Weekly round-up: February 14

More sociable female giraffes have a higher chance of survival

Female giraffes who are more sociable and spend time in larger groups with other females benefit from lower stress, more efficient foraging and co-operation in caring for young – resulting in longer lives.

A study of more than 500 females across multiple communities in Tanzania by the University of Zurich showed that less social individuals had a lower chance of survival, with numerous benefits gained by those maintaining long-term close bonds with other giraffes.

Lead author Monica Bond said: “Grouping with more females, called gregariousness, is correlated with better survival of female giraffes, even as group membership is frequently changing. This aspect of giraffe sociability is even more important than attributes of their non-social environment such as vegetation and nearness to human settlements.”

Watch some of the giraffes studied here.
Publication Proceedings of the Royal Society B

Sawfish have disappeared from half of their coastal habitats and are at risk of extinction due to overfishing, according to researchers at Simon Fraser University.

The five species of distinctive rays, which have a shark-like body and a long, flat nose lined with teeth, have previously been recorded along the coastlines of 90 countries, but a number are now presumed locally extinct in 46 of those nations. In 18 countries at least one species is no longer present, and two or more are missing in 28 countries.

A largetooth sawfish – the species is critically endangered (Simon Fraser University)

Sawfish are highly valued by the global shark fishing trade for their fins, while their teeth, or rostra, are sold sought after for novelty value, medicinal use or for spurs in cockfighting. Rostra also make them prone to entanglement in fishing nets.

SFU researcher Nick Dulvy said: “Through the plight of sawfish, we are documenting the first cases of a wide-ranging marine fish being driven to local extinction by overfishing. We’ve known for a while that the dramatic expansion of fishing is the primary threat to ocean biodiversity, but robust population assessment is difficult for low priority fishes whose catches have been poorly monitored over time. With this study, we tackle a fundamental challenge for tracking biodiversity change: discerning severe population declines from local extinction.”

Of the five species of sawfish, three are classified as critically endangered – the largetooth sawfish, green sawfish and smalltooth sawfish – while the narrow sawfish and dwarf sawfish are both endangered.
Publication Science Advances

Research suggests common pipistrelle bats may be attracted to wind turbines, but scientists are yet to understand why.

Bat activity was monitored around 23 British wind farms and similar control locations nearby, with activity around a third higher at the turbines. Periods of high activity were also twice as frequent around the wind farms.

Pipistrellus pipistrellus, aka the common pipistrelle bat (Gilles San Martin)

Possible causes include larger populations of the bats’ insect prey around the wind farms, or an attraction to the turbines themselves.

Lead author Dr Suzanne Richardson said: “Either way it means the risk of fatality at wind turbines is increased, and probably explains the high fatalities of common pipistrelle bats seen at some wind farms across Europe.

“Our findings help explain why Environmental Impact Assessments conducted before the installation of turbines are poor predictors of actual fatality rates. Turbines are generally built in areas where bat activity is thought to be low, but this may not be an effective strategy if bats are attracted once turbines are built. 

“Ongoing monitoring is required, and measures such as minimising blade rotation in periods of high collision risk are likely to be the most effective way to reduce fatalities.”

Common pipistrelle bats are among the most abundant species in Europe, and account for more than half of all bat fatalities caused by wind turbines across the continent.
Publication Scientific Reports

Juvenile white sharks are moving further north up the California coastline in response to warming seas caused by climate change.

Analysing data collected from tags deployed on juveniles since 2002 and temperature mapping, researchers with Monterey Bay Aquarium found that up until 2013 the edge of their range was near Santa Barbara, north of Los Angeles.However, since the extreme North Pacific heatwave between 2014 and 2016, juvenile white sharks have been sighted as far north as Bodega Bay, outside San Francisco, with the most common range edge around Monterey Bay, just south of the city.

California State University Shark Lab director and co-author Dr Chris Lowe said: “After studying juvenile white shark behavior and movements in southern California for the last 16 years, it is very interesting to see this northerly shift in nursery habitat use. I think this is what many biologists have expected to see as the result of climate change and rising ocean temperatures. Frankly, I’ll be surprised if we don’t see this northerly shift across more species.”

Monterey Bay Aquarium chief scientist and co-author Dr Kyle Van Houten said: “White sharks, otters, kelp, lobsters, corals, redwoods, monarch butterflies – these are all showing us that climate change is happening right here in our backyard. It’s time for us to take notice and listen to this chorus from nature. 

“We know that greenhouse gas emissions are rapidly disrupting our climate and this is taking hold in many ways. Our study showed one example of juvenile white sharks appearing in Monterey Bay. But let’s be clear: The sharks are not the problem. Our emissions are the problem. We need to act on climate change and reduce our reliance on fossil fuels.”
Publication Scientific Reports

Trees are absorbing and consuming more carbon dioxide than previously thought, according to West Virginia University researchers, further elevating the importance of forests in mitigating emissions and combating climate change.

Analysis of tree rings has shown an increase in water-use efficiency, and therefore photosynthesis – in which trees convert CO2, the dominant greenhouse gas, and water into sugars and ‘breath out’ oxygen. Since 1901, water-use efficiency has increased ~40 per cent, coinciding with a ~34 per cent increase in atmospheric CO2.

Co-author Professor Richard Thomas said: “This study really highlights the role of forests and their ecosystems in climate change. We think of forests as providing ecosystem services. Those services can be a lot of different things – recreation, timber, industry. We demonstrate how forests perform another important service: acting as sinks for carbon dioxide. 

Our research shows that forests consume large amounts of carbon dioxide globally. Without that, more carbon dioxide would go into the air and build up in the atmosphere even more than it already is, which could exacerbate climate change. Our work shows yet another important reason to preserve and maintain our forests and keep them healthy.”
Publication Proceedings of the National Academy of Sciences

Read Get involved with World Bonobo Day and read up about these fascinating primates – the last great ape to be scientifically described, these elegant animals are highly social and live in matriarchal societies.  

The red-capped manakin (Dominic Sherony)

Watch Love is in the air – and for the red-capped manakin, that involves ‘moonwalking’ to impress the ladies

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