At a time when the great global trends on our planet are being debated, such as climate change, greenhouse effect, the average increase in air and sea temperature, rise in sea level, increase in extreme weather events such as major droughts, floods or heat waves, the big question is: how do the different ecosystems on our planet behave?
An international team of scientists, including the Portuguese Miguel Pardal and Filipe Martinho, from the University of Coimbra (UC), developed a study to try to answer this and other questions and concluded that local changes in diversity sometimes do not follow the global trends.
The study, published in the journal Nature Communications, brought together 60 European researchers from around 50 institutions. Together, they analyzed more than 150 biodiversity time series (from 15 to 91 years old), covering 6,200 marine, terrestrial and freshwater species from 21 countries in Europe, in different bioregions (from north to south), encompassing different groups of organisms (insects, fish, birds, mammals, marine invertebrates, plankton, etc.). This research will have an impact on the development of effective conservation concepts.
The results reveal that local trends in abundance, specific richness and diversity differ between biogeoregions, type of ecosystem, taxonomic groups (birds, mammals, fish, insects, marine invertebrates, plankton), demonstrating that “changes in biodiversity at a local scale are complex phenomena that cannot be easily generalized. However, as predicted, there is an increase in specific richness and abundance with increasing temperature and decreasing human impact on each ecosystem, as well as a clear spatial pattern of changes in the composition of the community (ie, temporal taxonomic turnover. ) in most biogeoregions ”, indicate Miguel Pardal and Filipe Martinho.
The global trend on the planet and in Europe seems clear: for years, species diversity among almost all groups of animals and plants has declined at an alarming rate. “However, at the regional level, the picture is more complex – here, local factors, such as the loss of rare species and the establishment of new species, play a significant role in the overall results. The functions of the ecosystem, namely with regard to goods and services provided, therefore the benefits associated with humans, are always related to the respective abundance, number and diversity of species in each location, making it more difficult to make a more global generalization”, explain the researchers from the Center for Functional Ecology of the Faculty of Science and Technology of the University of Coimbra (FCTUC).
In other words, they add, “it is essential to know the different trends in biodiversity in each ecosystem and in each location, in order to implement sustainable protection measures“.
The researchers’ analysis also reveals that “in large areas of central and southern Europe, neither the diversity of species nor the number of species and individuals has changed, while in northern Europe there has been an increase in diversity and the number of species. The latter can be partly attributed to rising temperatures in the course of global climate change.”
In addition, underline Miguel Pardal and Filipe Martinho, “in many parts of Europe, traditional fauna and flora are being replaced by new species that are generally adapted to the warmer conditions“. Regarding this observation, the study’s authors warn that “most of the time series started before the 1980s when a significant loss of species had already become apparent. On the other hand, trends can differ significantly, depending on the biome and the group of organisms analyzed (taxonomic group). Although we could observe an increase in biodiversity in marine areas during the study period, this was not the case in rivers. On average, the diversity of algae in coastal areas decreases, while birds and aquatic invertebrates showed a surprising upward trend. This illustrates that trends are not always the same across species or entire ecosystems.
In light of the results of this study, the team recommends “an expansion of biodiversity time series and the standardization of European measurement methods in different habitats. This is the only way to develop significant conservation measures for each region with regard to fauna and flora ”, they conclude.
The scientific article, entitled “Meta-analysis of multidecadal biodiversity trends in Europe”, can be consulted at this link.