Forget about the rhino for a moment and spare a thought for the lions. When the rhino poaching problem subsides in five to 10 years, wild lions will be gone.

The continent's lion population has shrunk by 75% in the past two decades, according to wildlife experts.

They are currently "vulnerable" on the International Union for the Conservation of Nature's list of threatened species. In west and central Africa lions are classified as "endangered".

"The facts are these lions are declining at such a pace. We will have nothing left in a few years," conservation group Walking for Lions (WFL) founder Marcus Roodbol says.

"Have we ever thought what we will do when we realise the last lion has been shot or poisoned? What will we do when we sit in the African bush and not hear the lion roar?"

Trophy hunting, human encroachment, poaching, lion poisoning, and human/lion conflict have become a grave concern, prompting educational and awareness campaigns to save the king of the jungle.

In Asia, lion bones have become a popular commodity for healing and traditional purposes.

"This is a huge concern as the market is increasing for lion bones... to make lion soup or lion wine. It's properties were believed... to provide medicinal remedies, which is medically unfounded," says Roodbol.

The expanding agricultural sector has led to lions confining themselves to isolated areas, increasing their risk of extinction.

"We as humans have this ideal image that we can reintroduce lions back into the wild once they are gone. What makes us think this? If we cannot even save the last remaining wild lions and support the local communities living with these animals, what makes us think we can do it later?"

Wildlife photographer and conservationist Christina Bush says the most urgent threat to lions today is widespread use of pesticides and poison by farmers in retaliation for the loss of livestock.

"Every year more lions die as they are forced to make room for Africa's growth. In Botswana alone over 100 lions are killed each year in an attempt to protect livestock."

In South Africa around 1 500 lions are killed each year in the name of trophy hunting, she says.

"By killing the dominant male in the pride... hunters set off a chain reaction of instinctive behaviours in which the subsequent dominant male kills all the offspring of the previous dominant male lion. It is estimated that six to eight feline deaths results from each dominant male that is shot."

A lot more needs to be done to prevent the species' extinction.

"Wild African lions are at risk of extinction by the year 2020 unless drastic measures are taken to save them," she warns.

WFL in South Africa has taken up the plight to help preserve wild lions.

Roodbol and several others will embark on a 500 km walk from Namibia's capital Windhoek to Ghanzi in Botswana over two months starting May 1.

Their aim is to educate people, including farmers and schoolchildren, along the way about the importance of lion conservation.

The group will walk 30 km per day and film the campaign to promote global awareness through social networking sites.

Students from the University of Botswana and Cheetah Conservation Botswana are expected to join the march for a few days. Topics such as poaching, canned hunting, the illegal lion bone and fur trade, lion consumption, lion mitigation methods, and volunteering will be discussed.

"We would like to create global awareness and give people something to think about when it comes to various aspects of lion conservation," he says.

If enough money is raised through the walk, it will be used to help communities living with lions to ensure their survival.

"Through the years of working with wild lions and hand-raised lions we finally came to our senses that if we as a younger generation do not start working on the future of our wildlife, our children will not experience the beauty of Africa," Roodbol says.

According to Panthera, a wildcat conservation group, lions have vanished from over 80% percent of their historic range and are extinct in 26 countries.

Only seven countries, Botswana, Ethiopia, Kenya, South Africa, Tanzania, Zambia, and Zimbabwe are believed to each contain more than 1 000 lions.

On its website, Panthera says lions are increasingly coming into closer contact with humans as their habitat is converted for human use.

Kenya alone loses around 100 wild lions every year due to human contact. Experts believe there will be no more wild lions left in Kenya by 2030.

Panthera says there is a scarcity of wild prey due to over-hunting by humans. When wild prey are over-hunted, lions are forced to feed on livestock. This drives further conflict with humans in which the lion ultimately loses.

Beverly and Derreck Joubert, National Geographic explorers based in Botswana, say there will be environmental havoc if lions go extinct.

"They are the most vital centre point in many ecosystems. If we lose them we can anticipate eventual collapse of whole environments, right down to the water systems, as prey shifts or migrations stop, and species overgraze and destroy the integrity of important vegetation, especially along rivers."

It could also hurt the economic systems of people who rely on tourism to survive.

"Many come to Africa to see the big cats in the wild. Losing that could devastate areas where this tourism is the sole source of income," the pair believes.

"Saving the lions from extinction is a cause that not enough people know about. Lions are incredibly powerful cats, but even they need help from those who care about preserving wildlife for the future."