biodiversity

Worldwide, 349 species of migratory freshwater fish are at risk and meet the criteria for inclusion in the Appendices of the United Nations Convention on the Conservation of Migratory Species of Wild Animals (CMS), a global treaty designed to protect migratory animals. These fish are among the vertebrates most threatened by factors such as changes in river flow, habitat degradation, exploitation and pollution, the report warns. Among the priority species are 50 species from Europe, including the following freshwater fish from Spain: Alosa alosa (shad), Lampetra planeri (brook lamprey) and Salmo salar (Atlantic salmon).

Global biodiversity is threatened by human impact, which has already led to the extinction of hundreds of species. However, the known tree of life continues to expand with the discovery of numerous clades (groups of organisms that share a common ancestor and all its descendants), according to a international study pubished in PNAS. According to their estimates, made between 2015 and 2020, more than 700 new genera, more than 20 new families, and more than three new orders are described each year, all based on newly discovered species. According to the authors, many new clades remain undiscovered, and describing them before they become extinct should be a priority for research and conservation.

New research analysing more than 33,000 fish populations in the northern hemisphere between 1993 and 2021 reveals that chronic ocean warming is driving a long-term decline in biomass of up to 19.8% per year for species in the Mediterranean, North Atlantic and North-East Pacific. At the same time, in the short term, more fish are thriving in cold areas due to the heat, but these increases are temporary and the authors warn that relying on them would lead to unsustainable exploitation. The study, by the National Museum of Natural Sciences (MNCN-CSIC) and the National University of Colombia, is published in Nature Ecology & Evolution.

Meeting in Manchester (United Kingdom), the plenary session of IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services) ratified its Assessment on Business and Biodiversity, which presents data to understand the dependence and impact of businesses on nature and proposes more than 100 measures to improve the global situation. Three of its representatives explained the main results and proposals at a briefing organized by SMC Spain.

The claim that one type of tree—Picea abies—can anticipate a solar eclipse through electrical signals is based ‘on speculative interpretations and unsupported evolutionary assumptions,’ according to an opinion piece published in the journal Trends in Plant Science. The paper refutes another from 2025 that claimed these trees synchronised their bioelectrical behaviour hours before a solar eclipse in Italy's Dolomite region. According to the authors of the new article, this electrical activity can be explained by temperature changes and atmospheric electrical discharges.

An international team has analysed data from more than 700 mammal populations in zoos since 1970 and concludes that there has been an ageing of the animals and a decline in females of reproductive age. According to the authors, this jeopardises the role of zoos in conserving endangered wildlife species and promoting global biodiversity. The findings are published in the journal PNAS.

Since 2013, undeclared and uncertified exports of fins from five overexploited shark species have been illegal. Now, an international team has determined that illegal fins from four of those species remained prevalent in the market between 2015 and 2021. Among the countries cited as potential violators are Spain, China, and Taiwan. The study is published in the journal Science Advances.

Some ecosystems are able to adapt to moderate droughts, even if they last for several years. However, in scrublands and grasslands, when the phenomenon is extreme and prolonged, their capacity to store carbon plummets. This is the main conclusion of an international study that has assessed the effects of the duration and severity of droughts on the productivity of 74 grassland and pasture ecosystems on six continents. According to the authors, the most vulnerable areas are arid and semi-arid regions, such as those in the Mediterranean region and the southwestern United States. The study, published in Science, involves CREAF, CSIC and IICG-URJC, among other centres.

Extensive warm-water coral reefs are facing widespread mortality and, unless global warming is reversed, will be lost, warns the report Global Tipping Points 2025. This is the first tipping point reached by the Earth system, the first in a series of tipping points that will cause ‘catastrophic’ damage—melting ice sheets, death of the Amazon rainforest, and collapse of vital ocean currents—unless humanity takes urgent action. The report also identifies positive tipping points that have been crossed on a global scale, for example in the area of solar energy and the adoption of electric vehicles.

Four people have died in the fires that began last weekend on the Iberian Peninsula and have spread to different areas of Galicia, Castile and León, Andalusia, Castile-La Mancha, Extremadura and Madrid. The heatwave that continues to grip the country, strong gusts of wind and their changing direction, and the thermal drought are hampering firefighting efforts. The government declared on Tuesday a pre-emergency phase and thousands of people have had to be evacuated.