A Spectacular Thug Is Out of Control

GR: As I’ve often reported, only construction and total habitat destruction have done as much as invasive plants and animals to reduce global biodiversity and productivity. Introduction of invasive species is continuing its impact and the rate is accelerating. Global warming is gaining fast, and will combine with the others of the human impacts to push the human impact on the Earth to extremes that will require millions of years of recovery after we are gone. Here’s a report by Paul Simons on an invasion that will take years of intense labor to stop.

Invasive rhododendron ponticum spreading on the Isle of Mull, Scotland. Photograph: Mark Boulton/Alamy Stock Photo

“Rhododendrons are flowering now in a magnificent springtime spectacle – but they are thugs, invading some of our finest and most precious countryside with catastrophic impacts on wild plants and animals.

Rhododendron ponticum was first brought to Britain, probably from Spain or Portugal, around 1763 for botanical gardens and used on big estates as cover for game birds. But the shrub has spread out of control with huge damage to many native woodlands, heaths and other wild places like the Snowdonia national park. The plant now covers 98,700 hectares, roughly 3.3 per cent of Britain’s total woodland, a report by the Forestry Commission found, and Scotland has been hit particularly hard, where it covers 53,000 hectares.

Rhododendron grows into huge bushes with thick vegetation that blocks out sunlight and smothers most other wild plants and trees, stopping them from growing or regenerating. Its leaves are toxic to animals and repels wildlife from earthworms to birds. Many bushes have become infected with the highly pernicious tree disease called sudden oak death that threatens many types of trees and shrubs. Outbreaks of the disease in the UK, especially on larch trees, have often been linked to Rhododendron ponticum.

“Each plant can produce one million or more tiny seeds each year that spread in the wind, and it also spreads with massive tangles of branches rooting in the ground. The plant is incredibly difficult to get rid of by digging up or using herbicides. Snowdonia national park and several other sensitive areas have tried to destroy the invading rhododendron involving hundreds of people over many years digging up the plant. It’s expensive, time-consuming and takes years to completely eradicate.” –Paul Simons (Source: A spectacular thug is out of control | Science | The Guardian.)

Human habitat destruction is decimating giraffe populations

GR: The needs and desires of humans cause extinction, pollution, desertification, ocean acidification, and global warming. Failure is certain if we tackle any or all of these without first working to reduce the human population.

“In a year filled with many…memorable…milestones, 2016 closed with a truly depressing one, as giraffes were added to a list of “vulnerable” species headed towards eventual extinction for the first time. Their numbers have declined precipitously over the last three decades, according to a report released by the International Union for the Conservation of Nature, which maintains endangered species lists.

“The culprit? You guessed it—human population pressures.

“Habitat destruction due to human activity—such as logging, farming, and armed conflicts—is pushing giraffe populations to the breaking point throughout the African continent. An ever-expanding human population, largely unchecked due to a huge unmet need for family planning, is having a frighteningly damaging effect on these majestic animals.

“U.S. funding of international family planning programs has the greatest impact in the developing world, where women desperately want to limit their family size but lack the means to do so. All ten of the countries with the highest total fertility rates are currently located on the African continent. Home to some of the world’s most iconic wildlife, these nations are struggling to meet the needs of their human inhabitants while protecting the natural habitats that these animals depend on.

“And sadly, the implementation of the Global Gag Rule has thrown another huge obstacle into the path of slowing population growth throughout the developing world. It deeply undermines progress made towards smaller families and more sustainable communities. Humans and wildlife alike will suffer the consequences if we don’t keep fighting to make international family planning a funding priority.+ –Natalie Widel (Source: Human habitat destruction is decimating giraffe populations.)

Behind New Zealand’s wild plan to purge all pests

Invasive Species

GR:  After 1500 AD, sailing ships and then later on, motor-powered ships began transporting and introducing plant and animal species all over the globe. Freed from the predators and diseases of their homes, some of the introduced species became invasive–that is, they began spreading, replacing native species, and decreasing ecosystem stability and productive. This is not news, of course, biologists have long been aware of the devastation caused by invasive species.

Eradicating invasive species is very expensive and very difficult. National resolve and full public support are required. Eradication is something that we humans, who are responsible for spreading the invasive species, should be about everywhere.

However, it is essential to place greater focus preventing the initial introduction of non-native species. Prevention is cheaper and kinder than eradication. And again, prevention is not a new idea. Natural resource managers have known how to prevent invasions for the past century. In many instances, they just don’t take the necessary steps. Here are some articles on invasive plants.

New Zealand has one of the worst invasive plant and animal problems in the world. The article below describes an ambitious and necessary plan to do something about it.

New Zealand Eradication Plan

New Zealand has three invasive species of rat. The Pacific rat, or kiore (Rattus exulans), was introduced from Polynesia in about the twelfth century; the ship rat (Rattus rattus) arrived in the late 1700s; and the Norway rat (Rattus norvegicus) became established in the 1860s. All three prey on native birds, insects and lizards, and have been blamed for the decline or extinction of a variety of species.

“Razza the rat nearly ended James Russell’s scientific career. Twelve years ago, as an ecology graduate student, Russell was releasing radio-collared rats on to small islands off the coast of New Zealand to study how the creatures take hold and become invasive. Despite his sworn assurances that released animals would be well monitored and quickly removed, one rat, Razza, evaded capture and swam to a nearby island.

“For 18 weeks, Russell hunted the animal. Frustrated and embarrassed, he fretted about how the disaster would affect his PhD. “I felt rather morose about the prospects for my dissertation,” he says.

“Although there was a lot of literature on controlling large rat populations, little had been written about tracking and killing a single rodent, which turns out to be rather important in efforts to completely eradicate a species. “It demonstrated how hard it is to catch that very first rat as it arrives on an island — or, conversely, the very last rat that you’re trying to get off,” says Russell, now at the University of Auckland.

Brushtail possums are among the numerous invasive pests regularly culled in New Zealand.

“Razza’s escape became the subject of a paper in Nature1 as well as a popular children’s book. And now, with more than a decade of successful pest-eradication projects behind him, Russell is taking on a much bigger challenge. He is coordinating research and development for a programme that the government announced last July to eliminate all invasive vertebrate predators — rats, brushtail possums, stoats and more — from New Zealand by 2050 to protect the country’s rare endemic species.” –Brian Owens (Continue reading:  Behind New Zealand’s wild plan to purge all pests : Nature News & Comment)

The harlequin ladybird is a clever little devil

GR:  This is a good example of the unintended harm caused by human efforts to improve nature for human benefit.  Accidental and intentional introductions of plants and animals from one continent to another releases the plants and animals from their native predators and diseases. If they multiply, they can replace whole ecosystems and cause drastic reductions in biodiversity and productivity. After the immediate effects of habitat loss to construction, human-introduced invasive species are the most significant contemporary destructor of nature. As global warming effects grow, surviving humans will probably share the Earth with these species.

“Tricked out in Halloween orange and black, a harlequin moves awkwardly through a micro woodland of moss on the concrete as if it were wandering through an alien world, which in some respects it is. This is Harmonia axyridis succinea, a beetle that began its global travels somewhere in eastern Asia between Kazakhstan and Japan.

“Because its larva has an insatiable appetite for aphids and other small insects it was taken to America in the 1980s for the biological control of crop pests. It was so successful that it has been transported into European agriculture, too. To show its appreciation the beetle, called the Halloween ladybug in the US and the harlequin ladybird in Europe, has had a population explosion.

“This is such a common story of what happens when commerce controls nature for its own ends that it comes as no surprise that a creature pressed into servitude causes fear on liberation. It arrived here in 2004 and in 10 years spread throughout an area that took grey squirrels a century to colonise.

Harlequin ladybirds declared UK’s fastest invading species

“Described as a “voracious invader” with a frightening appetite for other ladybirds and the eggs of butterflies and moths, the harlequin causes understandable alarm, given the threat it poses to Britain’s beleaguered wildlife. By the time the harlequin arrived here it was far too late to do anything about it.” –Paul Evans (The harlequin ladybird is a clever little devil).