biologe

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

Tag: June 2019

Countryside of Berlin: urban green in a drone view (4K)

Many tourists from overseas use to visit European cities in a much too short time. For this reason they often miss an entire picture of for example the city Berlin, when inserting an only short interstop here. Especially winter tourists can experience the German capital as a sad a grey urban being with some architectural major sites and a remarkable party life only.

 

Climate and landscape types in Berlin

 

Berlin has a continental climate and shows a completely other face in summer. It’s a very green face. Not only is the center of the city then colorfully greened by numerous urban parks, which partly lay almost adjacent to each other, but also the outskirts, in major parts covered by forests and grasslands or fields, appear like green oases.

 

 

Countryside of Berlin as aerial videography, Copyrights Stefan F. Wirth, Berlin June 2019. Please give my video on youtube a like, in case you like it.

 

 

Lübarser Felder and surrounding

 

Lübarser Felder is an area of agriculture, being under the management of inhabitants of the adjacent village Lübars, which represents the only Berlin village that still practices agriculture. The village has a long history and still has architectural monuments, dating back to the 19th century. Lübarser Felder lay adjacent to a nature refuge area more in the north, consisting of different kinds of wetlands, such as bog meadows or lowland fens. Lake Köppcensee as part of that nature refuge area is visible from a bigger distance in one scene of my video.

 

Püttberge and surrounding

 

The sanddune-mounts Püttberge are located in the east of Berlin and belong to the nature refuge area Wilhelmshagen-Woltersdorfer Dünenzug. The area consists of sandy mounts, some of them reaching a height of up to 68 meters. They are part of the glacial valley of Berlin, which dates back to the Weichselian glaciation, which happend between 115,000 and 11,700 years ago and covered almost the whole Northern Europe. The dune elevations of Püttberge were formed due to windblown sand inside the glacial valley. My footage shows the Wilhelmshagen-Woltersdorfer Dünenzug in a greater distance seen from the edge of the whole area. Ecologically the Püttberge are characterized by numerous plants and animals, being typical for sanddune environments.

 

Lieper Bucht at river Havel

 

Lieper Bucht is a bathing beach area at river Havel, belonging to the Berlin city district Nikolassee in the South-West of Berlin. The adjacent forest area is the huge urban forest Grunewald. The riverside of Havel in Berlin is geologically charactrized as sandy with a tendency to the formation of dunes, being like Püttberge a relict of the Weichselian glaciation. Flora and fauna are correspondingly composed. Pine trees for example are typical representatives. The nearby Havel islands Lindwerder and Schwanenwerder are visibe in my footage.

 

Berlin, June 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