New Research on Biodiversity and Nature
A round-up of recent work published in scientific journals
Rising shark killing. Climate-driven extinctions. Conservation-climate-development synergies and trade-offs. Antarctic ocean acidification. Factors affecting US pollinators. Prognosis for Atlantic Forest trees.
More sharks are being killed despite protective regulations: Sharks play crucial roles in marine ecosystems as top-level predators, but they are among the planet’s most threatened species. Overfishing, ‘bycatch’ — the incidental capture of sharks by vessels fishing for other species such as tuna — and high consumer demand for shark fins are all to blame. According to this study, sharks are being killed in increasing numbers despite widespread legislation and efforts to reduce demand for shark fins. It estimates the number of sharks killed each year rose from 76 million to 80 million between 2012 and 2019. About one third of these sharks were threatened species. The authors say better regulations are needed to end overexploitation. Read the press release or the paper in Science.
How many species will be driven to extinction by climate change? The main threats to species today include habitat loss and overexploitation. But what about future threats from climate change? Estimates of how many species it will kill off vary greatly. This paper says past assessments may underestimate extinction by excluding rare species, and may overestimate it by failing to consider how species can adapt to change. Taking this into account, the authors suggest that 3-6 million species could go extinct in the next 50 years or so, even under intermediate climate change scenarios. Find the paper in Global Change Biology.
Mapping key areas for biodiversity and nature’s gifts to people: In this study, researchers looked at ten ways that nature contributes to people — such as through flood regulation, carbon storage, crop pollination and wood production. They found that conserving about half of the global land area would maintain 90 percent of current contributions to human wellbeing, while also protecting tens of thousands of bird, mammal, reptile and amphibian species. But more than a third of this area is also suitable for farming, extractive industries, urban development and renewable energy. And only 18 percent is currently protected. The study highlights the need for policymakers to consider synergies and trade-offs among targets for conservation, climate, and development. Read the press release or the paper in Nature Communications
Ocean acidification in Antarctic marine protected areas: When carbon dioxide produced by human activities dissolves in sea water it increases the water’s acidity. If seawater becomes too acidic, the plankton that form the base of marine food chains grow less well or die. Acidic water also weakens the shells of animals such as sea snails. This study considered future ocean acidification under different scenarios of greenhouse gas emissions. It found that even under an intermediate emissions scenario, water would increase in acidity by more than 40 percent. With high emissions, it would double. The authors warn of potential impacts across biodiverse marine protected areas, whose top predators include whales and dolphins. The study says severe acidification can only be prevented with rapid cuts in carbon emissions. Read the press release or the paper in Nature Communications.
Honey study shows factors affecting flowers and their pollinators: Yields of honey from managed beehives have fallen greatly in the United States since the 1990s. This suggests a decline in the availability of flowers providing pollen and nectar, which would affect not only honey bees but also wild insects that are pollinators. To identify what factors are involved, researchers used data collected across the country over five decades. They found that regional soil and climate conditions set the baseline levels of honey production, while herbicide use, changes in land use and weather patterns influenced how much is produced each year. The findings can support the development of strategies for boosting the resilience of flowering plants and pollinator species. Read the press release or the paper in Environmental Research.
High extinction risks for Atlantic Forest trees: The Atlantic Forest of eastern South America is a biodiversity hotspot, with many plant species that are found nowhere else. This paper assessed the conservation status of nearly 5,000 tree species there and found that about two-thirds of them are threatened with extinction — including 82 percent of those that live only there. The authors rediscovered five species thought to be extinct but also identified another 13 that may now be lost forever. They estimate that 35–43 percent of all trees worldwide are threatened with extinction due to habitat loss alone, making trees among the planet’s most at-risk groups of organisms. Read the paper in Science.
In case you missed it, earlier this week I published Nature Beat #11 — full of news, resources, jobs, great stories, and more.
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