Santa Cruz Island
Taking a look at our photo on today’s web report, one may believe that we have accidentally posted a picture from one of our Central American trips. Although the Galapagos Archipelago is bang in the middle of the latitudinal band contained between the tropics and Cancer and Capricorn, so could be expected to display tropical conditions on land and in the sea, it is bathed during much of the year by cold water currents that dramatically affect its climatic conditions. The cool waters of the Humboldt Current from the south and the Cromwell Current from the west are the main influence during our cool, dry season, which ranges from about June through November. During this time of year, waters can be as cool as 60 degrees Fahrenheit, and as a consequence a low cloud cover prevails, and practically no precipitation occurs. Most of the surface area of the Galapagos displays arid and coastal zone conditions, with subsequent consequences on the predominant vegetation, which is for the most part composed of desert-loving species such as cacti. Nonetheless, the whole picture is a lot more complex: five of the thirteen larger islands are tall enough to intercept the cloud layer, and the upper slopes, are consequently lost in swirling clouds laden with moisture. A continual fine mist called Garua creates the perfect conditions for cloud forests. What was lacking here were the trees to form such forests, an empty ecological niche that was eventually taken over by a member of the Asteraceae, or sunflower and daisy family. Normally occurring as herbs or small shrubs, a member of this family was to evolve into trees in the highlands of Santa Cruz, to fill the vacancy. The genus of this remarkable plant is Scalesia, one of seven genera endemic to the Galapagos, and one often considered as the “finch equivalent” of the plant kingdom due to the sheer amount of speciation that it has undergone. Scalesia pedunculata, endemic to the highlands of Santa Cruz, is the predominant plant of the fourth vegetation zone of this large island, and forms dense cloud forests. The branches of the trees are dripping in epiphytes, plants growing on other plants in order to take advantage of the moisture found higher up, which would otherwise be fully captured by the forest canopy. The term epiphyte is a general term that describes an ecological role rather than a phylogenetically related group, and is made up by several different species, genera, families and even orders of plants. Here in Galapagos, our epiphytic community is made up of common species such as the buttonhole and ionopsis orchids, various bromeliads, a couple of passion flower species, Peperomia, mistletoe,Tillandsia and several non-flowering plants such as liverworts.
After a morning spent visiting the famous Charles Darwin Research Station and the bustling port town of Puerto Ayora, we boarded buses for a delicious lunch in the highlands, before continuing on through the agricultural areas of Santa Cruz and back into protected National Park. It was here that we had the chance to explore the totally different environment described above, walking through this unique elfin forest as we searched for new finch species, vermilion flycatchers and giant tortoises in their natural habitat.
Taking a look at our photo on today’s web report, one may believe that we have accidentally posted a picture from one of our Central American trips. Although the Galapagos Archipelago is bang in the middle of the latitudinal band contained between the tropics and Cancer and Capricorn, so could be expected to display tropical conditions on land and in the sea, it is bathed during much of the year by cold water currents that dramatically affect its climatic conditions. The cool waters of the Humboldt Current from the south and the Cromwell Current from the west are the main influence during our cool, dry season, which ranges from about June through November. During this time of year, waters can be as cool as 60 degrees Fahrenheit, and as a consequence a low cloud cover prevails, and practically no precipitation occurs. Most of the surface area of the Galapagos displays arid and coastal zone conditions, with subsequent consequences on the predominant vegetation, which is for the most part composed of desert-loving species such as cacti. Nonetheless, the whole picture is a lot more complex: five of the thirteen larger islands are tall enough to intercept the cloud layer, and the upper slopes, are consequently lost in swirling clouds laden with moisture. A continual fine mist called Garua creates the perfect conditions for cloud forests. What was lacking here were the trees to form such forests, an empty ecological niche that was eventually taken over by a member of the Asteraceae, or sunflower and daisy family. Normally occurring as herbs or small shrubs, a member of this family was to evolve into trees in the highlands of Santa Cruz, to fill the vacancy. The genus of this remarkable plant is Scalesia, one of seven genera endemic to the Galapagos, and one often considered as the “finch equivalent” of the plant kingdom due to the sheer amount of speciation that it has undergone. Scalesia pedunculata, endemic to the highlands of Santa Cruz, is the predominant plant of the fourth vegetation zone of this large island, and forms dense cloud forests. The branches of the trees are dripping in epiphytes, plants growing on other plants in order to take advantage of the moisture found higher up, which would otherwise be fully captured by the forest canopy. The term epiphyte is a general term that describes an ecological role rather than a phylogenetically related group, and is made up by several different species, genera, families and even orders of plants. Here in Galapagos, our epiphytic community is made up of common species such as the buttonhole and ionopsis orchids, various bromeliads, a couple of passion flower species, Peperomia, mistletoe,Tillandsia and several non-flowering plants such as liverworts.
After a morning spent visiting the famous Charles Darwin Research Station and the bustling port town of Puerto Ayora, we boarded buses for a delicious lunch in the highlands, before continuing on through the agricultural areas of Santa Cruz and back into protected National Park. It was here that we had the chance to explore the totally different environment described above, walking through this unique elfin forest as we searched for new finch species, vermilion flycatchers and giant tortoises in their natural habitat.
