The description of the species-rich flora and fauna of the Tiefwerder Wiesen refers to the population of the 2000s.
Plants and plant communities Sedge reeds and reeds The flooded tall
sedge meadows that long dominated the Tiefwerder Wiesen are declining due to increasingly infrequent
flooding. However, the riparian sedge, growing up to two meters tall, can still be found along the water bodies' edges. Instead, the wet meadow areas and fallows are now characterized by slender sedge meadows from the sedge genus. The main plant in this community is the
slender sedge, a
perennial,
herbaceous plant that can reach heights between 30 and 150 cm. In the siltation areas, it is joined by the
bladder sedge, which is endangered in Berlin and occasionally forms a hybrid with the slender sedge. The slender sedge reed has a long survival capacity with increasing drainage but is displaced by reed
canary grass in areas of better-aerated soils. Extensive water swath reeds, also known as giant swaths or sweetgrass, dominate the wetter parts of the meadow, often forming pure stands. These sweetgrass plants can grow up to two meters high. From May to July, the cuckoo campion adds pink flowers and stands up to 60 cm tall in the sedge and reed-rich areas of the meadow.
Pennywort and yellow-flowered marsh
marigolds also bloom in this period, while the marsh marigold might also have a weaker second flowering phase between July and October. Later in the season, the meadow rue with yellow buttercups (June to August) and poison buttercups, especially in June, contribute to the yellow flowering display. From July to September, the dark purple flowers of the marsh thistle add contrast to the yellow blooms. In early summer, wild rose shrubs like the dog rose showcase many light pink flowers along the paths and shrubbery edges.
Reed belt and floodplain forest relics In the vast
reed and
cattail belts of the river arms and ditches, one can experience a beautiful array of colors provided by
sporadic purple loosestrife,
marsh zest, and the water
iris, which is classified as species protected under the Bundesartenschutzverordnung (BArtSchV) (Federal Species Protection Ordinance). The delicate hues of violet-red, burgundy, whitish, and yellow color create a picturesque landscape. The open riparian areas and watercourse edges are characterized by
willow bushes and floodplain forest relics, including silver willow and fluttering elm. Especially at the Havelaltarm Toter Mantel, which extends to Heerstraße, a softwood floodplain is preserved. In the zones with rich herbaceous flora, plants like the
marsh fern (Theylpteris palustris),
marsh ragwort,
stiff sedge, and common
loosestrife, which was formerly administered in folk medicine for
scurvy,
diarrhea, and
fever. Originally from the
Himalayas, the
balsam is spreading strongly on wet, nutrient-rich meadows, forming dense stands of dominance. The fast-growing and rapidly multiplying
neophyte was first imported to
England from
Kashmir in 1839, from where it reached the European continent as an
ornamental plant. It belongs to the
heterosporous plants, which were deliberately introduced ethelochor. Similar to other water lily plants, the yellow pond lily, which is protected in
Germany, covers large areas of open water with floating foliage. Rich yellow, hermaphroditic flowers 4 to 12 cm in diameter protrude from its sea of green leaves.
Mammals The
otter, occasionally spotted in the Tiefwerder Wiesen, finds its ideal habitat in the shallow, fish-rich Havelaltarms and the flood plains. This aquatic
marten species is listed as threatened on the Berlin
Red List of Endangered Species (as of 2003) and is strictly protected under the Bundesartenschutzverordnung (BArtSchV) (Federal Ordinance on the Protection of Species). Despite special surveys and conversation efforts by the state of Berlin to safeguard its population, uncertainties persist about the otter's ability to establish a stable presence in Berlin. Their habitats are constrained by bank construction, water pollution, recreational pressure, and potential losses from traffic and fish traps. Similarly, the
beaver also holds the same protection status and has been native to the Upper Havel and Lake Tegel since 1994 as a "true new citizen" with several beaver burrows.
Bats such as the greater mouse-eared bat (strictly protected according to the BArtSchV and listed in Annex II of the Fauna-Flora-Habitat-Richtlinie (FFH) (Habitats Directive); downgraded in Berlin 2003 from endangered to critically endangered) and the water bat (upgraded in Berlin 2003 from endangered to critically endangered) frequently use the Havel channel as a flight path and hunting ground. These nocturnal and highly social bats seek out the insect-rich Tiefwerder Wiesen for hunting, starting from their roosts in places like the Citadel or the old walls on Pfaueninsel.
Insects Among the insects, the presence of the black cobwater beetle
(Hydrophilus aterrimus) in the Tiefwerder is noteworthy, as it is highly endangered in Berlin. This heat-loving
water beetle, strictly protected under the Bundesartenschutzverordnung (BNatSchG), strongly resembles the large water beetle, and prefers larger, mostly perennial waters in sunny areas. Although many waters are suitable for adult large beetles (length up to five centimeters), they are not suitable for their
larvae. Especially the 1st and 2nd larval stages require extremely shallow, vegetated, and undisturbed shallow water areas. The young larvae, supported by plant growth, lift their food (small aquatic snails) out of the water to predigest it outside their body. Several
weevil species were last recorded in the Tiefwerder Wiesen in the 1980s and early 1990s. Since intensive searches did not yield any further findings, the small beetles (1.3–20 mm) are mostly considered lost in Berlin. Among them are the shore weevil (
Ceutorhynchus scapularis; last record August 1985, one specimen), the hollow-toothed weevil (
Datonychus angulosus; May 1990, four specimens), the suture-striped catkin weevil (
Dorytomus hirtipennis; February 1991, fifteen specimens found in the bark scales of a silver willow), and the broad silky weevil (
Smicronyx smreczynskii; June 1989, one specimen). The silt weevil (
Pelenomus velaris), which prefers vegetation-free, periodically flooded, waterlogged sand and mud areas, and its developing plant is not known. It was recorded in Berlin for the first and last time in May 1990 with one specimen. In December 2003, a specimen of the brown-red willow weevil
(Ellescus infirmus) was found for the first time on the sieve (soil sample) of a willow in the Tiefwerder Wiesen.
Other animals The reedbeds of the Tiefwerder Wiesen are home to the
grass frog, which is specially protected under the BNatSchG, but since a good population trend was noted as early as 1991, it is no longer classified as endangered on the current Berlin Red List of 2003. The
grass snake, however, remains endangered in Berlin. It also finds its preferred habitat in the area: structurally rich wetlands, both aquatic and terrestrial.
Grey herons are a common sight as they linger in the meadows before their autumn migration south to feed. The Tiefwerder Wiesen also serves rare and endangered bird species as breeding, migratory, and wintering grounds. For example, the
kingfisher, which is highly endangered in Berlin, can occasionally be seen. Due to its endangerment, this species, which is strictly protected under the BNatSchG, has already been voted Bird of the Year twice in Germany, in 1973 and 2009. The
sedge meadows,
reeds, and tall grasses are home to pond
warbler,
marsh warbler,
dunnock,
coot, and
little grebe, among others. The bird of the year 1983, the sand martin, is also found in the Tiefwerder Wiesen. Its young birds congregate in large numbers on roosts in the reeds and willow thickets after leaving the breeding burrows. == Nature conservation and trails ==