My Science School

Black kites, whistling kites and brown falcons are known as "firehawk raptors". They help spread wildfires in places like Australia by picking up and dropping lit branches or embers onto fresh patches of dry grass so as to scare out small animals. It makes it easier for them to swoop down to catch the fleeing prey.

Ongoing bird research will help answer questions, of course. “There’s loads to find out,” Bonta says, citing recent findings. “We just learned in 2016 that birds’ neurons are packed differently. They’re way smarter than we thought. We’re just beginning to understand avian memory. Crows’ problem-solving ability is amazing. There are a lot of tool-using behaviors.”

Part of the reason Westerners may have trouble accepting the concept of firehawks, Bonta suggests, is our lack of connection to our environment: “Westerners have done little but isolate ourselves from nature,” he says. Yet those who make a point of connecting with our earth in some form—he uses turkey hunters as an example—“have enormous knowledges because they interact with a species. When you get into conservation [that knowledge] is even more important.” Aborginal people “don’t see themselves as superior to or separated from animals. They are walking storehouses of knowledge.”

Credit : Penn State Altoona 

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The Great Pacific Garbage Patch is the name given to the floating waste, mostly comprising plastic, in the open ocean between California and Hawaii. Spread across 1.6 million sq km, the patch is estimated to contain 79,000 tonnes of plastic waste! It is the largest of the world's five trash-filled gyres, which form when plastic and other forms of waste are taken out to sea by surface currents and are then trapped and gathered together into great masses by rotating currents.

Bad? Indeed! But what's worse is that a host of coastal organisms have hitch-hiked on the drifting garbage all the way to the Great Pacific Garbage Patch and have made a comfortable home there. They are not only sustaining themselves in the open ocean, but are also thriving. Scientists have known that coastal species could catch rides out to sea on logs and seaweed in the past. But they haven't formed a community of their own because most times these logs and other natural carriers disintegrate along with their riders. But plastic waste is creating opportunities for coastal species to greatly expand beyond what was previously thought possible. Thus, the impact of plastic waste on marine organisms is not just ingestion and entanglement.

New concern

The arrival of these new coastal organisms (which can be invasive) has the potential to deeply affect an ecosystem that is already delicate and lacking in resources, warn scientists.

Scientists have documented more than 40 coastal species clinging to plastic trash, in a study published in the journal Nature Communications. These include mussels, barnacles and shrimp-like amphipods. The scientists found that a mix of coastal and open ocean species have joined together on the plastic-creating something entirely new. They call these new communities neopelagic 'neo' meaning new and pelagic referring to the open ocean.

The team is still unsure as to how the neopelagic colonies are finding food - it is possible the plastic itself is acting as a reef and attracting food sources to it. Nor are they sure whether such colonies exist in other trash-filled gyres. However, as the production of global plastic waste continues to increase, scientists think such colonies of coastal organisms in the open ocean will continue to grow.

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Scientists from the Society for the Protection of Underground Networks (SPUN) have launched plans to map the world's huge underground webs of fungi, which store billions of tonnes of carbon dioxide during their lifetime. The SPUN would collect 10,000 samples from around the world to identify sites with the potential to store more CO2 and withstand changes brought about by global warming. The project will also identify at-risk areas, where these networks are under threat from fertilizer use, urbanisation, deforestation, and pollution. Understanding the fungal network will help scientists focus on "underground conservation", which has been long overlooked.

Symbiotic relationship

A majority of land plants live in symbiotic relationship with soil fungi. The fungi cannot photosynthesise, as they have no access to light or chlorophyll, whereas the trees photosynthesise. Trees use the sun's energy to refashion carbon dioxide and water into sugar. Fungi get sugar and carbon from trees, and in return release nutrients such as phosphorous and nitrogen, as well as water (collected from their environment) to the trees. Some fungi are known to supply 80% of phosphorus to their host plants.

"Wood wide web"

The fungi are made up of a mass of thin threads, known as mycelium, through which they absorb nutrients from their environment. The roots of trees and mycelium join together to form the mycorrhizal networks. As fungi colonise many plants at the same time, the mycorrhizal networks connect individual plants and trees, forming a larger network. This network ferries nutrients and chemical signals (communication) between trees. They even connect trees that are miles away. German forester Peter Wohlleben dubbed this network the wood wide web".

Carbon sink

According to the SPUN, underground fungal networks sequester carbon in three ways. First, fungi use carbon to build rapidly expanding networks in the soil.

Second, sequestered carbon is used to create fungal exudates. Exudates are organic compounds that help form stronger soil aggregates, which act as a stable carbon reservoir. Third, sequestered carbon is stored in fungal necromass. Necromass are underground networks that are no longer active, but whose complex architecture is structurally woven into the soil matrix. It is responsible for up to half of the total soil organic matter and helps stabilise soils. Ecosystems with plants that feed carbon to underground networks store an estimated eight times more carbon compared to ecosystems with non-mycorrhizal vegetation, say scientists.

Other functions of the fungal network

Food web: Fungal networks lie at the base of the food webs because they feed the plants with necessary nutrients.

Sharing of resources: Trees and plants share nutrients with one another through the fungal network. There is also increasing evidence that some combinations of fungi can enhance soil fertility and plant productivity more than others.

A parent tree uses the fungal network to feed the seedlings that have sprouted under its shade. Researchers have found how old trees are able to survive with resources from younger ones.

Helps in tree 'communication': The tree-to-tree communication happens for various purposes and in many forms. It may not be a typical 'Hello'. But it is definitely a network of sharing and caring, and that ensures the survival of the community. Through the fungal network, trees send distress chemical signals about drought, disease or an insect attack. Other trees pick up these signals and increase their own resistance to the threat.

Boosts immunity of plants: A fungal network also boosts the host plants' immune system because when a fungus colonises the roots of a plant, it triggers the production defence-related chemicals in plants.

Threats to fungal network

Agriculture: Adding of fertilizer interrupts the dynamics of exchange between plants and fungi, while ploughing damages the physical integrity of fungal networks.

Habitat loss: Habitat loss led by logging and urbanisation also cause damage to the underground fungal networks.

Warming and climate change: Extreme temperatures, drought, and floods threaten the ability of global fungal networks to move nutrients and store carbon. And wildfires not only destroy trees, but also the fungal network underground.

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In a historic move, French lawmakers have voted to ban the use of wild animals such as tiger, lion, and bear in live circus shows. The legislation also bans the use of wild animals in television shows, nightclubs, and private parties. It intends to put an end to dolphin shows and mink farming as well in the coming years. The new law will raise the maximum penalty for mistreating animals to up to five years in prison and a fine of 75.000 Euros (approx Rs 62 lakh) and will tighten restrictions on the sale of pets. While a section of animal rights advocates welcomes the move, others have expressed disappointment that other controversial issues such as hunting, bull fighting, force feeding for foie gras and some animal-rearing practices have not been included within the scope of the legislation.

Like humans, animals and birds too deserve the right to life and freedom. Travel, confinement, and being forced to perform tricks deprive them of these rights. In turn, it affects their ability to satisfy their physical, emotional and behavioural needs.

Abuse and stress

• Animals such as bears, elephants, tigers, lions, camels, and monkeys are forced to perform demanding tricks Trainers use bullhooks, whips, electric prods, and other tools to make them perform. Beatings, punishment, and threatening are common. These put animals through a lot of stress. Countless suffer injury and pain. The same goes for aquarium animals such as sealions and dolphins that are made to perform tricks.
• Animals have also died from overheating in cramped cages and during transport between shows.
• During the show, the loud noise of the music, the cheers of the crowd, and the dizzying lights can disorientate them.

Poor living conditions

• Living spaces are cramped, often badly maintained and lack the basic comforts animals find in their natural habitat. In their natural environment such as forests, fields, rivers, lakes, and oceans, animals live a normal life roaming or swimming about hunting their own food, and interacting with other animals. But at circuses and other entertainment houses, they are confined to the four comers of a pen or an enclosure, leaving little room for free movement.
• For a tiger, a habitat is not just a place to live and prey in but also a place to congregate and to establish a sense of territory.

Tigresses also use the habitat to give birth to and raise cubs. A tigress will need a 20 sq.km. territory, while a male requires a larger territory, such as one that covers 60 to 100 sq.km.

Loneliness & separation

• Sea lions and elephants are highly social animals. Elephants live in herds of anywhere from eight to 100 individuals with the head of the herd being the oldest female. A circus life will present a lonely, isolated life, depriving them of their social interaction with and emotional dependency on each other.
• Intergenerational bonds are broken when individuals get uprooted from the wild.
• In addition to loneliness, captive dolphins face exposure to human infection, bacteria, and chemicals and suffer from stress-related illnesses.

Unsuitable weather and food

• Enclosures should maintain a temperature similar to the natural habitat. Ceiling panels, indoor pool, air-conditioning, sprinklers and ice blocks are to be made available for the animals to chill during hot weather.
• And each animal has its own specific food needs. For instance, adult elephants consume about 250 kg of food and require a minimum of 150 litres of water a day. It is not dear if a circus or a TV production house can provide these needs.

Foie gras is a French dish made with the liver of a duck or goose. Foie gras means fatty liver. To make this dish, the birds are force-fed using a feeding pipe inserted into the birds mouth, down its throat. A large quantity of food (usually corn with fat) is then delivered using a motorised pump. The birds are usually force-fed two or three times each day. This deposits large amounts of fat in the liver, which is preferred for the dish.

In 2018, the Central government of India notified the draft Performing Animals (Registration) (Amendment) Rules, 2018 proposing to prohibit performance and exhibition of all animals in circuses. But a law is yet to be passed. Though many circuses have shut business due to the COVID-19 pandemic, those that function have animals in possession.

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Like animals, birds too bear the brunt of climate change. Previous studies have shown how climate change affects birds migration, nesting, hatching and feeding habits. A recent study has shown how birds are evolving to develop smaller bodies and longer wingspans in order to adapt to the changes.

Published in the journal Science Advances, the study analysed the body size of birds in the Amazonian rainforest. Researchers analysed data collected on more than 15,000 birds that were caught, measured, weighed, and tagged over the course of 40 years of field work. In all, the scientists investigated 77 species whose habitats ranged from the cool, dark forest floor to the sunlit warm areas.

Lighter, but longer

Researchers found that nearly all the birds had become lighter since the 1980s. Most species lost an average of two per cent of body weight every decade, meaning a bird species that would have weighed 30 grams in the 1980s would now average 27.6 grams. A third of species simultaneously had developed longer wings, driving a decrease in mass to wing ratio. The birds that are known to fly more and are exposed to heat for longer, had the most pronounced changes in body weight and wing size.

But why?

The changes are thought to be a response to nutritional and physiological challenges, especially during the June to November dry season. The team hypothesised that this was an adaptation to utilise their energy better as they are now forced to travel longer to find food and shelter. Climate change has decreased the availability of fruit and insect resources for birds.

Longer wings, and a reduced mass-to-wing ratio, produce more efficient flight similar to how a glider plane with a slim body and long wings can soar with less energy.

A higher mass-to-wing ratio requires birds to flap faster to stay aloft using more energy and producing more metabolic heat Reduced size is perhaps beneficial under climate warming as the birds can cool themselves better. The data was not tied to a specific site but rather collected from a large range of the rainforest, meaning the phenomenon is ubiquitous. Researchers expressed that even the wildest parts of the Amazon untouched by humanity are being impacted by climate change.

Picture Credit : Google