Title: Natural History of the Galapagos Islands

Nothing gets lost,

nothing is created,

everything transforms.

-Lavoisier

Map of the Islands

Las Islas Encantadas= The Enchanted Islands Resources Pierre Constant Marine Life of the

Galapagos– Good maps and drawings = p12

Julian Fitter Wildlife of the Galapagos– page 7 = Conservation Plea– page 8 = Introduction

• 2 major conservation issues:– Introduction of invasive species– Population increase

DOMINANT GALAPAGOS THEMES: ISOLATION STRONG CURRENTS INACCESSIBILITY ARID CONDITIONS SANCTUARY EXPLOITATION BIODIVERSITY EVOLUTION CONSERVATION

Biodiversity Galapagos organisms are very susceptible to

competition from introduced species from S. America, etc

CDRS on Santa Cruz in Puerto Ayora focused on conservation– In early years, eradication of goats from Sante Fe

(by 1975 all were gone), Espanola and Pinta and rats from Pinzon was a priority

– Successful captive breeding program of tortoises and now land iguanas

– goats are biggest problem, other mammals are pigs, dogs, cattle, donkeys, horses, cats, rats and mice

– invertebrates are fire ants, blackfly, wasps– plants include quinine tree, guayava, elephant grass– expensive to eradicate--need human and financial

resources As population grows (5% annually), islanders must

help protect islands and provide answers for conservation

General Setting of the Islands

Stretch over a 320 km (174 mile) axis from east to west

600 miles west from coast of Ecuador Made of 19 islands and 42 + islets or

surfacing rocks Islands are purely oceanic Archipelago is entirely volcanic

Geology of the Islands Islands are situated on the confluence

of three of the earth’s tectonic plates– Pacific, Cocos and Nazca

• The three plates are pushed apart by convection currents caused by heat deep inside the earth

• The Galapagos drifts southeasterly at the rate of about 4-6 cm a year

• Hot Spot!

Tectonic Plates

Hot Spot Theory Hot spot has a fixed position A hot spot is related to a weakness of the oceanic

crust which leads to fissures on the ocean floor Under the Nazca plate, the hot magma is always

in motion due to convection currents The hot spot creates a magmatic plume when the

hot magma contacts the cold ocean water to build a platform

Platform grows and grows….into a cone

Hot Spot Theory continued A volcanic cone is created which in a few

years reaches the surface of the ocean This new island joins the others on the slow-

moving “conveyer belt” Once drifted away from the hot spot, an

island experiences little or no more volcanic activity and the now dormant volcano is eroded away by wind and sea

More hot spot…or is it “mantle plume” Islands originated through hot spot

activity no earlier than 3-5 million years ago

Hot spot also responsible for forming Hawaiian islands

Galapagos Plumology

Age of the Galapagos

Oldest islands in east and youngest to west – Espanola is oldest– Fernandina is youngest (hence volcano in

2009)

Climate Galapagos are desert islands Are considered subtropical Located on equator but don’t have equatorial

climate therefore have micro-climates Climate is largely determined by ocean currents 2 seasons

– warm, wet season from Jan to June– cool, dry season from July to Dec known as garua

(mist)

Oceanic Currents In cool season, the cold Humboldt (aka Peruvian)

current flowing from the southeast keeps the islands cooler than you would expect on the equator and the mist garua condenses in the air

In warm season, annual rains for first 3 months, SE winds and Humboldt vanish. Warm waters come from Panama and Columbia

Upwelling from currents allows for nutrients to be pumped to surface for plants to grow and the food chain to survive

Distribution of Currents (also on page 212 Fitter)

El Nino-La Nina Phenomenon Some years, warm water coming from north

increases around around Christmas time In 1982-1983, a big Nino brought nine

months of rain, increased humidity, suffocating heat, increased sea temp. therefore increase in animal mortality

Another in 1997-1998 Nina is counter event with cold period…good

for marine life

Facts about El Nino

As many as 50% of sea lions and marine iguanas dies

Increased rainfall promotes plant growth and rising sea levels cause loss of beaches resulting in major habitat change

Human History of the Galapagos 1535 = Bishop of Panama, Tomas de

Berlanga’s ship was swept off course; he described giant tortoises and iguanas

1570 = Abraham Ortelius, Flemish, draws the first map of the Insulae de los Galopegos (Islands of the Tortoises)

1600-1720 = Buccaneers use islands as bases for raids on Spanish ports; eat turtles, use wood

1790 = Alessandro Malaspina, Sicilian, leads first scientific mission to islands; records are lost

1793 = James Colnett, English, explores whaling on islands; Post office barrel established in Floreana

1795-1895 = Heavy exploitation endangers species; whales population destroyed, tortoises eaten

1813 = David Porter, U.S., destroys British whaling fleet

1819 = Major eruption of Fernandina volcano

1830-1832 = Ecuador becomes an independent republic and annexes the islands; establishes a penal colony on Floreana

1835 = Darwin visits the islands (only there 5 weeks of his 5 year voyage..visited San Cristobal, Floreana, Isabela, James Islands)

1836-1940 = attempts at colonization1850-1860 = Britain and US attempt to lease or purchase islands with no success

1928 to mid 1930’s = Floreana Island was inhabited by Ritters, Wittmers and Baroness of Vienna and Paris= murder mystery= Galapagos Affair

1934= Ecuador enacts the first protective legislation for the islands

1957 = Choose site for CDRS 1959 = Ecuador declares all islands except

already colonized are a national park; the Charles Darwin Foundation is formed

1968 = Conservation programs begin; Fernandina erupts and its calderan collapses

1969 = Organized tourism begins 1982-1983 = El Nino events cause changes in

population of organisms 1985 = Fire set by humans burns more than 200

sq km of S. Isabela Island 1986 = Ecuador govt establishes Marine Reserve 1997-1998 = Another El Nino

MORE NATURAL HISTORY…

FOUND IN REFERENCE SECTION OF YOUR COURSE READER:– “A Traveler’s Guide to the Galapagos

Islands” by Barry Boyce– Good information for Introduction Section of your

Paper = pages 7-37….mark this with sticky note