In Manizales, perched in the Colombian Andes, researchers are studying how a native species of small fresh-water crabs is faring in the city’s parks and streams.
Colombia has over 100 registered species of freshwater crabs (the second highest in the world) but they face threats from climate change, deforestation and urbanization. Globally, 43 of the 122 countries with freshwater crabs have species in need of protection.
Juan Mateo Rivera Pérez, a doctoral student in ecology at the Federal University of Pará (UFPA) Belém, Brazil and first author of a June 2023 paper in the journal Aquatic Ecology says the project was the first to determine and compare the ecological niche of freshwater crabs of the Strengeriana fuhrmanni species in Colombia.
“I am currently working to understand how anthropogenic changes, such as urbanization, agriculture, and livestock are affecting populations of endemic crabs of the Pseudothelphusidae family,” he says, adding that although crabs are sensitive to change and are often noted in environmental quality studies, they were never prioritized.
The study found the crab’s distribution pattern in Manizales city has been decreasing because of urbanization restricting the dispersal and foraging area of these crabs to the streams in the eco-parks of the city.
“On the other hand, this also has been a great opportunity since it has allowed us to find results such as identifying key areas, feeding relationships with other species such as frogs and correlating the environmental variables,” Rivera says.
Colombian carcinologist Ada Acevedo-Alonso, from the Corporación Autónoma Regional de Boyacá CORPOBOYACA), who is a researcher who wasn’t involved with the study, says that it was important to study the impact of urbanization on freshwater crustaceans.
“Urbanization can be many things, in terms of freshwater environments usually there are four impacts: channelization; loss of forest cover; dam construction; and pollution,” Acevedo-Alonso says.
Crazy About Crabs
Rivera is from Paso Nuevo, San Bernardo del Viento in Córdoba, Colombia, which is known as the “Land of the Blue Crab.”
“From a very young age, I had a very close relationship with crabs, learning about them, and their environment, I did my undergraduate degree at the University of Caldas ( Manizales, Colombia) where I was interested in the study of aquatic macroinvertebrates,” he says.
While there, Rivera began to study freshwater crabs in the department of Caldas with which he carried out different projects mainly in the Pseudothelphusidae family.
He moved to Brazil to study his Master’s degree, and is continuing his PhD work there, trying to understand how human-induced changes affect the diversity of aquatic insects.
“I am taking advantage of this new knowledge to apply it to the study of crabs in the region,” Rivera says, adding that importance of science in the Global South is the unique perspectives and understanding of the diverse ecosystems found there.
Acevedo-Alonso is another Colombian carcinologist.
She’s working on how to combat the invasive Louisiana crawfish (Procambarus clarkii) introduced into Colombia in the mid-1980s.
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