When Manuel Lopes-Lima got down to survey aquatic biodiversity on the Corubal River in 2022, he’d set his expectations very low. The river that straddles the West African nations of Guinea and Guinea-Bissau was, in spite of everything, very distant and grossly understudied.
Two expeditions later, the story has turned on its heels.
With the assistance of environmental DNA sampling and evaluation, Lopes-Lima and his crew recognized 125 species of aquatic and terrestrial vertebrates within the Corubal. This consists of critically endangered western chimpanzees (Pan troglodytes verus) and freshwater mussels (Pleiodon ovatus) in addition to 21 different species, largely fish, that weren’t identified to exist in Guinea-Bissau.
“We weren’t anticipating the large variety that we discovered,” Manuel Lopes-Lima, group lead on the Analysis Centre in Biodiversity and Genetic Assets on the College of Porto in Portugal, advised Mongabay in a video interview. “We have been anticipating so much much less.”
In a research= printed within the journal Bioscience, the crew laid out the methodology they used to filter DNA from water samples collected from the Corubal. In line with the research, the findings emphasize the “conservation significance of the Corubal, present a baseline for future monitoring, and spotlight the challenges and alternatives of eDNA surveys in distant tropical rivers.”
“Corubal is without doubt one of the final free rivers in Africa,” Lopes-Lima stated. “There’s no main massive metropolis alongside the river and no dams, and that makes this river notably fascinating when it comes to conservation wants.”
Flowing almost 560 kilometers (350 miles), the Corubal rises from the highlands of Guinea, kinds a piece of the border with Guinea-Bissau, then meanders by means of the latter nation earlier than emptying out into the Atlantic Ocean. Alongside the best way, it serves as a supply of freshwater for animals residing within the river basin. Massive-scale research to watch biodiversity within the river haven’t been undertaken in recent times. Nonetheless, smaller expeditions up to now have discovered the river and its basin to be residence to a large gamut of species, together with Senegal flapshell turtles (Cyclanorbis senegalensis), African manatees (Trichechus senegalensis), Nile crocodiles (Crocodylus niloticus) and hippos (Hippopotamus amphibius).
When Lopes-Lima and his crew determined to review the Corubal River, environmental DNA evaluation appeared like one of the best ways to grasp the biodiversity that lives there. Beforehand, Lopes-Lima used to dive or go snorkeling to review and monitor aquatic species. However this got here with challenges. “Particularly working in tropical rivers in distant areas, it’s typically harmful,” he stated. “There’s lots of parasites which is likely to be vectors of illnesses, and in addition harmful animals like crocodiles and hippos.”
Environmental DNA (eDNA) has discovered rising recognition as a noninvasive technique of conducting biodiversity surveys over massive areas. It requires amassing and detecting DNA left behind by animals in water, air and soil through their hair, fur and saliva, amongst different issues. Latest research have additionally explored swabbing leaves in forests to collect DNA samples of terrestrial animals.
Lopes-Lima and his crew undertook two expeditions, one in 2022 and one in 2023, to gather samples from the a part of the river that flows by means of Guinea-Bissau. Touring in slim canoes, the crew collected water samples from 25 factors alongside the river. From these, they extracted DNA to establish the species related to them.
The lately printed research covers solely the findings from the expedition in 2022. This consists of species that had beforehand not been recorded within the nation, such because the Egyptian fruit bat (Rousettus aegyptiacus) and the gray-throated rail (Canirallus oculeus). “It was fascinating to see that we may perceive the biodiversity of the river itself, but in addition the animals that use the river to drink water or as a refuge within the dry season,” Lopes-Lima stated.
The crew additionally concurrently labored on constructing a reference database for species within the area. For this objective, they have been accompanied by a crew of scientists who collected specimens and tissues from animals with a purpose to construct a database, particularly for bugs, mollusks and smaller mammals that haven’t been well-represented in DNA reference databases. “The issue is that lots of the species in Guinea-Bissau have been by no means sequenced,” Lopes-Lima stated. “As a result of they’re so distant and troublesome to review, we didn’t have references for a lot of of them.”
Whereas the crew analyzes the samples from the 2023 expedition, it’s additionally planning a 3rd journey that will probably cowl the upstream a part of the river that lies in Guinea. The power to collect and course of a lot biodiversity knowledge from a distant tropical river has additionally inspired the researchers to solid a wider web throughout the continent. Lopes-Lima stated he’s additionally at the moment working to coach scientists, develop eDNA protocol, and construct capability to conduct speedy biodiversity evaluation surveys in rivers in Namibia and different components of Southern Africa.
“We are attempting to standardize and optimize these strategies to maximise the biodiversity you get whereas minimizing the fee,” he stated. “Not solely to see the biodiversity developments, however to make use of it for monitoring and see if conservation actions are serving to or not.”
Quotation:
Lopes-Lima, M., Prié, V., Camará, M., Ceríaco, L. M., Fernandes, V., Ferreira, S., … Beja, P. (2024). Speedy eDNA survey reveals a singular biodiversity hotspot: The Corubal River, West Africa. BioScience, 74(6), 405-412. doi:10.1093/biosci/biae036
This article by Abhishyant Kidangoor was first printed by Mongabay.com on 6 September 2024. Lead Picture: One of many species that had beforehand not been recorded within the nation is the Egyptian fruit bat (Rousettus aegyptiacus). Picture by Simon Willison through Flickr (CC BY-NC 2.0).
What you are able to do
Assist to avoid wasting wildlife by donating as little as $1 – It solely takes a minute.
