Bats depend on teamwork when foraging over farmland

MARCH 26, 2020

by Forschungsverbund Berlin e.V. (FVB)

Scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) have reported in a paper published in the journal Oikos that bats forage on their own in insect-rich forests, but hunt collectively in groups over insect-poor farmland. They seem to zoom in on places where conspecifics emit echolocations during the capture of insects, an inadvertent clue that reveals high-yielding areas to others. However, "listening" to their hunting companions to find food only works when sufficient numbers of bats forage in the same area. If numbers continue to decline, density could fall below a critical level and joint hunting could become difficult or impossible. This could pose an additional threat to the survival of species such as the Common noctule.

Human activities have massively changed the Earth over centuries. While Central Europe was covered by dense primeval forests in ancient times, today, farmland, meadows and managed forests dominate the countryside. Humans have transformed natural landscapes into cultural landscapes and many wild animals disappeared, while others found new ecological niches. Bats were particularly successful in the latter process. As so-called cultural successors, many species were able to survive in modern environments, finding shelter in buildings and feeding above arable land and managed forests. But what is the secret of their success? Are they particularly efficient hunters?

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Forest-loving moose learning to thrive on farmland

Date: May 17, 2016

Source: University of Saskatchewan

While populations of moose have been declining in much of their North American range, research from the University of Saskatchewan shows how these icons of the northern boreal forest are finding success by moving south into farmers' fields.

"Thirty years ago, seeing moose in the farmland of Saskatchewan would have been very rare but over time they have expanded to these new areas," said Ryan Brook, a wildlife biologist with the Department of Animal and Poultry Science at the U of S. "It's unique to see populations well-established in areas with less than one percent forest cover that are dominated by crop production."

Brook, who leads the Saskatchewan Farmland Moose Project, has been working with his colleagues to discover how the moose are succeeding in what used to be considered highly unsuitable habitat. The research team used a net gun fired from a helicopter to capture 40 adult cow moose and fit them with GPS satellite collars in 2013 and 2014 to track the animals' movements for four years.

The team found that the animals are taking advantage of the area's "knob and kettle" land forms, that is, rolling hills with plentiful tree-ringed sloughs and wetlands. During the heat of the summer days -- "hot" for a moose being above 14 C -- the animals retreat to shade and water, coming out to feed once it cools off.

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What is killing off our farmland birds – loss of habitat or a rise in predators?

Even the wildest areas of the British Isles are managed by man. We intervene in nature at so many levels, from directly controlling some wild species, through culling or special protection, to introducing domestic stock and taming wild areas for food production. And we have done so for thousands of years. There are often unintended consequences from such intensive management, creating ideal circumstances for some species to thrive and squeezing others out. That means intervening again, to adjust the numbers that have been artificially boosted by our behaviour or give a helping hand to those we have inadvertently caused to decline.

Numerous scientific studies have sought to show why farmland birds – much loved by millions of people – have suffered such serious declines in the past half-century. For some of the most vulnerable species, numbers are down by 80 per cent or more.

The traditional view, promoted by a range of wildlife charities, is that intensive farming, which grubbed up hedgerows and sprayed insect and weed-killing chemicals around through the late-1960s and 1970s, was the culprit.

Yet we have now had several decades of reversing those habitat losses – planting new hedgerows and restoring those that remained; planting woodland and incorporating wild flower field margins with all-important seed-producing plants into arable land. Many millions in grant aid, from the European Union and the British Government, all paid for by UK taxpayers, has been invested in various projects.

Yet, as surveys repeatedly tell us, the declines for the most part continue. It is not a uniformly gloomy picture, by any means, but it is fair to say that, in spite of the best efforts of farmers and environmentalists, the medicine is not working as many would like.

Some studies suggest the changes made to farming practices have not yet taken effect or are not radical enough. Ian Newton, writing in Ibis, the international journal of avian science, concluded in an exhaustive report in 2004 that more time would be needed for the positive effects to be felt.

He wrote: "Although it is too early to assess properly the effects of recently introduced agri-environment schemes, earlier schemes were most successful when targeted to the needs of particular species, such as cirl bunting, lapwing, stone curlew and corncrake, and of some seed-eaters through winter seed provision."

Read on:  http://www.thisiscornwall.co.uk/killing-farmland-birds-ndash-loss-habitat-rise/story-16321467-detail/story.html

Threatened species need farmland

Several threatened species in the developing world are completely dependent on human agriculture for their survival, say scientists.

A study by researchers at the University of East Anglia (UEA), found at least 30 bird species that would be driven to extinction without farmland.

The research is published in the journal Conservation Letters.

This study focused on birds, but the team say the same probably applies to many other animals.

Dr Paul Dolman from the University of East Anglia led the research team.

He told BBC Nature: "The general principle is that where large herbivores used to graze the land and create this habitat, they have now gone and human farmers are doing the job instead.

"So wildlife now needs the farmers."

The team laid the foundations for their study with research into threatened bird species in Africa and Asia.

This revealed that some of the rarest and most threatened birds there were completely dependent on traditional grazing land.

Read more here ...

By Victoria Gill

Science reporter, BBC Nature