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Planet Earth

Four steps to make your lawn a wildlife haven – from green desert to miniature rainforest

If you could ask British insects about the habitats they prefer, they’d probably tell you that you can’t improve on grassland that’s rich with wildflowers. For farmers, though, grassland is said to be “improved” if it has been treated with fertiliser and sown with fast growing grasses.

“Unimproved” grasslands are those that have not had their productivity improved for agriculture. They’re semi-natural habitats, because if mowing or grazing stopped, they’d quickly turn to scrub and then woodland. These unimproved grasslands are extremely rich in the number of species they can support, sometimes having well over 40 species of flowering plant in a single square metre.

But since World War II, 97% of unimproved grassland habitats have vanished from the UK. This has contributed to the loss of pollinating insects – and the distribution of one third of species has shrunk since 1980.

Left – Grassland in Transylvania, where agricultural ‘improvement’ has been limited. Right – Potwell Dykes, Nottinghamshire – how much of the UK’s lost grassland would have looked.
Adam Bates

If you’re lucky enough to have a garden, your lawn can be thought of as a small patch of artificial grassland, which will usually have only a few species of turf grass. Most suburbs and villages still have around a quarter to a third of their area covered by grass.

Unfortunately, lawns are largely featureless and offer little refuge for small creatures like bugs and other invertebrates. Regular mowing also prevents plants from flowering and producing seeds, which is why carefully maintained lawns are mostly barren.

A traditionally managed lawn. There are few plant species and little structure for bugs to exploit. Spiders, for instance, have nothing to anchor their webs to.
Adam Bates

But lawns can be made into important wildlife habitat by changing how they’re managed. This is an idea that’s gaining traction – campaigns such as “Say No to the Mow” have made an “unkempt” garden more socially acceptable. For anyone wanting to create a wildlife lawn in their garden, there are four important steps to follow.


Adam Bates

1. Cut higher

The first step is simple. By raising the height that the mower blade cuts the grass to its highest setting – usually about 4 cm off the ground – you can provide more variety in the lawn’s structure and more refuge for other plant and invertebrate species.

2. Include mowing gaps

Fox-and-cubs (Hieracium aurantiacum) help feed leafcutter bees.
Jörg Hempel/Wikipedia, CC BY-SA

By mowing less often you can allow plants time to flower and provide a food source for bees and other pollinators. Leaving gaps between mowing in spring gives time for species like the cowslip to flower – a plant which has declined markedly in the UK but which butterflies like the Duke of Burgundy depend on for laying their eggs.

Summer gaps can allow species like cat’s ear and fox-and-cubs time to flower, providing an important source of food for species of leafcutter bee. Deciding how long to wait between mowing isn’t an exact science, but can be judged by seeing whether or not the plants in your lawn have had a chance to flower.

3. No fertilisers or herbicides

“Weed and feeds” are used on lawns in a one-bottle mix of herbicide – used to kill non-grass species that we’d usually consider weeds – and fertiliser, to add nutrients to the soil. Herbicides reduce biodiversity by killing other species, but it may surprise you to learn that fertilisers are no friend to biodiversity either.

When gardening or farming, usually the more fertility in the soil the better, because this promotes greater productivity. In other words, more grass, greener grass, more flowers and larger flowers. The selective actions of the gardener or farmer to promote the target species, whether prized rose or crop, means that only the target species benefits.

Without this selectivity, more fertility in your lawn only favours the one or two turf species that are best able to take up nutrients and outcompete other species. So, more fertility means fewer plant species, despite the more luxuriant green colour.

4. Remove the clippings

Removing the grass clippings after you’ve mowed the lawn also reduces the fertility in your lawn, preventing it from becoming dominated by one or two competitive turf species. Removing and composting grass clippings will gradually remove nutrients from the soil, lowering the fertility with each cut.

Beyond these four steps for improving the value of your lawn to wildlife, there are other things that can be done by the more committed gardener. Leaving small areas of the lawn deliberately uncut – such as strips at the sides or patches in the corners – can help small wildflower meadows to form. Cutting these at the end of summer will prevent them overgrowing into rank grassland with few species.

Wildlife value can also be added by spreading some locally-sourced wildflower seed on your lawn. If you’re gathering seeds from elsewhere, make sure to ask permission and don’t take too much.

A single suburban wildflower lawn – multiple plant species that can flower and seed, and high structural diversity.
Adam Bates

Enjoying your wildflower lawn

Wildflower lawns can have a variety of other surprising benefits, not least helping to slow global warming. Some studies have shown that lawns are actually sources of carbon dioxide due to the amount of energy needed to power the mower and manufacture “weed and feeds”. Reducing how often you mow, not applying “weed and feeds” and even using a manual lawn mower can change your lawn from a carbon source to a carbon sink.

Having taller vegetation in your lawn shades the ground, thereby reducing evaporation from the soil and reducing the need for sprinklers and hosepipes. Less mowing means less work to do and more time for you to enjoy watching the bees gathering nectar and pollen from your wildflower lawn.

Wildflower lawns, with spikes of colourful flowers and attendant bees, at least to my eyes, are far prettier than a carpet of grass, whether it’s stripy or not. Grass – especially when not in flower – is the most aesthetically boring part of a grassland. The species that have traditionally been disregarded as “weeds” are far more interesting.

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Planet Earth

Greenland is losing ice seven times faster than expected

Credit: University of Leeds / Youtube

Greenland is ceasing to be that vast white territory because it is losing ice at a speed seven times faster than in 1990.

The fatal scenario goes according to the context of global warming of Intergovernmental Panel on Climate Change (IPCC), which would expose 400 million people to coastal flooding in the year 2100.

A joint work of 96 scientists from 50 international organizations has generated the most detailed image so far of the ice loss from Greenland.

The team called Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) used 26 surveys to calculate changes in the Greenland ice sheet mass between 1992 and 2018.

The worst case scenario

The research results show that Greenland has lost so far 3.8 billion tons of ice, since 1992. This thaw is enough to raise the sea level by 10.6 millimeters.

The figures are alarming as they show a seven-fold increase in ice loss in just three decades.

Aerial photograph of icebergs discharging from the Jakobshavn glacier in Greenland Credit: William Colgan, Geological Survey of Denmark and Greenland

In 2013, the IPCC predicted that worldwide sea level would rise 60 centimeters by 2100, leaving 360 million people at risk due to coastal flooding. However, the new study shows that the ice loss is increasing faster than expected, which would generate an increase of even 7 centimeters more at sea level.

Andrew Shepherd in the University of Leeds, lead author of the research, he said in a statement:

As a general rule, for every one-centimeter increase in global sea level, another six million people are exposed to coastal flooding across the planet.

According to current trends, the melting of ice in Greenland will cause 100 million people to flood each year at the end of the century, which adds up to 400 million in total due to all the sea level rise. These are not unlikely events or small impacts; they are happening and will be devastating for coastal communities. ”

Caused by warming

The climate models regionals used by the team of researchers showed that half of the ice loss was due to rising air temperatures. The other half was caused by the rising ocean temperature.

Download glaciers that split icebergs in the waters of the Mogens Heinesen fjord in southwest Greenland. Credit: Benoit Lecavalier

The doctor. Erik Ivins of the Jet Propulsion Laboratory NASA and lead author of the study said in a statement:

Polar ice satellite observations are essential to monitor and predict how the climate change could affect ice losses and sea level rise. While computer simulation allows us to make projections from climate change scenarios, satellite measurements provide irrefutable evidence. ”

The team expects to continue monitoring the ice reduction in Greenland to determine the possible sea surge each year.

The research findings have been published in the journal. Nature.

Source: Leeds University / Phys.org

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Planet Earth

Bright Meteor Fireball Streaks over Phoenix, Arizona

Does it seem like these are on the rise?

via AZ Central:

By now, we all know, it didn’t really happen unless it’s confirmed via social media.

And that’s what was happening Friday night, as numerous Twitter posts surfaced from people who said they saw a bright light streak across the nighttime sky over Phoenix sometime around 9:30 p.m.

The posts described the sight as a green streak or light, possibly a large meteor or “shooting star,” but definitely more than a quick flash that such a phenomenon usually produces.

The Arizona Republic could not immediately confirm the source of the bright light, but several other Twitter posts reported seeing it from vantage points such as 32nd Street and Thomas Road, near the Phoenix Art Museum, or in north Phoenix.

Chris Coppola
AZ Central

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Planet Earth

Life on Earth can be explained by asteroid-eating bacteria

A new study suggests that asteroids can be a food source for living things, more specifically a microorganism called  Metallosphaera sedula , a metal-eating species.

M. sedula Picture: Tetyana Milojevic

Metallosphaera sedula  is a species of bacteria-like microbes, originally isolated from a volcanic field in Italy. The first part of the name can roughly be translated as a “metal mobilizing sphere,” while the word “sedulus” means busy. This describes the efficiency of these organisms in mobilizing metals, including those found in asteroids.

According to research led by University of Vienna astrobiologist Tetyana Milojevic, these microbes derive their energy from inorganic substances through oxidation, and can collect energy sources faster from extraterrestrial rocks than from simple ancient terrestrial minerals. Milojevic explains that the study was conducted to find “microbial fingerprints” left in meteorites. “This should be useful for tracking life-seeking biosignatures in other parts of the universe,” she concludes.

This kind of research, according to the astrobiologist, can provide her colleagues with “little tips” on what they can look for in their search for alien life. “If there was ever life on another planet, similar microbial fingerprints may still be preserved in the geological record,” she said.

The team examined how Metallosphaera sedula  interacts with NWA 1172, a rocky meteorite found in northwest Africa that contains about 30 different metals. Using various spectroscopy techniques and an electron microscope, the researchers documented the signatures left by the organism. Thus, they found that M. sedula  is able to consume extraterrestrial material much faster than it does with terrestrial minerals, resulting in healthier cells.

Inorganic Compounds of Meteorite NWA 1172 (Image: Tetyana Milojevic)

While terrestrial minerals provide only a few nutrients for the microorganism, “NWA 1172 iron is used as an energy source to meet M. sedula’s bioenergetic needs  as microbes breathe due to iron oxidation,” Milojevic explained. The wide range of metals in NWA 1172 can also be used for other metabolic processes, such as accelerating vital chemical reactions within cells. And because the meteorite is so porous, it can promote M. sedula’s improved growth rate.

That means iron meteorites could have brought more metal elements and phosphorus to Earth, making life’s evolution easier, according to Milojevic. In addition, research may also support the panspermia hypothesis, an idea that cannot yet be substantiated, but it is not ruled out either, as scientists have not yet completely unraveled the origin of life on our planet. And Milojevic is interested in exploring this possibility: To do so, her team plans to “test the survival of  M. sedula  under simulated and real environmental conditions from outer space,” the astrobiologist said. The plan, however, will have to find the funding needed to send the microorganisms into space.

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