Seeds offer a level of resilience to the harmful effects of climate change in ecosystems across the globe. But warming and increased precipitation is harming seeds in the Tibetan plateau and elsewhere, says new research.
When seeds are dropped into the soil, often becoming dormant for many years until they are ready to grow into plants, they become part of the natural storage of seeds in soil seed banks. These banks have been thought to better withstand extreme conditions than can the sprouted vegetation that exists above-ground.
A new study has now examinedhow warming and increased precipitation (rain and snow) harms the seeds in the ground of the Tibetan Plateau and elsewhere, according to a statement from the Ecological Society of America.
“Soil seed banks are essentially the last resort of natural resilience in ecosystems,” commentedScott Collins, professor at New Mexico University and an author on the paper. “Too often we focus on what we see above ground and base management decisions just on the appearance of the plant community.”
The Tibetan Plateau, a place that has been grazed for thousands of years, is an ideal place to study direct and indirect climate effects on vegetation in a fragile environment. The study states that as the highest plateau in the world, averaging over 12,000 feet in elevation, it is regarded as the third pole of the Earth. The warming rate here is nearly 1.5 times that of global warming due to climate change and annual rainfall has increased in most areas of the plateau.
“Climate change affects the ability of seeds to germinate, grow and survive,” explained Collins. “Although climate change affects adult plants, seedlings are delicate and stress from climate – drought, freezing, etc. – can cause high mortality of seedlings.”
The study states that temperature is a primary factor in controlling seed dormancy. With warmer temperatures, seeds may be triggered to sprout too early when conditions are not ideal for healthy growth. An abnormally warm spell of a few days – which is becoming more common – during an otherwise harsh winter can trigger those seeds to grow but ultimately make them fail.
Increasing temperature and precipitation can also affect seeds indirectly, by changing the environment around them. Pathogens that are harmful to seeds can grow more prolific under warmer and wetter soil conditions. The acidity of the soil can also change, which strongly affects microbial communities and the abundance of those pathogens.
Image credit Nikola Jovanovic via Unsplash