The importance of semi-natural habitats for European nature conservation is widely recognized due to their high species richness and vulnerability to land-use change.
The assessment of habitat conservation status has a key role in the definition of conservation measures, especially for those habitats that are subjected to rapid changes such as semi-natural grasslands. However, many member states still lack standard methodologies for this assessment that is mostly based on an expert-based evaluation lacking well-defined criteria.
We focused on grasslands belonging to the habitat 6210(*), i.e. Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco-Brometalia). In 2013-2014, we revisited 132 semi-natural grasslands along the Apennine chain that were originally sampled between 1966 and 1992 and that, at the time of their historical sampling, could be referred to the habitat. We measured the compositional dissimilarity between each newly sampled plot and the corresponding historical species pool and considered these dissimilarities as a measure of the occurred changes.
We aim at using this quantification of the occurred change to define a methodology for the assessment of the conservation status of the priority habitat 6210(*). We will integrate the information on Apennine grasslands with innovative and effective indicators based on plant species composition. These indicators will then be used to derive an index of conservation status for each of the 132 sampling units deriving from the 2013-2014 fieldwork.
Finally, the degree of change to which the habitat was subjected in the last decades will be used to test the index hypothesizing that a lower degree of compositional change from the original community is associated to higher values of the newly defined index of conservation status and viceversa.
Our project is innovative in its approach since it includes multi-temporal data in the definition of the current conservation status of a habitat. This is particularly valuable in semi-natural habitats that are by definition highly dynamic and are undergoing a massive compositional change in Italy and throughout Europe.
Through this project we will integrate indicators that were not yet officially tested and adopted for the evaluation of the conservation status, with a recently published methodology that allows to quantify the compositional change occurred in the habitat during the last decades.
By investing a relatively low effort, the information deriving by previous research activities carried out within the Department will be maximized in a project that will represent an advancement both in the research field of conservation biology and in the application of this research.
Up to know most of the information on habitat conservation status is based on an expert-based evaluation that is not grounded on well-defined criteria. This represents a substantial flaw in the process of assessment and monitoring since if the assessment has to be repeated every 6 years it is very likely that the experts that take care of the evaluation will change between two monitoring events. The differences over time will therefore reflect, at least partially, the individual perspective of each expert rather than changes in the habitat conservation status.
In addition to this general flaw in habitat monitoring strategies, grassland habitats have specific features that make their monitoring extremely complex. Firstly, these habitats are more difficult to map since even if the land cover of an area appears unchanged from remotely sensed images, the structure and composition of the habitat may have changed to such an extent that the area may not be referred to the habitat anymore. Therefore, for grassland habitats, species data are particularly valuable. Furthermore, grassland habitats have a very high species richness and include several taxonomically complex groups, which make a set of specific indicators extremely relevant for an effective assessment and monitoring.
The definition of a standardized methodology based on proper indicators will allow for these challenges to be faced and overcome, and will replace expert-based evaluation with a sound set of indicators that could be applied by different researchers and practitioners avoiding the risk of monitoring the experts' rather than the communities' change.