Date of Award

12-1-2001

Document Type

Thesis

Degree Name

Master of Arts (MA)

Department

Biology

First Advisor

Dr. Robert S. Egan

Abstract

Nebraska has five main pine forest regions dominated by Pinus ponderosa Laws, with other small naturally forested areas scattered in pockets across the state (Kaul & Rolfsmeier 1993). Three of these main forest areas occur naturally: the Pine Ridge in northwestern Nebraska, the Wildcat Hills south of the city of Scottsbluff, and the Niobrara River Valley in the north-central portion of the state. These three natural coniferous forest communities are similar in having gentle to steep slopes, well-drained sandy soils, and sandstone outcrops (Steinauer & Rolfsmeier 2000). The Pine Ridge area in Dawes, Sheridan, and Sioux counties is the largest pine-dominated forest in the state and is characterized by the Rocky Mountain ponderosa pine, Pinus ponderosa (Nixon 1967). This area also contains a variety of understory shrubs, deciduous trees in canyons, and prairie species on exposed ridges and among trees in savannas (Kaul & Rolfsmeier 1993). The Wildcat Hills is a pine woodland and savanna within Scotts Bluff County. A variety of lichen habitats can be observed in this region including canyons, rocky bluffs, and grassland areas. In addition to pine forest, the area is characterized by an understory with sparse woody plants and herbaceous growth typical of western escarpments (Kaul & Rolfsmeier 1993). The Niobrara River joins the Keya Paha River in Boyd County, Nebraska, and continues westward across the remaining length of the state. The area is unique due to the cooccurrence of three distinctly different forest types. Western coniferous forest, eastern deciduous forest and northern boreal forests are able to exist in a grassland biome due to unique hydrologic and geologic conditions. Because of this, the region has been referred to frequently as a “biological crossroads” (Kaul et al. 1993). Pine forests are common along the south facing slopes on the north, as well as along the upper slopes of canyons on the south side. The herbaceous understory is typical of the sandhills with a bunchgrass community, and the upper canyons have Pine Ridge species (Kaul & Rolfsmeier 1993).

Comments

A Thesis Presented to the Department of Biology and the Faculty of the Graduate College University of Nebraska In Partial Fulfillment of the Requirements for the Degree Master of Arts University of Nebraska at Omaha. Copyright 2001 Sara Morgan.

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