Zones of Galapagos

Distribution and Size of Islands zThe islands are heterogeneous in 3 features that are important to biota: yarea of island yelevation yisolation zNot all islands are entirely vegetated

Vegetation zZones are a function of precipitation and temperature zPredominant vegetation is dry, mainly deciduous forest at low elevations zTransitional forest and moist forest at high elevations zGrassy habitat at the highest elevations on a few islands

Vegetation Zones zSeven zones are distinguished but only big islands like Santa Cruz and San Cristobal have them all: y1. Coastal or Littoral Zone y2. Arid Zone y3. Transition Zone y4. Scalesia Zone y5. Brown Zone (sometimes left out) y6. Miconia Zone y7. Pampa or Fern Zone

Page 134 Fitter

Littoral/Coastal Zone

Littoral or Coastal Zone (p Fitter) zVery narrow stretch a few meters wide found on coast or around lagoons zVegetation influenced by salt and is made of shrubs and small trees zMangroves are dominant. The word mangrove is an ecological term rather than a classification since four species come from different families:

zSalt bush-provides shade for sea lions, pelicans and frigate birds zCarpetweed, an herb, Sesuvium spp. zThis zone is a habitat rich in invertebrates, molluscs, crustaceans and insects

Arid Zone

Arid Zone (p Fitter) zSpreads up to an elevation of meters zDominant vegetation are 3 endemic cacti: yOpuntia- tree-like prickly pear= 5-6 feet tall yJasminocereus-candlebra cactus= 23 feet tall yLava cactus-small cactus= 23 inches tall zPalo Santo tree is characteristic of this zone

zImportant zone because a high proportion of endemic plants have evolved under the harsh conditions of this zone with little moisture zPlants have a xerophytic adaptatin ysmall leaves, high rate of photosynthesis, spiny shrubs, deep roots zReptiles like land iguanas, lava lizards, and snakes are at home here zFinches, warblers appear where vegetation is zLichens are found here too

Transition Zone

Transition Zone (p Fitter) zZone climbs between meters zPalo Santo trees are found here too zThis zone is more dense and less desert- like in appearance zPega pega (stick stick)-tree with short stem and spread out branches zGuayabillo-white flowers and small fruit zGalapagos tomato plant found here

Scalesia Zone

Scalesia Zone (p Fitter) zFrom meters zFirst of the humid zones zWhere garua concentrates during dry season zFerns, grasses and mosses are abundant zPredominant species is Scalesia (broccoli) tree= can be 10 meters tall

zScalesia forests have been reduced by human-related activities ypigs and goats root out seedlings yland was cleared for planting or grazing yfires yGuava plant has infiltrated all the highlands; their dense growth squeezes out other plants in area

Brown/Zanthoxylum zone

Brown Zone (p Fitter) zEnds with scalesia zone zLiverworts are characteristic plants-cling to scalesia but do not depend on it zThese brown mosses fall from the branches of the scalesia

Miconia Zone

Miconia Zone (p Fitter) zHumid zone at about meters zEndemic to Galapagos zMost endangered plant in Galapagos zOnly found on Santa Cruz and San Cristobal

Pampa or Fern Zone

Pampa or Fern Zone (p Fitter) zRanges from 650 meters up to the summit of the island zWettest zone in islands zDominant plant is endemic Galapagos tree fern (tall as an adult) zIs represented by ferns, grasses and other plants adapted to water zMoist pampa is a microclimate in itself