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Temperature most significant driver of world's tallest trees

Understanding forest biodiversity and how carbon dioxide is stored within trees is an important area of ecological research. The bigger the tree, the more carbon it stores and a study in New Phytologist explores global variance in tree height, identifying temperature as the most important factor behind the tallest species.

Height gives canopy trees, the focus of much forest carbon research, a competitive advantage as they can place leaves at higher light levels while suppressing their competitors. Height also allows for wind-dispersed pollen and fruits to travel further.

The new study explores the role of temperature in driving tree height, a study which may allow us to forecast how forests adapt to climate change. The research examined the temperature-driven physiological model of tree height in order to explain the thermal climates in which the tallest individuals of the tallest tree species grow.

The tallest specimens of the world's nine tallest tree species were found to grow in climates with an unusually small seasonal temperature variation, which accounted for only 2.1% of global land area. In contrast their distance from the equator ranged from 3900 to 5500 km, their altitude above sea level from 50 to 1750 m, and the distance between the most distant localities ranged from 2700 km in Australia to 1400 km in western North America.

Insights on whale shark populations and evidence for their historic rise, recent decline

In the largest study on the genetics of whale sharks conducted to date, researchers found that the world's biggest fish likely exist in 2 distinct populations with minimal connectivity between the Indo-Pacific and the Atlantic Ocean. The findings suggest that mixing of whale sharks between the Indian and Atlantic was and is rare.

Climate change could stop fish finding their friends

Like humans, fish prefer to group with individuals with whom they are familiar, rather than strangers. This gives numerous benefits including higher growth and survival rates, greater defence against predators and faster social learning. However, high carbon dioxide levels, such as those anticipated by climate change models, may hinder the ability of fish to recognize one another and form groups with familiar individuals.

More carbohydrates make trees more resistant to drought

How well tropical trees weather periods of drought depends on the carbohydrates stored, as revealed by a novel experiment conducted by an international team of researchers headed by ecologists from the University of Zurich in contribution to the University Research Priority Program on "Global Change and Biodiversity." The findings are extremely important for assessing the resistance of tropical forests to climate change and reforestation.

New theory on cause of ice age 2.6 million years ago

New research in the journal Nature's Scientific Reports has provided a major new theory on the cause of the ice age that covered large parts of the Northern Hemisphere 2.6 million years ago.

The study, co-authored by Dr Thomas Stevens, from the Department of Geography at Royal Holloway, University of London, found a previously unknown mechanism by which the joining of North and South America changed the salinity of the Pacific Ocean and caused major ice sheet growth across the Northern Hemisphere.