Tim Griffin, Range manager

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This scenario accompanies the online lesson, "Perennial Plant Response to Defoliation", and is desgned to allow you to apply the concepts learned in that lesson to a real-life problem. In this lesson you will:

• Evaluate time and intensity of defoliation as key variables affecting plant response to grazing.
• Recognize consequences of plant defoliation at different stages of growth in relation to location of growing point.
• Identify when defoliation is least and most detrimental to grasses.
• Describe the role that carbohydrate reserves play in plant growth and survival. 

Tim Griffin is the Rangeland Management Specialist at the Nebraska National Forest, Bessey Range District, Halsey, NE. He is in charge of managing the Forest’s grasslands that are leased to local ranchers for cattle grazing. Based on lease agreements, each rancher is allocated a portion of the Forest’s grasslands for grazing. Tim sets the stocking rates, monitors the use and condition of the grasslands through the grazing season, and works with the ranchers in developing management and improvement plans. Tim is concerned about managing the Forest’s grasslands so that they provide ranchers’ cattle with excellent grazing while maintaining a healthy grassland ecosystem that can have other uses, including wildlife habitat, recreation, and ecotourism.

Figures 1 & 2. Tim Griffin, Rangeland Management Specialist, evaluating rangeland condition of grazingland on the Nebraska National Forest. (Walter Schacht, 2005)

In late summer, Tim went out to assess the condition of the grasslands and the plant health of desirable grass species. Grass species of particular interest are prairie sandreed and sand bluestem. His attention was drawn to two pastures in a particular allotment that were looking unhealthy: there were few desirable warm-season, mid- and tall grasses, and those remaining were in low vigor. There were eight pastures in this allotment and two herds of cows moved through a fixed sequence of four pastures each. The cattle were moved from one pasture to next every 25 to 40 days. Tim decides to review the grazing schedule records for the past several years to determine why the two pastures are in low condition. Help Tim figure out what’s going wrong and how to fix it by answering these questions.