When hundreds of elephants were found dead in northern Botswana in a mysterious mass die-off this July, scientists called it a "conservation disaster."

Investigations showed the elephants had died from toxins created by microscopic algae in their drinking water. While the blue-green algae occur naturally in still water, scientists say global warming is likely to make such toxic blooms more frequent.

But they are by no means the only threat to the natural world. Scientists estimate more than 1 million species are at risk of extinction within the next few decades, including many of those that humans depend on for food, freshwater, and oxygen.

A few scientific strategies and techniques have proved useful in fighting species loss.

Breeding behind bars

Just a few years ago, the California condor and the black-footed ferret were on the verge of extinction. When there were only a few left in the wild, scientists started breeding them in captivity with a view to rewilding them further down the line. The two species have since made a remarkable comeback.

This kind of captive breeding is common in zoos and wildlife reserves all around the world. Such programs have ensured the continued existence of animals such as Partula snails, Przewalski's horse, the Socorro dove, and Arabian oryx.

However, breeding programs only contribute to biodiversity in a sustainable way if the natural habitats of animals are protected as well. Otherwise, the species only survive in zoos.  

DNA to the rescue

Dolly, the first cloned sheep, marked a breakthrough in technology in 1996. But the lab method, which uses cells from one organism to create a genetically identical copy, was not the first foray into such brave new world experiments. Attempts actually began in 1928 and by 1952, the first animal — a tadpole — had been successfully cloned.

In more recent years, scientists have not just cloned a sheep, but endangered species, and have even resurrected extinct ones by using existing DNA.

But the breakthrough was not altogether successful. Many cloned endangered animals didn't survive for long and most did not reach adulthood due to various defects. Because of the low success rate of less than 1% and the high cost of the procedure, cloning is currently considered less effective as a conservation strategy for endangered species. 

Domestic species like cattle, however, have been successfully cloned for years to reproduce certain traits.

Recharging the land

The UN's Decade on Ecosystem Restoration is set to get underway in 2021. At an estimated cost of $1 trillion (€823 billion), some 115 countries have committed to restore up to 1 billion hectares of land lost to development — an area roughly the size of China.

The plan is to restore the health and productivity of the land by revitalizing various ecosystems, rebuilding the soil's ability to absorb carbon, and protecting habitats.

To save biodiversity, protected natural habitats for wildlife are of critical importance. But they are not the only spaces needed for survival, says Sara Scherr, who runs EcoAgriculture, a US non-profit to promote integrated landscape management. After all, agricultural landscapes are the principal habitats for many species and play a critical role as biological corridors for others.

Existing agricultural practices are posing a grave threat to the planet's biodiversity. Rampant use of chemicals has jeopardized the survival of many species. Researcher Florian Humpenöder of the Potsdam Institute for Climate Impact Research (PIK) stresses that only a "bold conservation and restoration effort" can slow down and eventually halt the loss of biodiversity.

Scientists argue that improving farmland diversity and reducing the usage of pesticides and fertilizers are key to reversing the continuous loss of soil life. Organic farming is touted as a possible solution.

Ban on wildlife trade and hunting

Pangolins, which are among the most trafficked species globally, are at risk of extinction as a result of illegal hunting for their scales and meat. All eight known pangolin species are protected under national and international laws, and three are listed as Critically Endangered on the IUCN Red List of Threatened Species.

But the scaly mammals have had a better shot at survival since June 2020, when China increased protection for the native Chinese Pangolin to the highest level. Additionally, China removed them from the official list of ingredients for traditional Chinese medicine treatments which was a major reason for pangolins being trafficked.

Illegal trade in wild animal parts remains a huge challenge for conservationists, despite a global clampdown on smugglers and poachers. India, however, has succeeded in increasing its endangered tiger population over the past decade, by providing them with well-protected habitats and good breeding conditions. Today there are fewer than 4,000 tigers living in the wild. Of them, 70% live in India.

Ravi Chellam is a wildlife biologist and CEO of the Bengaluru-based group Metastring Foundation that explores conservation strategies. He says the "recognition of the need for large stretches of habitat connected by wildlife corridors and a much better understanding of the ecology of many species" have played a role in conservation success stories.

Protecting marine ecosystems

Researchers are pushing for the Red Sea's 2,500 miles of coral reef to be declared a UNESCO Marine World Heritage Site. It is one of the longest continuous living reefs in the world but it is dying fast due to rising water temperatures linked to global warming.

Scientists fear between 70% and 90% of the Earth's coral reefs — which support a quarter of all marine species on the planet — will be destroyed by 2050 due to the warming of the oceans. But efforts are underway to change this.

In 2017, North Sea oyster reefs off the Netherlands were given a helping technological hand. Severely impacted by overfishing, disease and extreme weather, the reefs were under threat. The World Wildlife Fund (WWF) conservation group and local partners put 3D-printed reef structures into the sea and reintroduced a starting population of oysters. Those reefs are now home to a whole new generation of oysters and other local species.

Protecting marine ecosystems also helps to ensure the survival of humans, since more than three billion people rely on seafood for protein.