Securing biodiversity

Helsinki’s Action Programme for Securing Biodiversity 2021–2028 was completed and approved in spring 2021. A key objective of the programme is to take biodiversity into consideration in all operations of the City.

The threatened habitat types, valuable plant sites and species of Helsinki have been mapped

Between 2017 and 2020, the survey of threatened habitat types produced information on threatened and near-threatened habitat types. The survey serves as a basis for identifying Helsinki’s most valuable and representative habitat type sites.

There are 319 sites with threatened, near-threatened or otherwise notable vascular plants registered in the Nature Information System, and 33 of them are valuable cultural plant sites. Cultural plants refer to neophytes and cultivated plants that were introduced to Finland during the period between the 17th century and the year Finland became independent (1917).

According to a study conducted in 2020, there are 20 nationally threatened vascular plant species, 31 nationally near-threatened species and 40 regionally threatened species found in Helsinki.

During the updating of the list of mammal species sighted in Helsinki, five new species had been sighted since 2013: the Siberian flying squirrel, the serotine bat, the soprano pipistrelle, the wolf and the wolverine. Two species, the European polecat and the Baltic ringed seal, are thought to have disappeared in the 1990s.

The Siberian flying squirrel habitat network was supplemented based on a new Siberian flying squirrel habitat survey conducted in 2020. The materials take into account the core areas and habitats of Siberian flying squirrels and the routes between these areas. An operating model was also developed for taking Siberian flying squirrels into account in the City’s operations.

The pollinating insect censuses launched in the city’s green areas in 2019 were continued in 2020. The observed number of bumblebee species remained the same (approximately 20), but the number of individual bumblebees was found to have clearly increased compared to the previous year. In contrast, the number of individual western honey bees decreased by half compared to the previous year in several areas. The numbers of individual Papilionoidea were exceptionally low, similarly to 2019. The numbers of species and individual butterflies were very low on the lines inside Ring I in particular. The Papilionoidea year was also poor elsewhere in Southern Finland.

Bird censuses continued in Vanhankaupunginlahti, Östersundom and the archipelago. The censuses found that machine mowing had increased the number of birds observed in these areas in the autumn. For the first time, a white-tailed eagle nested in Vanhankaupunginlahti. The nesting was a big success, and all three chicks grew up. The nesting site is most likely the most urban place a white-tailed eagle has ever nested in.

Biodiversity is taken into account in planning and construction

The objectives of the green network, which covers the entire city, are presented in the city plan and taken into account in detailed planning. A consistent green structure promotes both biodiversity and recreational opportunities. The ecological networks of Helsinki include the network of urban forests and wooded areas, the meadow network and the blue network. The information on the current state and future of the city’s network of urban forests and wooded areas was supplemented in 2020. The meadow network also started its work in spring 2020.

The Urban Environment Committee reviewed the preliminary report on the National Urban Park of Helsinki in spring 2020. In addition to examining three areas of different sizes, the report includes an option covering the whole city. The report also reviews the City’s measures for achieving the objectives in line with the criteria for national urban parks with regard to recreation and nature networks.

In detailed planning, biodiversity is taken into account in the definition of starting points and objectives, planning solutions and plan regulations as well as the development of methods. For areas with natural values, appropriate nature surveys will be conducted as a basis for planning.

Of the key detailed planning projects, the parts of the forests with the most diverse natural values and the most elevated outcrop areas have been spared from construction in Karhunkaataja, for example. Additionally, plots must meet the green factor target level, stormwater must be treated in ground-supported block yards, and trees and shrubs of different sizes must be planted. Unbuilt parts of plots must be preserved in their natural state, reserved as agricultural land for the residents or planted with plants. A green roof must be built for all one-storey sections of buildings and canopies. In the detailed plan for the Maria start-up campus, roof gardens are used to promote the biodiversity of urban nature. The detailed plan solution for New Laakso Hospital also lays down regulations regarding the trees to be retained and added as well as green roofs.

A nature reserve has been established in the detailed plan area of Vallisaari and Kuninkaansaari, and any valuable natural environments, with their landscape values and unique characteristics, must also be retained elsewhere in the detailed plan area. The plan also lays down regulations regarding the management of the area in such a way that its environment will be retained in a semi-natural state, trees will be retained and they will retain their vitality. Conservation of the living conditions of bats must be taken into account in alteration work.

A green path on Vallisaari island.
Picture 14. A path on Vallisaari island. Photograph by Julia Kivelä.

The aim for the detailed plan area of Hermanninranta and Kyläsaari is to turn the area into an ecologically sustainable district built of wood, in which green infrastructure, stormwater management and biodiversity play a key role. The aim is to make the Hermanni shore park into a biodiversity park, the purpose of which is to support biodiversity and largely rely on its own ecological and hydrological processes.

Efforts have also been made to secure biodiversity by utilising industrial areas undergoing a change in their purpose of use and commercial plots without any existing natural values in additional construction in city planning.

Due consideration of the impacts on nature have played a key role in the construction of Jokeri Light Rail. Thick-shelled river mussels, which are classified as endangered, were moved from below the railway bridge in the Vantaa River. The state of Haaganpuro, Mustapuro and Mätäjoki has been improved in conjunction with construction by building spawning beds, increasing open water routes and improving the delaying of stormwater. Felled trees have been taken elsewhere and been left lying on the ground to secure the deadwood continuum. Topsoil peeled off during construction has been utilised in recycled substrate, which has allowed the soil seed bank to be retained and ensured that the substrate contains soil biota.

The biodiversity of green areas is increased

The Helsinki Urban Plant Life Guide, which provides instructions on the use of vegetation, was updated and revised in 2020. The Urban Plant Life Guide includes recommendations on plant species and information on the potential use of plants in various locations. The guide also lists plants that are not used, with the most important of them being invasive alien species. Through the revision, the guide now also includes information about plants that can be used to promote the biodiversity of urban nature.

A project called ‘Transforming lawns into flower fields and urban farms – helping the climate, pollinators and the Baltic Sea’ was implemented as part of participatory budgeting (OmaStadi). The project selected ten parks and traffic areas around the city and let the lawn in them grow into a meadow. Additionally, a new flower meadow was established at Maaherranpuisto park.

The number of decaying trees is increased in nature management and invasive alien species are combatted

One of the key objectives of the public area plans and nature and landscape management plans prepared in 2020 was to secure biodiversity and increase it systematically, particularly in forests and forested areas. These plans include the area plan for Oulunkylä and Maunula and the public area plans for Herttoniemi and Vuosaari as well as Malmi and Pukinmäki. Nature and landscape management plans at the implementation level include the plans for Pakila and Tuomarinkylä as well as Mellunkylä and Vartiokylä.

In the implementation of nature plans, biodiversity is increased by leaving decaying trees and groves for animals in managed forests, among other measures. Extensive forest areas have also been excluded from management measures as planned. In addition to the city area, this practice has also been followed in recreational areas owned by Helsinki in Nuuksio, for example.

Invasive alien species have been combatted in green areas primarily in connection with other management measures and through voluntary work events in cooperation with residents, educational institutions and organisations. A working group made up of prisoners from the open prison in Kerava was also utilised in combatting invasive plant species. Rugosa rose was combatted on bird islets in the archipelago in autumn. The plants were cut down and the plant waste was transported to the mainland and burned with mixed waste. Hogweed populations are monitored and combatted as necessary. Invasive alien plant species were also combatted in worksites in conjunction with the construction of Jokeri Light Rail.

The number of nature reserves increased and funding was received for the restoration of natural areas

Currently, 3.2% of all land area is nature reserves, as compared to 0.93% of water areas. When including protected habitat types, species protection areas, and Natura areas not protected by the Nature Conservation Act, the total protected area amounts to 4% of Helsinki’s land area and 1.4% of water areas. The new proposed nature reserves will increase the percentage of protected land area to 5.6%.

In 2020, the Uusimaa Centre for Economic Development, Transport and the Environment made a founding decision and approved management and utilisation plans for four nature reserves in Helsinki. Haltialanmetsä is the largest of them, with a total area of 137 hectares. The other areas were bird islets. The Ministry of the Environment provided Helmi project funding for the restoration of the wooded mire of Haltialanmetsä for 2020–2022. The updating of the management and utilisation plan for the Niskala arboretum was also completed in 2020 and approved by the Environment and Permits Sub-committee in early 2021. In 2020, the restoration of the bird wetlands of Helsinki received funding from the Helmi Habitats Programme for mowing the bird wetlands. In addition to mowing, the use of the wetlands as pastures will be expanded. The aim is to restore reeded areas to open coastal meadows. In 2020, Lammassaari island, which is surrounded by the bird wetland of Vanhakaupunki, was visited by approximately 200,000 visitors, which is approximately 45% more than the previous year. Helmi project funding was also received for nature management of the Bengtsår grove nature reserve owned by Helsinki in Hanko. The project will manage temperate deciduous forests and restore traditional biotopes from 2021 to 2022.

Erosion of the areas was increased in early 2020 by a winter of little snow and an increased interest in outdoor activity and nature reserves caused by the COVID-19 pandemic. Fences were built and signage was increased in the most popular areas in order to guide people away from sensitive natural areas.

Nature reserves in Helsinki: Currently, 3.2% of all land area is nature reserves, as compared to 0.93% of water areas. The largest nature reserves are Haltialanmetsä, Viikki-Vanhankaupunginlahti, the Kallahti bank and the Mustavuori grove.
Picture 15: Currently, 3.2% of all land area is nature reserves, as compared to 0.93% of water areas.

The COVID-19 pandemic restricted Korkeasaari Zoo’s operations 

2020 was, above all, marked by the COVID-19 pandemic, which affected the operations of Korkeasaari Zoo in many ways. The zoo was closed to the public for 2.5 months in the spring and was again closed in December. The pandemic also quieted the supply of animals, but Korkeasaari Zoo still gained new species and individual animals: golden lion tamarins, a pygmy marmoset, an emperor tamarin, a white-rumped shama, common agamas, African mantises, giant African olive millipedes, Chinese pond turtles, common gundis, Sambava tomato frogs and giant day geckos. New species in the aquariums included pinstripe dambas, red cherry shrimps, peacock gudgeons, reticulated hillstream loaches and tomato clownfish, while cardinal tetras made a comeback. Many new offspring were born and hatched at Korkeasaari Zoo in 2020. Species that reproduced for the first time on the island included pancake tortoises, fennec foxes, black-tailed prairie dogs, Malaysian forest scorpions and Bali starlings. The total number of species at Korkeasaari Zoo is 155, of which 34% are classified as threatened.

The pandemic posed challenges to the implementation of conservation programmes, as it was not possible to travel abroad for field work in 2020. However, WildForestReindeerLIFE, a project to reintroduce Finnish forest reindeer to the wild, continued in Finland. 12 forest reindeer were released in both Seitseminen and Lauhanvuori National Parks. Of these forest reindeer, Joiku and Juolukka were born in Korkeasaari Zoo.

In 2020, Korkeasaari Zoo’s Wildlife Hospital treated 1,704 animals. Approximately 25% of the patients were rehabilitated and returned to the wild. Korkeasaari Zoo participates in the conservation of animal species in the wild as part of a network formed by zoos and conservation organisations. In 2020, Korkeasaari Zoo and the Korkeasaaren ystävät ry association raised a total of EUR 72,714 for projects to conserve threatened species.

Nature trails were developed in projects

The Urban Eco Islands project operating with EU funding promoted the sustainable use of recreational areas by building new resting areas and a new nature trail on Vasikkasaari island. The environmental awareness of city residents and schoolchildren about urban nature was increased through means of citizen science by guiding people in using the iNaturalist nature application, which helps users identify species. Nature information is now also available about Vasikkasaari on the website.

A project that created two nature trails in the area of Pajamäki and Tali was implemented as part of participatory budgeting (OmaStadi). The Patterinmäki nature trail and the garden tour of Mätäjoki and Tali can be found on the citynature platform.

Eyes on the future

The positive trend in efforts to secure biodiversity will be continued, and this aspect will be taken better into account in all operations of the City. The green and blue network will be developed persistently, and erosion and the spread of invasive alien species will be prevented efficiently. We will prevent the erosion of nature and the spread of invasive alien species efficiently. Additionally, information on important species will be increased, and the habitats of these species will be secured.