Weekly round-up: November 29

UK bird populations declined 11 per cent between 1970 and 2018 according to a new government report. Farmland bird numbers fell 57 per cent over the same period, with seabirds showing a 28 per cent decline.

The study, which assessed 130 species, found numbers of some native birds had increased significantly over the period, including the buzzard, great spotted woodpecker and red kite, but that others, such as the turtle dove, willow tit, grey partridge and tree sparrow, now numbered less than a tenth of their 1970 population.

UK red kite populations are on the up (David Dixon)

Changes in farming practices in the 1950s and 1960s – such as a move from mixed farming, autumn crop sowing, increased pesticide use and hedgerow removal – were cited as the main contributors to a significant reduction in farmland species in the late 1970s and early 1980s, from which they have not recovered.

Of the 13 seabird species monitored, one, the razorbill, has more than doubled in number since 1970. However, the Arctic skua and black-legged kittiwake have fared worst, declining by 80 per cent and 64 per cent respectively since 1986 – although the latter showed a significant increase in numbers between 2013 and 2018. The effect of climate change on marine food webs, fishery pressures and predation by invasive non-native mammals have been identified as causes in the declines.

The number of black-legged kittiwakes has fallen sharply (Andreas Trepte)

The report states: “Bird populations have long been considered to provide a good indication of the broad state of wildlife in the UK. This is because they occupy a wide range of habitats and respond to environmental pressures that also operate on other groups of wildlife.”

In the US, a study suggests that a reduction in ozone resulting from the Clean Air Act 1970 may have saved 1.5 billion birds – around 20 per cent of the country’s current total. 

The authors write: “Our results highlight that in addition to protecting human health, air pollution regulations have previously unrecognised and unquantified conservation co-benefits.”
Source gov.uk
Publication Proceeding of the National Academy of Sciences

Bottlenose dolphins off the Northumberland coast (Walter Baxter)

Dolphins can adjust their heart rate depending on how long they plan to dive for, helping to avoid ‘the bends’ a new study suggests. 

Researchers trained three bottlenose dolphins to hold their breath for long and short periods, comparing them with spontaneous dives, and found not only did their heart rate alter before the dive, it was significantly lower immediately before and during longer dives, beneficial for both oxygen management and oxygen/carbon dioxide exchange during respiration.

Speaking to Science Daily, lead author Dr Andreas Fahlman of Fundación Oceanogràfic said: “Dolphins have the capacity to vary their reduction in heart rate as much as you and I are able to reduce how fast we breathe. This allows them to conserve oxygen during their dives, and may also be key to avoiding diving-related problems such as decompression sickness, known as ‘the bends’.”

The study also has implications for conservation in marine environments, particularly with regard to noise pollution.

“Man-made sounds, such as underwater blasts during oil exploration, are linked to problems such as ‘the bends’ in these animals,” said Fahlman. “If this ability to regulate heart rate is important to avoid decompression sickness, and sudden exposure to an unusual sound causes this mechanism to fail, we should avoid sudden loud disturbances and instead slowly increase the noise level over time to cause minimal stress. In other words, our research may provide very simple mitigation methods to allow humans and animals to safely share the ocean.”

Earlier this month three marine charities called for wind farm developers to stop the destruction of Second World War bombs through detonation due to fears the blasts can deafen whales and dolphins.
Publication Frontiers in Physiology

The platypus (Christine Ferdinand)

Platypus habitat has declined 22 per cent in the last 30 years – around 200,000km2, an area three times the size of Tasmania – according to a new study, prompting calls for the iconic Australian species to be listed as threatened.

Areas where river systems and water flows are modified have seen the biggest declines, with new dams, over-extraction, land clearing, fox and dog attacks, pollution and suburban sprawl listed as the primary factors in decreasing populations. Severe droughts and intense forest fires resulting from climate change are also now threatening the species.

Dr Paul Sinclair, campaigns director at the Australian Conservation Foundation which commissioned the research, said: “While our national environmental laws should be much stronger, listing the platypus as a threatened species is a critical first step towards conserving this iconic Australian species and putting it on a path to recovery.”

The platypus, which has the bill and webbed feet of a duck with a body and tail more like that of the beaver, lives on land but hunts in water. It is one of only two mammals to lay eggs, the other being the echidna – also native to Australia. The platypus is currently listed as near threatened by the IUCN. The study recommends reclassification of the species to endangered, while also classifying it as threatened under Australia’s Environment Protection and Biodiversity Conservation Act.
Source University of New South Wales

The shortfin mako shark can swim at up to 43mph (Patrick Doll)

Efforts to protect the shortfin mako shark have been blocked by the US and EU, overriding British and Canadian support for a ban on trade in the endangered species.

Numbers of the shortfin mako, which can swim at up to 43mph and leap six metres above the surface, have plummeted due to overfishing and are continuing to decline according to the IUCN, with no specific conservation actions currently in place. It is routinely targeted for sport and its meat and fins, while also caught accidentally as bycatch. 

However, the US and EU argued a ban on trade put forward at the International Commission for the Conservation of Atlantic Tunas (Iccat) would not be able to prevent bycatch – for which EU vessels are responsible for the majority of recorded incidents – resulting in a delay in any potential action until next year.

Shortfin mako sharks are caught for sport (Evan Crouse)

Ali Hood, director of conservation for the Shark Trust, said: “North Atlantic mako depletion remains among the world’s most pressing shark conservation crises, yet the EU and US put short-term fishing interests above all else and ruined a golden opportunity for agreeing a clear and simple remedy.”

The proposal marked the UK’s first official Iccat vote outside of the EU.
Source Independent

The coppery titi monkey (Hans Hillewaert)

Reproductive monogamy is rare in pair-living animals – including humans – but researchers at the German Primate Center have found coppery titi monkeys take fidelity very seriously, choosing a mate and sticking with them.

One theory for lack of genetic monogamy is an animal’s search for the best genes, which is limited in socially monogamous animals – possibly leading to inbreeding or an incompatible partner. As a result, even those animals who ‘mate for life’ will often seek another partner without the knowledge of their long-term mate, potentially benefiting from increased genetic quality and fitness of the offspring.

However, researchers found no evidence of extra-pair paternities (EPP) in coppery titi monkeys, suggesting true monogamy – and also found low average relatedness between individuals, thought to be as a result of natural dispersal.
Publication Scientific Reports

Freshwater turtles, otters and the endangered South Asian river dolphin are the species most at risk from plastic pollution in the Ganges river – specifically ghost gear discarded by fishers, according to a new study.

The impacts of ghost gear on species in marine environments has been well-documented, but less is known about its effects on freshwater systems. Researchers conducted riverbank surveys along the length of the Ganges, finding abandoned gear increased with proximity to the sea – while also recording the presence of illegal gear types. Fishing nets were the primary type of ghost gear by volume.

The authors identify air-breathing aquatic vertebrate species to be most at risk from entanglement, highlighting the need for “targeted and practical interventions to limit the input of fisheries-related plastic pollution to this major river system and, ultimately, the global ocean”.
Publication Science of the Total Environment

A new inventory of plant species has been unveiled, the largest in the world and a boon for research and conservation. The Leipzig Catalogue of Vascular Plants contains a reference list of 1,315,562 scientific names for all known vascular plants, across 13,460 genera, 564 families and 84 orders.
Publication Scientific Data

The art of flight (Alwin Hardenbol)

The stunning image of a Dalmatian pelican in flight has been crowned overall winner of the British Ecological Society’s 2020 Capturing Ecology photography competition.

The winning shot was taken by Alwin Hardenbol, a PhD candidate at the University of Eastern Finland.

“I gave this image the title ‘The art of flight’ because of how impressive this bird’s wings appear in the picture, you can almost see the bird flying in front of you despite it being a still image,” said Hardenbol, who also won the People and Nature category for his image of a black-legged kittiwake nesting on the tiny ledge of a wooden building in Varanger, Norway.

Ant Tale (Upamanyu Chakraborty)

Upamanyu Chakraborty took the overall runner-up prize with Ant Tale, a close-up of two weaver ants carrying an immature member of the colony.
Source British Ecological Society

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