Ch. 14 Notes

Ch. 14 Notes - Reading Study Guide Ch. 14 Wildlife and...

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Wildlife and Rangelands Rangeland covers about 47% of the world's land area and about 1/3 of the U.S. - much of it public land in the West. Rangeland is characterized by the utilization of forage by grazing animals, usually on land that us unsuited to producing agricultural crops. Rangeland occurs in a broad array of ecological communities from prairie grasslands to desert shrub communities, understory and openings in forested communities, and alpine and sub-alpine meadows. 1. Grasses 1. Importance of the growth form of grasses 1. grasses have a basal meristem - they grow leaves from the base of the plant, near ground level, rather than having an apical meristem, growth from the top of the plant, as in most forbs and shrubs. 2. This makes the growing part of the grass much less vulnerable to grazing than in apical plants 3. grasses also have a high ratio of vegetative to reproductive tissue - meaning there is less chance of grazing taking important reproductive parts of plant. 2. grasses vary in their rates of carbohydrate (CHO) production and storage and therefore, in their ability to withstand grazing pressure 1. critical is the time of grazing 1. fast accumulation of CHO means better able to survive early grazing (spring-summer) 1. cool-season grasses - most of growth during fall- winter-spring 2. slower accumulation of CHO means better able to survive late grazing (summer-fall) 1. warm season grasses - most of growth during spring-summer. 2. ideally grazing occurring at end of growth so that plant CHO accumulation reserves are not harmed. 2. The Animal Unit 1. This is the unit of currency by which we measure the amount of forage needed/used by grazing animals. 2. One AU = live wt. of a cow and calf (454 kg) it assumes that animals this wt. consume a constant amount of forage. 1. AU does not consider different types of foraging pressure (e.g., from different species elk, cattle, deer, or from different age or sex classes within species) 2. AU provides only an estimate of foraging pressure from animals without respect to the specific need of each. 3.
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This note was uploaded on 11/14/2010 for the course AGSC 2301 taught by Professor Middleton during the Spring '09 term at Texas Tech.

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Ch. 14 Notes - Reading Study Guide Ch. 14 Wildlife and...

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