The Galápagos Islands: The Land of Plant Pioneers and Flora Frontiersman
What flora you see now in the Galápagos Islands had to migrate to get there. The seeds had a difficult journey as they crossed the salty ocean from the mainland to the islands. By bird, by wind, by random raft of wood or vegetation or natural carrier, the seeds traveled to the isolated islands and began to adapt to their new home.
The plant life throughout the Galápagos Islands reflect the region’s geologic youth as many of them appear to be in the process of evolving. In effect, the classification process can be difficult and uncertain since the species are still “branching out” into new varieties.
Between 552 and 614 native vascular plant species and around 825 introduced species are believed to grow throughout the Galápagos Islands. Around 35% of the native plant species are endemic to the Galápagos Islands, and the islands are home to seven completely distinct endemic flora genera. That’s nothing compared to mainland Ecuador, with its 20,00 different plant species.
GALÁPAGOS VEGETATIVE ZONES
Due to the high diversity of vegetation between the islands, Galápagos flora may be classified into 7 different vegetative zones.
Littoral/Coastal Zone
The littoral zone begins at the ocean’s edge and can extend from 50 to 100 miles inland. The plants that grow in the coastal zone are adapted to its salty soil conditions and the possibility of further dispersal. The zone’s unstable and diverse environment have made it difficult for endemic species to thrive over time, and so few are found. South Plaza, North Seymour, and Floreana have extensive littoral zones where crustaceans, invertebrates, and flamingos thrive.
The most prominent vegetation within this region are mangrove trees that populate the littoral’s brackish lagoons. Four different mangrove species can be found throughout the islands: black mangroves, button mangroves, red mangroves, and white mangroves. The mangroves play an important role in the Galápagos ecosystem as they not only protect the coastline from erosion but protect nesting sites for many of the archipelago’s bird species as well as nurseries for much of its marine life. The detritus of fallen trees also supplies nutrients that sustain much of the marine life as well.
Other Common Vegetation in the Littoral Zone:
- Carpetweed
- Saltbush
- Creeping evergreen shrub
- Beach morning glory
See these beautiful plants (and more!) from up close on our Galápagos Island Cruise.
Arid Zone
The littoral zone transitions into the arid zone as you move inland, and it’s the largest vegetation zone found within the archipelago. The arid zone is much larger on the islands’ northern sides and reach higher elevations. While larger islands have extensive arid tracts, some of the archipelago’s smaller and lower islands, such as Bartolomé, are entirely made up of arid zone vegetation. The landscape is largely comprised of three types of endemic cacti: the candelabra cactus, the lava cactus, and the prickly pear cactus. The prickly pear cactus is a primary dietary component of the giant tortoises and land iguanas, and the two animals have unwittingly served as seed carriers and introduced the cactus onto several islands.
Other Common Vegetation in the Arid Zone:
- Floreana Daisy
- Galápagos lantana
- Manzanillo
- Muyuyo
- Palo verde
- Grey matplant
- Galápagos purslane
Transition Zone
As the name suggests, the Transition zone transitions from the arid lowlands to the moist, cool highlands and, as such, includes vegetation from both. The Transition zone, therefore, has the greatest plant diversity amongst the archipelago’s seven zones. That being said, the zone is dominated by small shrubs and trees with the endemic pega pega and hardwood matazarno being two of its most iconic plants.
Other Common Vegetation in the Transition Zone:
- Galápagos tomato
- Passion flower
- Guayabillo
Scalesia Zone
The Scalesia zone is found at higher elevations on the archipelago’s larger islands, usually from 650-1300 feet, and is the first of the Galápagos “moist zones.” Because the Scalesia zone is obviously more lush and cooler than the lower zones, it’s known as the “rain forest of the Galápagos.”
During the dry season, the garúa fogs keep the region damp enough to sustain its many epiphytes. The trees are much taller here, and the most famous trees of the zone are members of the Scalesia family that inhabit the Galápagos. Scalesia can reach up to 60 feet, and they are covered in water-loving vegetation such as mosses, ferns, and orchids. Though the once-dominant scalesia trees have been depleted by introduced goats, pigs, and guava plants, they remain an important part of the Scalesia zone.
Other Common Vegetation in the Scalesia Zone:
- Passion flowers
- Galápagos Cafetillo
FUN FACT:
Scalesia trees are sometimes known as the Darwin’s finches of the plant world as they have a astounding process of adaptive radiation, leading to 20 different species within the endemic genus found throughout the Galápagos.
Zanthoxylum or Brown Zone
Much like the bordering Scalesia and Miconia zones, the Zanthoxylum zone gets its name from the zone’s most dominant plant—the Zanthoxylum fagara, or “cat’s claw.”
It is also known as the Brown zone because the brown lichens that carpet the trees paint the landscape with a brownish hue. However, much of the environment has been fragmented by agriculture.
Miconia Zone
The Miconia zone can only be found on the islands of San Cristóbal and Santa Cruz at elevations around 3,200 feet. The zone gets its name from the once-prevalent Miconia shrub that covered the rising hills. Now, however, the Miconia shrub has become the most endangered plants of the Galápagos Islands’ due to the environmental impact of cattle grazing and invasive plants. If you happen upon Miconia robinsoniana, you might recognize it by its purple and pink flowers; if not, its impressive height reaching up to sixteen feet will confirm the shrub’s identity. Miconia robinsoniana is also known as “cacaotillo.”
Other Common Vegetation in the Miconia Zone:
- Galápagos cotton plant
Pampa or Fern-Sedge Zone
The Fern-Sedge or Pampa zone is relegated to the highest reaches of the Galápagos islands. The lush zone is carpeted in ferns, mosses, grasses, lichens, and orchids—a verdant world seemingly a world away from the arid, rocky landscape below. The water-loving plants in the Pampa zone congregate around newly-formed pools of water, and so the small gardens reappear and fade throughout the rainy seasons.
Other Common Vegetation in the Pampa Zone:
- Galápagos orchid
- Galápagos peperomia
Conservation Challenges for Galápagos Plants
Of the introduced plant species, 100 have become a fixed part of the islands’ wilderness ecological zones, and many of them are established invasive species that continue to draw concern. As about 90 percent of the known invasive plants were introduced to the islands on purpose—for either agricultural or decorative reasons—we have no one to blame but ourselves for the foreign vegetation bane that threatens the native plants.
While many of the invasive species are centered around the inhabited islands as well as Santiago, the archipelago’s islands all face unique vegetative challenges. While guava and quinine have the potential to crush the Miconia vegetative zone on Santa Cruz, blackberries are the delicious menace of the Scalesia zone’s endemic cafetillo and guayabillo.
Of course, all threats do not come in the green guise of invasive vegetation. Recent weather trends such as El Niño have created harsh conditions, and introduced animals have taken a rather big bite out of Galápagos plant life in a very literal way. Feral goats, cattle, and donkeys have devastated the vegetation by overgrazing and trampling on several islands. On Isabela Island, the hordes of feral goats decimated the plant life near Alcedo Volcano and, consequently, severely reduced the giant tortoise’s food source. In such a small ecosystem, seemingly simple changes can have drastic repercussions.
It’s not all gloom and doom on the sunny Galápagos Islands, however. While the percentage of introduced plant species seems high, it is doubtful that the introduction rate has increased in any significant way. Rather, the conservation issue is just recently getting more attention. Furthermore, The Galápagos Conservancy has stated that 95% of the islands’ native fauna and flora continue to exist throughout the archipelago. While the islands’ remote location and the isolated nature of the ecosystems leave the endemic plants susceptible to outside threats, these same factors serve as a form of protection.
GALÁPAGOS PLANT CONSERVATION EFFORTS
Though Ecuador’s protection of 97% of the Galápagos Islands in 1959 and the creation of the Charles Darwin Foundation (CDF), efforts to protect the islands’ endemic plant species have been made. These efforts have long since focused on the eradication and/or limitation of alien species. With the creation of the Galápagos Inspection and Quarantine System (SICGAL) in 1999, further programs and developments were made to prevent the introduction of new species and organisms from the Galápagos Islands.
SICGAL, working under the umbrella of the Ecuadorian Service for Agricultural Health, monitors the islands’ ports of entry as well as various agricultural zones. Further, they develop and manage fumigation protocols for incoming transport vehicles. Their work similarly extends to training related professionals and furthering research on the topic.
The Charles Darwin Foundation and the Galápagos National Park Service first used biocontrol—during which natural enemies are used to restrain invasive pests—in 2002. The target (aka invasive pest) was the cottony cushion scale, an Australian bug that has a thing for sucking sap.
The cottony cushion scale threatened over 60 endemic and native plants throughout the archipelago.
It took 6 years of research to research potential consequences, but the two organizations chose to release the ladybug beetle (another alien species) into the Galápagos on purpose in order to defeat the conquering Aussie. By 2009. The cottony cushion scale was reduced by 99%-100% on native and endemic plants.