Weather|The autumn heat has many effects on nature.
The summary is made by artificial intelligence and checked by a human.
The long-lasting heat affects the autumn migration of birds, blue-green algae and the mushroom harvest.
According to Birdlife Suomen’s Jan Södersved, the heat delays the departure of migratory birds, but it is not a major disadvantage.
According to Kristiina Vuorio of the Finnish Environmental Center, warm waters can prolong the bloom of blue-green algae.
The Natural History Museum’s Tea von Bonsdorff says that the drought weakens the mushroom harvest significantly.
Today warmth in autumn the weather has been enjoyed in Finland for an exceptionally long time. How does the heat affect bird migration, blue-green algae or mushroom harvest?
HS clarified the matter with various experts.
Does the long-lasting heat affect the autumn migration of birds?
“Yes it makes a difference,” says Birdlife Finland’s communications manager Jan Södersved.
According to Södersved, the long heat especially affects the departure of migratory birds in the fall, because the long-distance birds that hug far away have already left.
“For sports that have a long distance, what needs to be done when and where is very carefully ‘budgeted’ throughout the year.”
For example, insectivorous birds are not very affected by whether it is cold or hot, because they leave in the summer anyway.
Instead, the migration of birds that leave in the fall and fly to Europe depends more on the weather. If the wind is from the south and the weather is calm, the birds are waiting for a better migration day. A good moving day is one with a north wind blowing on your neck.
“In a downwind, the distance is covered with much less energy,” says Södersved.
Kurkia will arrive at Sarkkila in Hämeenkyrö in the spring of 2024.
Birds can wait for days or weeks for a suitable moving day. However, if it seems that there is no such thing in sight, they will also leave during bad weather.
Although the heat affects the departure time of the migratory birds, according to Södersved, it does not cause any great harm to the birds.
“It doesn’t really matter whether we come to the wintering areas in October or November.”
Delaying may even be beneficial if conditions are good in the country of departure: the birds leave in better condition.
However, if climate change makes winters milder, it may have wider effects. Species that have not been here before can stay in Finland for the winter. New species come here from the south and species that thrive in the cold have to move further north.
Climate change can also change the nutritional situation of birds. For example, it can happen that during the nesting season of long-distance birds, the nutritional situation is not at its best, but there are fewer insects than before.
Does blue-green algae multiply in warm weather?
“Yes, it can prolong the bloom time of blue-green algae,” says a specialist researcher at the Finnish Environment Institute Kristina Vuorio.
Growth is faster in warm water than in cold water. However, in addition to heat, blue-green algae also need nutrients to reproduce, so they are not agitated by heat alone.
Algae have the best chances to multiply if there are nutrients in the bottom that the wind mixes with the water for the algae to use, or if they are added to the watercourse from catchment areas.
If the sea stays warmer longer and the rains bring nutrients from land areas or the right kind of winds mix the water, algae can be present well into autumn.
Mountain it is too early to say how global warming will affect the increase in blue-green algae blooms, because there haven’t been many warm autumns yet.
“In lakes with scarce nutrients, warming hardly has that much effect if they don’t have blue-green algae blooms even in warm summer times.”
For example, blue-green algae blooms can be prolonged in the coastal areas of the Baltic Sea. If the sea stays warmer longer and the rains bring nutrients from land areas or the right kind of winds mix the water, algae can be present well into autumn.
“They can even be under the ice. When there was no snow in 2020, the satellite observed blue-green algae blooms under the ice of Lappajärvi in February,” says Vuo
rio.
Do mushrooms suffer when there is no water?
“Yes the mushrooms go into a rickety state very quickly, and no new ones grow, says the conservation planner of the Natural History Museum, biologist Tea von Bonsdorff.
Von Bonsdorff thinks that the season of tatt will be bad if it doesn’t rain soon.
“I’ve never been in sandals in a mushroom forest in September before.”
However, mushrooms are tough and can withstand temperature changes quite well. If it rains, new mushrooms will grow like in the rain.
If drought becomes a more permanent condition due to climate change, the consequences will be more serious. Fungi work in symbiosis with trees, and neither will do well if the other suffers.
Keltavahvero or chanterelle in Söderkulla in Sipoo on July 20, 2024.
It it is known that when the spring drought has killed spruce trees in southern Finland, mushrooms also suffer.
“It is interesting to see how the preferential growth periods change. Do the spring species start growing in June or are they even able to postpone their typical growth period,” says von Bonsdorff.
Shifts in the growing season have already been seen, for example observations of chanterelles have been made even in February. If the vegetation around the mushrooms changes, it is also a threat to the mushrooms.
“What really happens in the long term is practically still a mystery.”
#Weather #warm #autumn #weather #affect #migratory #birds #cyanobacteria #fungi
