Biomes

Question 1

Define biomes

Answer 1

the largest division of terrestrial ecosystems and strongly related to climate/soils (includes forest, shrub land, grassland, desert, and tundra)

Question 2

Ecosystem determinants

Answer 2

factors that determine ecosystem characteristics

vegetation = f (CL + O + R + P + T)

CL = climate (energy and water = soil water balance): factors responsible for general similarities in vegetation at sub-continental or regional scales, biomes and formations
O = organisms (litter and bacteria >>> nutrients)
R = topographic relief (elevation, slope, aspect)
P = parent material (basis of soil)
T = time since distribution
ORPT = local scale factors, cause variation between sites, habitats

Question 3

Forest biome types

Answer 3

types: low-latitude rainforest, monsoon forest, subtropical evergreen forest, mid-latitude deciduous forest, sclerophyll forest, needle-leaf forest (coastal temperate rainforest/montane forest)

Question 4

Coastal temperate rainforest (climate, soils, vegetation, human impacts)

Answer 4

Climate: winters mild and wet, summers warm and dry, soil water balance deficit in summer

Soils: podzols with leached Ae horizon and abundant leaf litter, local variation (geysolic water logged and organic bogs)

Vegetation: high productivity (trees and shrubs), multiple canopy layers, adaptations: large, long lifespan, shade tolerant, nurse plants on logs, old growth forest attributes from gaps in forest from fine disturbances

Human impacts: urbanization, forestry controversy over natural disturbances versus logging

Question 5

Grassland biome (location, climate, soils, vegetation)

Answer 5

Location: between deserts and forests, continental locations, lee side of mountains = rainshadow, prairies, pampa, stepps, veldt

Climate: continental location with relatively high range, distinct wet/dry season where summer is dry, moderate water deficit

Soils: chernozems with thick A horizon and dark = organics, high base saturation, very fertile

Vegetation: productivity depends on precipitation, limited by soil water in summer, herbaceous plants: graminoids (grass-like) and forbs (broad-leaved herbs in sunflower and legume families), dominant vegetation = 2 types of perennial grasses: sod (prostrate with below ground stems/rhizomes, vegetative reproduction, form mats, tolerant of grazing) and bunch grasses (erect stems in clusters, less tolerant of grazing), trees are rare except for riparian zones (streamside forests), plant adaptations: hemicryptophytes (below-ground biomass, access soil moisture, sprouting = adaptation to herbivory and fire), split growing season: growth in spring and fall with precipitation

Question 6

Tell me about fire

Answer 6

it is a natural disturbance that keeps the prairies, frequency every 2-10 years, igniting from lightning and managed by first nations

rapid spread 200km/day, no topographic barriers, strong winds

Post-fire green up: rapid regrowth from below ground rhizomes, new leaves can appear days after a fire