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RANGELAND MANAGEMENT NR 331

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RANGELAND MANAGEMENT NR 331Prof. Moh’d Khair El-Shatnawi

EX1 1/11 EX2 6/12

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RANGELAND MANAGEMENT NR 331Prof. Moh’d Khair El-Shatnawi

EX1 1/11 EX2 6/12

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RANGELAND AND MAN

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Rangelands

• All area of the world that are not barren desserts, farmed, or covered by solid rock, ice, or concrete.

• Deserts, Forests, and Natural grasslands

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Rangeland

• SRM- Land on which the native vegetation (climax or natural potential) is predominantly grasses, grasslike plants, forbs, or shrubs. Includes lands revegetated naturally or artificially when routine management of the vegetation is accomplished mainly through manipulation of grazing

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• Grazing: consumption of standing forage (edible grasses and forbs) by the animal

• Browsing: = of edible leaves and twigs from woody plants (trees and shrubs) by the animal

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Rangeland is uncultivated and capable of providing habitat for domestic and wild animals.

• Rangeland is uncultivated land that is suitable for grazing and browsing animals.

• Generally, rangeland is not fertilized, seeded, irrigated, or harvested with machines

• Rangelands are the principal source of forage for livestock, and they also provide habitat for a great variety of native plants and animals.

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PASTURELANDS:

• Forage source• Requires periodic cultivation, agronomic inputs• Pasturelands may also need irrigation or

fertilization, and they are usually fenced.

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Ecosystem:

• All the interaction parts of the physical and biological worlds. Organisms together with their abiotic environment, forming an interacting system, inhabiting an identifiable space.

•• a community of plants, animals, and a community of plants, animals, and microorganisms that are linked by energy microorganisms that are linked by energy and nutrient flows and that interact with and nutrient flows and that interact with each other and with the physical each other and with the physical environmentenvironment

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A rangeland ecosystem:

• is an area with similar ecological characteristics on which man has placed boundaries for management purposes. It includes both biotic (plants and animals) and abiotic (soil, topography, climate) components of defined area.

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Range Site (Ecological Site):

• An area of rangeland which has a potential to produce and sustain distinctive kinds and amounts of vegetation to result in a characteristic plant community under its particular combination of environmental factors (climate, soils) and associated native biota.

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Range

• Range. (n.) Any land supporting vegetation suitable for grazing including rangeland, grazable woodland and shrubland. Range is nota use. (adj.) Modifies resources, products, activities, practices, and phenomena pertaining to rangeland, cf. rangeland, forested range, grazable woodland, shrubland

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Pasture (Range Unit)

• Pasture (Range Unit) is land with vegetation cover used for grazing of livestock as part of a range or other unenclosed pastoral systems

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Ecology:

• The study of the natural environment and the relations of organisms to each other and to their surrounding.

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Most rangelands will not sustain cultivation, because:

• 1. Low precipitation• 2. Thin soil• 3. Rugged topography• 4. Cold Temperatures

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Rangelands uses:

• 1. Forage for livestock• 2. Sources of water• 3. wildlife• 4. Recreation

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Range Management (RM):

• is the manipulation of rangeland components to obtain the optimum combination of goods and services for society on a sustained basis.

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RM basic components are:

• 1. Protection and enhancement of soil vegetation complex, and

• 2. Maintaining or improving the output of consumable range products, such as red meat, fiber, wood, water, and wildlife.

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RM Concepts:

• 1. Rangeland is renewable resources• 2. Sun energy can be captured by green plants

which can only be harvested by grazing animal.• 3. Rangelands supply man with food and fiber

at very low energy costs

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RM Concepts:

• 4. Rangeland productivity is determined by soil, topographic, and climatic characteristics.

• 5. Food, fiber, water, recreation, wildlife, and timber can be harvested from rangelands.

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Range Science

• Is the organized body of knowledge upon which range management is based

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Relationship of Range Management to Other Disciplines

• 1. Plant Science• 2. Animal Science• 3. Abiotic Sc.• 4. Sociological Sc.

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Importance of Rangelands to Man

• 1. Source of food for human• 2. wild life• 3. water• 4. Recreation• 5. Plant products• 6. Wood and Minerals

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Desertification

• Is the formation of desertlike conditions, largely through human actions

• overgrazing & drought

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Problems Related to Range Management in Jordan

• A- Problems Related to Livestock Numbers• B- Problems Related to Cultivation of

Rangelands• C- Problems Related to Drought• D- Problems Related to Dry Season

• Declining Forage Quantity• Declining Forage Quality

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Problems Related to Range Management in Jordan

• E- Improper grazing time• Early grazing• Grazing during reproductive stage

• F- Socioeconomic problems

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RANGELAND PHYSICAL CHARACTERISTICS

• Physical characteristics is essential for understanding range management

• physical characteristics determine the type and productivity of vegetation in any area which determine the number and type of the animal that can support

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Physical characteristics include:

• 1. Climate: Timing of ppt'n, total annual ppt'n, and annual average temp. regime are the primary factors determining the climatic type of an area.

• 2. Soil• 3. Topography

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PRECIPITATION

• Is condensation from the atmosphere, falling as rainfall, snow, hail or sleet

• The most important single factor determining the type and productivity of vegetation

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Effective ppt’n:

• That portion of total precipitation that becomes available for plant growth. It does not include precipitation lost to deep percolation below the root zone or to surface runoff or to evaporation or which falls during the dormant season unless stored in soil for later use during the growing season

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• Forage production increased rapidly up to 500mm/year. >500mm soil characteristics become more important than ppt'n

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Critical characteristics of ppt'n that affect vegetation are:

• 1. total ppt'n• 2. distribution• 3. relative humidity• 4. ppt'n form• 5. Annual variability

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Most rangelands are characterized by:

• low total ppt'n <500m• variability in ppt'n increased as annual total

ppt'n <450mm• variability in timing of ppt'n is more important

than variability in total ppt'n

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Drought

• Is defined as prolonged dry weather generally when ppt'n is less than 75% of the long term average

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Humidity

• Refers to the amount of moisture in the air• Humidity is the amount of water vapor in the

air • -Expressed as relative humidity (RH)

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Relative humidity (RH)

• Relative humidity is defined as the ratio of the partial pressure of water vapor to the saturated vapor pressure of water at a given temperature. In other words, relative humidity is the amount of water vapor that is in the air at a specific temperature compared to the maximum amount of water vapor that the specific temperature is able to hold without the water condensing

• Relative humidity is expressed as a percentage

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Relative humidity

• RH is the percentage of the maximum quantity of moisture that the air can hold at prevailing temperature.

• - cool air can hold moisture less than warm air• -Evaporation and Transpiration increased as

air RH decreased

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TEMPERATURE

• Increasing temp. Above the average may increase forage production. However; above average temp. may occur concurrently with drought.

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TEMPERATURE

• COOL-SEASON PLANT: A plant which generally makes the major portion of its growth during the late fall, winter, and early spring. Cool-season species generally exhibit the C3 photosynthetic pathway. C-3 Plant: A plant employing the pentose phosphate pathway of carbon dioxide assimilation during photosynthesis; often a cool-season plant

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TEMPERATURE

• WARM SEASON PLANT: A plant which generally makes most or all its growth during the spring, summer or fall and is usually dormant in winter. warm-season species generally exhibit the C4 photosynthetic pathway. C-4 Plant: A plant employing the dicarboxylic acid pathway of carbon dioxide assimilation during photosynthesis; often a warm-season plant.

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FROST-FREE PERIOD

• Frost free days are the number of days in a year with minimum temperatures above freezing (zero degrees Celsius). The frost free season provides an indication of the length of the growing season

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WIND

• Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air

• Can reduce ppt'n effectiveness by increasing soil evaporation losses and increasing plant transpiration

• Wind velocity and Temperature

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TOPOGRAPHY

• -Differences in vegt'n and climate could be explain by differences in topography

• - Altitude• -Latitude• -Longitude• -Differences in species and growing periods

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A SPECT

• Aspect refers to the directional orientation of the slope

• -Temp. on slopes changes with changes in aspects

• -Temp increase as aspect changes from north to east to west to south

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DEGREE OF SLOPE

• Affects the vegt'n productivity and the use by the animal

• Increase slope% will decrease productivity and the use by the animal

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SOILS

• Defined as the upper, weathered surface of the earth crust that is capable of supporting plant life

• Collection of natural bodies occupying portions of the earth’s surface that support plants and that have properties due to the integrated effect of climate and living matter, acting upon parent material, as conditioned by relief, over periods of time.

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SOIL

• Soil characteristics and classification determine the productivity of soil within a particular climate

• Soil (minerals, O.M, LIVING FORMS)

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Soil Characteristics that are important to range management are:

• Color Texture Structure• Depth pH O.M• Mineral status ------> Fertility

• *Interaction bt. soil char., climate and topography determines the vegt'n type and quantity

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Soil Texture

• Soil Texture: Soil texture is a term commonly used to designate the proportionate distribution of the different sizes of mineral particles in a s • The way a soil feels• A name given a textural group based on the

relative proportions of each size of soil particle

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Soil Texture

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Soil pH

• pH= -Log [H+]• pH is a measure of how acidic or basic things

are and is measured using• The pH of soil or more precisely the pH of the

soil solution is very important because soil solution carries in it nutrients

• Toxicity, nutrient availablity, losses, Fertilizers type and doses

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Influence of Rangelands Physical Characteristics upon Range Animal

• - Climate X Soil X Topography ------> ----> ----> Potential of a particular range to support livestock and wildlife

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Warm wet rangelands :

• 1. High quantity of forage for livestock• 2. Increase parasites and disease problems• 3. Deficient in P, K, Cu, Co, Mg, Na, Zn

Because of severe soil leaching

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Temperate arid rangelands:

• 1. low forage• 2. less parasites and disease• 3. Cold Temp. and heavy snow can have

important adverse impact on both livestock and wildlife.

• 4. Supplemental feeding of livestock during winter is necessary on many temperate rangelands which increase the production costs.

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• - Annual weather variation has imp. in range animal productivity

• - Drought .........> Increase animal death• - Climate and Topography ...........> Selection of

types of livestock for particular range• e.g. Camels efficiently use hot desert because

of their low water requirements and ability to brows shrubby vegt'n

• - Native animals are much less affected than introduced domestic animals.

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• Native animals are much less affected than introduced domestic animals.

• Arid rangeland is adequate in P, K, Cu, Co, Mg, Na, Zn

• Native animals are much less affected than introduced domestic animals.

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GRAZING DISTRIBUTION AND USE OF RANGELANDS

(READING)

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Factors Causing Uneven Use of Rangeland

• Distance from Water• Rugged Topography• Diverse vegetation• Wrong type of livestock• Pests• Weather

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Distance from Water

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Slope

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Better Livestock Distribution Methods

1. Water Developments2. Shade 3. Food Supplementation4. Fencing5. Herding

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• Fertilization• Burning& Weed Control• Season of Use• Grazing System• Selection and breeding

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• Integrating several strategies appears to have the greatest potential to solve critical resource issues associated with poor livestock grazing distribution

• The strategies for increasing uniformity of grazing do not appear to be antagonistic and in several cases appear to be complementary

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DESCRIPTION OF RANGELAND TYPES

• GRASSLANDS• DESERT SHRUBLANDS• SAVANNA WOODLANDS• FORESTS• TUNDRA

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GRASSLANDS

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GRASSLANDS

• Most productive rangelands in the world when forage prod'n for wild and domestic animals is the major consideration.

• Dominated by family gramineae (grasses)• Free of woody plants• Relatively flat

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Grasses

• Grasses are herbaceous• Grasses are monocotyledonous, usually

herbaceous plants with narrow leaves growing from the base

1. Annual plants or 2. Perennials that die back to the ground surface

at the end of the growing season and then regenerate the next season by shoots developing from underground rhizome or root systems

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Stems

• Hallow, Jointed stems (must have Nodes and Internodes

• Stems of grasses typically have swollen nodes, or bases, and they are often hollow between the nodes

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• Fine narrow leaves with large parallel veins• The leaves are usually long and narrow and

have parallel veins. A specialized tissue such as a ligule or auricles may usually present at the location where a leaf sheaths to the stem

• Fibrous root systems

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Tiller

• Nodes, internodes, leaves

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Developmental MorphologyPhytomer Organization Tiller Organization Plant Organization

Phytomer 4

Phytomer 2

Phytomer 3

Phytomer 1

Tiller 1

Tiller 2

Tiller 3

Axillary Bud

Blade

IntercalaryMeristems

Node

Ligule

Sheath

Internode

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Tiller

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Grasslike plants

• Grasslike plants have leaves and roots like true grasses but differ by having non jointed-solid stems; e.g. Carex sp. and Juncus sp.

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Forbs

• Forbs important component of many grasslands• - Have tap root• - Broad leaves with netlike veins• - Solid nonjointed stems

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• The above ground parts of most grasses and forbs die back to the crown during winter in temperate areas or during the dry season in the tropics

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Shrubs

• Shrubs minor components of grasslands• -woody stems that branch near the base• - Long Coarse roots• - Stems remain alive during dormant periods

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Grasslands Climate and Soil

• - 250-900 mm annual ppt'n occurs as frequent light rains over an extended periods (90 days or more).

• -Warm-season grasses• -Cool-season grasses

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Soil

• Soil associated with grasslands are usually deep (>2m), Loamy textured, high in O.M., and very fertile. These characteristics make them highly suitable for cultivation.

• - Sandy arid areas with 300 mm of annual ppt'n and 60 cm deep can support grasslands, while deeper soil support shrublands.

• - >250 mm annual ppt'n , heavy clay soil support grassland; while surrounding Loamy and Sandy soils support Forests ?????

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DESERT SHRUBLANDS

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DESERT SHRUBLANDS

• Driest rangelands• woody plant < 2 m height with a sparse

herbaceous understory characterize vegetation of this type. Have received the greatest degradation by overgrazing and show the slowest recovery from degradation

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SAVANNA WOODLANDS

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SAVANNA WOODLANDS

• Dominated by scattered, low growing trees (<12m tall) and have productive herbaceous understory

• It could be a transition between grasslands and forests

• Fire ...........> grasslands• Overgrazing ..........> Shrubs and Trees

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FORESTS

• Distinguished form savanna woodlands by having trees over 12 m height and closely spaced (< 10 m apart)

• Managed for timber production• Logging and Fire can open the stand and allow

grasses to grow which make the forest useful for grazing.

• > 450 mm annual ppt'n• Low in fertility due to leaching

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Mycorrhiza

• A mycorrhiza (Gk.,: fungus roots, pl mycorrhizae, mycorrhizas) is a symbiotic(generally mutualistic) association between a fungus and the roots of a vascular plant.

• In a mycorrhizal association, the fungus colonizes the host plants' roots, either intracellularly as in arbuscular mycorrhizal fungi (AMF)

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Mycorrhiza

• In a mycorrhizal association, the fungus colonizes the host plants' roots, either intracellularly as in arbuscular mycorrhizal fungi (AMF), or extracellularly as in ectomycorrhizal fungi. They are an important component of soil life and soil chemistry

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TUNDRA

• Level, treeless plain in Arctic or high-elevation (cold) regions

• Frozen over 7 months/year• No trees• ppt'n is low (250-500 mm)• Short grazing season

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Characteristics of tundra

• Extremely cold climate• Low biotic diversity• Simple vegetation structure• Short season of growth and reproduction• poor nutrients

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DEVELOPMENTAL MORPHOLOGY

AND PHYSIOLOGY OF RANGE PLANTS

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BASIC CONCEPTS

• Range plant management is based on four fundamental concepts.

1. The plant is the only source of energy (food) for the support of grazing animals.

2. The formation of foods is first dependent on the photosynthetic process in the leaves

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BASIC CONCEPTS

3. Plants do not get food for their maintenance and growth from the soil. They obtain only the raw materials needed for photosynthesis and subsequent food elaboration. Green plants are therefore entirely dependent on green leaf tissue for their survival.

4. When leaves are removed from plants, food-producing capacity is reduced.

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DEVELOPMENTAL MORPHOLOGY AND PHYSIOLOGY OF RANGE

PLANTS

Vegetation is produced by a series of developmental and physiological processes within individual plants.Developmental Morphology is a series of structural changes displayed by organisms from inception to maturity - including cellular division, differentiation, and growth.

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Developmental Morphology

Developmental Morphology of plants defines their architectural organization, influences their palatability and accessibility to herbivores, and affects their ability following defoliation

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Physiological Processes

• Physiological Processes establish the capacity for solar energy capture and product synthesis necessary to sustain structural development.

• - PHOTOSYNTHESIS is the process by which plants convert energy from sun, carbon dioxide from atmosphere, and water and minerals from soil into food

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Physiological Processes

• Range management has little effect on CO2 available for photosynthesis

• Availability of H2O for photosynthesis is strongly affected by management

e.g. heavy grazing increase soil moisture stress by weakening root systems, causing excessive water runoff and evaporation from soil. Low soil organic matter

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Photosynthetic product used to produce complex compounds, these complex compound used for :

1. Root replacement2. Regeneration of leaves and stems after

dormancy3. Respiration during dormancy4. Bud formation5. Regrowth after gazing

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PLANTS CONSIDERATIONS IN DEVELOPING GRAZING SYSTEMS

1- Dormant period is the least critical period for foliage removal

2- Growth initiation is intermediate relative to defoliation responses; when temperature and moisture are optimum plant has opportunity to replace leaves removed by gazing, drought are most critical because low moisture severely reduce potential for photosynthetic activity in the mid and late stages of growth.

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PLANT CONSIDERATIONS IN DEVELOPING GRAZING SYSTEMS

3- The period from floral initiation to seed development is the most critical period for foliage removal. Because the plant demand for photosynthetic products is high and opportunity for regrowth is low.

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Range Manager can control grazing animal effects on plant by regulating :

1- Grazing Intensity; the most important because it govern the amount of leaf area remaining for photosynthesis

2- Grazing Time3- Grazing Frequency4- Grazing Selectivity

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GRAZING RESISTANCE

• Grazing resistance is an ambiguous term used to describe the moderate ability of plants to survive grazing

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Herbivory ResistanceGrazing Resistance

(Mechanisms enabling plants to survive in grazed systems)

Avoidance(Mechanisms that reduce the probability of grazing)

Tolerance(Mechanisms that increase growth following grazing)

MorphologicalCharacteristics

BiochemicalCompounds

MorphologicalCharacteristics

PhysiologicalCharacteristics

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GRAZING RESISTANCE

• An additional understanding can be gained by organizing grazing resistance into tolerance and avoidance components.

• Avoidance mechanisms reduce the probability and severity of plant defoliation (i.e., escape mechanisms)

• Tolerance mechanisms facilitate growth following defoliation (i.e., mechanisms of rapid leaf replacement)

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GRAZING RESISTANCE

1- Tolerance to defoliation

2- Avoidance to defoliation

• - Defoliation reduce the ability to compete in natural environment

• -Degree and season of defoliation

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General resistant characteristics

• Shape of non-structural CHO reserve cycle• Flexibility in resource allocation Compensatory

photosynthesis• Compensatory nutrient uptake

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Compensatory Photosynthesis

• Increased rates of photosynthesis following partial defoliation relative to similar aged leaves of nondefoliated plants is referred to as compensatory photosynthesis

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Compensatory PhotosynthesisP N

(% of p

recl

ippi

ngPs rate)

Time From Clipping (days)

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100

90

80

70

0 2 4 6 8 10

ControlModerately clippedHeavily clipped

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Flexibility in resource allocation

• Flexible patterns of carbon allocation may increase grazing tolerance by increasing the rate of leaf replacement and reestablishing the photosynthetic capacity of plants

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CHO reserve cycle

• Plants commonly store carbohydrates when most leaf growth is complete. Even though leaves still have a high photosynthetic capacity and sufficient leaf area for photosynthesis, there are few demands for new growth. Therefore, carbohydrates accumulate in roots and crowns and serve as storage organs for growth

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TNC Contribution to Shoot Regrowth• Carbohydrate reserves exist and they provide a

small amount of energy to contribute to initial leaf growth following severe grazing or leaf damage e.g., fire, late spring freeze.

• Current photosynthesis is the primary source for growth of new shoots.

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•

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Factors that Increase Grazing Resistance in Grasses, Forbs, and Shrubs

GRASSES• Higher proportion of culmless (stemless) shoots

than species with low resistance.• Greater delay in elevation of the apical buds than

species with low resistance.• Sprout more freely from basal buds after

defoliation than species with low resistance.• Higher ratio of vegetation to reproductive stems

than species with low resistance.

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FORBS• Produce a large number of viable seeds.• Delayed elevation of growing points.• Poisons and chemical compounds that reduce

palatability.

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SHRUBS• Spines and thorns that discourage browsing.• Volatile oils and tannins that reduce

palatability.• Branches make removal of inner leaves

difficult.• Only current year's growth of most shrub

species is palatable and nutritious.• Removal of apical meristem may stimulate

axillary bud development.

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Culmless Versus Culmed Tillers

Culmless

Culmed

Apical Meristem

Axillary Buds

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GRAZING OPTIMIZATION THEORIES

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Figure 5.10 Equation showing grazing impacts on

perennial grass plants

• Genetic potential of Plant + Growth Promoting Features -Detrimental Impacts Environmental constraints Plant Performance

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Detrimental Impacts

• 1. Removal of photosynthetic tissue• 2. Reduced carbohydrate storage • 3. Reduction of root growth • 4. Reduction of seed production

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Growth-Promoting Features

• 1. Increased photosynthesis• 2. Increased tillering• 3. Reduced shading• 4. Reduced transpiration• 5. Growth-promoting substance

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Negative Effects of Heavy Grazing on Range

Plant Physiology

1. Decreased photosynthesis.2. Reduced carbohydrate storage.3. Reduced root growth. 4. Reduced seed production. 5. Reduced ability to compete with ungrazed plants6. Reduced mulch accumulation. This decreases

soil water infiltration and retention. Mulch is also necessary to prevent soil erosion

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Possible Positive Effects of Light to Moderate Grazing on Range Plant Physiology

1. Increased photosynthesis.2. Increased tillering.3. Reduced shading.4. Reduced transpiration losses.5. Inoculation of plant parts with growth-promoting

substances.6. Reduction of excessive mulch accumulations that

may inhibit vegetative growth. Excessive mulch can provide habitat for Pathogens and insects that can damage forage plants.

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RANGE MANAGEMENT PRINCIPLES

• 1- Excessive removal of plant leaves destroys photosynthetic capability and ultimately kills the plant. Excessive accumulation of plant tissue also lowers the photosynthetic capability of the plant. The primary goal in grazing management is to maximize photosynthetic activity with controlled defoliation.

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• 2- Vegetation residue plays an important part in sustaining plant welfare throughout the year. Although more herbage can be removed during dormancy, adequate residues must still be maintained to protect the plant crown and soil.

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• Plants that are highly resistant to grazing are generally less productive and palatable than those with low grazing resistance. This is because photosynthetic products use for physical and chemical protection from grazing could otherwise be used for plant growth and reproduction.

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Range Animal Nutrition

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Primary Factors Determining Forage Selection By Animal:

• Body Size• Digestive System Size/Body Weight• Digestive System Type• Mouth Size And Shape

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Range Ungulate Divided into Three Groups Based on Their Foraging Habits:

• Grazers e.g.• Browsers e.g.• Intermediate Feeders e.g.

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Kind of Livestock

• Grazing animals can be divided into three groups based on their vegetation preference:• Grazers (cattle, horses), which have a diet

dominated by grasses;• Browsers (goats), which consume primarily

forbs and shrubs;• Intermediate feeders (sheep), which have no

particular preference for grasses, forbs, or shrubs.

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Range Ungulate Have Two Digestive Systems:

• Rumen • Large Cecum

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The Rumen System has two advantages over cecum system:

1- The Process of rumination (reguration and rechewing of forage)

• Rumination - bringing up partially digested food and rechewing it before swallowing it or spitting it out

• Regurgitation is the controlled flow of stomach contents back into the esophagus and mouth.

2- Microbes are passed from rumen into the Abomasum, where they are digested and absorbed

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The cecum System has advantage over Rumen system:

1. Fiber digestion is fast and 2. Fiber digestion is not complete • which result in high intake by cecum animal

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Rangeland Ecology

Rangeland Ecology

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Introduction

• Ecology involves the study of the interrelationships between organisms and their environment.

• Range management is applied ecology because it deals with manipulation of organisms and their environment with the goal of increasing output usable to man.

• The fundamental concept in RM is that the welfare of plants and animals depend on each other

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• Rangelands generally have low vegetation productivity compared to farmlands

• Inputs associated with regulating animals (control # of animals, timing of grazing, frequency of grazing ...etc.) are generally much lower cost than those regulating plant

• Inputs associated with regulating plants (fertilization, cultivation, weed control, seeding, irrigation) are generally higher cost

• Therefore, RM focused on manipulating vegetation and soil by control of the grazing animals

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Ecosystem

• Ecosystem is a functional unit consisting of organisms and environmental variables of specific area.

• Ecosystem has a structures and functions

• Rangeland Ecosystem includes a living and nonliving elements of a piece of rangeland in which man placed boundaries for management purposes

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Ecosystem components

• Ecosystem components is related functionally; change in one influences all others

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1. Abiotic components

• Soil, and Climatic factor• Soil- Anchorage of plants, reservoir of water

and nutrients, serves as a habitat for soil animals and m.o

• Soil Manipulation involves fertilization, Mechanical treatment to increase infiltration, water storage

• - Abiotic factors have direct effects on plant and indirect effects on animals and m.o

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2- Biotic components

• Primary producers• Consumers• Decomposers

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• Primary producers (Autotrophs)- plants with a pigment of chlorophyll which converts light energy to chemical energy that can be used by the plants and animals.

• Primary producers support all other groups of organisms

Primary producers

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Primary Productivity

• Primary Productivity kg/area/time: The rate of organic matter storage by photosynthesis of primary producers

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Biomass

• Biomass kg/area: weight of the organisms at a given time

• -Herbage = Biomass of herbaceous vegetation• - Forage/Brows = Herbage (biomass) - unusable

part of the herbage (biomass)= Usable herbage (biomass)

• - Biomass is highly variable during the growing season relative to dormant season why?

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Biomass

• Seasonal changes in plants shoots, roots and root/shoot ratio varies according to season, plant species, soil characteristics and grazing pressure

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Decomposers

• Decomposers - M.O. (Bacteria, Fungi, Lichens, Algae), have enzymatic activities

1. critical for nutrients cycling2. Prevent organic matter accumulations3. Affects soil fertility

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Primary Consumers

• Primary Consumers - such as Livestock, big game animals, destructive small animals (Grasshoppers and Rodents)

• Microconsumers - Ants, termites, and Nematodes; Nematodes is the most important and consumes the root systems• All biotic components which are not plants are

Hetrotrophs

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Functions of Ecological systems

1. Energy Flow2. Nutrients Cycling

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Functions of Ecological systems 1- Energy Flow

• Energy flow within the ecosystem may be viewed in terms of an economic way; ecology is concerned with the movement of valuable commodities (an article of trade or commerce) thorough a series of producers and consumers

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Food Chain

• Energy captured by autotrophs transferred to hetrotrophs into one of the two chains

1. Grazing Food Chain - Sun light-Plants-Grazing animals-M.O

2. Detrital Food Chain - Sun light-Plants-M.O

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Food Chain

• Food that will not go through grazing chain will decomposed by m.o

• Management should make balance bt. the two chains

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Energy Flow within an ecosystem governs by two thermodynamic laws:

• First law - Energy can be transformed from one form to another, but cannot be created or destroyed

• light energy----> chemical energy -------> Heat• Second law - Energy transformation is not

100% efficient; 90% of the chemical energy transferred between feeding levels converted into heat

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• Energy losses between feeding levels are: maintenance E (respiration and basal metabolism), gases, urine, and feces

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Primary Productivity Constraints

• Primary Productivity (The rate of organic matter storage by photosynthesis of primary producers, Plant growth/area/time) is limited by two Ecological Constraints:

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• 1- quality of solar radiation; only 45% of sun energy is within the appropriate region of the spectrum that are effective in photosynthesis, the other 55% is converted to heat, which affects the temp. of the atmosphere, soil and vegetation that will affect the plant growth in an indirect way

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• 2- Abiotic factors that prevent photosynthesis to maximized; e.g. water, temperature, nutrients limitation, and shading that prevent maximum leaves production or create dormant season for the plant

- Under ideal conditions plant leaves can convert only 20% of light energy to chemical energy and only 1% of the light energy will be converted to chemical energy under field conditions

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Secondary Productivity Constraints

• Secondary Productivity (The rate of organic matter storage by consumers from consumption of primary producers, animal growth/area time) is limited by two ecological constraints:

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1- The inability of herbivores to consistently consume the majority of the primary production produced. Primary production varies through time and space, making it difficult to balance herbivores density with fluctuating food resource. Primary production which is not entering grazing food chain will enter detrital food chain

- Most of primary production is located below ground as roots and crowns making it inaccessible to large herbivores.

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2- The quality of primary production (Nutritional value) ingested by herbivores. 90% of the food ingested by animal is lost as methane, urine, feces, and metabolizable energy (Only 0.002% of the light energy is converted to grazing animal body)

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• Efficient biomass utilization and primary production cannot be maximized simultaneously because of the contribution of leaf area to both processes

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Functions of Ecological systems2 Nutrients Cycling

• Availability and transfer of nutrients is the second function of the system. Mineral Nutrients available to the plant as inorganic forms

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INORGANIC NUTRIENTS <-------> ORGANIC NUTRIENTS

• Nutrients sources for the plants are either soil or atmosphere (Abiotic source). Animal mainly acquires nutrient by consuming plants. Nutrients, like energy, enter either grazing food chain or detrital food chain but in cycle forms. Nutrients should be cycled from organic into inorganic ion forms to become available to the plants

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Nutrients Cycling

• Livestock accelerate nutrients cycling by breaking down complex organic mater through digestion into simpler organic mater easy to break down by decomposers which affects nutrients availability and losses. Nutrients losses though livestock is small compared to losses due to leaching, erosion and changes to gases

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Succession & Climax

• Range ecosystems are dynamic and changing continuously; range manager should understand these changes and which ones influence management decisions

• Successional changes are among the most important ones

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succession

• The driving forces of succession are the changes created by the organisms (e.g. plants, animals, and microorganisms) and those created by major environmental changes.

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Plant succession is the replacement of one plant community by another until final community (Climax) is reached.

• Types of succession• 1- Primary successions are those starting

from bare ground and open water (primary areas)

• 2- Secondary successions are those occur following some type of disturbance such as overgrazing, drought, fire, deforestation, and after cultivation.

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Primary succession

• Primary succession occurs when the plants become established on land not previously vegetated.

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Secondary successions

• The invasion of land that has been previously vegetated but its vegetation was destroyed by natural or human disturbance. Secondary succession is the important succession type for range manager

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succession

• The barren soil surface in secondary succession is not as severe as in the case of primary succession, because much of the soil remains (but may be depleted) and plant propagules are already present in the soil.

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RANGE INVENTORY AND MONITORING

Are essential for RM plan

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Inventory

• Inventory involves an assessment of resources at one point in time.

• Inventories might include vegetation type, topography, soil,..... etc.

• Inventory provide an accurate representation of existing conditions

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Monitoring

• Monitoring is an evaluation process conducted to determine the response to some management program.

• Monitoring is used to determine changes over time

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Determination of Vegetation Attributes

1- Weight or Biomass refers to the wt. of organisms present at one time

2- Area and Cover,

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Area and Cover

• Canopy Area refers to the area covered by vertical projection of the crown of the plants onto the soil surface. Woody plants

• Basal Area refers to the area occupied at the inter section of the plant and soil surface. Herbaceous plants

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Density and Frequency

• Density = # of individual plants per area• Quadrate size is critical?• Frequency: the percentage of quadrates in

which the species occurs• Quadrate size is critical?

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Trend the direction of changes in range condition

• Range Condition the present situation of the range

• Ground cover, plant vigor, litter, erosion, and species composition

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