Threatened lichens of calcareous rocks

Calcareous rocks are threatened habitats where exceptionally many rare lichen species grow. Mining and construction are the main threats to these species. Calcareous rocks are also one of the habitats classified as “in need of protection” under the METSO-programme. Due to their small size calcareous rocks are especially vulnerable to any impacts caused by nearby land management.  The increasing growth of trees to species in open and semi-open rocks, and tree cuts in shaded rocks are threatening factors to species growing in these habitats.

Some 230 calcicolous lichen species are known in Finland, which is 14 per cent of the entire Finnish lichen flora. The proportion of calcicolous lichens of the total lichen flora is more than one hundred-fold compared to the corresponding proportion of suitable habitat area. The environmental requirements, distribution, abundance and state of lichens growing on calcareous rocks are very poorly known.  Potentially many new calcicolous lichen species are yet to be found in Finland.


The locations of calcareous rocks are well known compared to most other habitats.  The best habitats potentially in terms of lichen species can be determined on the basis of existing information about the habitats. In this project the potentially most significant calcareous rock habitats will be studied.

The aim of the project is 1) to determine the lichen flora of calcareous rocks and quarries in Finland, 2) to provide information about the environmental requirements, occurrence and state of species in different parts of Finland, 3) to find out the significance of different calcareous rock habitats to calcicolous lichens, 4) to assess the state of calcareous rock habitats with the help of lichen flora, 5) to study the effect of the number and composition of tree species on lichen flora growing on and around calcareous rocks, 6) to study the effect of forest management on calcicolouslichens, and 7) to study the conservation status of calcicolous lichens, the conservation status of threatened and rare species, and to determine the indicator value of lichen species in assessing the value of calcareous rocks.

Application of results

The project will produce new information on the present state of calcareous rocks in Finland. With this new information the conservation and management needs of calcareous rocks can be assessed and management plans can be developed. The research will provide information on the occurrence and state of calcicolous lichens, which enables a reliable assessment of the threat status of calcicolous species.

During this project, specimens will be collected from many poorly known and difficultly identifiable lichen species for which a genetic barcode is being developed in another PUTTE project
Deficiently known forest lichens - identification through DNA barcodes (Leena Myllys, The Finnish Museum of Natural History).

Further information

Juha Pykälä, Finnish Environment Insitute,, tel. +358 400 148 664

Published 2013-05-21 at 9:40, updated 2023-05-25 at 16:58

Target group: