Around 450 million people in North Africa and Asia live in or near oases, which are among the most densely populated habitats in the world.
Research from Germany now shows just how important these fertile spots in desert and semi-arid regions, which have access to water, are for people and wildlife. The study, published in the scientific journal PLOS ONE, shows that culture and biodiversity are particularly closely linked in these unique desert habitats, and should be considered together.
“For oases in the Sahara, the diversity of agriculturally-used plant and animal species is particularly important,” explains the study author Dr Juan Hernández-Agüero, a former scientific assistant at the Senckenberg Research Institute and Natural History Museum in Frankfurt, who now works at the VrijeUniversiteit in Amsterdam. "Date palm oases are a typical example.
"In addition to the economic importance of the fruits, they exhibit high genetic diversity and provide habitats and refuges for a variety of animals. Here, the close link between the evolution of human culture and biodiversity is particularly evident.”
To better understand the potential mechanisms of biocultural diversity in the Sahara, the scientists took a closer look at Algeria’s oases and analysed the interrelationships among various factors of biological and cultural diversity – such as the number of animal and plant species and the number of ethnic groups and languages.
“We studied 77 very different oases and 18 oasis groups,” reports Hernández-Agüero. “Collectively, the oases harbour 552 plant species, 14 amphibian species, 328 bird species, 98 mammal species, and 72 reptile species, although the diversity can be much higher.
"In addition, the Algerian oases are home to 12 ethnic populations, each speaking their own language, including five endangered languages. Thus, of the total of 22 languages found in Algeria – a country with only moderate diversity from a global perspective – over half are spoken in oases.
"Eight out of ten endangered large vertebrate species in the Sahara-Sahel region find refuge here. Oases are obviously of immense importance for the biocultural diversity of the entire country. Moreover, at the level of individual oases, we found a strong correlation between the number of species and languages.”
Globalisation, industrialisation of agriculture and tourism all increasingly contribute to changes in the Sahara’s oases. Besides traditional produce such as dates and olives, tomatoes and other vegetables are increasingly being grown for hotels and restaurants. This intensive activity is exacerbated by activities such as oil drilling and uranium mining.
“Over countless generations, traditional local cultivation practices have ensured the protection of biodiversity,” explains Professor Klement Tockner, director general of the Senckenberg Society and professor of ecosystem sciences at the Goethe University Frankfurt. “It is therefore crucial to consider biological and cultural diversity together in order to sustainably use as well as protect oases in the Sahara – and also globally – in terms of their diversity and importance for humans.
"After all, around 450 million people in North Africa and Asia live in or near oases. Because of their natural resources, oases are among the most densely populated habitats in the world. And they are more severely threatened than ever before.”
"The concept of biocultural diversity supports a holistic and interconnected view of nature and humans," adds Hernández- Agüero. “Our study is intended as an impetus for a more profound analysis of the mechanisms of biocultural diversity in oases in order to develop the best possible sustainable use and protection concepts for these unique habitats.”