Ejrnæs, R., Nygaard, B., Kjær, C., Baattrup-Pedersen, A., Brunbjerg, A. K., Clausen, K., Elmeros, M., Fløjgaard, C., Hansen, J.L.S., Hansen, M.D.D., Holm, T.E., Johnsen, T.J., Johansson, L.S., Moeslund, J.E., Sterup. J., Hansen R.R., Strandberg, B., Søndergaard, M. & Wiberg-Larsen, P. 2021. Danmarks biodiversitet 2020 – Tilstand og udvikling. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, 272 s. - Videnskabelig rapport nr. 465. http://dce2.au.dk/pub/SR465.pdf
In this report researchers from Aarhus University evaluate the current trend of biodiversity in Denmark and particularly whether we have achieved to political goal of halting the loss of biodiversity by the end of 2020. The report is a companion to a similar evaluation in 2011 evaluating the former target of halting the biodiversity loss by the end of 2010.
The evaluation relies on data from NOVANA, the National monitoring program for the aquatic environment and biodiversity as well as from the assessment of species in the Danish Red Data Book. The evaluation also includes research-based evidence and knowledge accumulated through decades of focused strategic research in Danish biodiversity. Biodiversity is so complex that no one can claim complete coverage. For a systematic approach we have divided Denmark in nine ecosystems covering the full variation in terrestrial, limnic and marine environments and a reseach team has been gathered to collectively cover the variation in habitats, species and processes within these nine ecosystems. The ecosystems include forest, coast, grassland/heath, mire/meadow, lake, stream, sea, farmland and urban. For each ecosystems the evaluation involves the selection and assessment of indicators representing the habitats, species and processes typical of the ecosystem. The assessment leads to either improving, stable, declining or unknown trend.
The result of the evaluation reveals that the disappointing conclusion from 2011 must be repeated here in 2021: We have not succeeded in halting the loss of biodiversity. On the contrary we can conclude that biodiversity is still declining and although the rate of loss might be modest, it is still significant and in most occasion takes place on a background of already strongly modified ecosystems in bad conservation status without representative assemblages of animals, plants and fungi.
Of 171 indicators of species, habitats and processes, 51% are estimated to be in continuing decline, while only 12 % are estimated to be predominantly stable or improving. Despite differences in the severity of decline between ecosystems – most severe for forests, grassland/heath and mire/meadow and least severe for coast, lake and sea – a predominant decline can be concluded for all nine ecosystems.
One aspect of the evaluation has improved significantly from 2010-2020: Our empirical data has improved and less indicators are reported as unknown and a larger share of evaluations can now be based on data rather than expert assessments. Especially for the species assesssments we are however still largely relying on expert assessments.
