biologe

Blog and online journal with editorial content about science, art and nature.

Tag: forest

Reawakening at very early spring

Morning mist

Forest in the morning, tree stems covered by a foggy most, borderless steam wraps slowly rising in the air and disappearing there tracelessly.

Forests as moisture reservoir, being released in the morning due to the awakening warmth. Morning mist is nothing else than a fog, only some meters over the ground. Consisting like each fog of numerous water bodies in gas conditions, which condensate due to the cold night and seem to have springled all plants and even insects and other sleeping animals with tiny water drops.

Especially in arid environments, that morning mist watering is most wanted and essential for surviving.

With the rising sun, warmth moves the misty clouds up, where they cover the forests in a mysterious light, before the fog disappears.

Sunlight

Consisting of all rainbow colors, each color of the spectrum being defined by a specific wave length. But sunlight also consists of physical components, particles, called solar wind.
Light as essential source for life on earth, sunlight as energizer, basis for the production of oxygen. Warmer sun beams as reawakener of a sleeping forest.

Blooming

They bloom most early in the year, do not avoid to attract early insects inmidst of snow layers: snowdrops, winter aconites and crocuses.

Snowdrops (genus Galanthus) generate thermal energy due to the absorption of sunlight. This energy is essential for growth processes in cold environments.

Winter aconites (Eranthis hyemalis) have their blossoms only opened in the sunlight. Blossoms are closed over night. Opening and closing are temperature dependent growth processes. The blossoms themselves are resistant against cold. When temperatures rise to 10 – 12 degrees, first honey bee visits can be observed.

In crocuses (genus Crocus) blooming depends on the availability of moisture and warmth. Some species bloom in autumn, others in the late winter period.

All early blooming plants save nutrients as energy resources in tubers or bulbs.

Blue hour

When the sun disappears behind the horizon, an explosion of colors in red or yellowish cover the sky. In fact indicating the end of a day, in some cultures even officially a new day was dawning, when the sun disappeared, such as in Judaism, Islam or ancient Germanic peoples.

Saying „the sun is setting“ is a relict of a geocentric model of perspective. Not the sun is moving, but the observer.

When the sun is far enough underneath the horizon, the blue light spectrum dominates and creates a shiny blue sky, forming a photogenic contrast to the silhouettes of trees and landscape structures.

Moon

The only recent Trabant of our earth, presumably sirvivor of two or even several natural earth satellites in early times of our solar system.

Reflecting sunlight at night, lightening up the sky in the dark. Orientation aid for nocturnal animals, especially insects. Rhythm generator for the reproduction periods of numerous organisms.

The only extraterrestrial body that was so far ever visited by human beings. The first, which might be colonized before Mars.

All copyrights Stefan F. Wirth, Berlin March 2021

The details about snow

Misty

In former times, when people lived in a mystic world, where elves, dwarfs, leprechauns and talking wolves did their dreadful state of affairs in the midst of dark and impenetrable huge forests, people thought that even the old trees in the woods had their own thoughts.

Park Rehberge in Berlin

Uncontrollable, sounds, the snorting of the deer, a mysterious hidden, permanently changing shades in a cold and misty twilight.

Biology

A forest is only then a forest, when a high concentration of trees is given. Woods bear a great number of species, produce a majority of oxygen in our world; they are huge reservoirs of water and stabilize the ground with their tangles of roots.

Snow

Snow consists of ice crystals. Their formation within clouds depends on the presence of ice nucleating particles and temperatures lower – 12°C.

Crystals possess a hexagonal symmetry, being prism-shaped at lower temperatures and dendrite-shaped at higher temperatures.

Temperate deciduous forests hibernate without functional leaves. Most trees throw off all leaves already in autumn to be protected from desiccation in winter frost periods.

Layers of snow are excellent thermal conductors and additionally protect all life underneath from frost damages in the cold season.

Waiting for the spring time

Most life forms hibernate together with their leafless trees. Especially accumulations of deadwood contain remarkable numbers of species, such as insects, spiders, mites or nematodes. Some already begin under their snow cover to prepare themselves for the warmer season.

When all snow is gone, winter colors in red, yellow, brown and some green reappear. Early blossoming plants are already germinating.

Fox and Witch – a fable – Part I

A fable about competition, hate and bullying

Once a fox and a witch had a competition about who of them would be the fastest runner over a distance of thousand meters through the wild forest. The fox won the competition with a big head start, but the witch was fully unwilling to accept this result, complaining she was in a disadvantage, because he was a fox and she a witch, who could fly like a bird, but had only two legs to run. The fox agreed without any opposition. But the witch could never forget her great failure nor could she ever forgive the fox his success.

Only two weeks later, the fox woke up in his earth-hole in a late afternoon. With narrowed eyes he lifted his snout in the air and smelled a hot summer day, knowing that it very soon would find its end, when a black cover of veil would swallow the red-glowing sun. The fragrance of wild roses and even lavender from the garden beyond the rotten big wall twirled with a slight gust around his head. Then the hissing beat of two heron wings, very close to his hole, which slowly disappeared flap by flap in the depth of the big forest with the huge swamplands at its opposite end.

The fox left his day’s lodging, and when he reached the top of the adjacent green hill, the cumbersome whirring of slowly tiring carder bees accentuated the magnificent final act of the passing day like a fainted opera orchestra . The sky pulsed in a deep bloody red, while streaks in purple and orange, billowing around the glowing horizon, were mercilessly drowning the setting sun. The entrance to the forest was close, and the fox already saw the two oaks, which since more than five hundred years guarded the bumpy path into the woods , and heard their continuous quiet creaking in that mild summer breeze.

When the fox was in order to enter the forest, the witch suddenly appeared. „Where are you going to?“ she asked. He answered: “ to the forest, my world, my habitat, the place, where I live.“

The witch laughed and informed him with a nasty laughter that the council of the forest had excluded him from the forest community of the old beech grove behind the green hills. „Excluded? Council?“ the fox responded surprised. „There is no council, the forest is a natural system, all regulation happens by itself.“ The witch, standing in the air and flying with her mysterious black robe, consisting of thousands of tiny black whirlwinds, laughed again, trying to make it sound compassionately: „I founded that council, because new times require new and much more efficient ways of organisation. All forest animals agreed, some of them representing the executive board members. The wise owl is the president, the tiny mushroom man its deputy. Our decision was democratic, not against you personally, it’s all about the safety of our woods. If you wouldn’t be a loner, if you only had a vixen, she would groom you at positions, which you cannot reach by your own, believe me, you miss something. The new pest of ticks in the woods can only be explained with you as their major vector. We reconstructed that very carefully. Different species of ticks, one even imported from Africa, by migrating birds. These bastards are so big. Once one of them followed me in my cottage and attached itself to my left butt cheek. …“. „I never had ticks in my life, never leave the human trails, didn’t you know that the ticks lie in wait in the grasslands and are dispersed by all their different hosts?“

 

IMG_20200612_081640_20200612181911179.jpg

Witch and fox, oilpainting on canvas, Berlin 11 June 2020, copyrights Stefan F. Wirth

 

„My dear friend, oh poor fox, loners never control their parasites, wait…“, and the witch swished down towards the fox’s head, intending to embrace him consolingly, but she flew so fast that her body accidentally overturned. She scraped with her enormous dentition over the fox’s forehead, her incisors densely covered with trumpet lichens, what she thought was the latest craze in fashion, and faster than the blink of an eye her left canine tooth, angular like a lump of rock, reached the Fox’s right ear and cut it off. The fox howled stridently. Instead of his hairy upright earlobe,only a black amorphic hole remained, filled up with viscous whirling blood. His whole body trembled, the control of his legs failed, and he fell to the ground. His voice didn’t want to obey him any more. His eyes stared into an impermeable black haze. „For all the heaven’s ghosts sake, what a mishap, what an incredible misfortune, a tragedy. If only we witches were able to conjure, I would heal you immediately, but we witches can only fly. Oh fox, the next time, when someone approaches you, don’t move unexpectedly, the consequences may harm you forever…“ . And with a short hiss only the witch disappeared without any other word.

Laboriously the fox rose his painful body up again. His brain pulsing excruciatingly with each heart beat. He cumbersomely trotted along the forest path, passing the two old oaks, representing since hundreds of years the entrance to a former oak forest, today consisting of beeches in most parts. The night was dark, only diffuse beams of light went astray in the dense crowns of trees, emitted by the almost full moon , still swallowed by the shades of the forest.

A narrow runlet of blood divided his forehead into two asymmetric parts, dropping rhythmically onto his nasal root, while he noted remarkable changes in the woods, unusual noises, the odor of autumn in the midst of summer, an air humidity like in rotten moors, an oppressive misty wall around him, which he never saw before.

The fox passed the clearing with its fern growth, their leaves drooping as if there was a longer drought, silence. Did all birds oversleep the night? He finally reached the red narrow stream, which he always used to cross by passing the huge fallen birch trunk. But the old deadwood was now decayed into many bulky fragments of wood, scattered around an area of several square meters.

There hadn’t been any unusual weather conditions, no drought, no thunderstorm and no temperature drop in the hours and days before, a steady summer time, only rarely some rain droplets. The birch trunk was still stable and elastic, when he saw it the last night. A miracle that it broke into pieces all of a sudden. Silence, only his fast heartbeat that echoed in his seemingly permanently weight gaining skull cavity. He inhaled a glutinous mass through his nostrils, warm with the smell of iron and perspiration.

The tiny stream purporting to be a rushing torrent, a disturbing costuming, as it had obviously happened with the entire forest, which was absolutely familiar to him until only one day ago, but now had become a strange world, with himself as a stranger in the midst of a trascendent otherworldliness.

The weird impetuous water movements whirled well audibly, at least with his uninjured left ear. A misty twilight hid much more than it revealed. But that ebullient barrier still needed to be crossed. The fox carefully tried to adjust his eyes to the darkness, but with only a very moderate success. In the midst of cumbersome dark shades of an unsettling night, he could recognize the arrangement of all single remains of the trunk.

At first, there were two almost similar shaped and sized pieces of dead wood, aligned offset to one another. Thus the foxes balancing act would begin with the left block of wood, whereby he would need to switch to the right, after having left three-quarters of the first piece behind him. The second birch log staggered in the water flow, but the fox was sure to master this task even despite of his meanwhile very restricted sense of balance. After passing both logs, he would even have the choice between a branch on the right with a medium diameter, not much wider than the fox’s snout, running parallel to a much bigger rounded trunk piece on the right. A clear obstacle course to cross a tiny stream, suddenly disguising itself as kooky torrential river.

Blood slowly dropped into his left eye, deafness of his right ear, and he felt anxious about his general ability to hear even with his left side. No croaking of frogs or toads, no chirping of crickets or cicadas. The water noises in front of him sounded far away. It was still dark, and the fox saw the wobbly single components of his bridge mostly as silhouettes.

But he decided not to lose any more time, the rebellious stream needed to be crossed as it was a firm component of a natural daily routine, an essential component for a successful coping of a fox’s future. A careful first step with his left paw, and he crossed the left log until the end of its third quarter, where he with a fluid movement switched to the right.

In the moment the fox had decided for inexplicable reasons to balance along the standing upright edge of the small branch instead of crossing the much bigger rounded trunk, the moon lost its last cover behind the skeleton of a dead pine and all of a sudden illuminating the entire night sky in its full splendor.

The fox, almost blind with viscous droplets of blood in his eyes, tipped slightly sideways to the left, an almost invisible and very subtle movement, when a thin somehow diffuse, but bright light beam was reflected from the seething water on his right side and disabled the fox’s sight completely for about two seconds. Two seconds with remarkable consequences, because his slight weight shift in combination with unpredictable water movements, his short sightlessness and the wounded ear resulted in a total disruption of his entire equilibrium sense.

As if the branch under his feet had perceived the loss of control of the fox’s body and as if this seemingly dead piece of wood suddenly acquired a spiteful liking for even more instability, it followed the left-side motion of the fox and rolled against the big log, which due to this friction in turn got on motion and turned in a clockwise direction against the adjacent branch.

When the two unequally sized remnants of the dead birch had decided to release a brisk impulse of new signs of life, centrifugal forces threw the fox’s body in the air, from where he roughly landed in a 90 degrees angle to the subjacent branch with his head directed towards the waterside. And his head, unfortunately not lighter than the moving crazy water surface, was submersed, while water immediately invaded all his facial cavities, even washing around his right drumhead, which lacked its external auditory canal almost entirely, a cold pain, which the fox tried to ignore. He only cumbersomely could lift up his head, gasping for breath, when his hind legs, pointing towards the big log, all of a sudden were pulled between the two unequally sized, still incessantly grinding against each other. A clearly audible crackling on both sides, followed by several further grating sounds, made the fox remark the smashing of all his leg bones. At the end, courageous natatory movements with his forelegs released him from this awkward situation. He slowly crawled with all his remaining powers to the opposite stream bank. And there, he rested for a felt eternity, being completely exhausted.

The fox felt no pain any more, but only indescribable weakness. Surrounded by an unreal silence, he licked his wounds.

END OF PART I

Berlin, 10June 2020, copyrights Stefan F. Wirth

Drone flights: Worth seeing nature around the fields of Berlin

The metropolis Berlin is the capital of Germany and much more than that. It represents an unusual green city. When using elevated viewpoints to watch the cityshape, then at least in summer visitors of Berlin can receive the impression of being in the midst of a greening huge landscapes with several villages in between.

 

Green areas in Berlin

 

 

Indeed related to other metropolitan cities of the world, Berlin is still partly not very densely populated and covered by remarkable huge natural countryside instead. The area of landing and runway strips of the former airport Tempelhof for example up to date represents the largest coherent green area inside a city worldwide. The so called Tempelhofer Feld was after the termination of the air traffic exposed to renaturation and is currently a very popular recreational park. It’s located in the South of the city.

Also the West and South-West partly represent nature reserve areas and are covered by the big urban forest Grunewald.

 

Meadows and wetlands in the North of Berlin as nature refuges

 

I am since two years discovering the Northern parts of Berlin, which according to my random observations (in comparison with other Berlin areas, such as Tempehofer Feld, Teufelsberg (Grunewald) and some urban parks in the center of the city; examples of species will be visible on my corresponding blog article) bears the greatest biodiversity in bloom visiting insects.

 

 

 

Mosaic of different landscape types close to each other

 

 

 

 

 

This is seemingly due to the complexity of different meadow-, field-, wetland- and bog-habitats, being originally shaped by the Weichselian-glaciers. I regularly visited the stream valley of the so called Tegeler Fließ with the lake Köppchensee. It’s a hilly area with different gradients of sunny slopes with partly Mediterranean climatic conditions, surrounded by different kinds of wetlands. This area is well known for its great biodiversity.

 

Between the villages Rosenthal, Lübars and Blankenfelde

 

But my drone flights present vast tracts in the South of that stream valley, consisting of fields, green meadows and wetlands. It is the area between the Berlin villages Rosenthal, Lübars and Blankenfelde. Inner urban agriculture is rare in metropolian cities worldwide, in Berlin there is only a small agriculture area in the South (Dahlem Dorf) and the fields between the named villages in the North.

 

Drone flights and bloom visiting insects

 

 

Fields and meadows with adjacent forests and wetlands in the North of Berlin, September 2019, copyrights Stefan F. Wirth. Please give my video also your like on Youtube.

 

Most part of the footage in my film represents the fields adjacent to the village Rosenthal. I newly discovered the partly quite tiny meadows between and adjacent to agricultural fields around Rosenthal this summer and discovered an impressive and steadily visible diversity of bloom visiting insects there. Fields as monoculture habitats usually bear a smaller biodiversity related to wild-growing nature zones. But due to the connection of the edges of fields with complex nature refuge zones around, I could observe a quite great number of species on closely adjacent meadows and even the natural border zones of these agricultural areas.

 

Videographic details

 

The footage was captured in 4K and D-cinelike quality using a Mavic 2 Zoom drone between September and October 2019.

 

 

Berlin, September/ October 2019, copyrights Stefan F. Wirth

 

Mite Histiostoma sp., putatively new species, from mud around ponds (Berlin) and its morphology

Gravel pit area „Im Jagen 86“ in Berlin as biotope

 

„Im Jagen 86“ is a former gravel pit area in the Berlin urban forest Grunewald. It today represents a dynamic biotope, consisting of different types of habitats: mud around ponds, sand dunes, dry grassland and forest. Since the early 2000th, its habitat composition partly changed remarkably. Out of several (smaller) ponds, only one bigger pond remained. All ponds originally were surrounded by sapropel, a habitat for different interesting organisms, such as beetles of Heterocerus, Elaphrus and Bembidion. The mite Histiostoma maritimum was commonly found phoreticaly on Heterocerus and Elaphrus. I additionally in those early 2000th described the new mite Histiostoma palustre from Hydrophilidae of Cercyon and Coelostoma, living inside the saporopel as well. Today only a few small areas with open sapropel exist. I so far did not look for Histiostoma maritimum again and don’t know, how common it still is. At least Heterocerus beetles are harder to find than in earlier years. I so far did not found Histiostoma palustre again.

 

Rearing conditions of a putatively new mite species

 

I collected new mud samples in March 2019 at different areas, but found developing histiostomatid mites in a sample from the edge between mud (sapropel) and mosses. It is a species I never found before there and which might represent a new species. Only females could be morphologically studied. Nymyphal stages (not deutonymphs) are only available as video footage. No males were found. I had added bigger potato pieces to stimulate microorganism growth as mite food into the soil sample (room temperature). After about one month, a few mites (females and proto/tritonymphs) developed on only one of these potato pieces and quickly died out shortly after my filming activities and after I could prepare a few females. I actually try to get them reared again. Due to the low temperatures in March, it is considered that these mites hibernate independently from insects in the substrate. No bigger insects could be found in the substrate, which might be the corresponding carriers. But different dipterans (e.g. Ceratopogonidae) developed, they had no mite deutonymphs after hatching in my sample.

 

 

 

 

Morphological reconstruction of females and important characters as well as behavioral observations

 

The females of Histiostoma sp. differ from other females, which I know, by the mosaic of the following characters: body conspicuously elongated with a distinctly big distance between hind ringorgans and anus, digitus fixus almost simple shaped, fringes or ridges on palparmembrane, 6 dorsal humps, unusually big copulation opening. Leg setation not yet studied. One pair of ventral setae hardly visible (not in the drawing). Nymphs were observed during burrowing activities (footage), females are may be also able to. Deutonymphs or males would be useful to decide, whether the species is new. Some species are only described by deutonymphs.

 

Berlin, March/ June 2019 All copyrights Stefan F. Wirth

Months passing, but where has all the life gone?

I am standing in Berlin. The sky is a grey monotony. And while tiny waves gently wash around the little sandy beaches, tree skeletons surround the hidden bays on the Havel river. A semi-lucid vapor is covering the branchage of leafless treetops, already early in the afternoon. It is December in Berlin. The entire spectrum of bright summer colors is overlaid by muddy shades. Only larger groups of pine trees gleam in a greenish-black out of a giant cemetery of seemingly inanimate bodies of beeches, oaks, birches and maples. The cry of a heron in a far distance, but where has all the colorful and manifold life gone?

T. S. Eliot (1888-1965) wrote („Journey of the Magi“):

„A cold coming we had of it, just the worst time of the year  For a journey, and such a long journey: the ways deep and the weather sharp, The very dead of winter…“

Shakespeare (1564-1616) on Sonnet  97:

„…What freezings have I felt, what dark days seen! What old December’s bareness everywhere!…“

Seeming emptyness of a Forest-waterside landscape in winter, copyrights Stefan F. Wirth, Berlin December 2018. Please like my video also on Youtube, in case you really like it.

 

Bareness, emptyness, death, attributes being combined with winter since mankind exists. From the evolutionary point of view a serious problem that early humans  had to master. The seemingly emptyness was for them a very real lack of sources. They needed to prepare the winter time, food needed to be stored and protecting clothes to be stiched. There was no well organized international trade of goods, no fresh apples and pears in winter, no cheap winter jackets made in China. Winter meant to fear for the basic survival.

Today we live a different life, being independent from the seasons. Life today means for us to fear for the basic survival of our environment. What are the effects of a global climatic change? What the effects of our environmental pollution? What changes are independent from all that and just represent natural processess as they happened again and again since about 470 millions of years, when the first plants appeared on shore?

 

Most life does not disappear in winter, it just hibernates – alive!

 

The Berlin nature refuges around the forest Grunewald-terrain are interesting due to their complex mosaics of different habitats close to each other. Forest Grunewald in Berlin and the sandy beaches and bays along the Havel river offer space for lizards, an interstitial insect fauna, dry grassland visitors such as butterflies, wetland animals like frogs and newts, aquatic inhabitants like river lampreys, numerous bird species and inhabitants of wood in all kinds of decomposition stages such as bark beetles, longhorn beetles or hermit beetles.

 

Migration

 

Some animal inhabitants of the Grunewald/ Havel-area in summer migrate during the winter season, but most species stay. They hibernate and are even now in December still there.

 

Birds

 

Many birds show a strict migration behavior to avoid northern winters, others migrate in greater numbers, while some specimens stay, and some migrate only over smaller distances. Which of those migration behaviors is exactly performed by which bird species might depend on climatic conditions and is object of scientific research. NABU for example regularly starts projects, to which the general public can contribute with own observations. One of them takes place in early January and is named „Stunde der Wintervögel“ („the moment of winter birds“).

Common cranes Grus grus and greylag geese Anser anser normally migrate over bigger distances and numerous bigger routes towards southern winter refuges. Especially cranes are in summer for examples inhabitants of the Havelland Luch, thus prefer areas more western of Berlin. A trend was observed by ornithologists that more and more often, obviously corresponding with a global warming, troops of crane specimens stay instead of migrating southward.

Migration behavior of common cranes and greylag geese in Linum, autumn 2018, copyrights Stefan F. Wirth

Female of the red-backed shrike in Berlin (Köppchensee). The bird is a typical long-distance migrating animal. Copyrights Stefan F. Wirth, 2018

 

Butterflies

 

The red admiral butterfly Vanessa atalanta is known as a migrating insect. The „normal“ case is that migration from Southern Europe towards Central Europe is performed in spring. There, a summer generation develops and in autumn either tries to migrate back southward or to hibernate as adult butterfly, where it hatched, for example in Germany. But specimens mostly do not survive their tries to hibernate during our cold winters. This makes the admiral to a rare example of our summer-fauna, which over here partly indeed dies out before winter begins. The migration routes of populations throughout Europe is still topic of research. The migration behaviors seem to change corresponding to a global warming.

Admiral butterfly in Berlin, copyrights Stefan F. Wirth, 2018

 

River lamprey

 

Also the river lamprey Lampetra fluviatilis obligatory needs migrations over bigger distances. But these migrations do not correspond primarily with our cold seasons, but instead with the complexity of its life cycle. Larvae, which differ morphologically from adults, hatch in our freshwaters and develop as filter feeders within about three years, in which they  hibernate inside their aquatic freshwater habitats. They then migrate after a morphological metamorphosis towards the Sea. There they live as ectoparasites on fishes until they reach sexual maturity and then return into freshwater-rivers to reproduce and finally die. It is still subject of research, whether they return for their reproduction to the areas of their original larval development.

 

Hibernation

 

Sand lizard

 

The sand lizard Lacerta agilis  hibernates in hideaways, which are able to hold a temperature around 5°C. There they fall into winter numbness due to their unability to regulate their body temperature independently from the environment. Juveniles and adult genders start their hibernations  at different times.

Sand lizard juvenile, found in Berlin Grunewald/ Teufelsberg, copyrights Stefan F. Wirth

 

Frogs

 

Toads and frogs hibernate after finishing their metamorphosis, juvenile and mature specimens spent a diapause as a total numbness such as in lizards. Amphibians and lizards are poikilotherm, thus their body temperature corresponds to their environment (some monitor lizards Varanus were found to have physiological abilities for a limited self regulation of their temperature, which is an exception within the taxon big Squamata).

Marsh frog Pelophylax ridibundus, pool frog Pelophylax lessonae and edible frog Pelophylax kl. esculentus survive the cold season in hideaways, which maintain acceptable environmental temperatures. While pool and edible frog hibernate on land, the marsh frog spends its diapause in aquatic habitats. Skin respiration then plays an even more imortant role, which is why these frogs require a high availability of oxygene. The edible frog is even from the evolutionary point of interest, as it represents a hybride between two closely related species, namely marsh and pool frog. It is in many of its populations non reproductive with other hybrides and needs one of the parental species to reproduce. But interestingly triploid specimens of the edible frog sometimes develop in populations and bear the complete genomic information of one of the parental species. These edible frogs can reproduce with other hybrides They can be found throughout Berlin. Such specimens are difficult to be determined morphologically, as they resemble in their outer appearance either to the marsh or the pool frog.

 

Sand wasps

 

Insects hibernate in different developmental instars, if holometabolic, egg, larva, pupa and adults are options, if hemimetabilic eggs, nymphs or adults perform the winter diapause. Some insects can even hibernate in all of their developmental instars.

The quite common red-banded sand wasp Ammophila sabulosa for example is part of the insect interstitial fauna and does not practise brood care, but maternal care. Females built up several single nests up to 20 centimeters into the soil, each of them containing only one cell for the deposition of always one egg. As food supply they hunt caterpillars preferrably of Noctuidae, stun them with a sting and carry them to their nests, which will be closed with soil particles afterwards. The last brood hibernates as pupa or larva inside the nest.

Sand wasp Ammophila sabulosa in Berlin, copyrights Stefan F. Wirth, 2018

 

 

Grasshoppers

 

The grasshopper Sphingonotus caerulans is a thermophilic species, which is a typical inhabitant of sandy areas in Southern Europe. It also appears in Berlin. Its eggs are deposited into deeper soil layers and hibernate there.

Grasshopper Sphingonotus caerulans, male, found in Berlin (Köppchensee). Copyrights Stefan F. Wirth, 2018

 

terrestrial Isopods

 

The common woodlouse Oniscus asellus for example hibernates as nymph or mature adult in hideaways inside deeper soil layers, dead wood or compost. These terrestrial curustaceans become inactive, when colder temperatures appear. Specimens can live over several years (usually about two years).

An example for a woodlouse, in this case a mediterranean species of genus Porcellio, copyrights Stefan F. Wirth, 2018

 

Hibernating animal communities

 

Communities of different animal species often hibernate altogether. I focus here on inhabitants of micro habitats. Especially long living insect nests can bear greater numbers of cohabitants. But also deadwood or compost bear many different animal species side by side.

 

Ant nests

 

Nests of the red wood ant Formica rufa represent complex animal communities, as it is typical for ant nests generally. Besides ants and their brood noumerous nematode and mite species inhabit nest mounts of F. rufa. Additionally different larvae of other insect taxa can be members of the ant community, I even discovered the larvae of the green rose chafer sometimes inside red wood ant nests in the area of the Berlin forest Grunewald. Also several species of pseudoscorpions are known to science to be adapted for a survival in nests of F. rufa in Europe: commonly found are for example the species Allochernes wideri and Pselaphochernes scorpioides. Pseudoscorpion species of genus Allochernes are known to practice a dispersal strategy named phoresy. They use bigger and better motile insects as carriers and that way are transferred to new habitats. Besides ants, their suitable phoretic carriers seem to be dipterans. Also different mite and nematode taxa inside nests of the wood ant perform phoresy. A mite example is the species Histiostoma myrmicarum (Acariformes, Histiostomatidae), which seems to be carried by ants and eventually additionally also by other arthropodes.

The larva of the green rose chafer inside a nest of Formica rufa, copyrights Stefan F. Wirth, 2011

Mite Histiostoma myrmicarum (Astigmata) collected from its hibernation habitat in the soil underneath an old oak in Berlin forest Grunewald, copyrights Stefan F. Wirth, 2018

 

Formica rufa itself hibernates inside its nest in absence of eggs, larvae or pupae. Only the queen and workers remain during the cold season. Not much is known about other nest inhabitants. More research is needed.

Typical ant cohabitants (with Formica rufa) do not necessarily need to hibernate inside their ant nests. I collected deutonymphs of the mite Histiostoma myrmicarum in winter 2017/18 from soil (some centimeters deep) underneath an old oak in the absence of ants and their nest. The well scleotized deutonymph (phoretic dispersal juvenile stage) might represent the hibernation stage.

The advantage for organisms, living in ant nests, is a higher and constant temperature due to the ant worker’s nest-care-activities. Additionally the defensive behaviors of ants offer protection for those organisms being adapted (based on evolution) to survive inside ant nests.

Due to suitable temperatures, many organisms inside nests of the red wood ant might stay even active in winter. Interactions between ant nest-cohabitants can be very complex. An example is the Alcon large blue butterfly Phengaris alcon, being adapted to other ant species: Myrmica rudinodis and M. rubra. The caterpillar resembles an ant worker due to the morphology of its cuticle and the production of ant-similar pheromones. Ant workers fail for this imitation, carry the caterpillar into their nests and feed it. The butterfly’s larva hibernates inside the ant nest as larva, molts into pupa in the subsequent spring season and finally leaves the nest as adult butterfly. Still inside the ant nest, the caterpillar can become a victim of the parasitic wasp Ichneumon eumerus. Its female invades the ant nest, only after recognizing that caterpillars of the blue butterfly are indeed inside. It then confuses the antworkers due to the release of different chemicals and then attaches its eggs to the caterpillar. The wasp’s larva hibernates there and molts into its pupa inside the host’s pupa. The adult wasp afterwards leaves the ant nest.

Phoretic mites of the taxon Astigmata inside a nest of Myrmica rudinodis, found on island Usedom, copyrights Stefan F. Wirth

 

Bark beetle galleries

 

Numerous mite and nematode species live inside the galleries of bark beetles. Such a complex fauna is known for many bark beetle species. Additionally the larvae of different other insects can be cohabitants. Depending on the species, they can perform all kinds of life-strategies: being predators of adult bark beetles or their offspring or of other gallery cohabitants, they can also be microorganism feeders and prefer the bark beetle galleries due to its ideal warmth-isolation or due to the specific micro-climate that is created there by the activities of all different inhabitant activities. Besides animals, also fungi and bacteria contribute to that climate.

Bark beetle Hylurgops ligniperda and phoretic mites, copyrights Stefan F. Wirth, 2016

Wood associated nematode Diplogaster sp. found in the tree fungus Laetiporus sulphureus in Berlin, copyrights Stefan F. Wirth, 2016

Mite deutonymphs of the Histiostomatidae mites inside the galleries of the bark beetle Tomicus destruens in Italy, Vesuvio National Forest, copyrights Stefan F. Wirth, 2016

Bark beetle Ips typographus with some of its gallery-cohabitants, such as phoretic mites, found in SW-Germany (Saarland), copyrights Stefan F. Wirth, 2015

 

Furthermore the composition of species in a bark beetle gallery changes with an increasing age of a gallery. Secondary infections are often performed by other wood parasiting beetles, after the bark beetle brood finished its development and left the gallery. A secondary parasitism can for example be performed by longhorned beetles.

The bark beetle Dendroctonus micans for example infests several conifer species: Picea, Abies, Larix and Pinus. This bark beetle can hibernate in all its instars: eggs, larvae or adults. Adults can in spring sometimes be found in specific hibernation-chambers. In a research project with russian collegues, I isolated beetles of that species in the early spring season in Siberia (Russia) out of such a chamber on Pinus silvestris. Adjacent to attached substrate particles, I found nymphal stages of the phoretic mite Bonomoia opuniae, a species of the Histiostomatidae (Astigmata), which was even new to science at that time. I described this species, which I so far only know from those siberian samples. It is still unknown, whether it also appears in Central Europe.

The nymphal stages (protonymphs and tritonymphs) of that mite species might represent the hibernating instars. They were not fallen into a numbness after the collection and even remained active in a refrigerator, where my samples were stored subsequently for a while. I doubt that the mite in winter can pass through different generations as it would happen in a warmer climate, because the found mite nymphs appeared -also active- still rather weak in their cold environment. Thus I assume these nymphs to hibernate throughout the winter season. But there is still much research missing about the ecology/biology of bark inhabiting mites.

Adult beetles of Dendroctonus micans with deutonymphs of Bonomoia sibirica, Tyumen/ Siberia, copyrights Stefan F. Wirth, 2017

 

 

Berlin, December 2018. Copyrights Stefan F. Wirth

 

 

 

 

 

Berlin Forest Grunewald and River Havel-Waterside

River Havel

 

The river Havel has its source in the Mecklenburg Lake Plateau and after 94 km flows in the area of the border between the federal states Brandenburg and Sachsen-Anhalt into the big river Elbe.

Havel runs besides the already mentioned states Brandenburg and Sachsen-Anhalt also through Berlin, the capital city of Germany. On its way, the river passes several bigger and smaller lakes, which serve as water reservoirs, even in hot summers, in which many german rivers and lakes from low water levels.

In its most parts, Havel is navigable, and weirs and locks regulate water levels and water supply.

Historically, Havel since at least 928 of our Western calculation played importent roles as natural border and water route. Through the middle ages up to times of the GDR wetlands as important ecosystems were stepwise drained. In more recent times the protection of unique nature refuges is proceeding. In 2004 for example, the Naturfreunde Deutschlands and the German Fishing Federation elected the Havel area as River Landscape of the year.

In 2005 the Federal Agency for Nature Conservation (BfN) and the Nature Biodiversity Conservation Union (NABU began the land restoration to create refuges for rare bird species , beaver, river lamprey, otters and other animals and plants.

The footage of my video was captured close to the bathing beach area „Lieper Bucht“. Visible are the Havel islands Lindwerder and Schwanenwerder as well as edges of the forest area „Düppeler Forst“.

River Havel and Forest Grunewald in Berlin, quadcopter footage. Copyrights Stefan F. Wirth, December 2018. Please like my video also on youtube, in case you like it.

 

Forest Grunewald

 

Adjacent to the Lieper-Bucht area, the huge urban forest Grunewald extends over 3000 hectare between the Berlin districts Charlottenburg and Zehlendorf.

It was elected as Forest Area of the Year by the Union of German Foresters in 2015. The Grunewald ecologically has a specific mosaic of ecosystems: heathlands, neglected grasslands, dunes, dandpits and marshlands. They all bear a remarkable biodiversity of rare animal and plant species.

Geomorphologically the Grunewald area was formed by galcio-fluvial processess during the Weichselian glaciation , which endet about 11600 years ago. Glacio-fluvial sands cobver the area in layers up to 20 meters and more.

The footage of my video also shows the so called Grunewald Tower. The memorial for the German Emperor  William I was planned in 1897 and finally built up by the architect Franz Schechten. The tower was finally inaugurated in 1899 and renovated between 2007 and 2011.

The footage was captured with a DJI Mavic pro quadcopter in mid December 2018.

 

 

Berlin, December 2018. Copyrights Stefan F. Wirth

Lake Teufelssee in Berlin as part of a glacial meltwater lead

Lake Teufelssee in the Berlin urban forest Grunewald is known since ancient times, but is even much older. This is unlike the adjacent hilly landscape, which is named Teufelsberg („Devil’s Mountain““, referring to the nearby lake). It represents an area of mounds of rubble, built up with debris of the destroyed Berlin after the Second World War. Teufelssee („Devil’s Lake“) however is part of a glacial chains of lakes, a result of a supraglacial stream from the period of the Weichselian glaciation.

Air-view footage of lake Teufelssee in Berlin. Copyrights Stefan F. Wirth, please like my video also on youtube,in case you like it.

 

Geomorphology of Berlin, lake Teufelssee and glaciofluvial sands

 

Berlin itself represents geomorphologically a push morain from the Weichselian glacier times (until 11.600 years ago). This until today explains the uniform and scarce vegetation in and around Berlin, which is due to specifically sandy ground conditions. Sand layers with a thickness of at least 20 m date back to glaciofluvial sands, being a result of the advance of a glacial tongue.

 

Vegetation and climatic zone

 

The stock of trees in the Grunewald area is dominated by oaks and pines, being well adapted to this ground composition and the Berlin geomorphology. The climate of the Berlin area is characterized as part of the temperate climate zone in the transition between maritime and continental climate. Aspects of the continental climate are predominant, which is why snowy winters as typical for the Southern parts of Germany are rare.

Instead winters are often very cold and with low precipitation unlike the hot summers, where most rainfall occurs. The winter 2018 to 2019 is following an unusually warm summer with long periods of heat and without rainfall. As a result, water bodies Germany-wide carried less water than usually. But in which intensity lake Teufelssee was or is still concerned is unknown to me. Differences to former years are not obviously visible.

 

Berlin recreation areas and the ancient origin of the term „devil“

 

Teufelssee and Teufelsberg represent local recreation areas and offer enthusiasts and families with children a popular playground in summer, and in case the lake is frozen, also in winter.

The appearance of the German word for „devil“ in Teufelssee and Teufelsberg is assumed to refer to an ancient place of worship in this area.

 

Copyrights Stefan F. Wirth, Berlin December 2018

What happens with our trees in Winter? A forest area of the naturerefuge Teufelsberg Berlin in air-view

The Berlin forest Grunewald in winter, shown from the area of the urban nature refuge Teufelsberg. The colors, brownish and grey with a little bit of green, dominate the winter landscape. This has biological reasons: Trees of a forest drop their leaves during the autumn-period. This happens in order to reduce water loss due to evaporation. Before they fall, leaves change their colors, sometimes into powerful red or yellow forms.

https://www.instagram.com/p/Bq9z41zFlvP/

Why do trees drop their leaves?

 

Chemically, the plant modifies chlorophyll into colorless components. Proteins (result of photosynthesis) out of these chlorophylls are resorbed by the plant (tree) in order to save nutrients for the cold season. Carotinoids then retain inside the leaves and appear in red or yellow shades. In winter, most trees are completely leafless and remind to skeletons, waiting for the next warm period.

Leafless trees in winter at nature refuge area Teufelsberg in Berlin, copyrights Stefan F. Wirth. Please like my videos also on youtube, in case you like them.

 

The Teufelsberg area in Berlin, a nature and  sports refuge

 

The Teufelsberg represents the second biggest mountain inside Berlin/Germany. It consists of rubble from the Second World War and extends about 80 m out of the plain around. It is named after a lake, which is located very nearby: the Teufelssee. The Teufelsberg is part of the „Grunewald“, an urban forest in the west of Berlin. Since 1950 the area was filled up with rubble from the city of Berlin, which was almost completely bombed down during the second World War.

Until 1972 about a third of all rubble from bombed buildings in Berlin were transported to the top of this mountain. After 1970 finally, the Teufelsberg was formed into a nature and free time area. Skiing and mountainbiking for example were enabled.

https://www.instagram.com/p/BrMY_BdFlgF/

Kites, US-listening-station and drone footage

 

Today, also during the summer, people use the winds on the top of the mountain to fly kites. Since the late 1950s during the Cold War a listening station was built close to the Teufelsberg, which still exists as a ruin. The footage was captured with a drone (Dji Mavic Pro).

https://www.instagram.com/p/BrE-c04lAnl/

 

Copyrights Stefan F. Wirth, Berlin December 2018.