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According to a new analysis in Science Advances, nearly 24 000km of new roads will be built through tiger habitats by mid-century, stimulated through major investment projects such as China’s Belt and Road Initiative.

A team of ecologists at the University of Michigan calculated the extent and potential impacts of road networks across the 1 160 000 sq. km, 13-country range of the endangered tiger and found that these roads total 134 000 km across tiger habitats and are already decreasing the population and its prey by more than 20%.

The team also found that 43% of breeding activity occurs within 5km of a road and 57% of land in protected tiger habitats sits within 5km of a road. Areas without any formal wildlife protections have road densities 34% higher than protected areas, showing the importance of legal conservation efforts in saving tigers, their prey and their habitats. 

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Tiger conservation landscapes (TCLs) vary considerably by protection status and country. These protected areas are important, because they support tiger ‘source’ populations that can disperse and repopulate larger landscapes; this is being threatened by higher road densities, which kill tigers either through vehicle collisions, or through the habitat intrusion caused by the development of roads. For example, the Bukit Tigapuluh Landscape, which has one of the highest road densities surveyed in the analysis, lost nearly 40 sq. km of forest from 2000 to 2012 largely due to the expansion of palm oil plantations; adult tigers in this region decreased from 36 to 22 in the same time period. Additionally, a simulation study in Central India found that tiger extinction risk rose steeply (through genetic isolation) when road traffic volume increased. 

Further, regional road policies may be creating ‘tiger islands’, whereby tiger source populations are becoming increasingly isolated from each other. Tiger dispersal and population expansion into the nonprotected forests connecting those populations are vital in facilitating growth opportunities for the species. 

Worryingly, even protected areas are not immune to road development; TCLs in India have the largest density of roads of any other tiger range country. Similarly, road encroachment into areas where tigers have been recently detected (2009-2014) is already pervasive and even greater than places where tiger presence is unknown or unlikely. 

Neil Carter, lead author of the study, says, “Tigers face a ubiquitous and mounting threat from road networks across much of their 13-country range. Tiger habitats have declined by 40% since 2006, underscoring the importance of maintaining roadless areas and resisting road expansion in places where tigers still exist, before it is too late.”

Just 4 000 tigers exist in the wild today, most of them living in South Asia, where development and population pressures are increasing rapidly. They are considered an umbrella species, which means that protecting tigers will also promote the conservation of many other threatened species and some of the world’s greatest biodiversity hotspots.

The infrastructure boom throughout forested regions of South and Southeast Asia, financed through China’s Belt and Road Initiative, will threaten tigers further. As signatories of the Convention on Biological Diversity, all tiger range countries have legally binding responsibilities to create legislation that minimises harm to threatened species, including tigers. This presents opportunities for the Initiative, whereby it could adopt biological conservation as one of its core values through planning and implementing a network of protected areas and wildlife corridors. The creation of bilateral agreements that include provisions for reducing wildlife poaching and trafficking between China and countries that are a part of the BRI would also lessen the impacts of infrastructure development on tigers and other threatened species. Another possible policy to minimise the impacts of roads on tigers and other wildlife would be to require Chinese-funded BRI efforts overseas to ascribe to the same environmental regulations on road development that now exist within Chinese borders. 

Featured image by: happymillerman

A new study states that it is not too late to save our planet’s coral reefs before they go extinct.

Coral Reef Extinction Facts

Coral reefs host a quarter of the Earth’s marine biodiversity and support livelihoods of more than half a billion people. But, the planet has already lost half of its coral reefs over the last three decades, and more than 90% of them might become extinct by 2050.

Corals face a number of threats including overfishing, diseases, and pollution, while the biggest of them all is climate change. The world’s largest coral reef system- the Great Barrier Reef, which is visible even from outer space- has lost half of its coral in the past two years because of extreme heat stress from global warming.

While conservationists around the globe are grappling with how to preserve the last surviving ‘underwater rainforests’, the most comprehensive study on coral reefs published last week has suggested a few ways to save them. As part of the research, an international group of 80 scientists surveyed more than 2,500 coral reef systems across 44 countries to determine how to protect them in the face of extensive damages caused by human activities and global warming.

“The good news is that functioning coral reefs still exist, and our study shows that it is not too late to save them,” said Emily Darling, the lead author of the study and a Wildlife Conservation Society (WCS) scientist leading the global coral reef monitoring program. “Safeguarding coral reefs into the future means protecting the world’s last functioning reefs and recovering reefs impacted by climate change. But realistically — on severely degraded reefs — coastal societies will need to find new livelihoods for the future.”

Examining coral abundance in the Indian and Pacific oceans, they found that many of the reef systems were full of complex species that created distinctive structures and were functioning in spite of deadly marine heatwaves in recent years.

Heatwaves had affected many coral reefs during the El Niño event between 2014 and 2017. But 450 reefs in 22 countries survived in protective cool spots. The scientists believe those areas should be the focus of urgent protection and management efforts. Previously, the Indo-Pacific reefs were also hit by mass coral bleaching and heat stress in 1983, 1998, 2005 and 2010, before the world’s most intense, longest and largest bleaching event between 2014 and 2017.

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A marine scientist gathering data on coral reefs in the waters of Fiji. Credit: WCS

How to save coral reefs?

The researchers outlined three conservation strategies to save the reefs: protect, recover, and transform. As part of the first strategy, the international network of coral reef conservation should focus on protecting functioning coral reefs found in East Africa to Southeast Asia, the Coral Triangle, and the Pacific. The second strategy is to promote rapid recovery of coral reefs impacted by the 2014-2017 coral bleaching event. To implement the third strategy, selected coastal communities around the world should be relocated to avoid dependence on reefs that are no longer functioning.

The scientists pointed out that strategic local management can help protect corals through tools such as marine protected areas, or other management restrictions that reduce threats and keep coral reefs above functional thresholds.

“While coral reef sustainability depends largely on reducing carbon emissions, identifying reefs that are likely to respond — or importantly, not respond — to local management is critical to targeting development and management strategies to build the well-being of the millions of people dependent on coral reefs across the globe,” said Georgina Gurney, study co-author from the ARC Centre of Excellence for Coral Reef Studies at James Cook University

The researchers also noted that limiting global temperature within two degrees Celsius over pre-industrial levels is the only way to ensure the survival of reefs.

“Saving reefs will require combining local and global efforts, such as reducing local dependence on reef fish to maintain a reef’s important functions while also reducing carbon emissions to keep warming below 1.5C,” said Tim McClanahan, co-author of the study and Wildlife Conservation Society senior conservation zoologist.

Gabby Ahmadia, director of marine conservation science at World Wildlife Fund and co-author of the study said that the study would help policymakers and conservationists make informed management decisions for coral reefs and the communities that rely on them before they go extinct.


The first ever global analysis of plant extinction found that over 570 species of plants have gone extinct in the last 250 years. Researchers believe even these numbers underestimate the true levels of the ongoing extinction.

571 plant species have completely disappeared from Earth in the last 250 years- more than twice the number of bird, mammal and amphibian species to have gone extinct in the same period combined.

The extinction rate is 500 times greater now than before the industrial revolution. The study was conducted by a team of researchers at the Royal Botanic Gardens, Kew, and Stockholm University.

The pattern of extinction of plants is strikingly similar to that of animals, though it doesn’t seem to be based on evolutionary patterns, as it is with the latter.

The majority of plant extinctions occurred in biodiversity ‘hotspots’ in the Tropics and the Mediterranean, including places like Australia, India, and Hawaii. Of all the extinct plant species numbered throughout the world, half were once found on islands and 18 percent once flourished in the Pacific.

“This probably reflects the high proportion of unique species (endemics) in island biotas and their vulnerability to biological invasion,” the authors suggest. “Consistent with this, we found that extinct species have narrower ranges than seed plants as a whole. We also found that most extinct plants were woody perennials and from the wet tropics or subtropics.”

Why do plants go extinct?

Many new plant species might also be headed for extinction because of habitat loss, climate change, and human exploitation. Around a third of the 90,000 species the team analysed could be considered threatened in some way.

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The Saint Helena olive, Nesiota elliptica, first discovered in 1805. It went extinct in 2003.
Photograph: Kew Gardens

To reach these conclusions, the researchers scoured every journal and plant database at their disposal, beginning with a 1753 compendium by pioneering botanist Carl Linnaeus and ending with the regularly updated IUCN Red List of Threatened Species, which maintains a comprehensive list of endangered and extinct plants and animals around the world. After combining and cross-checking the various extinction reports, the team compared the results to the natural or “background” extinction rates for plants, which a 2014 study calculated to be between 0.05 and 0.35 extinctions per million species per year.

Despite the gloomy outlook for planet Earth, the study does provide a glimmer of hope. The team found that 430 plant species which were thought to have gone extinct were rediscovered in the period they investigated. However, it should be noted that 90 percent of these rediscovered plants have a high extinction risk.

Researchers called for a number of measures to stop plant extinction: recording all the plants across the world, supporting herbaria, which preserve plant specimens for posterity, supporting botanists who carry out vital research, and teaching our children to see and recognise local plants. “We urge botanists to compile data on search effort, species density, abundance and detectability and to engage local people in the search for their missing biodiversity.” the authors say. “Such efforts will improve our understanding of genuine extinctions and help target future conservation action.”

Featured image: An artist’s rendering of extinct plant Sigillaria

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