Biomes Altudinal Biodiversity Gradient

1

ThedeephistoryoftheSouthwest

•  Whichgeologicaleventshaveshapedthisregion?

•  Howhasthefloraandfaunachangedover8me?

Biomes:ecosystemsoflargegeographicareasthataredeterminedbyclima8cfactorssuchas

temperatureandprecipita8on.

✔

✔ ✔

✔

✔ ✔

✔

✔

Classified in terms of vegetation.

Biomes

Clima8cfactorssuchastemperatureandprecipita8onaredeterminedbyla8tudeandeleva8on.Some8mesalsoaffectedbywindandfire.

Altitudinal climatic changes

Al8tudinalBiodiversityGradient

La8tudinalclima8cchanges La8tudinalBiodiversityGradient

2

Examples

Ants

Mammals Fishes

NotBees!

La8tudinalgradient:someexplana8ons

•  Climatestabilityhigherintropics•  Netprimaryproduc8vity(photosynthesis)ishigherinthetropics.

•  Spa8al/areahypothesis:thetropicsarethelargestbiome.

•  Bio8cinterac8onshypothesis:Strongerinterac8onsintropicspromotehigherpar88onofresources.

La8tudinalclima8cchanges

BiomesinNorthAmerica Biomesofthesouthwest

3

Biomes:Tundra

•  Thehighesteleva8onbiome.

•  SanFranciscopeaks(12,600feet)

•  Extremelycoldwinters,waterheldasice,highwinds)

•  Ground-huggingwoodyshrubs.

•  Notrees,noannuals.•  Lowspeciesdiversity

VertebratesinTundra•  Pika

Least chipmunk

Yellow-bellied marmot

Montane shrew(white-tailed ptarmigan)

Biomes:Coniferousforest•  Coldandwetforests.•  Dominatedbycone-bearingtrees.

Subalpineconiferforest

•  Fromabove7,200feetto8mberline(11,000f.).

•  25tomorethan39in.ofprecipita8on.Muchofthisprecipita8onfallsassnow.

(Engelman spruce)

Corkbark fir

Lepus americanus (Snowshoe hare)

Blue grouse Sapsucker

Woodpecker

LekkingBehavior•  Sites where males display to the females. •  The purpose of the display is to attract females and defend

territories. •  The males whose display is most attractive to the female, will get

to mate with her.

http://www.youtube.com/watch?v=LcnnkyGidzo

4

Cold-temperateconiferforests•  Between6,900and

7,950^.•  Mixedconiferseries:

Douglasfir,Whitefir,Limberpine,andaspen.

•  Ponderosapineforest

Pseudosuga menziesii (Douglas fir)

Pinus flexilis (Limber Pine)

Abies concolor (White fir)

Pinus ponderosa

Populus tremuloides (Aspen)

IncreaseinDiversity•  Bats:Southwesternmyo6s,Long-

earedMyo6s,Long-leggedMyo6s,Bigbrownbat.

•  Shrews:Vagrant,dwarf,Merriam.•  Chipmunks:Colorado,Gray-collared,

Grayfooted,Uinta.•  Voles:Montane,Long-tailed,

Mexican.•  CoFontails:Eastern,NuFal’s.•  Squirrels:Goldenmantled,Tassel-

eared.•  Porcupine.•  White-taileddeer,Muledeer.•  RockyMountainelk•  Merriamelk,GrayWolf(gone)•  Skinks:Southern,many-lined,

Westernslink.•  WesternraFlesnake,Twin-spoFed

raFlesnake.

•  Owls:Flammulated,Pygmy,SpoFed,Saw-whet.

•  Warblers:Yellow-rumped,Grace’s,Red-faced.

•  Goshawk•  Broad-tailedhummingbird.•  Westernandpineflycatchers.•  Stellerjay•  Browncreeper.•  WesternTanager.•  Warblingvireo,Solitaryvireo.•  Eveninggrosbeak.•  Wildturkeys.•  Aztecthrush.•  Tigersalamander.•  Lizards:Short-horned,Strippedplateau,

Bunchgrass,andArizonaalligator.•  Gophersnake.•  Sonoranmountainkingsnake

Biomes:Woodland•  Mildwinters,wetsummers.

•  AlligatorBarkJunipers,andPines(5400-7200f).

•  Evergreenoaks(4500-5400f).

Elaphe triaspis (green rat snake)

Lampropeltis pyromelana(Mountain Kingsnake)

Sceloporus virgatus (Striped plateau lizard)

Phrynosoma ditmarsi, (Ditmar’s Horned Lizard)

Eumeces callicephallus (Mountain skink)

Crotalus lepidus(Rock rattlesnake)

C. pricei (Twin-spotted rattlesnake)

Thamnophis eques (Mexican garter snake)

Chaparral•  3,150-6,000f.•  Shrubsthathavedense,

compactcrownsandsmallevergreensclerophyllousleaves.

•  Mostplantspecieshaveextensiverootsystemsandregeneratea^erburning.

Biomes:Grassland•  3,300-4,200f,9mmto18

in.ofrain.•  Warm,humidsummers

(moderaterain)andcold,drywinters.

•  Grassisthedominantlifeform.

•  Alsoannuals,scrubs,andgeophytes.

5

Desert

•  Extremearidity.

Biomes:Thornscrub•  Intermediatebetween

desertandtropicalforestbiomes.

•  12-20in.ofrain,mostfallsbetweenJulyandSeptember.

•  Shorttrees,shrubs,andcac8.

•  Soilshaveo^enlowdrainage.

Biomes:Tropicaldryforest

•  Determined by the absence of freezing temperatures.

•  Dry season that can last up to 8 months.

•  It supports a high diversity of animals and plants.

6

Bursera speciesThehistoryofEarth

•  Earthisabout4.5billionyearsold(basedonabsoluteda8ngofEarthandmeteoriterocks).

•  The arrangement of seas and continents has changed enormously because of plate tectonics.

Platetectonics•  TheEarthhasmany

layers.•  It has an iron-nickel core with a temperature of 13,000 degrees F,

• a mantle,• and the crust.

•  Theearth’slithosphereconsistsofplatesabout100kmthick.

•  Twokindsofplates:Con8nentalandOceanicplates.

•  Theplatesdri^allovertheglobe.Some8mestheyseparatefromoneanother,orcollide,slippastoneanother,orsliplaterally.

Platemovement•  Whenathin,oceanicplatecollides

withathickcon8nentalplate,theoceanicplateisforcedunderthecon8nentalplate;thisphenomenoniscalledsubduc8on.

•  Whentwocon8nentalplatescollide,mountainrangesarecreatedasthecollidingcrustiscompressedandpushedupwards.

•  Whentwoplatesmovesidewaysagainsteachotherthereisatremendousamountoffric8onwhichmakesthemovementjerky.Whenthepressureisreleasedsuddenly,andtheplatessuddenlyjerkapart,thisisan earthquake.

earthquake

Subduc8on

Rocky Mountainshttp://www.youtube.com/watch?v=0mWQs1_L3fA

7

Platemovements•  200-240millionyearsago

(Triassicperiod)allofthepresent-daycon8nentscombinedtoformasupercon8nentcalledPangaea.

•  TheclimatewashotandhumidalthoughtherewereglaciersinsouthernPangaea.

•  Theworldhadexperiencedamajormassex8nc8on.

•  InthelateTriassicAfricaandAsiastartedtoseparate

140 million years ago (Early Cretaceous; Beginning of diversification of flowering plants)

150 million years ago(Jurassic; radiation of dinosaurs)

65 million years ago (Late Cretaceous; mass extinction, end of dinosaurs, mammals begin radiation ) Today

•  SantaRitamountains,southernArizona,UpperCretaceousrockshaveremainsofthecarnivorousdinosaurGorgosaurus.

Araucaria trees

54.9-36.6millionyearsago(Eocene)•  Aperiodofglobalwarming.

Temperaturesofar6coceansatleast15degreeshigherthantoday.

•  Almostnola6tudinalstra6fica6onofvegeta6on.

•  BytheendoftheEocene,deciduoustreesbecomeincreasinglyabundantacrossNorthAmerica,thefirstindica6onofdryseasons.

•  Noevidenceforaregionaldesertclimateinthesouthwestyet.

Fossil sycamore leaf

36-6to23.7mya(Oligocene)

•  BythemiddleOligoceneaseriesofenormousvolcanicerup6onsgaveanotherupli_totheRockymountainsandtheSierramadreoccidental.

•  Changeofmarinecurrents.

•  Coolertemperatures.

8

BasinandrangetopographyHeating from below (30 mya)

Volcanism (25 mya)

Basin and range faulting (12-6 mya)

Today- basins filled with sand, and clay

Basin and range disturbance

Basin and range province 23.7to5.3mya(Miocene)•  Asclimatechangedand

mountainswereli^ed,themodernNorthAmericanbiomesareestablished.

•  Clima8cla8tudinalgradientsareestablished.

•  Increasingtrendsinaridity.

15-8mya(middleMiocene)

•  Forma8onoftheSonoranDesertandotherNorthAmericanDeserts.

15-5mya(lateMiocene)

•  Forma8onoftheBajaCaliforniaPeninsula

West coast of Mexico

GeologicTimeScale

1.8mya(Pleistocene)

•  TheEarthenteredanewclima8ceracharacterizedbyglacialandinterglacialperiods.

9

Glacia8onsandtheSouthwest

•  PlantremainsinfossilPackratmiddensdocumentanexpansionofwoodlandtreesandshrubsintoareasthathadbeendesert.

Neotoma sp. (Packrat)

Hola!

“garbage pile”

Fossilpackratmiddens•  Packratshaveanaffinityfor

collec8ngtrinkets(piecesofplants,bones,socks).

•  Theyproduceaveryviscousurinewhichtheyusetomarkitsterritoryandnest.

•  Whenurinecrystallizesitactsasglue,holdingallthegarbagetogether.

•  Debrisheldinmiddenbecomemummifiedandpreservedasfossils.

Yuccabrevifolia

Pinus monophylla

Quercus turbinellaJuniperus spp.

11,000years-today(Holocene)

•  Presentinterglacialperiod.•  Two-thirdsofthelargemammalsofNorthAmericawentex8nct.

For the last 20 MY, until 11,000 years ago, North America was teeming with wildlife. AMERICAN MASTODON

10

SABER-TOOTHED CAT

CAMEL (evolved in North America!) DIRE WOLF

GIANT SLOTH HORSE (evolved in North America!)

11

SomenowpersistinCentralorSAmerica

Smaller animals survived

Humans invade the New World

The Clovis people

The“overkill”ofnaïveanimalshypothesis.

Animals had not had any experience with humans before

Evidencefortheoverkillhypothesis

•  Soona^erhumansreachedAustraliaandNewGuinea40,000yearsago,themegafaunawentex8nctthere.

•  Humancoloniza8onofNewZealand,MadagascarandHawaiiallresultedinex8nc8onofbiganimals.

•  Intheabsenceofhumans,biganimalsremaintame.

Butwhyaretheres8llbigmammalsinAfrica?

12

Quaternaryex8nc8onofmammals

•  The“overkill”ofnaïveanimalshypothesis.

•  Theclimatechangehypothesis.

•  Extraterrestrialeventcausedclimatechange,theYoungerDryas(dryandcold).CausedbytheimpactofaseriesofcometsinNA

•  ✔The“overkill”ofnaïveanimalshypothesis.

•  Theclimatechangehypothesis.

•  ETcause????