Roos, R., Evju, M., Endrestøl, A., Nowell, M., Hanssen, O., Nordén, B., Andreasen, M., Kyrkjeeide, M.O., Bengtsson, F. & Hassel, K. 2024. Monitoring the effects of conservation measures for eight threatened species and one habitat type in 2024. NINA Report 2538. Norwegian Institute for nature Research
Norway has committed to halting biodiversity loss in line with the global nature agreement. Additionally, there are goals to improve the status of endangered and near-threatened species and habitat types. To achieve these ambitious objectives, management authorities need knowledge about the effects of conservation measures on endangered species and habitats, providing a basis for effective restoration efforts. Conservation actions for threatened nature include, for example, restoration efforts such as the removal of invasive species, management measures such as mowing or grazing, and conservation translocations to reintroduce species in areas where their populations are very small or have gone extinct. This report summarises the results from this year’s impact monitoring of ongoing conservation efforts for six species and one habitat type: open calcareous grassland in the boreonemoral zone, Northern dargonhead (Dracocephalum ruyschiana), Sticky Catchfly (Silene viscaria), Dune Tiger Beetle (Cicindela maritima), Northern Bear Spider (Arctosa cinerea), Reverdin’s Blue (Plebejus argyrognomon), and Heath Fritillary (Melitaea athalia). Additionally, two other threatened species under conservation management have been included in the project: Boreal Felt Lichen (Erioderma pedicellatum) and Trønder Bog Moss (Sphagnum troendelagicum).
- Open Calcareous Grassland (Apen grunnland kalkmark)
Monitoring continued at six sites where restoration measures were initiated in 2022 and 2023. The results indicate that the measures are effective, leading to a reduction in shrub layers and invasive species at several locations. However, there is a significant need for follow-up actions, as an increase in root sprouts of (invasive) shrubs and coverage of invasive and ruderal species has been observed following the implemented measures. A long-term perspective is necessary to assess whether the interventions have the desired effect on biodiversity over time. Close collaboration between stakeholders, documentation of follow-up actions, and continued monitoring in 2025 are recommended.
- Northern dragonhead (Dragehode)
Monitoring began at one site in 2023 and continued in 2024. So far, results do not indicate that the late mowing carried out in 2023 has led to changes in the dragonhead population. Another round of mowing is recommended in 2025, with follow-up through simplified data collection.
- Sticky Catchfly (Honningblom)
Ongoing monitoring at the species’ four known locations shows that Sticky Catchfly has had a relatively good growing season in 2024, and the populations appear stable under current conservation measures (mowing). Detailed vegetation analyses suggest greater variation in plant communities between locations than between plots with and without Sticky Catchfly. A preliminary analysis of the relationship between population size and drought conditions in the preceding summer shows contrasting effects between locations, likely due to local soil conditions. In 2025, we recommend continuing the monitoring and expanding it to include climate loggers. Additionally, we recommend prioritising the development of protocols for planting and monitoring propagated Sticky Catchfly at existing sites.
- Dune Tiger Beetle (Elvesandjeger)
The most significant changes in the Dune Tiger Beetle population compared to previous years were a lower total number of individuals and changes in habitat use within the two largest subpopulations. Impact monitoring results indicate that complete removal of lupines (an invasive alien species) has a positive effect on the beetle population, with an increase in larval numbers compared to partial or no removal. Without weeding, lupines form dense vegetation, reducing the beetle’s habitat. This effect is particularly evident in sites that have undergone repeated weeding, suggesting that regular and extensive removal helps create and maintain more suitable habitats for the species.
- Northern Bear Spider (Stor elvebreddedderkopp)
Complete removal of lupines (Lupinus polyphyllus) has proven effective in supporting Northern Bear Spider population. Without weeding, lupines spread and form dense vegetation cover, reducing the dynamic sand habitats that the spider relies on. The results also show that more frequent weeding has a positive effect, particularly on adult individuals, which is expected to contribute to an increase in juvenile numbers over time.
- Reverdin’s Blue (Klippeblaavinge)
2024 was the best year for the Reverdin’s Blue since monitoring began in 2010. A total of 2,192 eggs and larvae were recorded (1,938 eggs and 254 larvae) in Halden Municipality. As part of the monitoring efforts, introduced plug plants of the Reverdin’s Blue’s host plant, Orpine (Hylotelephium maximum), were surveyed at two locations. Of the plug plants planted in 2022, 62% were found alive at Hovsbruddet and 88% at Monolittbruddet, indicating significant mortality even two years after planting. Between 15–18% of the plug plants were utilised by the butterfly. We recommend continuing the baseline monitoring of Reverdin’s Blue in Halden Municipality and including Fredriksten Fortress, where conservation translocation efforts took place in 2024, in future monitoring.
- Heath Fritillary (Prikkrutevinge)
A total of 117 larval webs of Heath Fritillary were found across 20 sub-areas on Rauer Island in Fredrikstad Municipality in 2024. This is a higher number than in 2023 but still less than half of what was recorded in the record year of 2022. Larval webs were detected in seven new sub-areas, indicating good dispersal of the species on the island. However, the overall population remains small and confined to a single island, making it vulnerable to stochastic events. Simplified vegetation monitoring conducted in 2024 showed a strong increase in the number of flowering shoots of pollinator plants compared to previous years. Due to considerable variation in vegetation height between plots, no significant effect of mowing was found. However, it is noteworthy that in 2024, there was very little difference in vegetation height between plots that had been mown at least once and those that had never been mown. It is recommended to continue monitoring the Heath Fritillary population on Rauer and to conduct further vegetation analyses to better understand its habitat requirements.
- Boreal Felt Lichen (Tronderlav)
Monitoring of the Boreal Felt Lichen shows that its only remaining population is stable but highly susceptible to threats from both natural and human factors. A proposal for a conservation translocation protocol for Boreal Felt Lichen has been developed. Translocation should be carried out at new, suitable locations, and preliminary trials have been conducted on translocation methods, climate data collection, and thallus development to identify the best sites. The knowledge base for this species can be strengthened through research on cultivation, population genetics, and habitat requirements. Continued monitoring is recommended in 2025.
- Trønder Bog Moss (Trondertorvmose)
A decline in the Trønder Bog Moss population has been observed at the edge of its distribution range (Snåsa). If the species disappears from this site, conservation translocation will be necessary to re-establish and maintain its presence. A proposal for a conservation translocation protocol has been developed, and trials are underway to assess whether collected individuals can be propagated in greenhouses.
For all the habitat types and species included in the impact monitoring efforts, proper coordination, planning, and data collection before implementing measures are crucial. This ensures the best conditions for evaluating how planned interventions can be designed to improve the conservation status of threatened nature. Conservation translocation is expected to become increasingly relevant for more species to reduce the risk of extinction. The Norwegian Environment Agency has developed clear guidelines based on previous work by NINA to ensure that such translocations are successful and do not lead to unintended consequences. We strongly recommend that these guidelines be followed in future conservation translocations.
The report describing and interpreting the results can be found here: https://brage.nina.no/nina-xmlui/handle/11250/2735576 and cited as: Roos, R., Evju, M., Endrestøl, A., Nowell, M., Hansen, O., Nordén, B., Andreasen, M., Kyrkjeeide, M.O., Bengtsson, F. & Hassel, K. 2024. Overvåking av effekter av tiltak for åtte trua arter og en naturtype i 2024. NINA Rapport 2538. Norsk institutt for naturforskning
2020: https://brage.nina.no/nina-xmlui/handle/11250/265365 , 2021: https://brage.nina.no/nina-xmlui/handle/11250/2735576 , 2022: https://brage.nina.no/nina-xmlui/handle/11250/3035335 , 2023: https://brage.nina.no/nina-xmlui/handle/11250/3056939,
The repository has folders for the sub-projects where scripts were available. Each sub-project contains the data and scripts used for analysing the effects of conservation measures.
