Appendix S1. Overview of reviewed citizen science projects.

Name, location / Abbreviation / Description
Estimation of wolf population, Finland / WOLFolf / annual monitoring of population changes and planning of management measures (e.g. hunting licenses); population estimates based on field research; observations provided by a network of trained contact persons (volunteer hunters) and special counting events (open to volunteers)
Helsinki-Uusimaa Regional Plan 4, Finland / UUSIMAA / Part of the regional land-use plan addresses green infrastructure through a public-participation geographic-information-system survey (PPGIS) on cultural ecosystem services, during which citizens cogenerate a spatial database on valuable sites.
Sibbesborg local master plan, Finland / SIBBESBORGibbesborg / citizen engagement through an online PPGIS survey (open to anyone); local master-plan exhibitions used to collect citizen knowledge on cultural ecosystem services and to record it on maps
Porot - Reindeer, Finland / REINDEEReindeer / maps of reindeer-herding cooperative areas coproduced by researchers and reindeer herders working together on data collection; data were put into GIS; herders trained to update GIS data
Ladybird Survey, U.K. / LADYBIRDadybird / In 1968 the The first survey provided in 1968 to(meaning of launched in this context is unclear) records to the public of ladybird species across the U.K. and mapped their distribution by public. To date, tens of thousands of people across the country have helped track the spread of the harlequin ladybird through an online recording system ( http://www.ladybird-survey.org/ ).
Nature Observations' Database, Estoniaobse / OBSERVATIONbservation / repository for observational data on speciesand animal activities since 2002 through an open and free web-based platform; conducted jointly by the Estonian Environment Information Centre (state agency) and Estonian Naturalists’ Society (NGO); contains over 177,000 observations currently ( http://eelis.ic.envir.ee/lva/default.aspx?site=lva&lang=eng)
Vadonleső, Hungary / VADONLESŐ / repository for location data on certain protected species (11 animal and 3 plant species) collected by citizens; data entry either on the website or via mobile phone; validated data published on a Google Map based platform; organization sponsors regular public-awareness-raising events (mammal of the year program, drawing contest, fairy-tale writing contest) ( www.vadonleso.hu )
Marten Network, Belgium / MARTEN NETWORKarten Network / In 1998 a volunteer network of observers, couriers, and storekeepers (providing freezer space) was established throughout Flanders to collect native and non-native mustelid species killed by vehicles; this enabled exact species identification and collection of sample animals for autopsy research.
Open Farm Sunday Pollinator Survey, U.K. / OPEN FARMpen Farm / encourages people to visit farms on Open Farm Sundays to count the number and type of insects they see in different habitats, both in field margins or on crops, thereby contributing to the National Farm Pollinator Survey
Big Bumblebee Discovery, UK / BUMBLEBEEumblebee / collects citizen observations to determine how environmental changes affect insect populations and to understand potential future impacts related to food security and climate change
Virtual Biodiversity, Spain / VIRTUAL BIODIVERSITYirtual Biodiversity / online citizen platform aimed at collecting locations of diverse biodiversity components through georeferenced digital pictures (http://www.biodiversidadvirtual.org/ )
Catalan Butterfly Monitoring System, Spain / CATALAN BUTTERFLYatalan Butterfly / online participatory platform aimed at monitoring the butterfly populations in Catalonia through a set of fixed transects for the assessment of changes in butterfly populations across time and to relate these changes to environmental factors transects monitored by volunteers (http://www.catalanbms.org/ )
BioBlitz, Barcelona, Spain / BIOBLITZioblitz / nature-discovery events in the municipality of Barcelona promoted by the Natural History Museum of Barcelona; flora and fauna of a given area are sampled by teams of citizens of all ages assisted by volunteer naturalists ( http://w110.bcn.cat/portal/site/MuseuDeCiencies?lang=en_GB)
Amphibians and Reptiles –BirdLife Hungaryam / AMPHIBIANS / regular events of the Amphibians and Reptiles Mapping Program organized to raise public awareness and mobilize and motivate individual citizens to collect local data and to participate in the BirdLife Hungary network; prizes given for best data provider, best photo provider, etc. ( http://herpterkep.mme.hu/index.php )