Agli albori di una nuova grande trasformazione con l’avvento della rivoluzione tecnologica, la robotica e l’intelligenza artificiale, e nell’epoca delle grandi crisi (economica, ambientale, politica e del lavoro) in tutto il mondo risuona l’eco di una proposta che apre scenari inediti: un reddito di base per tutti. Nell’era del modello unico si dipana l’idea di un diritto economico nuovo, quello di garantire un reddito come uno dei principali diritti umani. Il reddito di base, garantito, universale è ormai divenuta una proposta che comincia ad avere gambe proprie per poter camminare. Dalle esperienze di reddito minimo garantito dei diversi paesi europei fino alle sperimentazioni di un reddito di base incondizionato in giro per il pianeta, il diritto ad un reddito garantito diventa chiave per entrare a pieno titolo e con fiducia nel terzo millennio. Un libro di agile e rapida lettura, scritto da due maggiori esperti italiani, per capire a che punto siamo e che cosa ci possiamo attendere.

Abstract: Aim: Population density is a key parameter in ecology and conservation, and estimates of population density are required for a wide variety of applications in fundamental and applied ecology. Yet, in terrestrial mammals these data are available for only a minority of species, and their availability is taxonomically and geographically biased. Here, we provide the most plausible predictions of average population density, their natural variability and statistical uncertainty for 4,925 terrestrial mammal species. Location: Global. Time period: 1970-2021. Major taxa studied: Terrestrial mammals. Methods: We fitted an additive mixed-effect model accounting for spatial and phylogenetic autocorrelation on a dataset including 5,412 average population density estimates for 737 species. Average density was modelled as a function of body mass, diet, locomotor habits and environmental conditions. We validated the model using spatial and taxonomic block cross-validation and used the estimated error to quantify the uncertainty around statistical predictions of population density for 4,925 mammal species. Results: Small body size, fossorial behaviour and herbivorous diets were associated with the highest population densities, whereas large size, aerial behaviour and carnivorous diets were related to the lowest densities. Species in non-seasonal environments yielded higher densities than species in environments with high precipitation seasonality. Empirical estimates of population density vary by about four times on average within the same species, and statistically independent predictions for the majority of species deviate by about five times from observed values, indicating that prediction errors are similar to the natural variability in population densities. Main conclusions: Our predictions and uncertainty estimates of average population densities open up a number of applications in macroecology and conservation biogeography, including biomass estimation, setting population targets in conservation assessments and planning, and supporting Red List assessments. The methodology can be replicated easily for other taxonomic groups with a representative sample of georeferenced density estimates