In 1995, 14 gray wolves (Canis lupus) were reintroduced into Yellowstone National Park after an absence beginning in the 1920s (Beschta and Ripple 2010). These wolves produced a trophic cascade, where a higher level of food chain affects a lower one. This cascade began by the wolves causing elk (Cervus elaphus) removal and relocation and led to trees quintupling in size. Seeing the positive effects wolves had on trees, more national parks and states began facilitating this natural ecology management. By initiating a wolf presence in certain areas, a trophic cascade occurs and thus allows for tree recruitment and renewal. Yellowstone is not the only park to introduce wolves to affect trees, but allowed for the movement to gain popularity,
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2015). As of 2012, the elk of Yellowstone’s northern range continuously decline in number due to pressure from wolves, resulting in decreased herbivory of woody plants (Ripple et al. 2015). Elk eat sprouts of woody plants and tread on any ground trees might thrive, causing growth suppression. Wolf control was also used for a resident moose population of Isle Royale, Michigan, where wolves had remarkable effects on forest composition. This was also revealed when top-predators of vertebrates were removed from a tropical forest in Venezuela, demonstrating an increase in herbivore population while producing a decline in tree seedling density (Frank 2008). As Frank noted, when there is a tight trophic linkage between consumers, plants, and decomposers in grassland and aquatic areas, a strong event of predator effects cascaded down food chains will occur while promoting top-down control of ecosystem processes (2008). By initiating a wolf presence, even in small groups, in areas throughout the world, a trophic cascade occurs and thus allows for tree recruitment and renewal. This is evident not only in Yellowstone National Park, where 14 wolves were reintroduced, thus increasing tree growth, but also other national parks and states who have implemented these top predators. When wolves cause elk removal and relocation, they have an overall positive effect on tree health, this creating a more beneficial environment for the
2015). As of 2012, the elk of Yellowstone’s northern range continuously decline in number due to pressure from wolves, resulting in decreased herbivory of woody plants (Ripple et al. 2015). Elk eat sprouts of woody plants and tread on any ground trees might thrive, causing growth suppression. Wolf control was also used for a resident moose population of Isle Royale, Michigan, where wolves had remarkable effects on forest composition. This was also revealed when top-predators of vertebrates were removed from a tropical forest in Venezuela, demonstrating an increase in herbivore population while producing a decline in tree seedling density (Frank 2008). As Frank noted, when there is a tight trophic linkage between consumers, plants, and decomposers in grassland and aquatic areas, a strong event of predator effects cascaded down food chains will occur while promoting top-down control of ecosystem processes (2008). By initiating a wolf presence, even in small groups, in areas throughout the world, a trophic cascade occurs and thus allows for tree recruitment and renewal. This is evident not only in Yellowstone National Park, where 14 wolves were reintroduced, thus increasing tree growth, but also other national parks and states who have implemented these top predators. When wolves cause elk removal and relocation, they have an overall positive effect on tree health, this creating a more beneficial environment for the