Beyond Barrier


One million species risk extinction


In May, an alarming headline was run by most major news organisations around the world ‐ ‘One million species face extinction, a UN report says’.

The report 1 was released by the United Nation’s Intergovernmental Science‐Policy Plaƞorm on Biodiversity and Ecosystem Services (IPBES) which is tasked with assessing the state of biodiversity and the ecosystem services it provides to human society.

Seven lead authors from universities around the world prepared the report, which also draws (for the first time ever at this scale) on indigenous and local knowledge.

The report found that one million animal and plant species are on the verge of extinction, many within decades, and more than ever before in human history. Species loss is linked directly to human activity.  “The health of ecosystems on which we and all other species depend is deteriorating more rapidly than ever. We are eroding the very foundations of our economies, livelihoods, food security, health and quality of life worldwide (4).”

The assessment’s authors ranked the five direct drivers of change in nature with the largest global impacts so far being: changes in land and sea use; direct exploitation of organisms; climate change; pollution; and invasive alien species.

Despite progress to conserve nature and implement policies, the report finds that global goals for conserving and sustainably using nature and achieving sustainability cannot be met at current trajectories. Goals for 2030 and beyond may only be achieved through ‘transformative changes across economic, social, political and technological factors’.

Increasing pressure on natural systems ‐ the facts at a glance

  • Three‐quarters of the landbased environment and about 66% of the marine environment have been significantly altered by human actions.

  • Urban areas have more than doubled since 1992.

  • About 60 billion tons of resources are extracted globally every year ‐ doubling since 1980.

  • The average abundance of native species in most major land‐based habitats has fallen by at least 20%, mostly since 1900.

  • The number of invasive alien species per country has risen by about 70% since 1970, across the 21 countries with detailed records.

  • In 2015, 33% of marine fish stocks were harvested at unsustainable levels; 60% maximally sustainably fished, and 7% harvested sustainably.

  • Plastic pollution has increased tenfold since 1980, and 300 to 400 million tons of heavy metals, solvents, toxic sludge and other wastes are dumped annually into the world’s waters.  

Climate change potential to accelerate island extinctions

Researchers are beginning to better understand how multiple threats, such as invasive species, habitat loss, and climate change, might effect island wildlife (1).

Several examples illustrate the very real compounding effects of these threats. For the Baird’s sandpiper (Calidris bairdii), a rare visitor to New Zealand, climate change is the number one threat. The species use environmental and climatic clues throughout the year, such as seasonality of food supply. If the timing of food availability changes, the birds are unlikely to rapidly adapt. Chicks emerging earlier in the season (before their food supply is at peak abundance) are less likely to survive.

Newborn hawksbill sea turtle. Photo: T. Hall/Island Conservation

Newborn hawksbill sea turtle. Photo: T. Hall/Island Conservation

Some species are already gone. The Bramble Cay melomys (Melomys rubicola) was a small mammal living only on Bramble Cay, off Australia. Historically, several hundred were on the island, which has been reduced in size by rising sea levels from 4 to 2.5 hectares. The last sighting of a melomys occurred in 2009.

Loggerhead and hawksbill sea turtles are facing serious climate‐related issues including changing currents, disturbances to food webs, and decreased nesting habitat. The temperature of incubation can influence the gender of offspring and hotter sand will lead to more females being born. Potentially beneficial in the short term, a major skewing of gender long‐term is likely to pose serious risk to their viability.

Despite species‐specific conservation efforts, climate change is very likely to lead to irreversible losses to species around the world, with island wildlife at extremely high risk.

Lord Howe Island commences rodent eradication project

Lord Howe Island, 780 km northeast of Sydney. Rats invaded from a sinking ship in 1918. Photo: I. Hutton

Lord Howe Island, 780 km northeast of Sydney. Rats invaded from a sinking ship in 1918. Photo: I. Hutton

Lord Howe is the largest inhabited island in the world to undertake a full scale eradication of rodents. Operations started in May and baiting is expected to take several months, with the island monitored for two years to confirm that the rats are gone 1 . The project has created tensions in the small island community of 350 people. Concerns range from health effects to the potential for accidental deaths of threatened species. In an interview for the Australian Broadcasting Corporation (ABC), the chair of the local board acknowledged the divisions on the island, which “are understandable” (2). The project was declared safe for residents and visitors, including in a 2017 human health risk assessment completed in by the NSW Office of the Chief Scientist (3). In the same ABC article, a sixth generation islander reflected on the loss of bird life.

“Growing up here, every weekend we’d go for a walk in the bush with Dad, and he would point out every bird’s nest, every tree. And slowly that’s being eroded away, to the extent now that we go for a walk in the bush and it’s quiet. There are species you rarely see, they’ve just been decimated.” (2)


1 https://lhirodenteradicationproject.

2‐06‐11/rat‐ infestation‐on‐lord‐howe‐island‐splits‐ residents/11180624

3 NSW Office of the Chief Scientist and Engineer. 2017. Report on the Human Health Risk Assessment for the Lord Howe Island’s proposed Rodent Eradication Program. Chief Scientist & Engineer. July 2017. Photo: I. Hutton Lord Howe Island, 780 km northeast of Sydney. Rats invaded from a sinking ship in 1918. Newborn hawksbill sea turtle.

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