When herbivores flood into the planet, humans think of the top predators who have been "taken away" by themselves. Therefore, in recent years, all kinds of big cats and big dogs have been invited back to their happy hometowns.
Iberian pear tree
It is well known that the disappearance of any one of the native species in the ecosystem will have a serious cascading effect. The more top-ended species have the more pronounced the impact.
Take the Iberian pear, a small heat-resistant and hardy tree found only in Spain, Portugal and Morocco. They are a sugar replenishment shop for many local animals, and although not rare at the moment, their numbers are declining at a rate comparable to that of some endangered species.
A 2009 study showed that local trees rely on small mammals such as foxes and Eurasian badgers to spread seeds. They unconsciously trade with the trees, eat the fruit for free, and then take charge of bringing the seeds to other areas, and spread the seeds in a way that everyone is very good at.
But when the local top big cat, the Iberian lynx, disappeared, the number of Iberian pears continued to decline, even though these trades were still going on. In recent years, after the reintroduction of the Iberian lynx, the distribution and number of Iberian pears have suddenly shown a gratifying increase.
Supposedly, carnivores do not have a direct impact on plants because they prey on animals. Burgos, an ecology researcher at the University of Juan Carlos in Madrid, wondered how the presence of lynx affected Iberian pears.
Lynx and pears
Burgos and colleagues set up an infrared camera in the Anduhar Mountains Natural Park, one of the largest surviving sanctuaries for the Iberian lynx. Infrared cameras can observe whether the presence of lynx affects where, when, and how red foxes, Eurasian badgers and stone martens forage for Iberian pear fruits in the region.
They found that within the territory of the lynx, the red fox became very "shy", rarely came to eat fruit, and often just passed; Stone marten evaporates directly from the human world; But our badger brother is very calm, should eat and drink. Pear orchards outside the lynx territory are more popular: 70 percent of foxes and 100 percent of stone mink visits to pear trees across the study area occurred outside the lynx's range.
So the researchers concluded that the lynx kept the flesh-eating animals moving and may have influenced the way they spread pear seeds.
Simply put, forced by the obscenity of lynx, these fruit-eating mammals are forced to eat fruit elsewhere, which will pull the seeds farther and more dispersed, expand the growth range of the seeds, and reduce their survival pressure. Because originally these fruits were eaten, they would only be pulled to a short range, there were too many seeds in the same area, the competitive pressure was high, and the fruit trees naturally did not grow well.
Ecologists and biologists have previously focused primarily on how the return of predators affects prey numbers. Now they're starting to realize that the effects of predators are inextricably linked.