On August 13th, 2017 we learned about

Automated image analysis set to track birds and bats near wind turbines

The outer tip of a wind turbine can move at 180 miles-per-hour. This is slower than a peregrine falcon when it dives, but much faster than the fastest birds (and bats) and move when flying horizontally. It’s a big concern, as flying animals have a bad habit of flying into moving turbines, leading to as many as 320,000 deaths a year. The speed of the blades isn’t the only worry, as stationary buildings also kill hundreds of millions of birds a year. That said, the novelty and expansion of wind-power has people actively looking for ways to reduce animal fatalities, even in the darkness of night.

To reduce the number of animal deaths from spinning turbines, one strategy is to try to deactivate the blades before animals are nearby. Radar is employed to search for flocks of birds, but that doesn’t help smaller groups or single birds. In extreme cases, protected species like the California condor actually wears tracking equipment to provide early warning to the turbine so that it can be turned off as the bird approaches. That’s not practical for every bird or bat in the sky though, and so research is being done to figure out more widely applicable technologies to get stop the turbine blades when necessary.

Vigilance with video

It turns out that some high-tech bird watching is looking very promising. Cameras with thermal imaging, or “night vision” are being augmented with ThermalTracker software to more accurately detect where animals might be flying. The complete package can then look out for birds and bats 24 hours a day, especially in shoreline areas that are harder for people to survey.  The actual observations are carried out by an algorithm that analyzes the movement of an animal’s wings and flight path to determine what kind of animal it is. Tests have found that this system can detect 81 percent of flying birds and bats, correctly classifying them 82 percent of the time.

Expanding this foundation, there are plans to add further sophistication to this system. Software will be refined so that analysis of the video can happen in real time, allowing recordings to be paused when no animal is in the sky. This should reduce costs, making this kind of tracking more accessible to wind farms everywhere. There are also plans to add second cameras, enabling stereoscopic comparisons of the sky. This enhancement would let the system estimate the animal’s distance more accurately, allowing for better judgments of the creature’s size and species. And thanks to the night-vision thermal imaging, it all works in various lighting conditions.

Searching for better sites

All this collected data can then be used to better inform turbine management, giving people a better picture of what species are active in a specific area. This can be crucial, as poorly-selected wind farm locations are actually thought to be the biggest cause of animal fatalities. Not all patches of the sky are equally trafficked, and so knowing who lives in the neighborhood can make a significant impact on conservation efforts.

Source: Night Vision For Bird- & Bat-Friendly Offshore Wind Power by Frances White, Phys.org

On August 8th, 2017 we learned about

Cocoa plants get protection from their healthy neighbors’ leftover leaves

The next time you’re about to enjoy a bite of chocolate, take a moment to thank the fungi and other microbiota that made it possible. Like the microbes humans start picking up at birth, organisms like Colletotrichum tropicale come to live on cocoa plants, helping them be more resilient to pathogens that would otherwise destroy the plant. Fortunately for farmers, and chocolate lovers, experiments suggest that this kind of fungal protection isn’t hard to spread between cocoa plants— sharing a bit of leaf litter from healthy neighbors should do the trick.

One of the biggest concerns for a cocoa, papaya and other tropical plants is Phytopthora palmivora, the “plant destroyer.” Once infected, a plant will start rotting at a variety of locations, from the roots to the fruit, and thus is a huge problem for farmers. The pathogen can be found in soil and water throughout tropical ecosystems, but fortunately protective fungi like C. tropicale aren’t too hard to come by either. Just as microbes can be shared between people when they touch, contact with leaf litter from healthy plants seems to be a good way to spread preferred microbes.

Testing leaf-based transmission

Researchers tested the effectiveness of leaf litter with cocoa plants initially grown from sterile seeds in sterilized chambers. Their leaves were verified as being fungus free before one-third of the plants had dead leaves from healthy cocoa plants placed in their pots. Other plants got mixed leaves from the forest, and some had none at all. They were all given a little time to grow outdoors in more “natural” conditions before purposely being exposed to P. palmivora. After three weeks, the plants with healthy cocoa leaves on their soil fared the best. DNA sequencing also confirmed that these plants leaves had a considerable population of the helpful fungus, C. tropicale.

While growing up in the leave litter of a healthy plant seems beneficial, there are limits to proximity. If a parent plant is infected, it can just as easily spread pathogens to its offspring. So cocoa farmers need to keep an eye on their plants to make sure the healthier plants are the ones dumping their leaves their neighbors.

Source: Litter Bugs May Protect Chocolate Supply, Scienmag

On August 7th, 2017 we learned about

Light pollution is driving nocturnal pollinators away from their favorite plants

Plants need light to grow, but many need a good dose of darkness as well. This is because some very effective pollinators wait until dark to visit plants’ flowers, meaning that a plant can work on reproduction night and day, growing more seeds for new plants. This has served plants well for millions of years, and a variety of very effective pollinators only come out at night, from moths to beetles to bats. Unfortunately, recent experiments in Switzerland indicate that humanity’s love of lighting may be casting a shadow over this otherwise efficient system.

The basic model to be tested was that artificial lighting is scaring nocturnal pollinators away from their favorite flowers. Setting up this experiment was tricky though, as artificial lighting in developed areas has left very few places in total darkness at night. This forced researchers from the University of Bern to head for the foot of the Alps to find some cabbage thistles (Cirsium oleraceum) that still enjoyed a decent amount of darkness each night, at which point they started shining lights on them. Half the thistle plants were left in natural conditions and monitored with night-vision goggles, while the others were illuminated by semi-portable LED lamps meant to imitate a streetlight, albeit one with a very long extension cord.

Staying out of the spotlight

Pollinators were counted and collected each night, and the various nocturnal critters clearly showed a preference for the dark. There were 62 percent fewer visits by pollinators, and 29 percent less variety among the pollinators that did risk exposure in the lights. Even though daytime pollinators visited both sets of thistles equally, the plants that missed their nighttime visitors showed a significant decrease in the number of seeds they produced. The decrease in seeds actually outweighed the decline in pollinator visits, suggesting that nighttime pollinators may do a better job of moving pollen on a per-visit basis. In other words, adding more bees and butterflies during the day wouldn’t easily replace the lack of moths and beetles at night.

One hope is that the plants still left in darkness are getting extra pollinator traffic from all the visitors that are scared off by human-made lighting. However, the pockets of darkness left in some areas are so isolated in many places that these more successful plants probably won’t make up for the losses experienced by their well-lit counterparts. This isn’t the only concern that’s been raised about artificial lighting, indicating that we may have to reconsider how badly we really need all our outdoor night-lights.

Source: Artificial Light Deters Nocturnal Pollinators, Study Suggests by Scott Neuman, The Two-Way

On July 25th, 2017 we learned about

Sound used to survey everything from specific species to entire ecosystems

Humans have a pretty considerable bias for visual information, but sometimes watching the world around us just isn’t a viable option. Sometimes observations need to be gathered in the dark in places where a spotlight isn’t an option. Sometimes the presence of a human would scare off the creatures we hoped to observe. And as great as photos and video are, there’s a lot of activity in the world that just can’t be seen very well, even if it’s right in front of you. Fortunately, sound can help with all these cases, and a number of different lines of research have tapped into audio recordings to find out what’s happening in the air, in the woods, and even in the sea.

Surveying bat squeaks

One of the more obvious targets to record is bats thanks to their advanced vocal abilities. Between echolocation and learned vocalizations, bats make plenty of noise to pick up with microphones. The microphones in question are set up in the Queen Elizabeth Olympic Park in London to detect when a passing sound is bat’s call, and then determine what species that bat is most likely to be. This allows for well-controlled surveys of local bat populations, all in a small package that doesn’t disturb people or wildlife. Monitoring bat populations is helpful for understanding the local ecosystem, but this audio-survey concept may soon be used for less distinct noises from other types of animals as well. To help people become of their flying neighbors, the data is also available online to see when the bats are out for their evening meal.

Capturing sounds among kelp

On the opposite end of the spectrum, researchers are also using audio to better understand organisms that don’t vocalize in any way at all. Rather than try to catch a noisy creature like a bat as it flies by, a team off the coast of Australia is using sound to monitor kelp forests. Almost like an artificial bat using echolocation to identify insects, small speakers and microphones at different depths are emitting “chirps” every second among the kelp. The changes in that chirp can then be analyzed to get a measurement of the water’s temperature, oxygen levels, acidity and more thanks to the way these variables affect a sound moving through the water. Building a baseline understanding of those effects has taken a lot of work, but the resulting system is much more practical for continued study than checking on kelp forests in person or with satellite imagery.

Diagnosing forest health with sound diversity

On a larger scale, sound recordings are being used in the rainforests of Papua New Guinea to survey the biodiversity of a wide range of animal species. Recording devices were installed at various locations in the forest with recordings taken for at least 24 hours at a time. The resulting soundtrack was then analyzed to pick apart the number of different creatures heard near each microphone, and what time of day activity took place. With that data in hand, conservationists could then see which areas of the forest had the most complex soundscapes as a proxy for being healthier portions of the ecosystem.

What they found was that forests get noisy when the birds and bugs start their day around dawn, and then again each night around dusk. Bird activity around the so-called “Dawn Chorus” has been studied in many different settings, and so this wasn’t a huge surprise. What was more surprising was how the audio data didn’t support conclusions made with visual surveys. Areas of the forest that were more geographically fragmented due to terrain or development had previously revealed more birds when they were counted in person. The microphones told a different story though, indicating that those fragmented areas of the rainforest were actually less diverse. It’s not that bird counting was wrong, but that looking for that kind of data might not be telling the whole picture.

Source: Forest Soundscapes Hold the Key for Biodiversity Monitoring by Justine E. Hausheer, Cool Green Science

On July 24th, 2017 we learned about

Restoring Spanish imperial eagle populations by relocating them to previously lost territory

Sometimes, even if you can go home again, it’s better if you don’t. This tough choice is confronting conservationists trying to restore the Spanish imperial eagle to its original territories in Span, Portugal and northern Morocco. While the large, predatory birds don’t need food sources more exotic than a supply of rabbits, many of the obstacles that endangered them in the first place, like electric power lines, aren’t going away any time soon. As such, their best option may be to start over somewhere new.

Spanish imperial eagles (Aquila adalberti) are some of the rarest raptors on Earth, at one point being reduced to as few as 380 breeding pairs. The number one concern is power lines, which are apparently hard to avoid for birds with wingspans reaching nearly seven feet across, as they’ve evolved for speed rather than maneuverability. In other parts of the world, people have attempted to train large birds to avoid power lines, but these eagles also face other obstacles. The second cause of death is poisoning, sometimes intentionally and sometimes indirectly, as the birds may end up eating or scavenging prey like foxes that contain dangerous amounts of poison. Steps have been taken to mitigate poisoning, as harming the eagles is now illegal, there isn’t much margin for error when populations are this small.

Some signs of success

Looking at the success of relocated sea eagles in Scotland, conservationists have moved around 87 Spanish imperial eagles to new territory 50 miles away from more recently established habitats. The new territory wasn’t picked strictly for its relative isolation, as eagles had lived there when their numbers were greater, decades ago. This makes it easier for them to find the prey they require while avoiding introducing them as an invasive species to a completely unprepared ecosystem. The hope is that the birds will be far enough away from their biggest threats, allowing them to regain a foothold in the Iberian Peninsula.

So far results haven’t been flawless, but they’re generally positive. People haven’t given up poisoning the protected birds completely, but criminal investigations will hopefully reduce the frequency of such deaths. Most importantly, the relocated eagles are have been found to be doing a better job at boosting their own numbers. Surveys have found that the relocated birds are raising twice as many chicks as the eagles living in their original stomping grounds. This is not only encouraging for the eagles, but for conservationists looking for strategies that might help other threatened animals around the world.

Source: Parachuting birds into long-lost territory may save them from extinction by Amy Lewis, Science

On July 23rd, 2017 we learned about

Scouring human skeletons for signs of scavenging by sharks

You’re probably never going to be attacked by a shark, much less killed by one. However, that doesn’t necessarily mean a shark will never try to make a meal of you. Forensic researchers in Florida are studying how to identify the aftermath of scavenging sharks, as it seems that while sharks aren’t looking to eat a lot of live humans, they might have less of a problem with eating those of us that have already died. This work may help with our understanding of sharks, but also help piece together deaths that might otherwise remain unsolved.

The first challenge of this work is that it’s being done entirely with human bones. The lack of flesh makes definitively determining the cause of death impossible, but that doesn’t mean that finding a skeleton on the sea floor is a dead end. The shape, size and texturing of damage to a bone can help reveal a lot about what damaged those bones, and when the damage took place. For instance, terrestrial predators like bears will leave smoother, puncture shaped marks in bone, while sharks (and unfortunately, sand) will leave striations and linear texture in areas that teeth have sliced through. In the cases were a shark did munching, the majority of those bites were the result of scavenging rather than actual predation on humans. We’re apparently more appetizing as leftovers.

Locations specified by species

In some cases there’s enough detail recorded in a bone to determine the type of shark involved. A dramatic example is the “candy caning” left by a bull or tiger shark. The shark will remove a limb from a deceased body, then spiral from one end to the other to pull flesh off, leaving a spiraled pattern of damage on the bone. Knowing the species of shark involved can then help investigators, because it indicates where a body must have been to encounter that species of shark. This can help piece together someone’s death, especially since ocean currents are so good at moving bodies around without regard to preserving a possible crime scene.

My four-year-old asked: Why are these people dead in the water in the first place?

Some deaths may have occurred elsewhere, and like a long-lost dinosaur, the body was later washed out to sea thanks to a river or temporary flooding. Boating accidents and drownings can also leave bodies in the surf that might be appealing enough for a shark to take a bite. These aren’t exactly common occurrences, but places like Florida’s shark and human populations are high enough to make this line of research worth investing in.

Source: Shark Scavenging Helps Reveal Clues About Human Remains by Mary-Lou Watkinson, Florida Museum

On July 10th, 2017 we learned about

Embryonic exposure to smells help snails and frogs sniff out danger

While humans may try to boost their babies’ brains by playing classical music to embryos, a variety of aquatic animals indicate that the real way to teach unborn offspring is with the smell of death. Snails, wood frogs and American bullfrogs have all been found to learn from smells associated with predation while still in their eggs. Once they hatch, they then use this information to stay safe, primed with information about what predators may lurk in their particular pond. This has both good and bad implications for ecosystems, as some of these creatures may be learning to be too successful for other animals’ good.

Exposure in the egg

This concept was first proven with pond snails (Lymnaea stagnalis) in 2014. Embryonic snails, still in their eggs, were exposed to the smell of tench, a predatory fish that eats the snails. Once the snails hatched, they were kept away from predators for a week, then exposed to that smell again as juveniles. The snails took the threat seriously, crawling out of the water in response, a behavior not seen in snails who hadn’t been “taught” about tench while in their eggs.

Similar studies have been now done with wood frogs (Rana sylvatica) and bullfrogs (Lithobates catesbeianus). In both cases, a third experimental condition was added. In addition to the eggs exposed to the smell of predators (salamanders and fish, respectively), eggs were also treated to the smell of predators with scents from injured or dead tadpoles. As you might expect, this trained the hatched tadpoles of both species to be especially vigilant in the presence of the predatory scents. The bullfrog tadpoles even showed some signs of developmental changes if their eggs had been exposed to smells of predatation. Aside from being quicker to hide behind barriers, the baby bullfrogs were also longer than control group tadpoles, possibly to enable faster movement.

Safety for which species?

From an ecological perspective, this sensitivity to smells creates opportunities and problems. Pond snails face invasive shrimp and crayfish in their environment, and so training embryos could be a way to help the snails cope with new predators. On the other hand, bullfrogs themselves are an invasive species in many environments, and this sensitivity only makes them more adaptable around would-be predators that might otherwise keep their population in check. The huge bullfrogs are known to eat just about any animal that fits in their mouth, so the idea that they’re also more robust as tadpoles means that they’re an even bigger threat to the other animals in the pond, regardless of smell.

Source: In the egg, American bullfrogs learn how to avoid becoming lunch by Chris Branam, Phys.org

On July 5th, 2017 we learned about

Ecological opportunities awaited survivors of Mesozoic mass extinctions

Mass extinctions can apparently be great, as long as they’re someone else’s extinction. The odds aren’t favorable in the case of an ecological collapse that could lead to the total destruction of a huge range of life forms at once, but like any long-shot, the payoff can be big. Surviving lineages can spread to new territories, diversify into new species, and essentially rule their dominions for millions of years… at least until the next mass extinction.

Dinosaurs enriched by volcanic eruptions

The extinction event usually associated with dinosaurs is the one that wiped them out at the end of the Cretaceous period, but they had previously survived a different collapse earlier in their history. The first dinosaurs evolved around 240 million years ago in the Triassic period, but they didn’t immediately dominate their world. Moderately sized spices like Nyasasaurus parringoni lived in the shadow of predatory Rauisuchians, a group of reptiles that closely resembled dinosaurs, but didn’t survive the disaster that shook the world 200 million years ago.

Recent samples of mercury in rock layers around the world suggest that the Triassic period ended with enormous volcanic eruptions all around the super-continent, Pangea. Intermittent eruptions flooded around 4.2 million square miles of terrain with lava, but it was the accompanying smoke and ash that likely caused ecosystems to collapse. Smoke could have done everything from hiding sunlight for plants to raising the acidity of the oceans, all of which proved too difficult to survive for as many as 76 percent of the world’s species. Among the survivors, dinosaurs were able to take over new niches, eventually taking over the world as everything from feathered birds to mountainous herbivores.

Dinosaurs were able to enjoy the opportunity presented by the Triassic’s period of volcanic activity for millions of years, but nothing lasts forever. Famously, an asteroid struck the Earth near the Yucatan Peninsula 65 million years ago, creating waves of devastation fairly reminiscent of the extinction event that first put the dinosaurs on top of the food chain. In this case, the only dinosaurs to carry on were the precursors to today’s birds, but they weren’t the only survivors. While mammals arguably benefited from the end of dinosaurs’ reign the most, researchers recently confirmed that frogs were also big winners.

Families formed from a few surviving frogs

Genetic studies of modern frog species found that 90 percent of today’s frogs evolved from just three lineages. That genetic bottleneck was traced to the same extinction event that wiped out the non-avian dinosaurs. However, frogs were apparently well positioned to take advantage of the newly-reset ecologies, and quickly diversified into new niches and species. For instance, some families of frogs moved into trees for the first time, while others evolved to live most of their lives on dry land, giving up the tadpole stage of their development.

Researchers are digging into the three lineages that survived the asteroid’s impact 65 million years ago in order to see what got them through that difficult time. Frogs are already known to become dormant underground when resources are stressed, but it’s not clear if that was what got them through fire, brimstone, cold, and worse. They want to know if there was some shared trait that made those frogs extinction-proof, and how well that resilience may have stuck with our amphibians today.

Source: How Frogs Benefited From The Dinosaurs' Extinction by Merrit Kennedy, The Two-Way

On June 28th, 2017 we learned about

Pierced sea shells allow researchers to quantify how predators have scaled up over time

It seems like common sense to assume that over time, bigger predators can dominate their local ecosystem more than smaller ones, but common sense isn’t enough for scientific study. To really prove this idea, researchers needed a consistent mode of predatation that could be compared over time, encompassing a variety of hunters, so that size was the primary variable being tested. Flashy attacks like shark bites or lion claws would therefore be hard to quantify in this way, but the patient, slow attacks of sea snails on shelled prey turned out to be the perfect way to test if bigger is better.

Specifying predators’ changing sizes

Predatory snails, forams, octopuses and more have been drilling holes in shelled prey since the Ordovician Period,  488 million years ago. Animals like brachiopods, clams and mussels have all been found in the fossil record with small, precise holes, bored into them by the aforementioned predators in order to extract the softer bodies that lived inside. This strategy is still in use today, and modern predators prove that larger attackers leave larger holes. With all these reference points, researchers could then quantify just how much predators did or did not change in size over millions of years, based on the size of the holes they left in the fossilized shells.

It turns out that the data backs up the initial hypothesis. The average hole was 0.35 millimeters 450 million years ago, but is now up to 3.25 millimeters— an increase of over 900%. This doesn’t mean that modern snails are 900% bigger than their ancient ancestors, but it is a safe bet to say that evolution favored their larger family members.

Persistent methods of predation

As much as the point of attack has gotten bigger, the exact mechanics behind boring into a shell aren’t thought to have changed all that much. Marine snails, for instance, switch back and forth between excreting enzymes to soften their prey’s shell, then drilling into it with the abrasive teeth that line their “tongue,” better known as a radula. Once the hole is made, the squishy, nutritious body of the clam or mussel is sucked out to be devoured, only now that can happen through a larger hole.

Interestingly, some of this increase in predator sizes may have been promoted by prey. The early brachiopods had less meat in their shells hundreds of millions of years ago, but they were later eclipsed by clams and mussels, both of which offer more nutrition to a predator. This meant that the slow process of piercing a shell was actually more profitable, enabling predators to grow larger more easily. The main catch would be that as these boring predators grew larger, they probably put themselves on the menu of other predators, like fish and crabs. So while bigger may be provably better from one perspective, it seems to have come with its own set of compromises.

Source: Marine predators bulked up over eons to dominate their prey by Robert Sanders, Berkeley News

On June 11th, 2017 we learned about

Tadpoles look to their parents to save them from their starving siblings

Even the hungriest tadpole wouldn’t suggest that they could “eat a horse,” but they might consider munching on their brothers and sisters. For all the accounts of how tadpoles grow limbs and lose their tails to mature into frogs and toads, they often gloss over the fact that these little amphibians need to eat, just like any other animal. They generally prefer small fare like algae, insects or even brine shrimp over each other, but to growing big in a small pond can sometimes push diets to the extreme. Fortunately for vulnerable siblings, mom or dad can sometimes come to the rescue.

Parental protection

Tadpoles often have to share a small pool where resources can be scarce, especially that that pool is at risk of drying up. As conditions become more tense, poison dart frog tadpoles have been observed eagerly trying to get onto their parents’ backs if an adult enters the water. No cues or participation were noted on the part of the adult frogs, but tadpoles seemed very intent on getting a ride away from stressed, hungry siblings. The offspring seemed to be more aware and concerned about their lack of resources, and were taking things into their own hands, er… stubs.

Avoiding feeding on the family

Obviously, eating one’s kin isn’t a common strategy among frogs other other animals, although it’s not unheard of either. The conditions that seem to encourage eating one’s brothers and sisters are basically the threat of starvation coupled with a shrinking environment in the form of evaporating water. The tadpole that can secure more nutrients might mature faster and thus be ready to move to a more accommodating location before it’s too late. That might come at the expense of one’s siblings, but eating them just isn’t that big of a boost.

Tadpoles have been observed eating each other as a true last resort. Competition and starvation seemed to be the only things that made eating kin attractive, as otherwise the tadpoles ate every other available option, right down to cornmeal which isn’t a common staple for animals that live in the water. In the end, eating each other wasn’t even found to be terribly helpful— eating brine shrimp seemed to spur growth more than eating tadpole meat. So the tadpoles fleeing on their parents’ backs may be doing everyone a favor by spreading the family out before anyone gets too hungry.

Source: Tadpoles Turn to Cannibalism Only When Desperate by Laura Poppick, Live Science