A study published in ‘Nature’ uses plant species missing in 119 regions around the world to determine in a novel way the human impact on biodiversity
In regions heavily affected by human activities, ecosystems contain only one in five potential species, according to the work
The Desertification Research Center (CSIC-UV-GVA) participates in this international study providing data from the Sierra de la Calderona Natural Park.
Identifying potential species that could live in a certain place but are absent. This is what is known as ‘dark diversity’, a new way of measuring the impact of human activity whose most complete work to date was published yesterday in the prestigious journal Nature. The study, in which the Center for Desertification Research (CIDE), a joint center of the Spanish National Research Council (CSIC), the Universitat de València (UV) and the Generalitat Valenciana (GVA), participates, analyzed vegetation records from 5,500 sites in 119 regions around the world, showing an impact of human activities on natural vegetation that would not have been detected with traditional methods.
The results show that, in regions with little human impact, ecosystems contain more than one third of potentially suitable species, while other species remain absent for natural reasons, such as limited dispersal. In contrast, in regions heavily impacted by human activities, ecosystems contain only one in five potential species. Traditional measures of biodiversity, such as simply counting the number of species recorded, failed to detect this impact because natural variation in biodiversity between regions and ecosystems masked the true extent of human impact, according to the researchers.
The study was conducted thanks to the international DarkDivNet collaboration, which started in 2018 from an idea by Meelis Pärtel, a professor of Botany at the University of Tartu (Estonia) who coordinates the network and is the lead author of the study published in Nature. "We had introduced the theory of dark diversity and developed methods to study it, but to make global comparisons we needed consistent sampling in many regions. It seemed like an impossible mission, but many colleagues from different continents joined us," Pärtel recalls.
Human Footprint Index
The level of human disturbance in each region was measured using the Human Footprint Index, which includes factors such as population density, land use changes (such as urban development and agriculture) and infrastructure (roads and railroads). The study found that the plant diversity of a site is negatively influenced by the level of the Human Footprint Index and most of its components in a surrounding area, up to hundreds of kilometers away.
"These results are alarming because they show that human disturbances have a much wider impact than previously thought, even in nature reserves. Pollution, logging, garbage, trampling and human-caused fires can exclude plants from their habitats and prevent their recolonization," Pärtel says. “We also found that the negative influence of human activity was less pronounced when at least one third of the surrounding region remained pristine, which supports the global goal of protecting 30% of the land,” he adds.
40 sampling points in the Valencian Region
Despite the challenges posed by COVID-19 and the global economic and political crises, data were collected over the years thanks to the DarkDivNet network, through which more than 200 researchers contributed records from 5,500 sites in 119 regions worldwide for analysis at the University of Tartu. Data from several places in the Valencian Community also appear here thanks to the contribution of the team of CSIC researcher Francesco de Bello at the CIDE.
"Our results, based on samples collected at about 40 sampling points in the Comunitat Valenciana, exemplify the effects described in the article. This is a region with a considerable Human Footprint, despite the fact that the sampling points are located within the Sierra de la Calderona Natural Park, between the provinces of Castellón and Valencia," explains de Bello, a Meelis collaborator for more than a decade and also the author of the paper.
In addition to CIDE, other CSIC centers such as the Experimental Station of Arid Zones (EEZA-CSIC), the Experimental Station of Zaidín (EEZ-CSIC) and the Botanical Institute of Barcelona (IBB-CSIC) are participating in the work.
Reference:
Pärtel, M., R. Tamme, C. P. Carmona, K. Riibak, M. Moora, J. A. Bennet, A. Chiarucci, M. Chytry, F. de Bello et al. (2025). Global impoverishment of natural vegetation revealed by dark diversity. Nature. DOI: 10.1038/s41586-025-08814-5
CIDE Communication
