In northern Germany some plants are flowering much earlier than usual. This has serious impacts on the finely tuned ecosystems, because insects may miss flowering. These species have to adapt or they'll die out.
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The field of phenology involves the study of recurrent natural events in relation to seasonal changes. The phenological calendar divides the year into 10 seasons, each of them beginning with a biological state of a specific plant. The calendar starts with hazelnut blossoms and ends with larch trees shedding their needles.
But there's been a shift in the phenological seasons — as is evident from a comparison of data from today and the period 1961 through 1991. Instead of on March 3, spring now dawns more than two weeks earlier, on February 14, which at the same time makes winters shorter.
And that shift is a consequence of climate change. Apple-trees starting to blossom — another typical indicator of spring — has moved forward in Germany by 10 days over the last 50 years. And there have been similar changes in the animal world too.
Short-distance migratory birds and those that hibernate, such as tits, now start reproducing about two weeks earlier. And at this point, potential breeding site rivals — long-distance migrants like pied flycatchers and red-starts — have yet to return from Africa. The timing of their migration is genetically programmed and based on the length of days.
The incredible journeys of migratory animals
From the Arctic to the Serengeti, whales, butterflies and other animals on the move make some extraordinary journeys. They mainly travel for food or sex, but some even set off in search of exfoliating skin treatments.
Image: picture-alliance/blickwinkel/McPHOTO/E. u. H. Pum
Pole to pole
It isn't unusual for animals to migrate to avoid harsh winters, but the sun-seeking Arctic tern takes this strategy to extremes. The small seabird flies between the Arctic and Antarctic to take in two summers each year and more daylight hours than any other animal. Making a round trip of 35,000 kilometers (21,748 miles), the tern breaks all records for migratory distances traveled.
Image: picture-alliance/blickwinkel/McPHOTO/E. u. H. Pum
Uphill struggle
If the tern takes prize for distance, the salmon surely deserves special commendation for effort. Hatching in rivers, they swim downstream to spend most of their lives at sea. But the hard work comes as they battle against the current and leap up waterfalls to make it home. If this wasn't struggle enough, hungry bears, eagles and people lie in wait for the exhausted fish as they near their goal.
Image: Imago/ZUMA Press/J. Mather
Midnight wanderers
By day, straw colored fruit bats hang from Africa's city trees like assemblages of broken umbrellas. But at twilight, they take gracefully to the air, traveling up to 180 kilometers before dawn and dispersing seeds and pollen as they feed. They span even greater distances by season, and in colossal numbers. Each fall, around 10 million of these "megabats" arrive in Zambia's Kasanka National Park.
Image: imageBROKER/picture-alliance
Spa break
Many whales hunt in polar regions but can travel 18,000 kilometers each year to enjoy warmer waters. Scientists had assumed they prefer to give birth in the tropics. But new research suggests they might be migrating for the sake of their skin. Whales need to molt, and in icy waters where their blood supply is drawn away from the skin, dead cells build up and put them at risk of infection.
It's hard to imagine a creature as tiny and fragile as a butterfly undertaking epic migratory journeys. And yet, surfing air currents, the monarch butterfly can travel up to 3,000 kilometers. In summer, they're at home in northern regions of the US, but when temperatures fall, they head south to California or Mexico to overwinter. Roosting together in large numbers helps them keep warm all year.
Image: M. Watson/picture-alliance/Mary Evans Picture Library
Third eye
Leatherback turtles travel up to 10,000 kilometers, from Canada to the Caribbean and Alaska to Indonesia. No one knows how they find their way from feeding grounds rich in their favorite foods like jellyfish to the beaches where they breed. But scientists believe a spot on top of the animal's head may allow light to reach its pineal gland, triggering its journey at the right moment of the year.
Image: Imago/Nature Picture Library
Following the herd
The mass movement of wildebeest across the African plains is perhaps the planet's greatest migration spectacle. With no real beginning or end, their circular route takes 1.5 million wildebeest, and a good number of zebras, gazelles and other grazers, through the Serengeti-Mara — crossing crocodile-infested rivers and dodging lions and packs of painted wolves —- in search of fresh food and water.
Image: S. Meyers/picture-alliance/blickwinkel
Slow food
Famous for their parental devotion, emperor penguins lay their eggs a good 100 kilometers from the Antarctic ocean where they feed. Mother and father must take turns to travel across the ice, fill up on fish, and make the long shuffle back to regurgitate it for their young. Their partner, meanwhile, goes hungry for weeks to shield the chick from cold that would otherwise kill it in minutes.
Image: Raimund Linke/picture-alliance/Zoonar
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The winners and losers of 'season creep'
There are winners and losers. The earlier arrival of spring is called "season creep" and has an effect on reproductive cycles, feeding relationships and competitive systems. Less exposure to light is bad news for plants.
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Ecosystems are sensitive by nature, and interactions between plants and animals are finely tuned affairs. Their life cycles are like interlocking gears, where one partner engaging too late or too soon can disrupt these fragile systems.
The advent of spring sees flowering plants pollinated by insects and then blossoming. Insects become more active as temperatures rise. Plants, on the other hand, take their cues to sprout from other signals, such as soil humidity and longer days.
Sometimes, insects might not be out and about while the plants are in blossom. And as they miss each other, the former are denied food and the latter their pollinators.
The phenomenon has yet to be thoroughly researched. But what is already clear is that extreme weather conditions in the wake of climate change increase the likelihood of a plant-pollinator mismatch.
Where have all the butterflies gone?
Everyone likes butterflies. They're beautiful and they don't sting or bite us. But these colorful insects have seen a dramatic decline in the past few decades. And the reason why is even more alarming.
Image: picture-alliance/dpa/T. Schmitt
Delicate creatures
Across the globe, butterflies are under threat. According to the German Wild Animal Foundation, the number of butterfly and moth species present in Germany has halved over the last 30 years. For diurnal butterflies, that decline is nearer 70 percent. This photo shows Colias hyale, which was selected as Germany's "butterfly of the year" in 2017.
Image: picture alliance /Nothegger, A./WILDLIFE
Sweet juice
Butterflies adore the sweet sap from flowers and blossoms, and enjoy a broad palate. But plant diversity is dwindling, particularly in regions where intensive monoculture agriculture dominates, which leaves little choice for our beloved butterflies.
Image: picture-alliance/dpa/R. Weihrauch
Butterflies don't like pesticides
Crop protection products like herbicides and pesticides destroy biodiversity. Wild herbs, plants or flowers can't survive in areas with monoculture farming. In many parts of Germany, the scarce Swallowtail butterfly pictured here was once a common sight, but has now vanished from the landscape.
Image: picture alliance/blickwinkel/S. Ott
Insects are dying off
The big problem is that pesticides aren't only harming butterflies. Studies show that some regions have seen 80 percent decline in insect numbers compared to 30 years before. Bees, bumblebees, dragonflies, wasps, flies, bugs and butterflies - they all struggle to survive in our intensive-agricultural world of pesticides and fertilizers.
Image: picture-alliance/K. Nowottnick
Not enough to eat
A recent study shows that bird numbers are also in a decline. One reason: They can't find enough insects for food. The population of northern lapwings in Germany, for example, is estimated to have shrunk by 80 percent between 1990 and 2013. The number of whinchats has dwindled by 63 percent and black-tailed godwits by 61 Prozent.
Astonishingly, the butterfly decline is particularly obvious in the countryside. In towns and cities butterflies are more numerous. They thrive in parks, on cemeteries, on uncultivated land but even in city centers. Here, they obviously find the plant diversity which they miss in the countryside.
Image: picture-alliance/Arco Images/L. Werle
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Butterflies and other species at risk
Among the species at acute risk are specialists like the scarce large blue butterfly (Phengaris teleius). To produce young, it's dependent on its sole host plant — the "great burnet" — blossoming at the same time that it lays its eggs.
The butterfly is one of around one million species under threat from climate change, roughly one in three species of plants and animals. And those reliant on their own little niche are especially vulnerable.
And the disappearance of species means that ecosystems start to break down. They come under increasing pressure and face a growing struggle to recover from extreme weather events. And that in turn fuels the extinction of further species.
Their demise also means the loss of functions that are crucial for humans. Many of the crops we grow, eat or feed to livestock need animals to help generate seeds and fruit. So, while earlier springs at first sight seem like something to welcome, they mean excessive stress for nature and, for a lot of ecosystems, a major threat.
