As acacia ants have dwindled, elephants have been in a position to knock down and eat extra whistling thorn timber. With fewer timber, lions have misplaced the duvet they depend on to stealthily assault zebras, their main prey.
The examine, which was revealed Jan. 25 within the journal Science, discovered that lions are much less more likely to kill zebras in uncovered areas. They killed 25 p.c fewer zebras between 2003 and 2020, the examine stated.
“When you may have invasive species, they will have an effect on different species that wouldn’t appear to have something to do with the species invasion in sort of bizarre, unpredictable methods — methods which can be hidden, however very severe,” examine co-author Jacob Goheen, a College of Wyoming zoology professor, informed The Washington Publish.
The findings had been a results of years of analysis on animals and bugs in a nature conservancy in Kenya. A examine from March 2015 discovered that whistling thorn timber, that are native to East Africa and might develop about 18 toes tall, had been struggling after big-headed ants had invaded the Ol Pejeta Conservancy in Kenya’s Laikipia County.
Acacia ants stay in whistling thorn timber, which give them nectar. In return, the ants shield the timber from predators — a symbiotic relationship. However after big-headed ants kill acacia ants and eat their eggs, larvae and pupae, elephants are not warded off and so they can break down extra timber in these areas. Roughly 75 p.c of the conservancy’s timber have vanished, Goheen stated.
One other examine revealed in Might 2019 discovered that lions killed extra zebras in areas of the Ol Pejeta Conservancy that had extra tree cowl. Lions sometimes hunt zebras by hiding behind timber and chasing them once they strategy.
Researchers from each research labored collectively to attempt to join their findings to find out whether or not the invasive ants had been affecting lions’ conduct.
In Might 2018, researchers hooked up GPS collars to 6 lions within the Ol Pejeta Conservancy. Utilizing computer systems, researchers then tracked the lions’ places within the roughly 140-square-mile protected savannah.
Lions normally moved quick, and generally in teams, once they had been chasing prey. So when researchers noticed a cluster of pink monitoring factors on their computer systems — indicating that a number of lions had been transferring shortly across the identical space — they predicted that lions had hunted prey there. Inside just a few days, researchers drove to the world to document which animal the lions had killed and the way a lot tree cowl was close by. They drove with an armed safety guard in case an animal attacked them, researcher Douglas Kamaru stated.
Researchers continued that routine for about two years, figuring out that the six lions they had been monitoring had killed about 140 animals. Roughly half of these kills had been zebras, which lions had been greater than two instances extra more likely to kill in areas with tree safety than in uncovered areas, the examine stated.
Regardless of lions consuming fewer zebras, researchers don’t anticipate the weak species’ inhabitants to dwindle within the conservatory. That’s as a result of lions discovered a brand new meals supply: African buffalo.
Whereas zebras normally run away once they spot lions, buffalo usually combat again, making cowl much less necessary earlier than the hunt. Nonetheless, buffalo aren’t lions’ first alternative for meals, Goheen stated. Killing a zebra takes one or two lions; killing a buffalo takes between 5 and 10, Goheen stated.
As big-headed ants proceed to broaden within the space, researchers stated different issues may emerge. For instance, endangered black rhinos eat whistling thorn timber however may lose their meals supply, examine co-author Corinna Riginos stated.
“The massive-headed ant invasion is sort of altering every little thing, and it takes time for all these dynamics to play out,” Riginos stated. “We’ve already seen proof of massive adjustments. What occurs subsequent?”