Week 3:Rangelands

Global Meat Production and Industrialized Farming Systems

• Meat Production Statistics: Approximately half ($50\%$) of the world’s meat supply is derived from livestock that graze on grass in unfenced rangelands or enclosed pastures.

• Industrialized Factory Farm System: The remaining half of meat production occurs via an industrialized factory farm system.

• Concentrated Animal Feeding Operations (CAFOs): This system involves breeding large numbers of animals to gain weight rapidly. Animals are housed in crowded feedlots or in very crowded pens and cages within massive buildings known as concentrated animal feeding operations (CAFOs).

• Challenges of Industrialized Systems:

  • Chemical Additives: In certain instances, animal feed is supplemented with growth hormones and antibiotics to accelerate livestock growth, which raises significant health and environmental concerns.

  • Environmental Impact: Due to high animal density, animal wastes and runoff from feedlots and CAFOs result in serious negative impacts on both air and water quality.

Definition and Composition of Rangelands

• Core Definition: Rangelands are open areas used for grazing or hunting animals. They are characterized by native vegetation that is predominantly suited for grazing or browsing by domestic livestock or wild animals.

• Vegetation Types:

  • Grasses: Typical primary forage.

  • Grass-like plants: Includes species similar to grasses in structure.

  • Forbs (herbs): These are herbaceous (not woody), broadleaf plants that are not grass-like.

  • Shrubs: Woody plants used for browsing.

• Global Extent: Rangelands comprise almost half ($50\%$) of the world’s total landmass.

• Biomes included in Rangelands:

  • Grasslands

  • Shrublands

  • Woodlands

  • Wetlands

  • Deserts

Distinguishing Rangelands from Other Land Types

• Exclusions: Rangelands do not include barren deserts, farmland, closed canopy forests, or land covered by solid rock, concrete, or glaciers.

• Rangelands vs. Pastures: The primary distinction is that rangelands grow mostly native vegetation, whereas pastures consist of plants established and maintained by humans.

• Comparison of Rangeland and Pastureland:

  • Origin: Rangelands are natural/uncultivated; Pasturelands are cultivated.

  • Grass Type: Rangelands feature perennial grass; Pasturelands feature annual or perennial grass.

  • Species: Rangelands contain indigenous species; Pasturelands contain exotic or indigenous species.

  • Longevity: Rangelands are permanent in nature; Pasturelands are temporary in nature.

  • Diversity: Rangelands are highly diversified; Pasturelands are less diversified.

  • Maintenance: Rangelands are naturally maintained; Pasturelands are artificially maintained (through irrigation, fertilization, and periodic cultivation).

  • Enclosure: Rangelands are open/natural; Pasturelands are fenced.

Characterization of Major Rangeland Types

• Grasslands:

  • Primary Vegetation: Grasses and herbs.

  • Tree Density: Minimal to none.

  • Climate: Varies (temperate, tropical, and semi-arid).

  • Precipitation: $250-900\,mm$.

  • Soil: Variable, including loamy and clayey soils.

  • Biodiversity: Moderate to high.

  • Wildlife: Herbivores, small mammals, birds, and insects.

  • Human Impact: Affected by agriculture, urbanization, and habitat alteration.

• Desert Shrublands:

  • Primary Vegetation: Shrubs and bushes.

  • Tree Density: Sparse.

  • Climate: Arid to semi-arid with temperature extremes.

  • Precipitation: Less than $250\,mm$.

  • Soil: Sandy, rocky, and alkaline.

  • Biodiversity: Moderate.

  • Wildlife: Desert-adapted mammals, reptiles, and insects.

  • Human Impact: Vulnerable to overgrazing and habitat degradation.

• Savanna Woodlands:

  • Primary Vegetation: Grasses and trees.

  • Tree Density: Scattered trees.

  • Climate: Tropical with distinct wet and dry seasons.

  • Precipitation: $500-1500\,mm$.

  • Soil: Often fertile and well-drained.

  • Biodiversity: Moderate to high.

  • Wildlife: Herbivores, carnivores, and large herbivores.

  • Human Impact: Impacted by grazing and agriculture.

• Forests:

  • Primary Vegetation: Trees and shrubs.

  • Tree Density: Dense.

  • Climate: Varies (temperate, boreal, tropical, subtropical).

  • Precipitation: $500-3000\,mm$.

  • Soil: Diverse types, including acidic and loamy soils.

  • Biodiversity: High.

  • Wildlife: Diverse mammals and birds.

  • Human Impact: Affected by logging, deforestation, and habitat loss.

• Tundra:

  • Primary Vegetation: Low shrubs.

  • Tree Density: Sparse.

  • Climate: Cold, with short growing seasons.

  • Precipitation: Less than $500\,mm$.

  • Soil: Typically poorly drained and acidic.

  • Biodiversity: Low to moderate.

  • Wildlife: Few large mammals and migratory birds.

  • Human Impact: Highly vulnerable to climate change.

Distribution and Regional Presence of Rangelands

• Global Distribution: Rangelands make up $47\%$ of the world’s surface.

• Global Livestock Usage: Almost $4\text{ billion}$ cattle, sheep, and goats graze or browse on $42\%$ of the world’s rangelands.

• Rangelands in Kenya: Approximately $75\%$ of Kenyan land is classified as rangeland. These areas are primarily located in the North Eastern, Eastern, Rift Valley, Coast, and Nyanza provinces.

Economic and Ecological Activities in Rangelands

1. Livestock Production: Nearly half of the world's livestock graze on natural rangelands or managed pastures. This includes forms such as nomadic pastoralism and commercial ranching.

2. Wildlife Habitat: Most national parks are situated on rangelands. In Kenya, wildlife in these areas attracts tourists, which earns foreign exchange for the country.

3. Crop Production: Subsistence farming occurs in specific areas within rangelands, particularly along river banks.

4. Economic Gain: Grass from rangelands is harvested to produce hay for sale.

5. Recreational Uses: Activities include hunting and bird watching.

6. Mining Activities: Extraction of oil and minerals.

7. General Aesthetics: The intrinsic beauty of open spaces.

8. Scientific Research: Utilization of the land for study and data collection.

Ecosystem Services Provided by Rangelands

• Soil Formation: Natural processes that create topsoil over time.

• Erosion Control: Vegetation prevents the loss of soil to wind and water.

• Chemical Cycling: Support of nutrient cycles required for life.

• Carbon Sequestration: Storage of atmospheric carbon dioxide ($CO_2$) within biomass, aiding in climate mitigation.

• Biodiversity Maintenance: Support for a vast range of plant and animal species.

Threats to Rangeland Productivity

1. Overgrazing: This occurs when too many animals graze for too long, exceeding the area's Carrying Capacity (the maximum number of individuals of a species that can be sustained indefinitely in a specific area).

   • Effects of Overgrazing:

     • Lowers Net Primary Productivity (NPP).

     • Reduces grass cover.

     • Combined with prolonged drought, it leads to desertification.

     • Exposes soil to erosion.

     • Compacts soil, reducing its water-holding capacity.

     • Encourages the invasion of woody shrubs.

     • Limits overall livestock productivity.

2. Land Conversion: Continued conversion of rangelands for other uses, such as croplands and human settlements.

3. Invasive Species: The spread of noxious plants, such as Prosopis juliflora in the Baringo rangelands of Kenya.

4. Socio-economic Issues: Community conflicts regarding grazing land rights.

5. Fire Regimes: Damaging or altered patterns of wildfire.

6. Human Development: Infrastructure and residential expansion.

7. Global Climate Change: Alterations in precipitation and temperature patterns.

Sustainable Management and Grazing Systems

• Livestock Control: Managing the number and distribution of animals.

  • Livestock naturally aggregate around riparian zones (natural water sources).

  • Management includes moving animals between grazing areas (pastoralist practice) and fencing off riparian areas.

  • Ranchers can provide supplementary feed or strategically locate water holes, tanks, and salt blocks.

• Grazing System Types:

  • Continuous Grazing: Animals graze one area for the entire growing season.

    • Pros: Less labor, cheaper.

    • Cons: High risk of overgrazing and damage to riparian areas.

  • Rotational Grazing: Alternating grazing between multiple areas within or among growing seasons.

    • Pros: Better range condition, protection of riparian areas.

    • Cons: Requires more work and detailed planning.

• Precision Grazing Systems: Utilizing GPS technology to map grazing units and develop precise management plans similar to precision farming.

• Restoration: Degraded rangelands can be restored by banning grazing and off-road vehicles. An example is the San Pedro River in Arizona, which showed restoration after $10\text{ years}$ of such protections.

Vegetation Control and Community Awareness

• Vegetation Management: Controlling unwanted invader plants.

  • Methods: Herbicide spraying, mechanical removal, or controlled burning (these are expensive and less common).

  • Cheaper Options: Controlled short-term trampling by high densities of livestock.

  • Replanting: Re-seeding barren areas with native grass seeds is an expensive method for restoring severely degraded lands.

• Awareness Programs:

  • Community meetings and informative sessions.

  • Inter-county and national negotiations to limit over-extraction, industrial pollution, agricultural runoff, and devegetation.

  • Establishment of water treatment plants.

  • Implementation of aggressive soil conservation measures, including tree planting and proper cultivation.

Importance of Riparian Zones in Rangelands

• Definition: Riparian zones are land areas adjacent to rivers, streams, creeks, or other water bodies, characterized by unique vegetation influenced by water.

• Water and Forage: Higher soil moisture makes these areas vital for wildlife and livestock as reliable sources of water and food.

• Biodiversity: Supports high diversity, including trees, shrubs, wetland vegetation, birds, mammals, and amphibians. They provide critical habitats.

• Erosion Control: Roots of trees and shrubs stabilize streambanks, preventing sediment from entering the water and degrading quality.

• Water Quality: These zones act as natural filters, trapping pollutants before they reach the waterbody.

• Carbon Sequestration: Riparian vegetation sequesters $CO_2$, contributing to climate change mitigation.

• Recreation and Aesthetics: These areas are popular for fishing, birdwatching, and hiking due to their unique environments.