In the summer and autumn seasons of 2014, a team of nature experts
studied in detail several natural territories all over Latvia, with the
most interesting discoveries found in and around Lake Sīvers. Here they
found the largest cluster of Najas (Najas tenuissima) aquatic plants in
In the research territory in and around the lake, 16 EU-protected
habitats were determined, as well as 20 natural habitats protected
under Latvian legislation.
Botanist Uvis Suško discovered 39 rare and/or protected plant
species in and around Lake Sīvers in Latgale Province (eastern Latvia).
Out of these plant species, the Najas tenuissima and Najas flexilis
aquatic plants must be highlighted. Up until now, the rare Najas
tenuissima aquatic plant was found to grow in only about 25 places in
the world. This aquatic plant species was discovered in Lake Sīvers for
the first time, and is believed to be the largest cluster of Najas
tenuissima in the world. Meanwhile, the Najas flexilis aquatic plant is a
rarity in Europe, and is known to grow in only about 25 places around
the continent. Lake Sīvers is also believed to hold the largest cluster
of Najas flexilis aquatic plants in Europe as well. Najas flexilis
aquatic plants have become extinct in many parts of Europe over the past
100 to 150 years due to pollution and the degradation of eco-systems.
Both of the rare Najas species have been included on the EU’s list of
After studying the eco-system in and around Lake Sīvers, the
nature experts concluded that the lake is a true gem. Many other rare
plant species were found on the lake’s shores and in its crystal clear
waters, such as: Subularia aquatica, Littorella uniflora, Isoetes
lacustris, Lobelia dortmanna, Myriophyllum alterniflorum, Callitriche
hermaphroditica, Liparis loeselii and Gentiana cruciata.