Tag Archives: restoration damaged ecosystems

De-Extinction: Horse Revival


A little baby horse named Kurt is a symbol of renewed hope for the survival of his kind. Born on 6 August 2020, he is the world’s first ever successfully cloned Przewalski’s horse, an endangered wild horse native to the steppes of central Asia. What makes Kurt even more exciting is that he was cloned from genetic material cryopreserved 40 years ago – reviving genetic diversity thought to have been lost decades ago…

Przewalski’s horses roaming the steppes declined dramatically after World War II, due to a combination of factors such as hunting, competition with livestock as humans moved into their territory, and severe winters. The last confirmed sighting of a Przewalski’s horse in the wild was in 1969. Luckily, some of the horses still remained in zoos. But not many. A total of 12 horses made up the ancestors of a captive breeding program – 11 Przewalski’s horses wild-caught between 1899 and 1902, and another caught in 1947. Thanks to this breeding program, there are around 2,000 individuals today. That’s incredibly impressive, but the growing population isn’t without problems.

Those 12 ancestor individuals represent what is known as a population bottleneck – when a species undergoes a severe reduction in numbers. From that point, a population can recover, but it can also be the beginning of the end. One of the reasons for that is lower genetic diversity. With less variation, a population is less able to adapt to potential stressors or changes to their environment…

Enter a Przewalski’s horse named Kuporovic, who lived from 1975 to 1998. An analysis of the captive breeding pedigree revealed that Kuporovic’s genome had unique ancestry from two wild founders. This meant he offered significantly more genetic variation than any of his living relatives, so in 1980, scientists took a sample and preserved it in San Diego Zoo’s Frozen Zoo.  San Diego Zoo partnered with wildlife conservation group Revive & Restore and pet cloning company ViaGen Equine to create an embryo using Kuporovic’s genetic material. This embryo was implanted in a domestic horse (Equus ferus caballus) surrogate, and was born healthy after a normal pregnancy.

Excerpt from Scientists Clone an Endangered Przewalski’s Horse For The First Time, Science Alert, Sept 7, 2020

When Restoration Is Eradication: Palmyra Atoll

On the Palmyra Atoll in the central Pacific Ocean, conservation biologists are in the midst of a massive, unprecedented experiment. They are trying to rid this remote island of all but a few coconut palms. The gangly tree is an icon of idyllic tropical islands, but also an aggressive invasive species that crowds out native plants and animals. By removing 99% of Palmyra’s millions of palms, biologists hope to create more room on the atoll’s three dozen islets for indigenous forests and seabirds, including the world’s second largest colony of red-footed boobies…

Red footed booby

Ripping out the palms has long been on the list of restoration projects on Palmyra. First, however, managers decided to attack another invader, black rats, which likely arrived on ships during World War II. With no predators, rats multiplied into the tens of thousands. They ate the seeds and gnawed the saplings of native trees and attacked seabird colonies, including those of sooty terns, which nest on the ground. Rats are the key suspects behind the absence on Palmyra of eight other species of ground or burrow-nesting birds, including shearwaters and petrels, all found on central Pacific islands that have remained rat-free. The first attempt to eradicate the rats in 2002 failed, partly because Palmyra’s abundant land crabs out-competed the rodents for the poisonous bait. The crabs’ physiology allowed them to eat the poison—the anticoagulant brodifacoum—without ill effect.

The second effort was successful only after [researchers] radio-collared rats and discovered that the rodents liked to hang out in the crowns of coconut palms. The crowns became a convenient platform for stashing cotton gauze sacks of poison bait, delivered by workers firing slingshots or dangling from helicopters. Crabs do not reach the palm tops.

Once rats were exterminated in 2011, researchers watched with delight as native tree saplings began to spring from the forest floor. There were also happy surprises. Scientists discovered two additional species of land crabs that had likely gone undetected because voracious rats suppressed their numbers. And researchers realized they were no longer being bitten by Asian tiger mosquitoes, a pest that attacks during the day and can carry dengue and yellow fever. It appears the mosquitoes depended on rats rather than humans or birds for blood meals…

Excerpts from Ridding Paradise of Palms, Science, Aug. 28, 2020, at 1047

The Fight Against Toxic Algae

Signs posted around the Grand Lake, Ohio read: “Danger: Avoid all contact with the water.”  When dangerously high levels of toxins from blue-green algae in Grand Lake, Ohiio were publicized in 2009, many residents and tourists stopped using the 13,000-acre lake in northwest Ohio. Hotel revenue and home values sank for several years as algae bloomed in the state’s largest inland lake.

Greenish water still laps at Grand Lake’s shores, but recent water samples show that the amount of algae-feeding nutrients entering the lake is down significantly. State, federal and private donations covered more than $10 million in projects aimed at improving water quality. More people are boating on the lake again. Grand Lake could now serve as an example for communities with algae problems across the nation, experts say.

Algal blooms are on the rise, from Lake Erie to the Florida Everglades. In August 2019, the Environmental Protection Agency listed algae-related beach closures or health advisories in 23 states, and it said other blooms may not have been reported. In 2010, the EPA found that 20% of 50,000 lakes surveyed had been affected by phosphorous and nitrogen pollution, which feeds algae.e  Cleaning up bodies of water choked with toxic algae has proved difficult. The project to repair Grand Lake, once one of the most polluted by algae in the nation, is one of the clearest successes. It shows cleanup is possible, but also expensive and time-consuming.

“It’s not restored yet, but it’s on the road to recovery,” said Stephen Jacquemin, an associate professor of biology at Wright State University-Lake Campus in Celina.  Beginning in 2012, wetlands areas were built around the lake, which was hand dug in the 1830s. The thick stands of bulrushes and other plants have reduced phosphorous and nitrogen levels in water entering the wetlands before reaching the lake by as much as 90%, Dr. Jacquemin said.  Three wetland areas, which cost a total of about $6 million to build, are constructed as a series of interconnected pools that allow particulates to settle out and plants and microbes to remove nutrients.

Areal View of Artificial Wetlands, Great Lake Ohio

 The state’s Department of Natural Resources has also dredged the lake bottom to remove nutrient-loaded sediment, and tried to clean up one of Grand Lake’s beaches near St. Marys by building a rock jetty and installing aerators and a curtain to filter water. Recent water tests there showed levels below 6 parts per billion of the toxin microcystin, under Ohio’s threshold of 20 parts per billion for avoiding contact with water.

As Green Algae Forces Beaches to Close, Ohio Lake Offers Hope, WSJ, Sept. 18, 2019

Leveling: How a 5,000 km/h Speed Feels on Earthlings

Hypersonic missiles [weapons faster than the speed of sound]— specifically hypersonic glide vehicles and hypersonic cruise missiles — are a new class of threat because they are capable both of maneuvering and of flying faster than 5,000 kilometers per hour. These features enable such missiles to penetrate most missile defenses and to further compress the timelines for a response by a nation under attack.

Hypersonic missiles are being developed by the United States, Russia, and China. Their proliferation beyond these three could result in other powers setting their strategic forces on hair-trigger states of readiness. And such proliferation could enable other powers to more credibly threaten attacks on major powers.  The diffusion of hypersonic technology is under way in Europe, Japan, Australia, and India — with other nations beginning to explore such technology. Proliferation could cross multiple borders if hypersonic technology is offered on world markets.

There is probably less than a decade available to substantially hinder the potential proliferation of hypersonic missiles and associated technologies. To this end, the report recommends that (1) the United States, Russia, and China should agree not to export complete hypersonic missile systems or their major components and (2) the broader international community should establish controls on a wider range of hypersonic missile hardware and technology.rs.

The unavoidable requirement is for the United States, Russia, and China to agree on a nonproliferation policy. France could play a key role in bringing other governments into agreement on a broader control policy.

The technical and economic barriers to developing hypersonic technology are great enough to add to the effectiveness of a nonproliferation policy.

A two-tiered approach to containing the spread of hypersonic systems and components appears to be the most promising.

First, we recommend a policy of export denial for complete hypersonic delivery vehicles and enough major subsystems to effectively provide access to complete hypersonic missiles.

Second, given dual-use concerns, we also recommend a policy of case-by-case export reviews for scramjets and other hypersonic engines and components, fuels for hypersonic use, sensors, navigation, and communication items for hypersonic flight, hypersonic flight controls, design tools and modeling for such uses, and ground simulation and testing for hypersonic systems.

The necessary first step is for the United States, Russia, and China to agree not to export complete hypersonic missiles or their major subsystems.

Excerpts from Richard H. Speier et al., Hindering the Spread of a New Class of Weapons, Rand Corporation, Sept. 2017