科學家們預告，現存的人類將經歷地球生物史上第六次大滅絕，近一半的動植物將因此消失殆盡。在所有的生物中，部分物種與其他物種相較起來，對於維繫生態系統運作上有著極大的重要性；科學家們鑒此踏遍世界各地的草原，最後發現具獨特基因的生物，正是最具價值物種所在。
生態學助理教授卡汀那（Bradley Cardinale）與其研究團隊，目前正試圖確定哪些物種須立即受到保護。他們的跨國性研究計劃檢視了全球40份關於草原生態體系的報告，並透過植物基因結構比較法，重新建構這些報告中177種開花植物的演進歷程。
卡汀那表示，「這份報告針對美國及歐亞大陸上所有知悉的植物進行研究，因此研究成果的可信度相當高。我們的研究結果顯示，基因多樣性將可辨別某一物種在維繫生態系統上的重要程度」。
報告書的主筆、國家生態整合與分析中心研究員卡托特（Marc Cadotte）指出，「由於全球已有多樣生物從生態系統中消失，我們必須趕緊釐清哪些物種最具重要性，並竭盡所有心力予以最適妥的保護」。
卡托特特別點出毛莨是演化得最獨特的物種。舉例來說，毛莨在整個生態系中的角色，是雛菊或是葵花也取代不了，因此毛莨若消失，影響所及將更勝其他兩者。
科學家們推論，由於雛菊與葵花的基因模組相似，因此假使葵花界臨消失，雛菊多少可替代葵花在體系中的位置。
近年來的研究皆指出，生態系統中生物物種較少者，其蘊涵的生物量相較於物種較多者，普遍要少許多。植物生物量愈低代表從大氣中吸收的二氧化碳愈少，相對地無法產生更多的氧氣。換句話說，當地球上的植物量萎縮，大氣中提供生命所需的氣體，在組成上將會明顯受到影響。到時，草食性動物的食物來源變得有限；整個食物鍵可能因此產生混亂，並阻斷穀物和漁獲的生產。
另外，那些看似與其他物種無直接關聯的物種一旦消失，對於整個生態系統生產力造成的影響，事實上要比與其他物種有直聯關聯的物種消失還來得嚴重。且生態系統中單一物種的基因愈是不同，對於體系內生物量的影響相對愈大。
6,500萬年前遐邇聞名的白堊紀──第三紀大滅絕事件，正是地球生物史上最近一次與此次科學家預測程度相當的大滅絕，而科學家們普遍堅信事件主因是由慧星撞擊地球所致。地球受到撞擊後造成的氣候變化，讓非禽類恐龍絕種，且大量的植物物種也在當時消失。
The sixth mass extinction of both plants and animals is underway, scientists say, warning that nearly 50 percent of all species could disappear within the lifetimes of people now living on Earth.
Some species are more critical than others in preserving the functions of ecosystems and scientists researching grasslands around the world have found that the most valuable species are those that are genetically unique.
Bradley Cardinale, assistant professor of ecology, and his team are attempting to determine which species must be saved. Their international study reviews 40 studies of grassland ecosystems around the world and reconstructs the evolutionary history of 177 flowering plants used in these studies by comparing the genetic makeup of the plants.
"This study includes studies of plants that are found throughout the U.S., Europe, and Asia. We can have a high degree of confidence in the results. And the results show that genetic diversity predicts whether or not species matter," said Cardinale.
"Given that we are losing species from ecosystems around the world, we need to know which species matter the most and which we should pour our resources into protecting," said first author Marc Cadotte, a postdoctoral fellow at the National Center for Ecological Analysis and Synthesis.
Cadotte explained that the buttercup is a very unique species, evolutionarily. Losing the buttercup would have a much bigger impact on the system than losing a daisy or a sunflower, for example.
A daisy and a sunflower are closely related species with similar genetic makeup. Each could, therefore, help fill the niche of the other, if one were to be lost, the scientists reason.
Recent studies show that ecological systems with fewer species produce less biomass than those with more species. Less plant biomass means that less carbon dioxide is absorbed from the atmosphere and less oxygen is produced.
So, as the biomass of plants shrinks around the globe, the composition of gases in the atmosphere that support life could be profoundly affected. There will be fewer plants for herbivorous animals to eat. Entire food chains can be disrupted, which can impact the production of crops and fisheries.
The loss of species that are not closely related to other species in the ecosystem reduces productivity more than the loss of species with close relatives. And the more genetically distinct a species is, the more impact it has on the amount of biomass in an ecosystem.
The last mass extinction near the current level took place 65 million years ago, called the Cretaceous Tertiary extinction event. Scientists believe it was the result of a meteor hitting the Earth. It is best known for the extinction of non-avian dinosaurs, but large numbers of plant species also became extinct at that time.
