The Impact of Apex Predators
By Adelaide Keller
By Adelaide Keller
People often tend to fear or dislike big predator animals because they eat livestock, or other cute fluffy creatures. This can sometimes result in people killing these animals if they see them as a threat, or don’t like them. However, when an apex predator disappears from an ecosystem, it can cause the whole ecosystem to crumble. Apex predators help a number of other animals and plants indirectly, including the little fluffy ones.
One big example of the importance of apex predators is the instance with the wolves of Yellowstone National Park. When the park first opened in 1872 gray wolf packs were all over, but by 1926 the last remaining pack had been wiped out. With a large predator gone the elk population in the park skyrocketed. Elks were afraid of wolves - they made up 90% of the wolves' winter prey, and had to constantly keep moving so they wouldn’t be eaten. When wolves disappeared elk overgrazed the park, eating most of the brush and young trees. This caused problems for a number of species of plants and animals, here are a few of the problems that came when wolves were gone from the park:
As you can see, the loss of wolves had a devastating effect on the ecosystem of Yellowstone National Park.
On January 12, 1995 the first gray wolves from Jasper National Park in Canada were introduced to Yellowstone. They were first put in acclimation pens to get used to their new habitat. Eventually, they were released to roam the park on their own. From 1995-1997 41 wolves were introduced to the park. With wolves back, the elk populations decreased, restoring the natural balance and benefiting lots of animals in the park. Wolf populations in Yellowstone have stayed within 83 and 108 since 2009, probably their carrying capacity. Hopefully the wolf population in Yellowstone will remain there and healthy for lots more years to come.
People might not like apex predators because they eat the harmless ones, but these predators keep a natural balance and actually help some harmless animals. Without these predators it causes trouble for the whole ecosystem. It's important to not make impulsive decisions and wipe out animal or plant species in some places, every species is important. Even though one species can seem insignificant all on its own it can play a larger part in the ecosystem and food web.
Sources
National Park Foundation - Reintroducing Wolves to Yellowstone National Park: https://www.nationalparks.org/connect/blog/reintroducing-wolves-yellowstone-national-park
National Park Service - Gray Wolf: https://www.nps.gov/yell/learn/nature/wolves.htm
National Science Foundation - Yellowstone Ecosystem Needs Wolves and Willows, Elk and...Beavers?: https://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=126853&org=NSF
Yellowstone National Park Trips - 1995 Reintroduction of Wolves in Yellowstone: https://www.yellowstonepark.com/park/yellowstone-wolves-reintroduction
Image: https://www.yellowstonepark.com/things-to-do/presence-of-wolves
One big example of the importance of apex predators is the instance with the wolves of Yellowstone National Park. When the park first opened in 1872 gray wolf packs were all over, but by 1926 the last remaining pack had been wiped out. With a large predator gone the elk population in the park skyrocketed. Elks were afraid of wolves - they made up 90% of the wolves' winter prey, and had to constantly keep moving so they wouldn’t be eaten. When wolves disappeared elk overgrazed the park, eating most of the brush and young trees. This caused problems for a number of species of plants and animals, here are a few of the problems that came when wolves were gone from the park:
- With wolves gone, elk could stay anywhere they wanted for as long as possible. They liked staying by their sources of water, where they ate almost all the plants along those streams/creeks or rivers. Elk couldn’t eat the adult trees, but they could eat all the young trees that were growing, making it so there were no new trees to replace the old ones that had died. This caused many tree populations to decrease in the park, including willow and aspen.
- With fewer trees birds had less places to nest in, making nesting space a lot harder to come by. The absence of trees also heated the water in the streams because there was no shade - making it harder for water-dwelling creatures to breath because their dissolved oxygen particles were further apart. With no new tree roots to stabilize them the stream banks also started to erode, making the water murkier and contain more sediment.
- The beaver population in the park decreased as well because the elk were eating away willows which slowed stream flow. Beavers like slow-moving waters, so when the waters sped up they left to find a new home. Their dams slowly disintegrated, making many other stream dwelling animals lose their beaver-made habitats, including fish and amphibians.
- As elk overgrazed they ate a lot of the plants other species needed to eat. Bears need berries to help build up hibernation fat, but they lost those berries because the elk were eating the berry plants. Small herbivores including rabbits also lost the grasses and plants they needed to eat, because the elk were getting to them first.
- Scavengers that ate the remains of wolf catches and creatures that tried to steal the catches including ravens, magpies, coyotes, bears, and eagles lost some of their food source. They couldn’t get any leftovers anymore from wolves, who left their remaining food uncovered and easy to access for scavengers.
As you can see, the loss of wolves had a devastating effect on the ecosystem of Yellowstone National Park.
On January 12, 1995 the first gray wolves from Jasper National Park in Canada were introduced to Yellowstone. They were first put in acclimation pens to get used to their new habitat. Eventually, they were released to roam the park on their own. From 1995-1997 41 wolves were introduced to the park. With wolves back, the elk populations decreased, restoring the natural balance and benefiting lots of animals in the park. Wolf populations in Yellowstone have stayed within 83 and 108 since 2009, probably their carrying capacity. Hopefully the wolf population in Yellowstone will remain there and healthy for lots more years to come.
People might not like apex predators because they eat the harmless ones, but these predators keep a natural balance and actually help some harmless animals. Without these predators it causes trouble for the whole ecosystem. It's important to not make impulsive decisions and wipe out animal or plant species in some places, every species is important. Even though one species can seem insignificant all on its own it can play a larger part in the ecosystem and food web.
Sources
National Park Foundation - Reintroducing Wolves to Yellowstone National Park: https://www.nationalparks.org/connect/blog/reintroducing-wolves-yellowstone-national-park
National Park Service - Gray Wolf: https://www.nps.gov/yell/learn/nature/wolves.htm
National Science Foundation - Yellowstone Ecosystem Needs Wolves and Willows, Elk and...Beavers?: https://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=126853&org=NSF
Yellowstone National Park Trips - 1995 Reintroduction of Wolves in Yellowstone: https://www.yellowstonepark.com/park/yellowstone-wolves-reintroduction
Image: https://www.yellowstonepark.com/things-to-do/presence-of-wolves