Drones Are Dropping Poison on Recently Re-invaded Rats in the Galapagos – via Herp Digest

Scientists hope that they've built a better rat trap with flying poison distribution. Eliminate major predator of tortoise eggs and juveniles and bring back ex-situ breeding on islands.

By David Grossman 1/24/19 Source - Wired

ISLAND CONSERVATION

For as long as people have been creating organized communities, rats have been there to pick off the remains. As an invasive species, they're practically unparalleled in their success, much to the chagrin of the people living with them. But when they recently re-invaded Ecuador's Galápagos National Park, a new weapon proved extremely effective in the fight: drones.

While the Galápagos islands are historic for being the site of Charles Darwin's discoveries about evolution, other visitors have been less helpful. Rats first came to the Galápagos along with pirates or whalers sometime in the 17th or 18th century. While the exact timeline is unknown, they've done their damage over the years. They've curbed the births of tortoises and have laid waste to local fauna.

The rats were beaten back from the tiny North Seymour Island in 2007, but they found their way back ten years later. Since then, the challenge has been how to attack the rats without inflicting further damage on a very delicate ecosystem.

Drones provided an ideal solution. Painted blue to make them less noticeable to birds, they dropped poison pellets wherever rats were spotted. "The use of drones is more precise," says Karl Campbell, the South American director of the nonprofit group Island Conservation, in a press statement. "It also increases feasibility, and reduces eradication costs of invasive rodents in small and midsize islands worldwide.”

Earlier this month, two six-rotor drones began lacing North Seymour and a nearby islet with rat poison. Each drone could carry 44 pounds (20 kilograms) worth of poison and fly around for 15 minutes. While one of the drones suffered a mechanical difficulty, according to Nature, they were still able to cover half the island in valuable poison. The breakdown even afforded the chance for an experiment—workers spread the rest of the poison over the island by hand, allowing for an evaluation of the drones.

Island Conservation - A pilot remotely operating a drone as it flies over North Seymour Island.

Drones can't cover every part of the land—for some remote islands, only a helicopter will do. But as Campbell tells Nature, “you have to have a helicopter for a month, sometimes shipped by boat. Your expenses very quickly add up.” Drones allow for more flexibility at a cheaper price.

Craig Morley, an invasive-species specialist at the Toi Ohomai Institute of Technology in Rotorua, New Zealand, says that the drones have a chance to change how scientists view conservation work. “You used to be able to see your opponent. Now, you just a press a button and you fire a missile,” he tells Nature, drawing a comparison between scientific and military drones. “You become a little bit detached from the reality that you have killed something or somebody over there.”

While it is important to keep that detachment in mind, it is unlikely anyone in the Galápagos will miss the rats too much.

Poisonous amphibian defenses are linked to higher extinction risk

Date: November 22, 2016

Source: Swansea University

Research published by a Swansea University scientist has found amphibians which have a toxic defense against predators -- such as the iconic poison dart frogs -- have a much higher risk of extinction than species which use other types of defense mechanisms.

The key finding of Dr Kevin Arbuckle's latest study, published in the journal Royal Society Open Science, is that poisonous species are 60% more likely to be threatened than species without chemical defenses.

Amphibians are usually considered the most threatened group of vertebrate animals and are experiencing population declines globally, raising conservation challenges.

The threats to amphibian biodiversity are numerous and include rapid habitat destruction, exploitation, and pollutants entering the environment.

Many characteristics of animals may be linked to contemporary extinction risk. For instance, certain traits are either known or suspected to influence factors such as mortality rates or the ability of populations to recover after declines, and are therefore potential predictors of extinction risk.

The work by Dr Arbuckle, Lecturer in Biosciences (Evolutionary Biology) in the University's College of Science, used amphibians as a model system and tested whether chemical antipredator defense is associated with contemporary extinction rates. This is possible by using conservation status (e.g. 'endangered', 'vulnerable') as a measure of extinction risk in species alive today.

Dr Arbuckle said: "The results of this new study suggest that while toxic defense can be great for avoiding predators, it might be bad news in the long-term for a species. It's another example of how evolution doesn't act 'for the good of the species', but instead for the good of the individual.

"The results also suggest that how a species defends itself might be part of the puzzle of working out which species are in need of conservation efforts.

"The study builds on my previous work, which found that toxic amphibians were also more likely to become extinct over their evolutionary history, and the next step is to figure out what mechanism is behind the link between defense and extinction.

Dr Arbuckle previously suggested three main possibilities to explain higher extinction rates in toxic amphibians, and figuring out which of these have been important are the focus of another study.

The different ideas are:

            •           Costly chemical hypothesis: Chemical defense is energetically costly;

            •           Marginal habitats hypothesis: Chemical defense allows shifts to 'marginal' (low carrying capacity) habitats, which are intrinsically more vulnerable, and;

            •           Slow life-history hypothesis: Chemical defense is associated with slow life-histories, which damages the recovery of populations after declines.

Story Source:

Materials provided by Swansea University. Note: Content may be edited for style and length.

Journal Reference:

            1          Kevin Arbuckle. Chemical antipredator defence is linked to higher extinction risk. Royal Society Open Science, 2016; 3 (11): 160681 DOI: 10.1098/rsos.160681

Poisonous amphibian defenses are linked to higher extinction risk

Date: November 22, 2016

Source: Swansea University

Research published by a Swansea University scientist has found amphibians which have a toxic defense against predators -- such as the iconic poison dart frogs -- have a much higher risk of extinction than species which use other types of defense mechanisms.

The key finding of Dr Kevin Arbuckle's latest study, published in the journal Royal Society Open Science, is that poisonous species are 60% more likely to be threatened than species without chemical defenses.

Amphibians are usually considered the most threatened group of vertebrate animals and are experiencing population declines globally, raising conservation challenges.

The threats to amphibian biodiversity are numerous and include rapid habitat destruction, exploitation, and pollutants entering the environment.

Many characteristics of animals may be linked to contemporary extinction risk. For instance, certain traits are either known or suspected to influence factors such as mortality rates or the ability of populations to recover after declines, and are therefore potential predictors of extinction risk.

The work by Dr Arbuckle, Lecturer in Biosciences (Evolutionary Biology) in the University's College of Science, used amphibians as a model system and tested whether chemical antipredator defense is associated with contemporary extinction rates. This is possible by using conservation status (e.g. 'endangered', 'vulnerable') as a measure of extinction risk in species alive today.

Continued

Queensland shuts down 'inhumane' goat cull using poisoned dingoes

Environment minister orders all dingoes to be removed from Pelorus Island, where they had been introduced to kill goats

Australian Associated Press

Thursday 18 August 201604.02 BST

An “inhumane” program that used surgically sterilised dingoes as a form of pest control for goats on a far north Queensland island has been shut down by the state government.

The Hinchinbrook shire council had decided to release dogs implanted with time-delayed poison pellets on Pelorus Island, north of Townsville, to kill baby goats as a form of pest control.

The plan was slammed by the RSPCA and community groups as “outright” animal cruelty.

The Queensland environment minister, Steven Miles, on Thursday issued conservation orders to shut down the program and remove all dingoes from the island within 14 days.

Miles said that in the 1990s a similar plan saw dingoes released on Townshend Island but it later caused problems for native birds.

“Pelorus Island currently has no significant predators to the birds on the island,” he said.

Bird species on the island included a threatened species of ground-dwelling shorebird, the beach stone curlew.

The minister also said while some Liberal National party members had contacted him concerned about the “horrendous” plan, the Hinchinbrook MP, Andrew Cripps, declared his support.

Read more  

One snake's prey is another's poison: Scientists pinpoint genetics of extreme resistance

Date: June 9, 2016

Source: Virginia Tech

A select group of garter snakes can thank their ancestors for the ability to chow down on a poisonous newt and live to tell the tale.

Common garter snakes, along with four other snake species, have evolved the ability to eat extremely toxic species such as the rough-skinned newt--amphibians that would kill a human predator--thanks to at least 100 million years of evolution, according to Joel McGlothlin, an assistant professor of biological sciences in the College of Science and a Fralin Life Science Institute affiliate.

The nature of that evolution was recently established by McGlothlin's team and will be published June 20 in the journal Current Biology.

The international team of researchers discovered that the ability to withstand the toxin that the newt produces evolved following a 'building blocks' pattern, where an evolutionary change in one gene can lead to changes in another.

In this case, over time, amino acids in three different sodium channels found in nerves and muscle changed, allowing select snakes to resist the numbness and paralysis typically brought on by the toxin.

Resistant muscle gives snakes the best protection against the newt's toxin, but there's a catch: resistant muscle can only evolve in species that already have resistant nerves. McGlothlin's team found that the ancestors of garter snakes gained toxin-resistant nerves almost 40 million years ago.

"Garter snakes and newts are locked in a coevolutionary arms race where as the newts become more toxic, the snakes become more resistant," said McGlothlin, who is also affiliated with the Global Change Center at Virginia Tech. "However, without the leg-up provided by those resistant nerves, snakes wouldn't have been able to withstand enough toxin to get this whole process started."

This arms race is most intense in pocketed regions along the West Coast, where rough-skinned newts and garter snakes co-exist.

Read on …