tundra

TUNDRA

tunturi (Finnish) means “a treeless plain”

Coldest of all biomesextremely low temperatureslittle precipitationpoor nutrientsshort growing seasonsSimple vegetation

Where is it found?

Tundra is separated into two types:

Arctic tundraAlpine tundra

Arctic tundra

Arctic tundraat high latitudecold, desert-like conditionsA land dotted with lakes and crossed by

streams where ground is low and moistOn high drier areas where ground is bare and

rock-covered, vegetation is scant and scattered

permafrost

frost hummocksRounded knoll of

iceCaused by slow

and unequal pressure in the main body of the packed ice

Frost boil

Continuous thawing and freezing pushes fragments of stone outward in a ringed patterns

Earth stripesExaggerated

stretching of frost boils produces parallel strands of rocks and soil

stone polygons

Alpine tundra

Alpine tundraAt high altitudesMostly confined to very high elevationsLittle permafrostSoils are drierHigher precipitation than in Arctic TundraSteep topography induces a rapid runoff of

water

AbioticTemperatureSoilWind and waterNutrients

Temperatureshort summer days ; very long and cold

wintersThe alpine tundra is also cold, but not nearly

as cold as the arctic.Temperatures at night are almost always

below freezing, but daytime temperatures still permit plant growth for about half the year.

limits the types of species that can live there

Soil

Inactive layer (permafrost)If the permafrost melts, it alters the temperature

and topography of a region, which threatens the existence of many species living in the tundra.

Active layer (top of the permafrost)thaws in the summer months which allows

vegetation to grow and enables the chemical processes necessary for sustaining life to occur.

Wind and waterextremely windy and have small amounts of

rainfallhigh winds make it difficult for any large

plant species to surviveDespite the low rainfall, the arctic has high

humidity, because water is slow to evaporate

Nutrients

Phosphorous and nitrogen are the major nutrients that exist in the tundra biome

Precipitation produces phosphorous, while a bio-chemical process creates nitrogen.

Through photosynthesis, plants harvest energy from the sun, which they use to absorb these key nutrients and grow. 

Simple Structure and Low Diversity Characterize the

Vegetation of Tundra

•Vegetation – simple; although it appears homogeneous, the pattern of vegetation is patchy.The combination of micro relief, snowmelt, frost heaving, and aspect, among other conditions, produces an endless change in plant associations from spot to spot. •Number of Species – few•Growth- slow•Biomass and functional activity are confinedto a few groups.

ArcticOnly those species able to withstand

constant disturbance of the soil, buffeting by the wind,

and abrasion from wind- carried particle of soil

and ice can survive.

•Low ground- cotton grass, sedge, dwarf heath, sphagnum moss Complex.

•Well drained sites- heath shrubs, dwarf willows and birches, Dryland sedges and rushes, herbs, mosses, and lichens.

•Driest and most exposed sites-(flat topped domes, rolling hills, low lying terraces)- sparse vegetation,Scattered heaths and mats of dryads, crustose and foliose lichens.

Alpine TundraThe environment is even MORE severe for plants. It is a land of strong winds,

snow, cold, and widely fluctuating temperatures.

Rocky strewn slopes, bogs, alpine meadows, and shrubby thickets.

Cushion and mat- forming plants , rare in Arctic, are important in the Alpine Tundra

Low, and ground hugging- able to withstand windCushionlike blanket- traps heatInterior of cushion may be 20C warmer than the surrounding air which insects use as microclimate.

Animals

•Segmented whiteworms•Collembolas•Flies•Blackflies•Deerflies•Mosquitoes-( scarce in alpine)•Beetles•Grasshoppers•Butterflies

•Butterflies keep close to the ground•Other insects have short wings or no wings at all•Insectdevelopment is slow•Butterflies may take two years to mature•Grasshoppers three years

Carnivore•Wolf- dominates;preys on muskox, caribou, and lemmings•Arctic fox- preys on arctic hare, andweasels which preys on lemmings•Snowy owls and Hawklike jaegers- lemmings

Alpine Tundra•Haycutting pika, marmots, mountain woodchucks- hibernate over winter• mountain goats, sheep, elk, voles, and pocket gophers,

Human Impact

• Hunting•Global warming•Oil Drilling•Over Development•Pollution