The life cycles of vegetation in Europe and North America are changing, and a new study shows the southern hemisphere is following suit.
University of Otago botany professor Steven Higgins used satellite pictures to discover that between 1981 and 2012, the growing seasons of plants around the world lengthened, shortened or shifted. The study examined large regions over Africa, Australia and South America for the first time.
The period that plants were ‘in leaf’ has changed severely across 54 per cent of the planet’s land surface, and there was at least some change over 95 per cent of the surface.
The timing of leaves emerging or dying can change for many reasons, such as temperature, rainfall or carbon dioxide in the air. It varies between regions because plants will react differently depending on region and plant species—grassland in one region can thrive, while suffering in another.
However, changing this timing puts animals that have synchronised life cycles to these periods at risk. Higgins suggests that several bird species, insect pollinators and even deer around the world have already declined because of seasonal change.
What’s more, alterations in vegetation patterns could cause further climate change: plants affect cloud formation and carbon exchange, and also control the exchange of heat between the land surface and air.