Successful habitat restoration in “Ziemeļu Mires” Nature Reserve

PUBLISHED: 24. 04. 2019

In April, 2019, after snow melting, raised bog restoration area of “Ziemeļu Mires” Nature Reserve was visited to evaluate success of habitat restoration and hydrology stabilization. Dam building on drainage ditches was performed in autumn, 2018, within the frame of LIFE project “Wetlands”.

Peat dam on ditch Ezergrāvis. Photo: Līga Strazdiņa

Ditch Ezergrāvis was the main source of water outflow from raised bog Sakalaura Mire for more than 100 years. After building of five peat dams, stabilization of water regime and peat becoming moister was observed all along the ditch.

Stabilized water regime in Ezergrāvis after management. Photo: Krišjānis Libauers

Roots of trees that have grown here due to drainage, are now under water. Die-off of these trees is expected during next years. However, it is a natural process after raised bog management, as formation of tree level is an indicator to peatland degradation. Tree die-off will promote to even further development of peat-forming plant communities since evapotranspiration through trees will decrease over time.

Tree level has established along ditch but will die-off in next years. Photo: Līga Strazdiņa

Negative effect from drainage was observed also in Lake Ramatas Lielezers. Wave erosion induced bank corrosion, peat particle rinse into lake and increase of biogenesis in water. As a result, lake animals, plants, algae and microorganisms were negatively impacted, and quality of protected habitat 3160 Natural dystrophic lakes and ponds decreased. However, after building of dams, water level in Lake Ramatas Lielezers is stabilized and do not fluctuate as in previous years, therefore wave erosion is not so intensive anymore.

Water level in Lake Ramatas Lielezers is stabilized and wave erosion is not degrading water ecosystem anymore. Photo: Krišjānis Libauers

Results showed that half of year after dam building on drainage ditch Ezergrāvis has already improved favourable conditions for degraded raised bog habitat restoration, increased occurrence of rare and protected plant species (like Betula nana and Trichophorum cespitosum), as well as restricted bank erosion of Lake Ramatas Lielezers.