teacher is essential not...

The Anthropocene is an unofficial unit of geological time defined as the most recent period in our planet’s history, starting in the 1950s, when human activities began to have a significant impact on the Earth’s ecosystems and climate. During this time, humans have increasingly modified natural landscapes and endangered <a href="https://www.earth.com/news/biodiversity-loss-weakens-ecosystem-functioning/">biodiversity</a>.&nbsp;



According to a new study led by <a href="https://www.stanford.edu/">Stanford University</a>, small animal communities from the Anthropocene are less diverse and differently structured than those a few centuries ago, during the Holocene (approximately 500 years ago). Fortunately, the experts found that even small protected spaces can play a fundamental role in conserving native small mammal communities, highlighting their importance for urban conservation projects.&nbsp;



Small mammals such as rats or shrews are excellent indicators of ecosystem health. This is due to their abundant numbers, small individual geographic ranges, habitat specificity, and low extinction rates caused by their high fertility and growth rate.



The researchers surveyed small mammal communities along a geographical gradient of human modification – the Jasper Ridge Biological Reserve (least human modification), Stanford’s Student Observatory (average human modification), and the Stanford University campus (high human modification). The scientists found that, although they are fairly resistant to extinctions, small mammal communities are often altered by human activities and environmental changes in less obvious ways.



“We examined thousands of small mammal bones and teeth from modern (Anthropocene) raptor pellets and three (Holocene) archaeological sites along the gradient, representing different levels of human modification today,” said study lead author Maria Viteri, an expert in Conservation Science, Ecology, and Paleontology at Stanford.



The analysis led to three major findings. “First, small mammal diversity decreased with increasing human modification today. Second, the overall make-up of today's small mammal communities is fundamentally distinct from past communities, even 500 years ago,” Viteri reported.&nbsp;



Luckily, the third finding was much more optimistic: “Our results demonstrate that even a relatively small, protected space can at least partially protect native faunal communities.”&nbsp;



Although previous research has argued that larger protected areas do a better job of conserving biodiversity, this study shows the importance of smaller protected areas in urban environments, where large spaces for conservation are lacking.&nbsp;



“The study shows that the way that we manage lands matters, and that it is not too late to protect our lands in order to protect biodiversity.” However, “while biological preserves can buffer biodiversity change across spatiotemporal gradients of human impact, they cannot completely mitigate the overwhelming signal of the Anthropocene on today’s ecosystems,” Viteri concluded.



The study is published in the journal <a href="https://www.frontiersin.org/articles/10.3389/fevo.2022.916239/full">Frontiers in Ecology and Evolution</a>.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer&nbsp;&nbsp;

Small mammals of the Anthropocene are deeply altered

The Anthropocene is an unofficial unit of geological time defined...

Pleuroploca clava

Taxonomic tree: