Weekly round-up: February 7

A wide range of marine life depends on sound for communication, navigation and feeding

Noise pollution from human activities in the ocean is causing significant harm to marine fauna, affecting their behaviour, physiology and reproduction – in some cases resulting in death – according to a new study.

Sound is vital to marine animals, including for communication, navigation and hunting. Since the Industrial Revolution however, the ocean soundscape has become increasingly chaotic as noise from sea travel, transport, leisure, fishing, energy extraction and myriad other activities competes with ocean residents.

Researchers from across the globe analysed more than 10,000 papers, distilling the results into one compelling body of evidence highlighting the impact of human-made noise on the whole range of marine life, from invertebrates to whales.

Co-author Ben Halpern said: “The landscape of sound – or soundscape – is such a powerful indicator of the health of an environment. Like we have done in our cities on land, we have replaced the sounds of nature throughout the ocean with those of humans.”

Halpern, also director of the National Center for Ecological Analysis and Synthesis at UC Santa Barbara, added: “We all know that no one really wants to live right next to a freeway because of the constant noise. For animals in the ocean, it’s like having a mega-freeway in your backyard.”

The authors called for national and international policies to better regulate and mitigate marine noise, adding that, unlike other forms of human pollution such as chemicals and greenhouses gases, the effects cease as soon as the noise is reduced, resulting in immediate benefits.

Listen to a compilation of ocean soundscapes – with and without human-made noise pollution – here.
Publication Science

President Biden has put the brakes on one of the Trump administration’s final environmental rollbacks, opening up a controversial amendment to the Migratory Bird Treaty Act to public consultation.

In January, the Fish and Wildlife Service put forward a rule removing liability for the accidental killing of birds, a move widely expected to result in oil and chemical companies removing voluntary protections – which could also impact other species.

A rule proposed by the Trump administration would remove liability for birds harmed by environmental disasters from the companies involved (Brocken Inaglory)

However, under the new administration, the US Department of the Interior is delaying the amendment pending a 20-day comment period – given broad opposition from the public, it is expected the rule will be unlikely to pass in its current form.
Source Audubon Society

The greater the fragmentation of habitat, the more stressed its residents are, according to a study which has analysed hormones in fur.

Deforestation is destroying landscapes across the globe, trapping animals in smaller, fragmented areas of habitat and leaving them unable to travel beyond their borders for food or to mate – also reducing genetic diversity, an additional threat to survival.

This is particularly true of South America’s Atlantic Forest, which runs along the eastern coast of Brazil south and west into Argentina and Paraguay. Once more than 1,000,000km2, the forest is now only seven per cent of its original size. 

South America’s Atlantic Forest is a fraction of its original size due to logging and increased urbanisation (Jose Eduardo Camargo)

A team of researchers, led by Rhodes College associate professor Sarah Boyle, studied several rodent and opossum species from forest patches ranging between two and 1,200 hectares, finding that glucocorticoid stress hormone levels were higher in animals from smaller fragments of habitat. 

Prolonged stress also reduces the body’s immune response, increasing the risk of animals harbouring viruses and disease – while fragmentation of forest due to development and urbanisation results in closer contact between wildlife and humans.

Noé de la Sancha, associate professor of Biology at Chicago State University and a co-author, said: “By destroying natural habitats, we’re potentially creating hotspots for zoonotic disease outbreaks.”
Publication Scientific Reports

Nature and its goods should be assigned a monetary value – ‘natural capital’ – in order to better ensure protection and prevent further damage as demand exceeds supply, according to The Economics of Biodiversity: The Dasgupta Review, commissioned by the UK Treasury in 2019.

The review, written by Professor Sir Partha Dasgupta – Frank Ramsey Professor Emeritus at the University of Cambridge – states that global prosperity has come at a “devastating cost to nature”.

“Collectively, we have failed to manage our global portfolio of assets sustainably. Estimates show that between 1992 and 2014, produced capital per person doubled, and human capital per person increased by about 13 per cent globally; but the stock of natural capital per person declined by nearly 40 per cent.”

It is estimated the world’s current living standards would require 1.6 Earths to maintain.

Headline messages include managing demands, increasing supply and the need to adopt a different measure of economic growth to GDP – one including natural assets. The review also calls for improvements in women’s access to finance, information and education, ensuring greater fertility choices – which has been shown repeatedly to lower birth rates, thus reducing global demand for resources.

Professor Dasgupta said: “Truly sustainable economic growth and development means recognising that our long-term prosperity relies on rebalancing our demand of nature’s goods and services with its capacity to supply them. It also means accounting fully for the impact of our interactions with Nature across all levels of society. COVID-19 has shown us what can happen when we don’t do this. 

“Nature is our home. Good economics demands we manage it better.”
Source gov.uk

Brookesia nana (Frank Glaw/ZSM/SNSB)

A chameleon the size of a seed is thought to be the world’s smallest reptile after researchers unveiled two tiny individuals discovered in Madagascar.

The team found two specimens of Brookesia nana, a male just 21.6mm from nose to tail and a larger female, 28.9mm in length. Both sexes were pale brown with darker colouration in patches – with no ability to transform their colour for camouflage as seen in many larger species. They are thought to eat mites and other small invertebrates found on the forest floor.

The pair were discovered during a 2012 expedition, but the research team published their findings this month – no other individuals have been found, and the species may be threatened by extinction, having only been discovered in an area of degraded montane rainforest in the north of the country.
Publication Scientific Reports

Small mammals are better at coping with warmer, drier conditions caused by climate change than birds, reports a study published in the journal Science.

A team of researchers that previously recorded a collapse in bird populations in the Mojave desert and its surrounds have shown that while the ‘cooling costs’ required to survive in rising temperatures are too great for many winged species, small mammals are better adapted, with the ability to escape daytime heat in underground burrows and a tendency to be more active at night.

Lead author Eric Riddell said: “It’s becoming clear that animals across the planet are responding to climate change by shifting where they live and shifting when they breed, and we’re starting to get really strong evidence of population declines in certain areas that may be associated with warming. Some estimates now suggest that one in six species will be threatened by climate change over the next century. Figuring out which species those are, what kind of traits they have, will be critical.”

The Mojave desert has seen an approximate 2C increase in average temperature and a 10-20 per cent drop in precipitation over the last century.
Publication Science

The UK government has proposed a complete ban on bottom trawling in four of the country’s Marine Protected Areas (MPAs) – including the Dogger Bank Special Area of Conservation.

MPAs have previously been branded ‘paper parks’, with bottom trawling and other damaging fishing practices taking place in 98 per cent of protected regions, but a full ban in the four zones will preserve species and ecosystems across an area the size of Northern Ireland.

The move to better protect British seas has been welcomed by conservationists – who also stressed the need to go further.

Jean-Luc Solandt, the Marine Conservation Society’s MPA specialist, said: “While only for four of a possible 74 areas of protection, this is an encouraging start. After years of degrading our seas are we finally starting to see measures that can provide recovery?”

Greenpeace UK also called for all MPAs to receive better protection. 

The consultation, launched by the Marine Management Organisation, is being proposed under the new Fisheries Act – domestic legislation introduced after the UK’s departure from the EU.
Source gov.uk

Activities such as hunting and recreation can affect animal behaviour as much as logging and urbanisation – if not more – with research showing an average 70 per cent increase in wildlife movement to avoid humans. 

Analysis of studies from across the globe showed a significant restructuring of animal movements, which could have critical consequences on species populations and ecosystem services that are essential to our survival.

Human activity was also found to reduce movement in some cases, either due to increased access to food or physical barriers limiting the ability to relocate.

Lead author Dr Tim Doherty, a wildlife ecologist at the University of Sydney, said: “The consequences of changed animal movement can be profound and lead to reduced animal fitness, lower chances of survival, reduced reproductive rates, genetic isolation and even local extinction.

“As well as the direct impact on animal species, there are knock-on effects. Animal movement is linked to important ecological processes such as pollination, seed dispersal and soil turnover, so disrupted animal movement can have negative impacts throughout ecosystems.”

Doherty stressed the need to factor the findings in future policy decisions, such as managing recreation activities in wilderness areas to reduce the impact on local wildlife.

The study assessed 37 bird species, 77 mammal species, 17 reptile species, 11 amphibian species, 13 fish species and 12 insect species.
Publication Nature

Read Nine ways to build a wildlife friendly garden

Watch Giant Cassowaries – modern day dinosaurs

One thought on “Weekly round-up: February 7

Comments are closed.

%d bloggers like this: