#Ecoute 3.0.8 drivers

Historical data collected in different years by different projects are surely a valuable but often overlooked source of information, available for the evaluation of the conservation status of species, communities, and ecosystems.

In other cases, many data is available, although these have often been collected within projects with a specific purpose other than long-term monitoring. From the past century, many bird monitoring programs have been started in many countries worldwide, both at a continental scale (e.g., the Pan-European Common Bird Monitoring Scheme-PECBMS-in Europe, the North American Breeding Bird Survey-BBS-) and at a national scale (e.g., in Finland, the Breeding Bird Survey-BBS-in UK ). One of the most monitored taxa worldwide are birds, an animal group of large conservation interest, target of several conservation policies in different countries, as well as at a continental scale (e.g., Birds Directive 2009/147/EC in European Union). Population trends represent one of the most informative proxy of the status of populations’ health, from local to continental spatial scales. Wildlife monitoring programs are fundamental to implement species conservation strategies and to verify to what extent they are effective.

#Ecoute 3.0.8 drivers

Further studies should focus on investigation of the relationship between long-term trends and species traits at large spatial scales, and on quantifying the effects of specific drivers across multiple functional groups. Ecological traits analyses showed that plant-eaters and species feeding on invertebrates, farmland birds, and ground-nesters declined, while woodland birds increased. Life history traits analyses revealed a general decrease of migrants, of species with short incubation period and of species with high annual fecundity. Results showed that 45% of the species increased, 24% decreased, and 31% showed non-significant trends. Trends were quantified and tested for significance by weighted linear regression models and using yearly population indices (median and 95% confidence interval) predicted through generalized additive models. The aims of this study were to assess population trends of breeding birds in Lombardy (N Italy) from 1992 to 2019 and to explore the relationships between trends and species sharing similar ecological and life history traits. In addition, trends observed in functional groups (e.g., trophic guilds) can provide the foundation to test specific hypotheses about the drivers of the observed population dynamics. Long-term population trends are considerable sources of information to set wildlife conservation priorities and to evaluate the performance of management actions. Moreover, by analyzing the population response of the functional groups, we identified which of them experienced the most significant population changes, providing the foundations to implement studies aimed at quantifying the effects of specific divers responsible of the observed population changes in these groups. In conclusion, our study provided a portrait of the status of common breeding birds in the region. Only populations of woodland birds increased. Similarly, populations of plant-eaters, of species feeding on invertebrates, and of farmland birds decreased.

Regarding species groups, we found that populations of migrants, of species with short incubation period, and of species with high annual fecundity declined. However, about 24% of the species declined, with worrying negative trends (greater than −50%) for two-thirds of them. We found a general positive or stable situation for 76% of the species.

We assessed population trends for breeding birds in Lombardy (N Italy) from 1992 to 2019 and investigated the relationships between the observed trends and groups of species sharing similar characteristics (i.e., functional groups).