Chapter 17: Global Biogeography

VEGETATION

Natural vegetation = little human impact and natural forces; Human-influenced = modified and mid-latitudes

Natural Vegetation

a plant cover that develops with little or no human interference; It is subject to natural forces, storms, or fires that can modify or even destroy it; Most of the arctic tundra and the boreal forest of the subarctic zones is in a natural state

Human-influenced vegetation

vegetation that has been influenced in some way by human activity, for example, through cultivation, grazing, timber cutting, or urbanization; Most of the midlatitude land surface is totally under human control; Humans have also moved plant species from t

Biogeographers

are less concerned with individual species, and more interested in plant converge as a whole

Life-form

the physical structure, size, and shape of the plant

TREES

Large; Woody; Perennial; 1 Trunk; Branching Crown

Trees

large plants with a single upright main trunk, few branches in the lower part but branching in the upper part to form crown; They are perennial, meaning that their woody tissues endure from year to year, most having life spans of many many years

SHRUBS

Woody; Perennial; Branching Stems

Shrubs

stems branching from a base near the soil surface, creating a mass of foliage close to ground level; They are perennial, meaning that their woody tissues endure from year to year & most have long lifespans

LIANAS

Woody; Vines; Supported

Lianas

woody plants, but they take the form of vines supported on trees and shrubs; EX: English ivy, poison ivy or oak, and Virginia creeper; Include tall, heavy vines in the wet equatorial and tropical rainforests and also some woody vines of midlatitude forest

HERBS

Small & tender; Shape & Leaf type Range; Annuals vs. perennials; Low

Herbs

lack woody stems, small, tender plants, wide range of shapes and leaf types; Some are annuals (living for only a single season), and some are perennials; Some herbs are broad-leaved, and others are narrow-leaved, such as grasses; Herbs share few character

MOSSES & LICHENS

Mosses=Ground, Soft, and Damp/Shady; Lichens = Ground, Algae & Fungi, and Mutualism

Lichens

algae and fungi live together, forming a single plant structure; Annuals = living only for a single season; Perennial = woody tissues endure annually; Lichens also grow closely to the ground; Lichens dominate the vegetation in some alpine and arctic envir

FORESTS & WOODLANDS

Forests=Crowns contant, shrubs, herbs, mosses; Woodlands=Crowns NOT contact, shrubs, herbs

Forest

a vegetation structure in which trees grow close together; The crows of forest trees often touch, so that their foliage largely shades the ground; Many forests in moist climates show at least 3 layers of life-forms: the tree, shrub, and herb layers

Woodland

tree crowns are separated by open areas that usually have a low herb or shrub layer

Ecosystem

group of organisms and the environment with which the organisms interact; fall into two major groups (Aquatic & Terrestrial)

Aquatic Ecosystem

ecosystem of a lake, bog, pond, river, estuary, or other body of water
Include marine environments and the freshwater environments of the lands

Terrestrial Ecosystem

ecosystems of land plants and animals found on upland surfaces of the continents; They are directly influenced by climate

Biome

largest recognizable subdivision of terrestrial ecosystems, including the total assemblage of plant and animal life interacting within the life-layer; Green plants dominate simply because of their enormous biomass

Formation classes

subdivisions of biomes based on vegetation structure and life-form

desertification

the degradation of land in arid, semiarid, and dry subhumid areas.

effects of desertification

Loss of topsoil; Increased soil salinity; Damaged vegetation; Regional climate change; Decline in biodiversity

5 principal biomes

Forest, Grassland, Savanna, Desert, and Tundra

Formation classes continued

The pattern of formation classes depends heavily on climate; In both low- and midlatitude environments, strong precipitation gradients produce vegetation types grading from forest to desert; At high latitudes, decreasing temperatures control the transitio

Formation classes continued

In low latitudes, savanna and grassland formation classes are found in regions with a distinct dry season; In midlatitudes, west coasts are marked with a strong summer dry period, providing sclerophyll vegetation in coastal regions, and farther poleward,

FOREST BIOME

Tree Dominant; (Near) Closed Canopy; Soil Water; Mostly Moist; Warm (Season)

Forest Biome

is dominated by trees, which form a closed or nearly closed canopy; They require an abundance of soil water, so they are mostly found in moist climates; Requires a warm season, if not warm temperatures the year round; Three principle types of forest as se

Forest Biome

Low-latitude Rainforest
Monsoon Forest
Subtropical Evergreen Forest
Midlatitude Deciduous Forest
Needleleaf Forest
Sclerophyll Forest

Low Latitude Rainforest

Equatorial/tropical; Layers = Emergent, Canopy, Under story, and Floor; Largest species diversity

Low-Latitude Rainforest

found in the equatorial and tropical latitude zones (lat. 10� to 25� N and S) along monsoon and trade-wind coast that consists of tall, closely spaced tree; Tree crowns = uppermost layer; Shrubs = intermediate layer; Herbs = lower layer; Mosses and lichen

Low-Latitude Rainforest

These rainforests develop in a climate that is continuously warm, frost-free, and has abundant precipitation in all months of the year; Highland regions, temperatures cooler, orographic rainfall ; Large numbers of plant and animal species; Broadleaf everg

Layers of Low-Latitude Rainforest

Highest layer: scattered "emergent" crowns that protrude from the closed canopy, to 130 ft; Emergent species: wide buttress roots for support; Second, continuous layer: 50 to 100 ft high; Third layer: small, slender trees, 15 to 50 ft, narrow crowns.

Epiphytes

air plants" are common in low-latitude rain forests; These plants attach themselves to the trunk, branches, or foliage of trees and lianas; their host is used solely as a means of physical support

MONSOON BIOME

(forest); Monsoon or Wet Dry Tropical; Deciduous; Open canopy; Lower layer development

Monsoon Biome

typically open, grades into woodland, with open areas occupied by shrubs and grasses; Open cover of deciduous trees (shed leaves during pronounced dry season); Wet-dry tropical climate (South America to Africa and southern Asia), where a long rainy season

Deciduous

meaning that most of the trees shed their leaves because of stress during the long dry season that occurs at the time of low sun and cool temperatures

SUBTROPICAL EVERGREEN BIOME

(forest); Moist subtropical; Natural replaced by Agriculture; Formation classes = Broadleaf (SE Asia) and Needleleaf Evergreen Trees (SE USA)

Subtropical Evergreen Forest

winters are mild, and there is ample rainfall throughout the year; Moist subtropical climate regions; Often has a well-developed lower layer of vegetation; This forest occurs in two forms: Broadleaf (SE Asia): a formation class of the forest biome compose

MIDLATITUDE DECIDUOUS BIOME

(forest); Tall dense summer canopy; Sheds leaves for winter; Layers and Ground layer Species diversity

Midlatitude Deciduous Forest

plant formation class within the forest biome, that is dominated by tall, broadleaf deciduous trees, found mostly in the moist continental climate and marine west-coast climate; Is dominated by tall, broadleaf trees that provide a continuous and dense can

Broadleaf Forest

broad-leaved species dominate over a lower layer of smaller plants. New South Wales, Australia, and includes many species of Eucalyptus.

NEEDLELEAF FOREST

Tall evergreen conifers; Continuous shade; Mountains; Boreal climate; Taiga; Coastal

Needleleaf Forest

composed largely of evergreen tree species, such as spruce, fir, and pine; Evergreen forest inhabits dry, sandy soils, occasional droughts, fires; Lower layers of vegetation are sparse or absent, except for possibly a thick carpet of mosses; Conifers; Str

Boreal Forest

cold-climate needleleaf forest of high latitudes. Two continental belts, North America & Eurasia; It occurs in two great continental belts, one in North America and one in Eurasia; These belts span their land masses from west to east in latitudes 45� N to

Taiga Biome

in which the winters are cold but summers are mild enough to allow the ground to thaw

Coastal Forest

a distinctive needleleaf evergreen forest of the Pacific Northwest coastal belt, ranging in latitude from northern California to southern Alaska; Here, in the band of heavy orographic precipitation, mild temperatures, and high humidity are perhaps the den

SCLEROPHYLL FOREST

Mediterranean climate; Small thick leaves; Minimize water loss; Chaparral- California

more info?

The native vegetation of the Mediterranean climate is adapted to survive through the long summer drought; Shrubs and trees that can survive such drought are equipped with small, hard, or thick leaves that resist water loss through transpiration; these are

Sclerophyll Forest

dominated by low trees with thick, leathery leaves, well-adapted to long summer drought of the Mediterranean climate; Is limited to west coasts between 30� and 40-45� N and S latitude; Southern California's chaparral, found on coast-range slopes, is a for

The formation class of the Sclerophyll Forest includes

Sclerophyll woodland: an open forest in which only 25-60% of the ground is covered by trees; Includes extensive areas of scrub: a plant formation type consisting of shrubs covering somewhat less than half of the ground area

SAVANNA BIOME

Tropical wet-dry climate; Formation classes include: Woodland(wetter) and Thorn-tree grassland(drier)

Savanna Biome

is usually associated with the tropical wet-dry climate of Africa and South America; It exhibits an open cover of trees with grasses and herbs underneath; Vegetation: woodland to grassland, tress spaced widely apart because insufficient soil moisture to s

Savanna Woodland

(wetter); trees are spaced rather widely apart because there is not enough soil moisture during the dry season to support a full tree cover; The open spacing lets a dense lower layer develop, which usually consists of grasses; Green landscape identifies t

Thorntree-tall-grass savanna

(drier);a formation class transitional to the desert biome; long dry season of the tropical wet-dry climate restricts the vegetation to grasses and open canopy of drought-resistant trees; The trees are largely of thorny species; Vegetation is described as

GRASSLAND BIOME

Seasons; Formation classes include: (1)Tall-grass (prairie) = Midlatitude/subtropical and (2) Short-grass (steppe) = Dry continental

Grassland Biome

develops in regions with moderate shortages of soil water; includes tall-grass prairie and short-grass prairie (steppe); Tallgrass prairie: provides rich agricultural land suited to cultivation and cropping; Shortgrass prairie: occupies vast regions of se

Tallgrass (prairie)

(grassland biome); a ground cover of tall grasses with also some broad-leaved herbs, named forbs
Grasses are deeply rooted and form a thick and continuous turf.
Are associated with the drier areas of moist continental climate

Shortgrass (steppe)

(grassland biome); consists of sparse clumps of short grasses; Steppe grades into semidesert in dry environments and into prairie where rainfall is higher; Correspond well with the semiarid subtype of the dry continental climate

DESERT BIOME

Formation Classes= (1) Semi-desert: Tropical to Midlatitude, Xerophytic Vegetation, Thorny trees && (2) Dry Desert: Sparse Vegetation, Dormant, Bare Areas

Desert Biome

Includes organisms that can survive a moderate to severe water shortage for most, if not all, of the year; Includes semidesert and dry desert, and occupies the tropical, subtropical, and midlatitude dry climates; Temperatures can range from very hot to co

Semi-desert

(desert); a transitional formation class found in a wide latitude range, from the tropical zone to the midlatitude zone; Consist mostly of sparse xerophytic shrub; Is made up of xerophytic trees and shrubs that are adapted to a climate with a very long, h

dry desert

(desert); is a formation class of plants that are widely dispersed over only a very small proportion of the ground. It consists of small, hard-leaved, or spiny shrubs, succulent plants (such as cactus), or hard grasses; plants widely dispersed over small

TUNDRA BIOME

Species= diversity low, but number high; Formation classes = Arctic & Alpine

Tundra Biome

Is limited by cold temperatures; Includes low plants, adapted to survival through a harsh, cold winter. They grow, bloom, and set seed during a short summer thaw; Tundra vegetation is also found at high elevations, above the limit of tree growth and below

Arctic tundra

tundra climate; Plants grow during brief summer of long days and short (or absent) nights. Air temperatures rise above freezing, and a shallow surface layer of ground ice thaws.

Alpine tundra

at high elevations, above the limit of tree growth and below the vegetation-free zone of bare rock and perpetual snow.

elevation

Climate factors of temperature and precipitation vary with ________ and over space

altitude

Vegetation patterns often show zonation with _______ and systematic variation on long transects

TRANSECTS

Elevation up = temp down, but precipitation up; Vegetation zones

The upper transect

stretches from the Equator to the Tropic of Cancer in Africa; Climate ranges through all 4 low-latitude climates: wet equatorial, monsoon and trade-wind coastal, wet-dry tropical, and dry tropical; Vegetation grades from equatorial rainforest, savanna woo

The middle transect

a composite from the Tropic of Cancer to the Arctic Circle in Africa and Eurasia; Climates include: dry subtropical, Mediterranean, moist continental, boreal forest, and tundra; The vegetation cover grades from tropical desert through subtropical steppe t

The lower transect

ranges across the United States, from Nevada to Ohio; The climate begins as dry midlatitude; precipitation increases gradually eastward, reaching moist continental near the Mississippi River; The vegetation changes from midlatitude desert and steppe to sh

Continental transects

clearly demonstrate how patterns of climate are related to patterns of biomes and formation classes