Berlin is an unusually green metropolis. Besides numerous urban park landscapes and the huge forest area Grunewald, there is a unique countryside north of Berlin, including the area of the old village Lübars, being surrounded by numerous fields (Lübarser Felder) and a stream pasture landscape, named Tegeler Fließ, with bog meadows.
Nature sites Lübarser Felder, Arkenberge, Schönerlinder Teiche in 4K, copyrights Stefan F. Wirth. Please also like my video on Youtube.
Mounts Arkenberge and pondlandscape Schönerlinder Teiche
In the northeast, around the urban village Blankenfelde, the currently highest elevation of Berlin can be found, the Arkenberge. Originally, they represented a chain of smaller mounts as natural remnants of the Weichselian glacier. One of these mounts is especially conspicuous and is acually prepared to become accessible for people and forms with a height of 122 m over NHN the highest mountain of Berlin. It represents despite of its natural origin a rubble landfill site, which was formed beginning in 1984.
Adjacent to the Arkenberge, several wetland areas attract nature enthusiasts for hiking tours: the pond landscape „Schönerlinder Teiche“ (Brandenburg) and the lake Kiessee Arkenberge.
Lowland area of the stream Tegeler Fließ as remnants of the Weichselian glacier and adjacent calcareous tufa area
The stream Tegeler Fließ is a wetland nature site with a high biodiversity of plants and animals. It is surrounded by different types of bog meadows. The Tegeler Fließ lowland is also a result of the last glacier period.
The stream lowland is additionally adjacent to a calcareous tufa area, which is well visible from top of the Arkenberge. Calcareous springs and calcareous tufas created here calcareous rush- marshes with an interesting biodiversity of for example species of mosses and snails.
The city of Berlin geomorphologically consists of witnesses of the Weichselian glacier. The modern city itself and adjacent federal states represented end moraine areas with fluvio-glacial debris accumulations, even well visible today due to a very sandy soil composition and a corresponding vegetation, creating landscapes, which partly almost look like from around the Mediterranean Sea.
Sands carried by the glaciers towards their end positions remained in partly huge layers with a thickness of up to 20 meters or more.
Gravelpit zone and its history
Also the area of the old gravelpit zone, called „Sandgrube im Jagen 86“, in the Berlin forest Grunewald is located inside such an end moraine zone, which was represented by plates belonging to the geological Teltow-plateau. In the time period between 1966 and 1983, gravel was excavated for industrial purposes. After 1983 a part renaturation was supported by nature conservationists. In 1992 in total 13 hectares of the former gravelpit area were allocated as nature conservation areas.
Other parts of this unique landscape remained accessible for the public. They represent today popular places for leisure and experiences of nature. Especially the huge sand dune is a popular destination for families with children.
Aerial videography of the gravelpit area in January 2019, copyrights Stefan F. Wirth. Please like my video also on Youtube, in case you like it.
Gravelpit zone and its ecology and biodiversity
The whole area – nature protection and accessible zones – show a complex mosaic of different landscape types, offering numerous animal and plant species a well suitable refuge. Neglected grasslands and dry meadows are surrounded by sandy areas free of any vegetation („dunes“) and moist osier beds and wetlands with ponds. The wetlands represent breeding grounds for numerous amphids. Lizards such as the sand lizard Lacerta agilis and snakes such as the grass snake Natrix natrix can regularly be observed. Sandy habitats offer space and specific ecological conditions for a interstitial fauna, consisting for example of different bee and sand wasp species.
In total the area bears more than 300 ferns and flowering plants, 16 breeding bird species, 7 amphibian species and 188 butterfly species.
My own scientific mite research in the gravelpit area
I was performing scientific research in that gravel pit landscape during the work on my phd-thesis between 2000 and 2005. My interest was (and one of my interests is still) focussed on specific organisms living around the shoreline of ponds.
The whole area of the gravelpit landscape is a good example for ecological changes that happen naturally with the ongoing time or even being affected by climatic changes. Between 2005 and 2018, the landscape partly changed significantly. Neglected grasslands and dry meadows covered less space originally, and instead several smaller ponds existed and offered amphibs and wetland inhabiting insects additional habitats. But some of the ponds already years ago dried out permanently. Their remnants are now covered by extended dry grasslands.
In former times of my phd thesis and even today, my research interests focus and focussed on the mite fauna in and around the muddy shorelines of ponds inside this former gravelpit area. The ponds are mostly surrounded by sapropel, a seemingly black and brownish mud, which is colored that way due to the incorporation metal sulfides. These muddy areas develop due to biochemical modifications of organic material in the absence of oxygen. Different insects, especially beetles live on top of these waterside habitats or even inside. Carabids of genera Elaphrus or Bembidion represent predators, while heterocerid beetles of genus Heterocerus are substrate feeders, presumanly with a preference for diatoms. Also water beetles of Dytiscidae and Hydrophilidae inhabit these habitats.
The mites Histiostoma maritimum and Histiostoma palustre
I discovered some of these beetles as dispersal carriers for specific mites. The dispersal strategy to take a ride on bigger animals to become carried from one habitat to another is called phoresy. Mites of the Astigmata represent typical phoretic organisms. I am scientifically specialized in a specific family of the Astigmata, which is named Histiostomatidae, and I discovered the mite species Histiostoma maritimum Oudemans, 1914 on Heterocerus fenestratus and H. fusculus as well as on Bembidion and Elaphrus species insside and on top of these muddy zones. I was the first acarologist, who ever studied the biology of this mite species. I furthermore discovered another mite species that was completely new to the scientific knowledge, and thus I scientifically described it as Histiostoma palustre („palustris“ = „muddy“) in 2002.
This species deserves particularly mention due to an unusual biological phenomenon: populations show a so called male dimorphism (better diphenism). Besides males with a „normal“ morphology, morphologically modified males appear. Their second legs differ from the typical shape of a mite and are modified into clasping organs. The function of these conspicuous organs could so far only be interpreted in the context of male to male competition conflicts for a female. In such situations, I observed the organs being used as arms against other males, against such ones with and such ones without clasping organs.
Right modified leg of a male of Histiostoma palustre. Copyrights Stefan F. Wirth, 2002/ 2019
Modified leg of a H. palustre male in closed position. Copyrights Stefan F. Wirth, Berlin 2002/ 2019
Underside of a H. palustre male with modified leg. Copyrights Stefan F. Wirth 2002/ 2019
Asymmetry: male of H. palustre with only the right leg modified. Copyrights Stefan F. Wirth 2002/ 2019
Asymmetry: male of H. palustre with only the left leg modified. Copyrights Stefan F. Wirth 2002/ 2019
Copulation of a Histiostoma palustre male with both-sided modified legs. Copyrights Stefan F. Wirth, Berlin 2002/ 2019
Details of a copulation with a modified male, copyrights Stefan F. Wirth, 2002/2019
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.
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.
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.
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.
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.
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).