A new scientific study points out that the prey and predator numbers do not increase at the same pace, therefore this would explain why predators’ numbers have been decreasing, including lions. So it seems that the issue is not with the hunters, but rather with the predator-prey proportion.
Ian Hatton, McGill PhD student, discovered that prey reproduced less than they would in environments where their numbers weren’t that significant. Therefore, to be more precise, the prey reproduced less in crowded settings. This means that the lion populations’ numbers do not rise either.
Thus, biologists have been debating a new mathematical law of nature, which would analyze ecosystems globally.
The lead author of the study, Hatton, said that he wanted to observe African animal communities in order to draw a comparison in between how the number of carnivores was related to the prey numbers.
Hatton’s scientific team discovered a specific pattern between carnivores, for instance – lions, and herbivores (buffalos), but a particular predator-prey relationship hasn’t been clearly pointed out.
Hatton said that
“until now, the assumption has been that when there is a lot more prey, you’d expect correspondingly more predators.”
But this wasn’t the case, as the specific predator-prey ratio seemed to be reduced, even in the most abundant ecosystems. Therefore, prey species had fewer offspring, whereas their rates of reproduction were decreased as well, meaning that predator numbers was limited as well.
Moreover, Hatton’s team also took into account the food pyramid, and the correlation predator-prey in environments such as tropical rainforests, the Canadian Arctic and the Indian Ocean. It seems that carnivore populations, such as lions, leopards and hyenas, in the African savannah do not grow at an increased rate as expected, in comparison to prey numbers. This is what happens in the ocean as well, with microbe-eating fish etc.
In these different environmental instances, they found out that, according to the reproduction pattern of the prey, predator populations were limited.
Michel Loreau, adjunct professor in McGill’s Biology Dept., and co-author of the study, finally reported that “the discovery of ecosystem-level scaling laws is particularly exciting”, even though the specific driving factor of the pattern is still a mystery.
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