Medium-sized carnivores most at risk from environmental change

Date:  December 4, 2017

Source:  Imperial College London

In a surprise ecological finding, researchers discover medium-sized carnivores spend the most time looking for food, making them vulnerable to change.

Mammalian predators (commonly called carnivores) spend a significant part of their day foraging for food, and the more time they spend, the more energy they use. This makes predators that spend a long time foraging more vulnerable to changes in the environment that affect their primary resource: their prey.

It had been thought that foraging time decreases as animal size increases, but new research by Imperial College London and the ZSL (Zoological Society of London) shows this is not the case.

The team used data on land predators worldwide, from small predators such as weasels to some of the largest such as tigers, to demonstrate that among all species, medium-sized ones (between about one to ten kilograms in weight) spent the greatest part of their day foraging. Examples of such medium-sized carnivores include the Malay civet, Iriomote cat, Leopard cat and Crab-eating fox.

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Butterflies illustrate the effects of environmental change

24th July 2014

1 hour ago

Changes in butterfly fauna are yielding surprising insights into our changing environment. The effects of nitrogen from fertilizer or precipitation on the food plants and microclimate of caterpillars have a significant impact on butterfly communities in Northwestern Europe. This according to research by Wageningen entomologist Michiel Wallis de Vries published in the latest edition of Basic and Applied Ecology.

Changes in land use, climate and nitrogen deposition are considered as the main driving forces behind the quality of our natural environment. We can determine how these forces influence different species by examining the ecological traits of these species. "We seldom get past the circular argument that specialists are facing increasing pressure and generalists are becoming increasingly common," says Michiel Wallis de Vries, special professor of Insect Ecology and Conservation at Wageningen University. "We recently made a breakthrough beyond that circular reasoning with an extensive analysis of the characteristics of butterflies in Northwestern Europe, which has led to surprising insights."

Read more at: http://phys.org/news/2014-07-butterflies-effects-environmental.html#jCp

Seal teeth reveal environmental change at Lake Baikal

Scientists at Wellesley College are focusing their research on the teeth of Baikal seals in order to uncover the effects of pollution and climate change on Lake Baikal in Russia.

The lake is the deepest, oldest, and most bio-diverse lake in the world, and the Baikal seal, or the nerpa, is found only here. In addition, it is the only seal in the world to live solely in fresh water.

The reason why the seals’ teeth are of special importance to the scientists is that they are essentially a chemical record of the lake. Living up to between 40 to 50 years, the layers of dentine in the teeth of the seals can be studied in relation to environmental patterns and changes.

The Baikal seal is at the top of the food chain in the lake, which makes them particularly interesting for the scientists due to biomagnification – the process by which the concentration of a substance increases with each level of food in the food chain.

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Environmental change 'triggers rapid evolution'

By Mark KinverEnvironment reporter, BBC News

Researchers were surprised how quickly the mites evolved as a result of environmental changes

Changes to their surroundings can trigger "rapid evolution" in species as they adopt traits to help them survive in the new conditions, a study shows.

Studying soil mites in a laboratory, researchers found that the invertebrates' age of maturity almost doubled in just 20-or-so generations.

It had been assumed that evolutionary change only occurred over a much longer timescale.

The findings have been published in the journal Ecology Letters.

"What this study shows for the first time is that evolution and ecology go hand-in-hand," explained co-author Tim Benton, professor of population ecology at the University of Leeds, UK.

"The implicit assumption has always been, from Darwin onwards, that evolution works on long timescale and ecology works on short timescales.

"The thinking was that if you squash a population or you change the environment then nothing will happen from an evolutionary point-of-view for generations and generations, for centuries."

Running wild

Prof Benton said that the soil mites experiment was set up to help shed light on whether the change in the size of harvested fish species, such as North Atlantic cod, was a result of an evolutionary change.

"The advantage of what we have done is that we have got free-running populations of organisms that do their own thing," he told BBC News.

The findings mean that managing populations will have to take into account evolutionary factors

"You cannot do those sort of experiment with large organisms that live in the wild."

Read on:  http://www.bbc.co.uk/news/science-environment-22039872

DDT Linked to Long-Term Decline of Insect-Eating Birds in North America, Through Analysis of Bird Droppings

ScienceDaily (Apr. 18, 2012) — New research findings highlight how deposits of animal droppings are scientifically important for determining the impact of environmental change on threatened species.

Analysis of 50 years' bird droppings inside a large decommissioned chimney on Queen's campus provided evidence that DDT and bird diet may have played a role in a long-term decline for populations of insect-eating birds in North America. The chimney had been a roosting spot for chimney swifts.

"Certainly there are many other deposits in large chimneys around North America and elsewhere, forming important environmental time capsules," says biology professor and co-author John P. Smol, Canada Research Chair in Environmental Change, and previous winner of the Natural Sciences and Engineering Research Council of Canada (NSERC) Herzberg Gold Medal as Canada's top scientist. "It may be a stinky job, but someone has to do it!"

Continued:  http://www.sciencedaily.com/releases/2012/04/120418143759.htm