Spring flowers may arrive as much as three weeks earlier in the US over the next century, owing to rising global temperatures, scientists have projected.
The results have long term implications for the growing season of plants and the relationship between plants and the animals that depend upon them, researchers said.
The researchers from the University of Wisconsin-Madison in US applied the extended Spring Indices to predict the dates of leaf and flower emergence based on day length. These general models capture the phenology of many plant species.
Their results show particularly rapid shifts in plant phenology in the Pacific Northwest and Mountainous regions of the western US, with smaller shifts in southern areas, where spring already arrives early.
“Our projections show that winter will be shorter – which sound great for those of us in Wisconsin,” said Andrew Allstadt, an author on the research paper published in the journal Environmental Research Letters.
“But long distance migratory birds, for example, time their migration based on day length in their winter range,” said Allstadt.
“They may arrive in their breeding ground to find that the plant resources that they require are already gone,” he said.
The researchers also investigated the so-called ‘false springs’ – when freezing temperatures return after spring plant growth has begun.
They showed that these events will decrease in most locations. However a large area of the western Great Plains is projected to see an increase in false springs.
“This is important as false springs can damage plant production cycles in natural and agricultural systems. In some cases, an entire crop can be lost,” said Allstadt.
“We are expanding our research to cover all kinds of extreme weather, including droughts and heat waves,” said Allstadt.
“We are particularly interested in how these affect bird populations in wildlife refuges,” he said.