Climate, the study: 150 years of changes have changed biodiversity in Italy

Temperatures increased by 2 ° C in the last century, rainfall decreased by 12%, population density six times greater than in the mid-nineteenth century in the most populated areas: these are just some of the results just published in Nature Ecology & Evolution that analyze for the first time the effects of climate change, human population growth and land use changes on invertebrate biodiversity in Italy, using data collected over the last 150 years. The research team of the University of Milan was coordinated by Silvio Marta and Francesco Ficetola of the Department of Environmental Sciences and Policies and demonstrated how climate (temperature and precipitation), population density and ecosystems have changed in a way In the last century, temperatures have risen by an average of 2 ° C, but that’s not all. Over the same period, rainfall decreased by an average of 12%, while human population density increased steadily until 1980, and then stabilized at current levels (about six times higher than at the beginning of the series). Furthermore, the amount of natural and semi-natural habitats decreased until 1950, and then increased by about 15%, especially in mountain areas. Changes in rainfall are the factor that had the greatest impact on biodiversity: animal communities. have changed more in areas where rainfall has decreased the most, generally leading to increased extinction and colonization rates. Precipitation impacts have been particularly strong in areas that have experienced an increase in human population or temperatures. Increases in temperatures have had less impact than changes in precipitation. As expected, the increase in natural areas has had beneficial effects on diversity, favoring colonization and increasing diversity, while the increase in human population has usually been associated with decreases in biological diversity. This highlights once again how human disturbance and direct and indirect impacts have deleterious effects on biological communities. “Studies of the impacts of climate change on biodiversity often focus on the effect of temperature increases – explains Silvio Marta, coordinator of the study. – However, in Mediterranean areas such as Italy, the effects of precipitation must not be neglected, which can have dramatic impacts “.” Italy – he adds – is one of the countries in which biodiversity has been studied for the longest time, and collections of our museums provide invaluable data, allowing us to reconstruct the changes that have occurred in our country over the last 150 years, and to establish a direct link between environmental changes and loss of biodiversity. Understanding what has happened is a fundamental basis for managing the changes that are underway now and will take place in the next decades ”.