Geology and Ecology of National Parks

Ecology of Bryce Canyon National Park

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Introduction

In general, the area around Bryce Canyon is arid (dry, with little precipitation). Plant and animal life has adapted to be drought resistant, surviving (and thriving) with little water. The plateau in Bryce Canyon is somewhat cooler and wetter as a result of elevation, seeming like a green island in a red desert. A wide variety of trees and flowers can grow here due to higher rainfall and snowfall. The pink cliffs in the park, however, are mostly bare of vegetation. There is very little soil, only rock, and the cliffsides are mostly inhospitable due to steep slopes and active weathering. [1]

The range of elevation in Bryce Canyon National Park creates a variety of ecosystems. The three distinct zones are the spruce/fir forest, the Ponderosa pine forest, and the pinyon juniper forest (from highest to lowest elevation)[2]. There is a total change of about 2000 ft of elevation, or 650 m. Each ecosystem has unique characteristics and some plants and animals move between ecological zones. The relative isolation of each of these zones has created high biodiversity.[3]

Climatic Zones[4]

The area near the top of the canyon is named for fir, spruce, and aspen trees. Blue Spruce trees are relatively rare because they require greater amounts of water, but can be found along streams. Douglas firs are fast growing, tall evergreens that thrive in shade. Their seeds are a tasty treat for forest critters like insects and small rodents, that commonly take the cones, while larger animals like Mule Deer, Elk, and Grouse eat new growth low to the ground. They also need a good deal of water, but manage to thrive in moist soil or shady areas. Quaking Aspens, another of the characteristic trees of Bryce Canyon’s high elevations, are much less common. They require alot of sunlight and relatively high amounts of water, and are often overcrowded by firs and spruces. Aspens are particularly interesting because they are really one giant organism, a root system underground that sprouts upward growth that appear as individual trees. This is known as vegetative (asexual) reproduction, meaning that the trees can live thousands of years. Beneath the bark is a green photosynthetic layer that allows the tree to produce sugars even in the winter, which provides food for deer and other animals during the sparsely vegetated winter. The aspen system thrives immediately following fires, as the root system is unaffected, and there is nothing blocking the sun. Many animals (deer, squirrels, chipmunks, insects, and a variety of birds) can be found in this area of Bryce Canyon, though few are unique and are found throughout the park.

Ponderosa Pine trees are characteristic of the middle altitudes of Bryce Canyon. These large evergreens are found in dry areas and can grow over 200 ft tall. They are also important in understanding the climate history in the region. By studying the tree rings, scientists can determine whether a year had heavy rainfall (wide rings) or light rainfall (thin rings). Seeds are wind-dispersed and are a source of food for many animals. Found with the Ponderosa Pines is Greenleaf Manzanita, a shrub similar to heather. Rocky Mountain Juniper is another tree common in the mid altitudes. They are adapted to their dry, shady environment by having small waxy leaves, almost like scales, that retain water. One or more seeds are found inside cones that are similarly coated to prevent evaporation, and are often mistaken for berries. These cones are a common meal for Bryce Canyon animals, which gain nutrition but cannot digest the seeds. The process of eating and attempting to digest the seeds softens them so they can germinate, and the animal disperses the seeds as waste. The animals benefit by getting food, and the tree benefits by getting free seed dispersal. This is an example of a mutualistic relationship, in which both species benefit.

The Colorado Pinyon and Utah Juniper are primarily found in the lower altitudes. Both require dry soil, like much of the plant life in the park. Colorado Pinyons, also known as Pinyon Pines, are adapted to the lack of water by having large root systems so as to make available as much water as possible. These trees have a mutualistic relationship with several species of birds. The seeds, known as pine nuts, are consumed by Pinyon Jays and Clark’s Nutcrackers. The birds gather and store the seeds, so they get food, but some seeds are not consumed and instead are transported where they can grow new trees. Both the tree and the birds get use out of the symbiosis. This elevation zone experiences rapid erosion, high heat in the summer, and freeze-thaw cycles in the winter that make it difficult for plant life to thrive. As a result, plants here tend to be sparser. Even within this zone, however, there is variation in type and presence of plant life due to variations in slopes and soil conditions creating microclimates.

Flowering Plants[5]

Wildflowers are common throughout the park, primarily growing in meadows or along trails. Many wildflowers in the park are adapted to the rocky soil, including columbines and the Rocky Mountain paintbrush. Some species are more dependent on moist and soft soils, and tend to have more narrow ranges in which they can be found. Bryce Canyon wildflowers can be found in every color, and range in size from tiny to almost a meter tall. They can be found at all elevations, flowering in the summer, especially from May to July. Many of these plants depend on insects such as bees, moths, and butterflies for pollination, offering nectar in return. Some, such as the rock columbine and bush cinquefoil, are eaten by livestock and deer. A particularly interesting plant native to the area is the paintbrush, several species of which can be found in Bryce Canyon, including the Wyoming Paintbrush and Bryce Canyon Paintbrush. These plants are semi-parasitic, meaning that they rely on other plants to get some of their metabolic needs. The roots of these plants penetrate the roots of plants nearby, stealing resources and harming the other plant in the process. They are only semi-parasitic because paintbrushes still produce some of their own needs through photosynthesis. In total, there are over one thousand plant species found in the park.

Animals

Bryce Canyon is home to 59 mammal species[6], over 100 bird species[7], and numerous reptiles. There are thought to be at least a thousand insect species (including over 45 butterfly and moth species)[8], but the insects of Bryce Canyon have not been heavily researched. They are an ongoing area of study for scientists, and are integral to pollination and food webs in the park.

Most animals in the park can be found almost everywhere. They are less confined to the climatic zones that the plant species are bound by, and may travel between elevations and habitats to find food, water, and shelter. Some of the most common mammals in the park are quite small: three species of chipmunk and two species of ground squirrels can be found nearly anywhere in the park, though some hibernate in the winter. In meadows, you can find Utah Prairie Dogs. Ringtails, relatives of raccoons, can be found in forested areas. Some of the larger mammals include deer, antelope, elk, and mountain lions. Of the birds that can be found in Bryce Canyon, some are migratory and are only found temporarily, while others can be found year-round. Peregrine Falcons, ospreys, jays, California Condors, hummingbirds, and Clark’s Nutcrackers are a few of the many species, representing a wide variety of sizes and ecologies. Some, like the hummingbirds, eat mostly insects and nectar, while others are predators or scavengers. Reptiles and amphibians are less common in the park because the cold winters prove dangerous, but rattlesnakes, salamanders, and short-horned lizards are a few species found in Bryce Canyon.[9]

Additional Resources

 

Vegetation Classification and Mapping Project Report, Bryce Canyon National Park

https://www1.usgs.gov/vip/brca/brcarpt.pdf 

 

List of mammals and reptiles and where to find them

https://www.nps.gov/brca/learn/education/upload/mrachecklistweb.pdf