For those of us lucky enough to travel to the Galapagos Islands – one of the most magical places on Earth – one thing that we inevitably come to understand is the importance of conservation......
Many of the plant species found in the Galapagos Islands are as interesting and unique as the islands’ renowned animal life. Still, many first-time visitors are surprised by the arid, almost lunar landscape that greets them as they step off of the plane. When compared to many parts of mainland South America or to other tropical island groups throughout the world, the Galapagos Islands are home to relatively few native plant species and are not particularly lush, except at higher elevations on the larger islands.
Scientists believe that there are around 600 native species of vascular plants here – not many when you consider that mainland Ecuador alone is home to over 20,000!
This discrepancy makes sense when you consider the obstacles that the ancestors of today’s Galapagos plants faced in getting there. First, seeds had to somehow make it across 600 miles of salty ocean from the mainland, carried by birds, the wind, or on rafts of wood and vegetation. And because the islands lie within the Pacific dry belt, they receive little rainfall at lower elevations in normal years, resulting in semi-desert conditions throughout much of the archipelago. Once on land, the newly-arrived seeds had to establish themselves and adapt to this foreign and often harsh environment. Finally, because the islands are relatively young in geologic terms, the plants that did make it have had relatively little time to branch out, evolutionarily speaking, into new varieties and species.
In spite of all of this, the flora of the Galapagos is endlessly complex and fascinating. Thirty percent of the native vascular plants here are found nowhere else on Earth and there are seven entirely distinct endemic genera. The endemic genus Scalesia, for example, is comprised of fifteen different species of trees found nowhere else on earth. They have been called “the Darwin’s finches of the plant world” because of their remarkable pattern of adaptive radiation.
Because of the variation in plant life found at different elevations and from island to island, the flora of the Galapagos is generally categorized into seven distinct vegetation zones:
Littoral (or Coastal) Zone
This zone extends from the edge of the ocean to around fifty to one hundred miles inland and is populated by plants that are well adapted to living in salty conditions.
Four species of mangrove can be found along the edges of the numerous saltwater lagoons in this area. In addition to limiting erosion caused by waves and storms, mangroves provide habitat and nesting places for many bird species, including finches, herons and mockingbirds. The shallow waters of mangrove swamps also provide safe nurseries for young fish, mollusks, shrimps and other species that are crucial links in the Galapagos food chain.
The arid zone is the next vegetation zone you’ll encounter as you move inland from the littoral zone. It is the largest vegetation zone in the archipelago, extending to 300 feet on the wetter, southern sides of the islands, and as high as 1,600 feet on the drier, northern sides. Some of the smaller and lower islands are located entirely within this zone. Three types of endemic cacti dominate the landscape here; lava, candelabra, and prickly pear, the staple diet of land iguanas and giant tortoises.
As you move up from the arid zone, you will encounter the transition zone. As its name implies, this zone lies between the arid lowlands and the cooler, moister highlands and is home to species from both. As such, this zone has the greatest plant diversity among the seven vegetation zones. Small trees and shrubs, including the endemic pega pega and the native hardwood matazarno, dominate this landscape.
This zone is often referred to as the “rain forest of the Galapagos.” Sitting at elevations ranging from about 650 to 1,300 feet on the larger islands, the Scalesia zone is notably cooler, moister and more lush than the zones below it. It is named for the Scalesia forests found here. Some of the trees can grow to over sixty feet tall and are covered in ferns, mosses and orchids. Unfortunately, introduced pigs, goats and plants have decimated these once great forests.
Zanthoxylum (or Brown) Zone
The Zanthoxylum zone is named after the predominant plant found here: the Zanthoxylum fagara, or “cat’s claw.” It is also sometimes referred to as the “brown zone” because the brown lichens that cling to the trees give them a brownish hue. This zone has largely been destroyed by agriculture, unfortunately.
The Miconia zone can be found at elevations starting around 3,200 feet on the islands of Santa Cruz and San Cristóbal. It is named for the Miconia shrub, which once carpeted the region, but is now one of the most endangered plants in the archipelago due cattle grazing and the impact of invasive plants. The Miconia robinsoniana can grow to sixteen feet and has purple and pink flowers.
Pampa or Fern-Sedge Zone
Here in the highest elevations of the Galapagos (above 3,200 feet) exists an otherworldly realm of ferns, grasses, mosses, lichens and orchids. The plants in this zone crowd around temporary pools of water and disappear and reappear seasonally based on rainfall. The only tree found here is the endemic Galapagos fern tree, which can grow to nine feet tall and has a trunk that can grow to eleven inches in diameter.
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