biologe

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

Tag: nature

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

 

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

Isopoda: locomotion and aggregation behavior

Isopods represent Arthropoda. But they are no insects, no arachnids and no myriapods, although the glomerids or pill-millipedes can have a similar shape. Isopods are indeed crustaceans.  And the shape of pill-millipedes is a result of independent evolution (convergent evolution).

Isopoda represent a clade of the Malacostraca, whose members are originally native to aquatic habitats. Also isopods from the phylogenetic point of view represent aquatic/ marine organisms. But one clade, the Oniscidea, also named terrestrial isopods, evolved mechanisms to survive ashore.

The footage shows a species of Oniscidea of genus Porcellio from mediterranean habitats in Croatia. Land isopods retained their gills and thus usually prefer moist habitats. My model-isopods are reared in a terrarium, were they use to aggregate under moist pieces of bark.

As most terrestrial isopods, they are destruents and feed on decaying organic material. I add regularly pieces of fruits or vegetables and thus create conditions comparable with compost. Most of my footage is presented in slow motion.

I thank Jana Bedek, Croatian Biospeleological Society, for her determination of the isopods on a genus level.

Copyrights: Stefan F. Wirth, Berlin May 2017/ November 2018

Orange tip butterfly Anthocharis cardamines

Anthocharis cardamines is a butterfly species, belonging to the big taxon Pieridae. Members of this group with about 1100 species worldwide are typically characterized by a more or less white color. There is even evidence that the popular term „butterfly“ refers to a pierid species, namely the brimstone, Gonepteryx rhamni, which British researchers considered as looking like a butter-colored fly.

The video introduces some morphological characters of a male specimen of Anthocharis cardamines. In this gender the most conspicuous character concerns the orange colored tip on the insides of both wings. That color character represents a sexual dimorphism, as female wings are completely white.

The quite common butterfly is distributed in Europe and temparate Asian zones. Interestingly adult A. cardamines strictly prefer specific habitats, which differ in males and females. While males inhabit the edge areas of forests close to adjacent meadows, females prefer the open meadows. Both genders fly only in a bright sunlight and strictly avoid the shadow, even then, when a suitable host plant for the egg deposition grows in a shady environment. Females select their mating partners using pheromones, which either attract or reject a male. Mated females in order of their egg deposition will always reject male approaches.

Other female pheromones are used as markers to characterize a host plant as already containing eggs. This will prevent a new egg deposition by another female specimen, which happens to improve a positive breeding success, as caterpillars show a cannibalistic behavior against other eggs. Host specificy, mating behaviors and reproductiion are result of evolution.

 

Berlin May/November 2018. Copyrights Stefan F. Wirth