Paradoxically, an overall environmental detriment, such as the proliferation of invasive species, can have certain positive effects for some predators. This situation otter of the spanish riversis improving, in part thanks to the fact that it has switched to eating American crabincreasingly exotic species in the country.
A study of the feeding habits of otters in the Valencian rivers demonstrates the increasing role of invasive American crayfish in the diet of this endangered mammal, showing that: changes in its diet could have had a significant impact on the recovery of the species has occurred in recent years.
Aguas de Valencia recently presented the results of the report, thanks to the agreement signed with the Limne Foundation in collaboration with the Climate Emergency Department that allows hundreds of volunteers to monitor otter populations in Valencia’s rivers, report project responsibles.
Change in the feeding habits of the otter
The most recent studies, based on the control and analysis of the composition of this mammal’s pellets or feces, Possible change in otter feeding habits have important implications for their survival.
The report by Adrián Lacomba and David Campos-Such opens the door to new research that could confirm or relativize this working hypothesis and initial results, but its authors argue that: “The wide distribution of the American crab, procambarus clarkiiIt seems to be one of the factors that has led to an increase in the number of otters.With the improvement in the rivers as a result of the wastewater treatment works that started in the 1990s,” he said.
However, because it does not have many environmental requirements, the crab is also found in degraded rivers and unstable ecosystems. “significantly” expands the areas where the otter can expand its territory and access new basins”.
Otter Expansion Areas
The case described is a invasive species cause significant imbalances and can alter pre-existing ecosystemsalmost always a negative, but a positive effect is described for the otter and in this particular case.
Collaboration between the two foundations began in 2019 and allowed, among other actions, the collection and analysis of more than a hundred pellet samples, as well as the identification of new ranges of otters in the Community of Valencia.
striking Improving water quality in Spanish rivers Over the last three decades, as a result of the widespread use of sewage treatment plants, Europe has allowed a rapid increase in otter populations (lutra lutra), the only semi-aquatic mammal on the continent On the verge of extinction in the Iberian Peninsula in the 1970s, Over the last century, due to the pollution of river beds and the proliferation of sewage, reservoir and hydraulic works.
As is often the case, there is no harm that goes wrong, and another contributing factor to the otter’s resurrection is the already existing Found in 55% of Spanish river basinsThere has been an abundance of invasive species, such as some fish introduced for sport fishing, such as carp or rainbow trout, or the American red crab, which acts as food to replace several similar native species that the mustelid has contributed to control. from their population.
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