Development and calculation of an indicator of connectivity of bird populations in Catalonia in the context of climate change

One of the proposed generic measures by the Catalan Strategy for Adapting to Climate Change 2013-2020 (ESCACC) is establishment of a monitoring system and indicators for the adaptation measures in order to evaluate how well climate change adaptation is progressing. Also, in the framework of the LIFE MEDACC, which the Ministry of Land and Sustainability, through the Catalan Office for Climate Change, is a coordinating beneficiary, it also provides a scheme for developing a set of indicators of adaptation to the impacts of climate change.

The Global indicator of climate change adaptation in Catalonia, prepared by the Catalan Office for Climate Change (OCCC), obtained a first synthetic indicator of adaptation that allows to monitor the evolution of the adaptive capacity of Catalonia to climate change impacts. Unfortunately, any indicator of biodiversity could be included because the indicators found were only qualitative, or because there were insufficient observations to allow the application of a principal component analysis.

In this context, the Catalan Institute of Ornithology (ICO) has begun to support the OCCC in the development of indicators to assess the degree of compliance with measures to increase the adaptive capacity of biodiversity.

To evaluate the response of biodiversity to the adaptation measure "Improving ecological connectivity in order to strengthen the resilience of species to global change" proposed in the ESCACC, the ICO has developed an indicator of climate connectivity in bird populations. This indicator has been built considering two variables in a total of 88 species: changes in climate predicted distribution, and changes in the average size of the optimal zones.

Two interpretative hypotheses emerge from the results of the study:

a) The good connectivity in the areas of birds distribution in Catalonia could offset the effects that cause climate change on populations.

b) The indicator does not reflect temporary changes as these are not given (yet) because they are masked by the effect of other global change factors.

This work opts for the second interpretive hypothesis. Previous studies in Catalonia reveal that, overall, open spaces species populations show a negative global trend due to increasing rural abandonment, while forest species populations increase due to natural growth of vegetation.

Therefore, it must be attentive in the future to changes in connectivity as possible responsible for population changes.