Aarhus University Seal / Aarhus Universitets segl

No. 458: Investigation of alternative data sources in the NOVANA programme's habitat type monitoring

Moeslund, J.E., Nygaard, B., Normand, S. & Madsen, B. 2021. Udredning af alternative datakilder i NOVANA-programmets naturtypeovervågning. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, 70 s. - Videnskabelig rapport nr. 458. http://dce2.au.dk/pub/SR458.pdf

Summary

Here, Danish Centre for Environment and Energy (DCE) report a screening of alternative data sources for the indicators that are used in today’s mapping and monitoring of terrestrial NATURA2000 habitats in Denmark. We have digested more than 1500 studies within the scientific fields remote sensing, environmental DNA and acoustics. We present – both for current and for a number of suggested new indicators – alternative data sources and discuss the possibilities of using these to make the aforementioned mapping and monitoring more cost-efficient and if possible, better.

In the report, we present a number of alternative data sources that are relevant for both current and possible new indicators for mapping and monitoring danish habitats at the geographic scale of 5–15 m circular sample sites or polygons delineating the extent of individual habitat types. However, we found no ready-off-the-shelf products which could be included for these purposes right away, and therefore development and testing is needed should authorities wish to include these alternative data sources in mapping and monitoring. Our screening can form the basis for a prioritization of which new data sources it makes the most sense to implement first. Specifically, we suggest that the current indicators “tree cover”, “cover of woody species > 1 m” and “light conditions” (measured with a densiometer) could be constructed using alternatives to the field-based data sources used today with a rather small effort. In addition to this, we recommend exploring the possibilities for using alternative data sources for the indicators “shrub cover”, “vegetation height”, “forest lakes and other forest wetlands”, “dwarf shrub cover” and “bare soil”. Alternative data sources could be relevant for these indicators but likely further out in future and with a higher development and testing effort. Also, we consider it possible that the indicators “species rich understory in forests”, “water cover”, and “lichen cover” can be based on alternative data sources in the long run.

We recommend that authorities start testing eDNA methods in assessment of NATURA2000 habitats in not so distant future as these methods potentially gives a plethora of new possibilities that may be both more cost-efficient and could improve the monitoring in the long term for several of the indicators that are currently based on plant species lists. Notably, we suggest a new indicator ”eDNA-index” that could form a good indicator conveying a high level of information about the current conservation value in nature areas. On the other hand, in foreseeable future and some years beyond that, we do not see any alternatives to the plant species list that field personnel records today, and we emphasize that this plant species list is crucial for the mapping and monitoring of NATURA2000 habitats in Denmark as it holds essential information about nature condition and -quality and abiotic factors. In addition to the “eDNA-index”, we foresee a potential in the long term for creating new indicators of “coastal dynamics”, “flower resources”, and “water level dynamics” based on alternative data sources.

Finally, we emphasize that using alternative data sources as suggested in the report would likely improve the spatial and temporal coverage of some of the current indicators. In that way, the mapping and monitoring and the objectivity hereof would likely improve as human bias would have a lower effect on the indicators in question than today.