Number of Trees in Southern Sahara Exceeds Previous Expectations

A lone camel walks in Niger's Tenere desert region of the south central Sahara on Wednesday, May 30, 2018. (AP Photo/Jerome Delay)
A lone camel walks in Niger's Tenere desert region of the south central Sahara on Wednesday, May 30, 2018. (AP Photo/Jerome Delay)
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Number of Trees in Southern Sahara Exceeds Previous Expectations

A lone camel walks in Niger's Tenere desert region of the south central Sahara on Wednesday, May 30, 2018. (AP Photo/Jerome Delay)
A lone camel walks in Niger's Tenere desert region of the south central Sahara on Wednesday, May 30, 2018. (AP Photo/Jerome Delay)

The southern Sahara and the Sahel are home to more trees than thought, which have a "crucial role" in biodiversity and people's lives. An international research team has developed an artificial intelligence (AI) pattern recognition program to count trees with a plant surface of more than 3 square meters, from over 11,000 high definition satellite images, AFP reported.

Over an area of 1.3 million square kilometers in the south of the Sahara, the Sahelian strip, and sub-humid zones in West Africa, they were able to count more than 1.8 billion trees, the researchers wrote in the journal Nature.

Based on the findings, the average tree number is 13.4 per hectare, with a median plant cover of 12 square meters. The researchers noticed that this vegetation, certainly sparse, "plays a crucial role for biodiversity and for the ecosystem as carbon storage, food resources, and shelter for human and animal populations."

"Although the total vegetation cover is low, the relatively high density of isolated trees calls into question the prevalent idea of desertification of drylands, as even the desert could offer a surprising density of trees," they added. The density increases as it descends towards the wetter areas in the south, from 0.7 trees per hectare in the "hyperarid" areas to 9.9 in arid zone, 30.1 in semi-arid zone, and 47 trees per hectare in subhumid zone. In addition to this count, the study offers a new method to study the presence of trees outside dense forest areas, and in particular their role in climate change mitigation and potentially poverty, through their contribution to agricultural systems.

"This kind of data is very important to establish a base. And in two or ten years, we could repeat the study to see if efforts to revitalize vegetation are effective", one of the researchers, Jesse Meyer from the NASA explained in a statement.

"The used artificial intelligence technique also suggests that it will soon be possible, within certain limits, to map the location and size of all trees. This information is fundamental to our understanding of ecology on a global scale," estimated Niall P. Hanan and Julius Anchang of the University of New Mexico, in an analysis of the study.



'Amphibious Mouse' among 27 New Species Discovered in Peru's Amazon

A clearwing butterfly (Oleria sp.) specimen, from one of the 218 species of butterflies observed during an expedition to the Peruvian region of Alto Mayo, is pictured, June 8, 2022. Conservation International/photo by Marlon Dag/Handout via REUTERS
A clearwing butterfly (Oleria sp.) specimen, from one of the 218 species of butterflies observed during an expedition to the Peruvian region of Alto Mayo, is pictured, June 8, 2022. Conservation International/photo by Marlon Dag/Handout via REUTERS
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'Amphibious Mouse' among 27 New Species Discovered in Peru's Amazon

A clearwing butterfly (Oleria sp.) specimen, from one of the 218 species of butterflies observed during an expedition to the Peruvian region of Alto Mayo, is pictured, June 8, 2022. Conservation International/photo by Marlon Dag/Handout via REUTERS
A clearwing butterfly (Oleria sp.) specimen, from one of the 218 species of butterflies observed during an expedition to the Peruvian region of Alto Mayo, is pictured, June 8, 2022. Conservation International/photo by Marlon Dag/Handout via REUTERS

An "amphibious mouse" with partially webbed feet that eats aquatic insects was among 27 new species discovered during a 2022 expedition to Peru's Amazon, according to Conservation International.

Scientists also discovered a spiny mouse, a squirrel, eight types of fish, three amphibians and 10 types of butterflies, Trond Larsen, head of Conservation International's Rapid Assessment Program, told Reuters this week.

He added that another 48 species found by investigators were potentially new, but needed further study.

The new species were found in Alto Mayo, a protected area with several ecosystems, Indigenous territories and villages.

"Discovering so many new species of mammals and vertebrates is really incredible, especially in such a human-influenced landscape as Alto Mayo," Larsen said.

The expedition between June and July 2022 was made up of 13 scientists plus local technicians and members of Indigenous groups.

"It was really fantastic to work so closely with the Awajun people. They have extensive traditional knowledge about the forests, animals and plants they live side-by-side with," Larsen said.

Among the new species, Larsen highlighted the spiny mouse that has stiff fur, the amphibious mouse, and a dwarf squirrel that measures 14 cm (5.5 in).

"(The squirrel) fits so easily in the palm of your hand. Adorable and beautiful chestnut-brown color, very fast," Larsen said. "It jumps quickly and hides in the trees."

Another favorite discovery was the blob-headed fish, a type of armored catfish, he said.

A total of 2,046 species were recorded during the 38-day expedition using camera traps, bioacoustic sensors and DNA sampling. Among them, 49 were classified as threatened, including the yellow-tailed woolly monkey and the tree monkey.

Larsen said the discoveries reinforced the need to protect the area.

"Unless steps are taken now to safeguard these sites and help restore parts of the landscape ... there's a strong chance they won't persist in the long term," Larsen said.