Moreover, it needs to be emphasized that assessments of temporal declines or increases are impossible without explicit reference to scale.
While a dedicated global monitoring system might be ideal, it would be impossibly expensive and not manageable. Hence, bottom-up approaches, such as combining data from different monitoring schemes usually carried out with the objective to inform conservation at the local or national scales, are the only realistic options to assess the global state and trend of biodiversity now and in the coming years. The success of this integration to produce relevant estimates and maps of biodiversity changes will greatly depend on the quality of data combined and on relevant tools for integration (Kosztyi et al. 2014). These objectives raise several practical, methodological, conceptual and coordination issues about both the collection and the analyses of data.
Monitoring sites should be representative at the spatial scales relevant for the monitoring targets and should spatially cover variation in processes that may drive biodiversity changes. It is of particular importance to recognize that drivers of change may act on different spatial and temporal scales and their relative importance may also change with them: at one scale it may be climate change that determines biodiversity loss, whereas at another scale it may be habitat loss and fragmentation or disturbance. Given this scale-dependency much can be gained from nested spatial designs (with e.g. one or two nested levels). While small-scale designs can be used to address local concerns (e.g. effectiveness of protected areas), they should always be coupled with monitoring over broader scales (national to European scales). Those couplings can be used as benchmarks to discriminate the role of local vs. large-scale drivers of biodiversity change. A primer for biodiversity monitoring across scale and Kosztyi et al. (2014) outline basic principles for the design of monitoring schemes.
Effective planning involves appropriate priority setting as it is impossible to monitor all species or habitats (Henle et al. 2013). Kosztyi et al. (2014) outline various options. One option, the use of the concept of national responsibilities, is explained and illustrated within the SCALETOOL.
Ideally, identical monitoring protocols are used for data collection as this facilitates analyses. Unfortunately, we are still far away form such designs. Therefore challenges arise how to optimally integrate different monitoring schemes across scales. Usually, such data are highly heterogeneous and their integration requires advanced statistical methodologies. Basic principles for the integration of monitoring schemes and methodological recommendations can be viewed via the BioMAT tool. BioMAT also provides recommendations for the analyses of species and habitat monitoring data, describes relevant methods, and further provides background information about biodiversity monitoring and relevant policies. This includes a glossary of terms and links to policy portals relevant for biodiversity monitoring.
In addition, BioMAT allows the creation of overview graphs of the coverage and characteristics of monitoring schemes in Europe that match criteria specified by the user, e.g. country, taxonomic group, launching reason for the monitoring schemes, or design criteria that are relevant for assessing their suitability for integration. These graphs show for example that most monitoring schemes are carried out at the local to national level, that the different taxonomic groups are unequally represented and that volunteers play an overriding role in the collection of species monitoring data but not in the collection of habitat monitoring data.
The pivotal role of volunteers stresses the importance of creating and maintaining citizen science networks to support long-term monitoring programs (see below), as without long-term data any judgement about status and trends retains substantial uncertainty. Whereas in western and northern EU countries a range of well-established volunteer monitoring schemes exists, there is still a substantial deficit in eastern and southern European countries (McConville et al. 2014).
Kostzyi, B., Henle, K., Lengyel, S. (2014) Biodiversity monitoring and policy instruments: Trends, gaps and new developments. Pp. 137-142 in: Henle, K., Potts, S.G., Kunin, W.E. Matsinos, Y.G., Similä, J., Pantis, J.D., Grobelnik, V., Penev, L., Settele, S. (eds.): Scaling in Ecology and Biodiversity Conservation. Pensoft Publishers, Sofia. SCALES book
McConville, A., Margerison, C., McCormack, C., Apostolopoulou, E., Cent J., Koivulehto, M. (2014) Biodiversity monitoring and EU policy. Pp. 142-145 in: Henle, K., Potts, S.G., Kunin, W.E., Matsinos, Y.G., Similä, J., Pantis, J.D., Grobelnik, V., Penev, L., Settele, S. (eds.): Scaling in Ecology and Biodiversity Conservation. Pensoft Publishers, Sofia. SCALES book
Schmeller, D.S., Maier, A., Evans, D., Henle, K. (2012) National responsibilities for conserving habitats - a freely scalable method. Nature Conservation 3: 21-44. DOI: 10.3897/natureconservation.3.3710
Tzanopoulos, J., Mouttet, R., Letourneau, A., Vogiatzakis, I.N., Potts, S.G., Henle, K., Mathevet, R., Marty, P. (2013) Scale sensitivity of drivers of environmental change across Europe. Global Environmental Change 23: 167-178.