According to the US Daily Science Network, scientists say that the earth is in the sixth mass extinction of species, and half of all animal and plant species are disappearing. These remarks are not entirely alarmist. Two years ago, Zhugraf, executive secretary of the United Nations Convention on Biological Diversity, warned: Humanity is at a critical juncture of the sixth mass extinction of species since the extinction of the dinosaurs, and it is human beings who are directing this tragedy. . Excessive human activities are leading to a crisis of extinction of plant and animal species.
Due to the current global economic crisis, in order to use limited funds to save more endangered species, biologists at the University of California, Santa Barbara are working around the clock to determine whether Which species are protected?
Their international research results on grassland ecosystems have been published in the latest issue of "Proceedings of the National Academy of Sciences".
Bradley Cardinale, an assistant professor in the School of Ecology, Evolution and Marine Biology (EEMB) who is engaged in this research, said that the current species extinction events are attributed to human activities and human overuse of the earth. resources, creating a lot of pollution and causing a serious ecological crisis. At the current rate of species extinction, half of all species will disappear in our lifetime. Today we should know which species are most deserving of our protection and rescue. He explained that the most recent mass extinction occurred 65 million years ago, called the "Cretaceous Tertiary Extinction Event," which led to the extinction of the dinosaurs that dominated the earth, and a large number of plants also suffered. Many scientists believe that this catastrophic mass extinction may have been caused by a meteorite impacting the Earth.
According to existing research, many genetically unique species are critical to an ecosystem, and they are the species that scientists recommend for priority protection. "Now that we know that ecosystems around the world are losing species, we have to know which species are the most important in the ecosystem," said Mark W. Cadote, a postdoctoral researcher at the National Center for Ecological Integrated Analysis (NCEAS) at the University of California, Santa Barbara. , which species should we invest our resources in protecting?"
Cadotte and other colleagues have conducted nearly 40 important detailed studies of grassland ecosystems around the world. They compared the genetic maps of plants. The evolutionary history of 177 flowering plant species was reconstructed. They found that some species are actually more important than protected species in terms of ecological functions, and many of these species have unique genetic characteristics. So they are looking to species' evolutionary histories to guide conservation efforts for the most important species, and to gain insight into the potential consequences of the extinction of these important species.
Recent research shows that ecosystems with fewer species produce less biomass than those with more species. Less plant biomass means they absorb less carbon dioxide from the atmosphere while releasing There is correspondingly less oxygen. So when global biomass falls, life-supporting oxygen in the atmosphere will be severely affected. Additionally, there will be insufficient grass for herbivores to eat. The entire grassland food chain will be destroyed, which will affect crop and fishery yields.
The extinction of a very unique species would have worse consequences than the extinction of some of its close relatives, scientists say. Plant communities that show a longer evolutionary history are more productive. Cadotte explained that, for example, ranunculaceae are a very unique species with a long evolutionary history, and their extinction would have a greater ecological impact than the extinction of daisies or sunflowers. Daisies and sunflowers are closely related species and have more similar genetic makeup. Even in a small ecological environment, if one plant becomes extinct, another can take its place and play its role in the ecosystem. Cadotte said the study was comprehensive and included grassland plants found in Europe, America and Asia. And the results show that genetic diversity can predict whether a species is important.