Biomes

FIELD BIOLOGY & METHODOLOGYFall 2014 Althoff

Lecture

04

Biomes

• “______ units” (i.e., not political boundaries)

• Defined: the major terrestrial unit of vegetation with the fundamental characteristic being the “__________” of the plants dominating it.

Form vs. Species

• Biome classifications based on _____________ (i.e., grasses, deciduous trees, conifers, etc.) rather than ________ (red maple, sugar maple, red pine, white pine, etc.)

• Similar “forms” found in _________ regions of the world

Growth Forms

Plants with ___________ (adaptations) that enable them to dominant the local landscape once established.

Growth forms…con’t

• Grasses establish _________systems and withstand conditions better in Great Plains than trees. And, they recover from fires quicker—a common natural disturbance for prairies

• Trees, when established, out compete grasses in Northeast because fewer fires and more annual rainfall… ___________ grasses

What role does climate play?

Biomes ARE PREDOMINATELY influenced by ___________ & ________________ patterns =

CLIMATE

__ Major ______ – according to Whittaker

• Tropical rain forest• Tropical seasonal

forest• Subtropical desert• Woodland/shrubland• Temperate rain

forest

• Temperate grassland/desert

• Grassland (shrubland)

• Boreal forest• Tundra

Whittaker’s Classification

• Based on a) annual precipitationb) average temperature

• KNOW Ricklef’s biomes (handout)…be able to label 9 biomes according to precipitation & temperature

Whittaker vs. Walter (handout)

• Each has “9” zones/divisions• Both based on precip & temp• More refined view: zones defined mostly

by the conditions of moisture & cold stress

• Whittaker = veg zonesvs.

• Walter = climate zones

Other factors influence composition of plant communities

• Topography

• Soils

• Fire

• Seasonal variation in climate

• _______________

Topography, Soils & Local Distribution

• Back to physical factors...

• Understand relationships expressed in handout (Beals & Cope) that highlights:

forest floor plant distribution relative to ____ and _____________ content

% organic matter

% c

alci

umOccurrence of four forest floorPlant species with respect to calcium and organic matter content of soil in woodlands of eastern Indiana

Beals, E.W. and J.B. Cope. 1964. Ecology 45:777-792.

_________ Factors

Conditions in the soil: nutrient status, water availability, toxic mineral content.

Distribution of plants on and adjacent to campus a good example

Concept of SPECIALIZATION

• Adaptations that enable organisms to survive (thrive) in a particular, restricted range of environmental conditions

• Examples: a) Sages: Table 5.1 (handout;

Ricklefs1996) b) Oak leaves: Fig. 5.7 (next slide; Ricklefs1996)

Figure 5.7 (Ricklefs 1996)Silhouettes of a sun leaf and a shade leaf of white oak. The sun leaves have more edge per unit of surface area and therefore dissipate heat more rapidly

SUN LEAF

SHADE LEAF

Biomes in Aquatic Systems???

• Does ____ “match” as well since biomes in terrestrial system based on vegetation growth forms…therefore not used in same way

• Aquatic biomes based on salinity, water movement, depth...

Aquatic Environments

• Fluvial systems

• Lakes

• Estuaries

• Oceans

Fluvial Systems

“River systems” distinguished by the materials (plants & animals & other materials) continually moving downstream by currents

Lakes

•Any kind of depression, usually a product of _________ glaciation.

• Three zones: littoral, limnetic, benthic

Littoralzone

Limnetic zone

Benthic zone

Estuaries

Special environments found at the mouths of rivers influenced by enclosed landforms or barrier islands. Unique because of “mix” of fresh and salt water.

Oceans

Understood! However, must recognize tremendous ___________ in temp, depth, current, substrate, and tides. _________ “biome” on surface of the the earth

In Summary….• Geographic distribution of plants on

_________________ scales determined primarily by climate…

• …but by topographic and soils on a ____ basis• Climate profoundly affects evolution of plants

and animals…which results in specializations to deal with the physical environment

• Plant growth forms directly relate to climate…so major types of vegetation match temperature and precipitation allows for _____________ to be classified into biomes

In Summary….con’t• Characteristics of biomes are further

“influenced” by soil, climatic seasonality, fire, and grazing.

• ___ major approaches to ______ classification: Walter climate zonesWhittaker vegetation zones

• Aquatic systems are not classified (typically) as biomes because they ____ the equivalent of terrestrial vegetation. But we can distinguish among streams, lakes, estuaries, and oceans