The geology of the Galapagos Islands - Article 1
Many consider the Galapagos Islands to be the result of a mantle plume which occurs when columns of heated rock are pushed upwards from deep within the earth. When the rocks approach the surface, they begin to melt as a result of forces of decompression at play. This continues until the plumes surpass the lithosphere’s surface. As this is happening, the structures that are located on the lithosphere are also pushed upwards which, combined with the magnetic thickening of the earth’s crust, allow for the Galapagos Platform to come into creation. This platform is the shallow region of the ocean in which the Galapagos Islands are located.
Geologists have recorded that the islands are older the further south-southeast that they are located. The Galapagos Islands are beneath the Nazca Plate, a chain of seamounts that have been made which are called the Carnegie Ridge and the Cocos Ridge. It was observed that a chain of volcanoes were produced on both of these plates which forced the Galapagos Spreading Center to move its base to a more northern location. These ridges are also known to disappear into subduction zones which makes it difficult to determine the exact age of the Galapagos plume. Scientists have estimated that the plumes can be up to 90 million years old at the time of publication of this article. This was attributed to the high quantity of volcanic rocks ,that are from the Cretaceous age, which occur in the Caribbean and the northwest margin of South America.
There are two types of volcanoes which can be found in the Galapagos: inverted soup-bowl and smaller shield. The inverted soup-bowl volcanoes can be found in the western portion of the islands, which include Isabela and Fernandina. In this portion, the volcanoes have very large calderas in comparison to the size of the volcanoes. The calderas are responsible for the flat tops of the volcanoes. These calderas are formed as a result of the magma chamber collapsing. This happens when magma is withdrawn from the reservoir and the surrounding rock might not be able to tolerate the force. On the other hand, the smaller shield volcanoes can be found in the east and they have more gentle slopes. There are two main types of volcanoes because the lithosphere thickness can impact the morphology of volcanoes.
Geologists have recorded that the islands are older the further south-southeast that they are located. The Galapagos Islands are beneath the Nazca Plate, a chain of seamounts that have been made which are called the Carnegie Ridge and the Cocos Ridge. It was observed that a chain of volcanoes were produced on both of these plates which forced the Galapagos Spreading Center to move its base to a more northern location. These ridges are also known to disappear into subduction zones which makes it difficult to determine the exact age of the Galapagos plume. Scientists have estimated that the plumes can be up to 90 million years old at the time of publication of this article. This was attributed to the high quantity of volcanic rocks ,that are from the Cretaceous age, which occur in the Caribbean and the northwest margin of South America.
There are two types of volcanoes which can be found in the Galapagos: inverted soup-bowl and smaller shield. The inverted soup-bowl volcanoes can be found in the western portion of the islands, which include Isabela and Fernandina. In this portion, the volcanoes have very large calderas in comparison to the size of the volcanoes. The calderas are responsible for the flat tops of the volcanoes. These calderas are formed as a result of the magma chamber collapsing. This happens when magma is withdrawn from the reservoir and the surrounding rock might not be able to tolerate the force. On the other hand, the smaller shield volcanoes can be found in the east and they have more gentle slopes. There are two main types of volcanoes because the lithosphere thickness can impact the morphology of volcanoes.
Figure 1: An image of a volcano which is located on Isabela Island.
The geology of the Galapagos Islands - Article 2
The Galapagos Archipelago is known for having a high concentration of endemic species. There have been many recorded observations that detail the relationships between the geological and biological systems that are present in the Galapagos islands. Due to the young age of the archipelago, biologists were curious about its inhabitants - more specifically its iguanas. Some biologists had found that there was a common ancestor between marine and land iguanas that existed approximately 10 million years ago when this article was published.
Geologists have conducted research into the concept that ocean islands sink while being carried away from a hotspot. This was found to be the result of the thermal contraction that occurs in the lithosphere. This was proven to be the case for the Galapagos when sunken islands were discovered downstream of the Cocos and Nazca Plates. Geologists were able to determine that there had been multiple sets of paleo-Galapagos islands that had existed They also concluded that the endemic species were results of the evolutionary stepping-stones of these islands.
Among the islands in the Galapagos is Santa Cruz which is considered to be unique for its geology. The bedrock of this island contains two main geologic parts: the Platform Series and the Shield Series. The Platform Series is older than the Shield Series and it is also made up of submarine flows and limestones. On the other hand, Shield Series have lavas which are considered to be indistinguishable from the bimodal alkali olivine series of the islands of Santiago and San Cristobal.
On the island of Santa Cruz, there is a pair of pit craters known as Los Gemelos. These craters are located on the border between the leeward and windward sides of the summit of Santa Cruz. They are located in the scalesia forest which is important because of the variety of birds and vegetation. The scalesia forest is also a spot in which individuals can observe the rampant issue of invasive species.
Geologists have conducted research into the concept that ocean islands sink while being carried away from a hotspot. This was found to be the result of the thermal contraction that occurs in the lithosphere. This was proven to be the case for the Galapagos when sunken islands were discovered downstream of the Cocos and Nazca Plates. Geologists were able to determine that there had been multiple sets of paleo-Galapagos islands that had existed They also concluded that the endemic species were results of the evolutionary stepping-stones of these islands.
Among the islands in the Galapagos is Santa Cruz which is considered to be unique for its geology. The bedrock of this island contains two main geologic parts: the Platform Series and the Shield Series. The Platform Series is older than the Shield Series and it is also made up of submarine flows and limestones. On the other hand, Shield Series have lavas which are considered to be indistinguishable from the bimodal alkali olivine series of the islands of Santiago and San Cristobal.
On the island of Santa Cruz, there is a pair of pit craters known as Los Gemelos. These craters are located on the border between the leeward and windward sides of the summit of Santa Cruz. They are located in the scalesia forest which is important because of the variety of birds and vegetation. The scalesia forest is also a spot in which individuals can observe the rampant issue of invasive species.
Figure 2: An image of Los Gemelos.
How did animals get to the islands
The Galapagos Island is in such a position on the globe which allowed for different situations to arrive that brought in different species to the islands. The Galapagos Islands are located on the equator which means that the air temperature is warmer and displays the physical geographic features of equatorial latitude zones. In contrast, the islands have two main cool currents, the Humboldt and Cromwell ocean currents, which bring in cooler water and species that can thrive in such an environment. This difference in temperature between the land and sea causes a large variation in the species that are located in the islands.
From the beginning of the islands, which is thought to have happened anywhere from 5 to 10 million years ago, species have gotten onto the islands in many different ways. One method is via air travel. Species such as ferns, mosses, and lichens have seeds that are easily carried through the wind and dispersed. Insects and small snails are also known to catch a ride on strong wind currents. Birds that do not have such strong flying abilities (i.e. some smaller land-birds and bats) would have most likely arrived to the island with the assistance of the wind. Seabirds are thought to have flown their way over to the islands. Through the seabirds, different seeds were able to be brought to the islands once they defecate or once their feet dislodged any potential seeds. It was thought that most of the seeds that were brought to the islands were in unfavorable areas for its survival and reproduction. The plants that were most successful in the colonization of the islands were the more weedy species that had high tolerances for the climate of the area and were able to reproduce through wind pollination.
Animals were also thought to arrive on the islands via the ocean by swimming or floating. Animals that are exceptional swimmers (i.e. sea lions, sea turtles, and penguins) were able to swim to the islands with the help of ocean currents. Other species, such as rats, reptiles and other small mammals, most likely arrived to the islands via rafts. This raft theory would explain why there are no native amphibians, few mammals, and a large quantity of reptiles on the islands. The reptiles would be so plentiful due to the fact that they are more well adapted to withstand the harsh salty and sunny conditions of the weeks that they would have had to spend at sea.
From the beginning of the islands, which is thought to have happened anywhere from 5 to 10 million years ago, species have gotten onto the islands in many different ways. One method is via air travel. Species such as ferns, mosses, and lichens have seeds that are easily carried through the wind and dispersed. Insects and small snails are also known to catch a ride on strong wind currents. Birds that do not have such strong flying abilities (i.e. some smaller land-birds and bats) would have most likely arrived to the island with the assistance of the wind. Seabirds are thought to have flown their way over to the islands. Through the seabirds, different seeds were able to be brought to the islands once they defecate or once their feet dislodged any potential seeds. It was thought that most of the seeds that were brought to the islands were in unfavorable areas for its survival and reproduction. The plants that were most successful in the colonization of the islands were the more weedy species that had high tolerances for the climate of the area and were able to reproduce through wind pollination.
Animals were also thought to arrive on the islands via the ocean by swimming or floating. Animals that are exceptional swimmers (i.e. sea lions, sea turtles, and penguins) were able to swim to the islands with the help of ocean currents. Other species, such as rats, reptiles and other small mammals, most likely arrived to the islands via rafts. This raft theory would explain why there are no native amphibians, few mammals, and a large quantity of reptiles on the islands. The reptiles would be so plentiful due to the fact that they are more well adapted to withstand the harsh salty and sunny conditions of the weeks that they would have had to spend at sea.
Figure 3: An image of a land iguana that can be found in the Galapagos Islands.
Challenges in eradicating feral pigs, donkeys and goats from islands
Pigs
Since some species were introduced to the Galapagos Islands, some of these species have negatively impacted the environment. Pigs, goats, and donkeys are among the species that are detrimental to the ecosystem of the islands. Feral pigs, sus scrofa, found on Santiago Island in the Galapagos archipelago, Ecuador have been noted to be the largest insular pig removal at the point that this paper was published in 2005. During this process to eradicate the feral pigs, various methods were used such as hunting and poisoning. Since the feral pig removal was successful, the techniques that were used in order to accomplish this are being used in other circumstances as well. The authors of “Conservation Action in the Galàpagos: Feral Pig (Sus Scrofa) Eradication from Santiago Island.” argue that we need to increase the efficiency of eradication. With the decrease in funding for conservation, governments can no longer afford such lengthy campaigns to eradicate negative species.
To explain the history of the introduction of pigs onto the islands, they were brought to the Galapagos in 1835 when Charles Darwin visited the islands. By the year 1875, the quantity of feral pigs were much greater. Since then, the feral pigs have had many adverse impacts on the biodiversity of Santiago Island because of their diets. These pigs feed on plants, invertebrates, as well as the eggs and hatchlings of Galapagos tortoises, lava lizards, green sea turtles, Galapagos petrels, and many other native vertebrates. It is noted that these pigs and other feral mammals have played a large role in the extinctions that have occurred on the islands.
The hunting practices that were used to eradicate the feral pigs was intensive. There were between 250-500 hunter days per year over the course of ten years. In the year 1995, the hunting effort was increased to add non-specialist hunting dogs. To further their efforts to eradicate the pigs, they also turned to poisoning which typically included poisoning bait that the pigs would feed upon. This poison was sodium monofluoroacetate (1080) in which 700mg was injected into a goat carcasses in nine places. By 1999, there were only a few pigs that remained and the last pig that was believed to be alive was shot in April of 2000. When comparing the two techniques used for eradicating feral pigs, the poisoning campaign killed less pigs and was less cost-effective than the hunting method.
To explain the history of the introduction of pigs onto the islands, they were brought to the Galapagos in 1835 when Charles Darwin visited the islands. By the year 1875, the quantity of feral pigs were much greater. Since then, the feral pigs have had many adverse impacts on the biodiversity of Santiago Island because of their diets. These pigs feed on plants, invertebrates, as well as the eggs and hatchlings of Galapagos tortoises, lava lizards, green sea turtles, Galapagos petrels, and many other native vertebrates. It is noted that these pigs and other feral mammals have played a large role in the extinctions that have occurred on the islands.
The hunting practices that were used to eradicate the feral pigs was intensive. There were between 250-500 hunter days per year over the course of ten years. In the year 1995, the hunting effort was increased to add non-specialist hunting dogs. To further their efforts to eradicate the pigs, they also turned to poisoning which typically included poisoning bait that the pigs would feed upon. This poison was sodium monofluoroacetate (1080) in which 700mg was injected into a goat carcasses in nine places. By 1999, there were only a few pigs that remained and the last pig that was believed to be alive was shot in April of 2000. When comparing the two techniques used for eradicating feral pigs, the poisoning campaign killed less pigs and was less cost-effective than the hunting method.
Figure 4: An image of a feral pig.
Donkeys
Donkeys were first introduced to the Galapagos Archipelago in 1834 on Floreana Island. These donkeys were brought to the island by oil seekers so that the donkeys could assist in the transportation of tortoise oil to ships and settlements. The feral donkey population on the Galapagos Islands should be removed due to the fact that they negatively impact the vegetation. When considering techniques to eradicate such species, aerial and ground hunting are utilized due to their efficiency. In the year 2004, aerial hunting operations began on Santiago and Isabela Island in order to remove goat and donkey populations. The massive removal of donkeys on these islands were a component of an unprecedented island conservation program.
Figure 5: An image of a feral donkey.
Goats
Feral goats (capra hircus) negatively impact the ecosystem with their overgrazing and other behaviors. This overgrazing degrades the ecosystem and causes there to be biodiversity loss. The eradication of goats on the Galapagos Islands is pertinent in order to restore ecosystems and prevent the extinctions of species. Methods to eradicate such mammals would be trapping, poisoning, biocontrol, or a combination of these techniques. The problem with these methods is that once the goats are in smaller quantities, it is more difficult to fully remove them from the islands. The most prevalent of these methods is hunting, which the government of Ecuador had utilized to remove goat populations from the islands. Ecuador had actually utilized an interesting method in order to combat the issue of the last few lonesome goats which will be presented during the next section.
Figure 6: An image of a feral goat.
Podcast
This podcast provides many different topics of discussion that I will outline in this section. The one host of the podcast, NPR, discusses that he when he arrived to Ecuador, he had stumbled upon a rally of sorts. There was an election rally that was going on which consisted of a procession of rolling cars for approximately 15 minutes. This rally had the goal of raising and expressing support for the incumbent. During this, he sees someone that is waving a white flag and after further conversation with this man, the host figures out that he is running for the presidency as well in order to be the voice for mother nature.
The host then brings in a women who discusses the garua that would roll over forests and drip pools that would occur. These drip pools would provide tortoises with water and a spot to rest. When this individual came back 15 years later, she had noticed that the drip pools were mere dust bowls and the forest was very thin. She had described that she had seen multiple tortoises that were crowded around a few remaining stalks of these trees in order to have some shade from the intense sun. The host then goes into detail about why this occurred with other experts. Since there is a goat population on the islands, the goats have eaten away at the forests. Originally, the goats were not present on Isabella Island because of the black lava rock which was difficult for them to walk across. By the 1990s, the goats had crossed this obstacle and populated the islands with hundreds of thousands of goats.
In order to rectify the situation that the goats were causing, a tortoise summit was held in 1994 to discuss an action plan. Many people thought that the eradication of these goats were near impossible, and it took eight years for the project to get to Isabela Island. From the year 2004 until 2006, helicopters were loaded with shooters which followed and hunted goats. Eventually, they came up with the concept of Judas goats in which they would take a female goat, put a tracker in them, and then increase their hormones so that males are more attracted to it. In addition to attracting male goats, lone goats find other groups of goats because they are herd animals. This method works until the point where the judas goat gets pregnant because then they become solitary.
After this campaign to eradicate the goat population, the forests that were originally destroyed were starting to regain life. Slowly, the drip pools began to form again with the steady growth of the trees.
In addition to goats negatively impacting environment, there is also one other major threat: humans. Augustine Lopez had told the host of the show about how in the 70s and 80s, fishermen were able to fish all year round with no restrictions as well as killing and selling sea cucumbers. Since the goat eradication campaign, the National Park had told Ecuador that they needed to limit catches. Paul Watson had explained how the citizens of Ecuador were going after national park buildings and they blockaded roads, burned buildings, kidnapped people, and killed thousands of tortoises by slitting their throats.
Located in Pinta Island used to be the pinta tortoises. The ecosystem is out of balance because of the lack or tortoises. In the year 1994, the Phoenix project worked towards taking census of tortoises on all of the islands. During this, the researchers took a small sample of blood from each of the species that they identified on each island. With this, they had concluded that a group of tortoises had a lot of similarities to the DNA that the Pinta tortoises had. It was thought that by taking the babies with the most similarity in order to eventually revive the Pinta tortoises.
The host then brings in a women who discusses the garua that would roll over forests and drip pools that would occur. These drip pools would provide tortoises with water and a spot to rest. When this individual came back 15 years later, she had noticed that the drip pools were mere dust bowls and the forest was very thin. She had described that she had seen multiple tortoises that were crowded around a few remaining stalks of these trees in order to have some shade from the intense sun. The host then goes into detail about why this occurred with other experts. Since there is a goat population on the islands, the goats have eaten away at the forests. Originally, the goats were not present on Isabella Island because of the black lava rock which was difficult for them to walk across. By the 1990s, the goats had crossed this obstacle and populated the islands with hundreds of thousands of goats.
In order to rectify the situation that the goats were causing, a tortoise summit was held in 1994 to discuss an action plan. Many people thought that the eradication of these goats were near impossible, and it took eight years for the project to get to Isabela Island. From the year 2004 until 2006, helicopters were loaded with shooters which followed and hunted goats. Eventually, they came up with the concept of Judas goats in which they would take a female goat, put a tracker in them, and then increase their hormones so that males are more attracted to it. In addition to attracting male goats, lone goats find other groups of goats because they are herd animals. This method works until the point where the judas goat gets pregnant because then they become solitary.
After this campaign to eradicate the goat population, the forests that were originally destroyed were starting to regain life. Slowly, the drip pools began to form again with the steady growth of the trees.
In addition to goats negatively impacting environment, there is also one other major threat: humans. Augustine Lopez had told the host of the show about how in the 70s and 80s, fishermen were able to fish all year round with no restrictions as well as killing and selling sea cucumbers. Since the goat eradication campaign, the National Park had told Ecuador that they needed to limit catches. Paul Watson had explained how the citizens of Ecuador were going after national park buildings and they blockaded roads, burned buildings, kidnapped people, and killed thousands of tortoises by slitting their throats.
Located in Pinta Island used to be the pinta tortoises. The ecosystem is out of balance because of the lack or tortoises. In the year 1994, the Phoenix project worked towards taking census of tortoises on all of the islands. During this, the researchers took a small sample of blood from each of the species that they identified on each island. With this, they had concluded that a group of tortoises had a lot of similarities to the DNA that the Pinta tortoises had. It was thought that by taking the babies with the most similarity in order to eventually revive the Pinta tortoises.
Figure 7: An image of a Pinta Island Giant Galapagos Tortoise.
Galapagos biodiversity
Plants
The Galapagos Archipelago’s land area is comprised of brown and gray vegetation which is often found in deserts. Since the Galapagos Islands are located in the Pacific Dry Belt, only the highest altitudes of the islands receive enough precipitation to sustain tropical plant life.
Researchers can observe that the island’s plantlife reflects that the Galapagos Islands are young. Currently, there are over 600 known native species of vascular plants as well as over 825 species that were introduced to the islands. The mainland of Ecuador has approximately 20,000 known species. One of the reasons for the large variation of these numbers is that the barrier of salt water makes it difficult for species to travel to this new environment.
It is noted that there are three major vegetation zones: the coastal zone, arid zone, and humid highlands. Located in the coastal zone are mangroves. Mangrove trees are crucial for the ecosystem in this area because it provides breeding sites for many birds, shady regions for iguana and sea lions, and a place of refuge for sea turtles.
Researchers can observe that the island’s plantlife reflects that the Galapagos Islands are young. Currently, there are over 600 known native species of vascular plants as well as over 825 species that were introduced to the islands. The mainland of Ecuador has approximately 20,000 known species. One of the reasons for the large variation of these numbers is that the barrier of salt water makes it difficult for species to travel to this new environment.
It is noted that there are three major vegetation zones: the coastal zone, arid zone, and humid highlands. Located in the coastal zone are mangroves. Mangrove trees are crucial for the ecosystem in this area because it provides breeding sites for many birds, shady regions for iguana and sea lions, and a place of refuge for sea turtles.
Figure 8: An image of cacti located in the Galapagos Islands.
Giant tortoises
Two main morphological forms of Galapagos tortoises exist: the domed carapace and the saddle-backed carapace. Domed tortoises are known to be larger in size, live longer, and are located on higher islands with humid highlands. On the other hand, saddle-backed carapaces are known to evolved on more arid islands, and their carapaces are angled upwards which allows the tortoise to extend its head higher in order to reach higher vegetation.
The Galapagos tortoises were originally brought to the islands via buccaneers, whalers, and fur sealers when they discovered that they could have fresh meat for their long voyages since the tortoises had adapted to survive for a long time without key nutrients such as food and water. Not only were the tortoises exploited for their meat but also for their oil. This had gone on for two centuries which had resulted in anywhere from 100,000 to 200,000 tortoises as well as the extinction of three species - four if you consider the more recent loss of Lonesome George in 2012. It is estimated that there are only between 20,000 and 25,000 wild tortoises that live on the islands currently.
There are 15 species known that fall under the genus of Chelonoidis. There is one giant tortoise species on the following big islands: Española, Fernandina, Floreana, Pinta, Pinzón, San Cristóbal, Santa Fe and Santiago. There are two species on Santa Cruz as well as one species for each of the five major volcanoes on Isabela Island which are Wolf, Darwin, Alcedo, Sierra Negra and Cerro Azul. Due to volcanism, tortoises on Fernandina have become extinct. Exploitation is the cause of the extinction of tortoises from the islands of Floreana, Santa Fe and Pinta.
The Galapagos tortoises were originally brought to the islands via buccaneers, whalers, and fur sealers when they discovered that they could have fresh meat for their long voyages since the tortoises had adapted to survive for a long time without key nutrients such as food and water. Not only were the tortoises exploited for their meat but also for their oil. This had gone on for two centuries which had resulted in anywhere from 100,000 to 200,000 tortoises as well as the extinction of three species - four if you consider the more recent loss of Lonesome George in 2012. It is estimated that there are only between 20,000 and 25,000 wild tortoises that live on the islands currently.
There are 15 species known that fall under the genus of Chelonoidis. There is one giant tortoise species on the following big islands: Española, Fernandina, Floreana, Pinta, Pinzón, San Cristóbal, Santa Fe and Santiago. There are two species on Santa Cruz as well as one species for each of the five major volcanoes on Isabela Island which are Wolf, Darwin, Alcedo, Sierra Negra and Cerro Azul. Due to volcanism, tortoises on Fernandina have become extinct. Exploitation is the cause of the extinction of tortoises from the islands of Floreana, Santa Fe and Pinta.
Figure 9: An image of my mother and I behind one of the tortoises that was in a sanctuary on one of the islands.
Lizards and Iguanas
The Galapagos lava lizards can be found on all of the major islands of the Galapagos. Some of the species of the lava lizards can only be found in distinct areas of certain islands. The lava lizards have different colors based on their gender as well as what area they are from.
It is estimated that the divergence between land and marine iguanas happened approximately 10.5 million years ago. More specifically, geneticists estimate that the pink iguana had diverged from other land iguanas about 5.7 million years ago which was before most of the current island existed.
Marine iguanas (Amblyrhynchus Cristatus) are found on rocky shorelines of the islands. They are known to be the only lizard that is able to survive and thrive in oceanic environments. These iguanas feed on seaweeds that grow on rocks in sub-tidal areas. Marine iguana mate and nest on land despite their ability to survive in aquatic areas. The marine iguanas have adapted so that they have flattened tails which aid them in swimming. Another adaptation that has occurred overtime would be that they are able to expel excess salt through their nostrils.
It is estimated that the divergence between land and marine iguanas happened approximately 10.5 million years ago. More specifically, geneticists estimate that the pink iguana had diverged from other land iguanas about 5.7 million years ago which was before most of the current island existed.
Marine iguanas (Amblyrhynchus Cristatus) are found on rocky shorelines of the islands. They are known to be the only lizard that is able to survive and thrive in oceanic environments. These iguanas feed on seaweeds that grow on rocks in sub-tidal areas. Marine iguana mate and nest on land despite their ability to survive in aquatic areas. The marine iguanas have adapted so that they have flattened tails which aid them in swimming. Another adaptation that has occurred overtime would be that they are able to expel excess salt through their nostrils.
Figure 10: An image of marine iguanas that I had taken on the front steps of our beach front hotel on one of the Islands.
Mammals
The Galapagos Sea Lion (Zalophus californianus, subspecies: wollebacki) is noted to be the largest animals found in the Galapagos with full-grown males that can weigh up to 550 pounds. The sea lions typically gather as a group of females and one dominant male. The dominant male will patrol the area in order to protect its position with the females. These harems are mostly found in picturesque locations such as beach locations, unlike the bachelor colonies which are located in less desirable places such as on top of rocky cliffs.
Fur seals are different from sea lions for many reasons. One of these reasons would be that fur seals prefer more rugged, rockier, and shadier shores which are less frequented by humans. They are also less tolerant of heat. Fur seals are also nocturnal hunters, specifically during full moons, who search for fish and squid to fill their diet.
There are also Rice Rat species that exist in the Galapagos. There are four species and all of these are located on the three islands, Santa Fé, Santiago, and Fernandina, that are not inhabited by humans. Since when humans came to the other islands, they had brought black rats with them that had carried a plague which knocked out these species of rat.
Bats can also be found on the islands. The Hoary Bat (Lasiurus cinereus) is from North America and roosts in Mangrove trees during the day. This species of bat can mainly be found on the islands of Santa Cruz, San Cristóbal, Isabela, Santiago, and Floreana. Lasiurus brachyotis can be found on Santa Cruz and San Cristóbal in the highland and coastal zones. This species migrates between the two areas depending on the season.
Fur seals are different from sea lions for many reasons. One of these reasons would be that fur seals prefer more rugged, rockier, and shadier shores which are less frequented by humans. They are also less tolerant of heat. Fur seals are also nocturnal hunters, specifically during full moons, who search for fish and squid to fill their diet.
There are also Rice Rat species that exist in the Galapagos. There are four species and all of these are located on the three islands, Santa Fé, Santiago, and Fernandina, that are not inhabited by humans. Since when humans came to the other islands, they had brought black rats with them that had carried a plague which knocked out these species of rat.
Bats can also be found on the islands. The Hoary Bat (Lasiurus cinereus) is from North America and roosts in Mangrove trees during the day. This species of bat can mainly be found on the islands of Santa Cruz, San Cristóbal, Isabela, Santiago, and Floreana. Lasiurus brachyotis can be found on Santa Cruz and San Cristóbal in the highland and coastal zones. This species migrates between the two areas depending on the season.
Figure 11: An image of a sea lion that I had taken prior to going scuba diving on one of the islands.
Land birds
Of the endemic bird species, thirteen out of the twenty-two are known as Darwin’s finches, four of them are mockingbird species, and five of them are the Galapagos Hawk (Buteo galapagoensis), the Galapagos Dove (Zenaida galapagoensis), the Galapagos Flycatcher (Myiarchus magnirostris), the Galapagos Rail (Laterallus spilonotus), and the Galapagos Martin (Progne modesta). There are four endemic taxa that at eh subspecies level include the Galapagos Short-eared Owl (Asio flammeus galapagoensis), the Galapagos Barn Owl (Tyto alba punctatissima), the Galapagos Mangrove Warbler (Dendroica petechia aureola), and Vermilion Flycatcher (Pyrocephalus rubinus nanus). There are three indigenous species which are the Dark-billed Cuckoo (Coccyzus melacoryphus), the Common Gallinule or Moorhen (Gallinula chloropus) and the Paint-billed Crake (Neocrex erythrops). The land birds include two of the most impressive examples of evolutionary change in the Galapagos which are Darwin’s Finches and Mockingbirds.
Other birds of the island include Galapagos Doves, Broad-billed Flycatchers, Vermilion Flycatchers, and Galapagos Rails. There have been six introduced bird species which have become naturalized overtime. These species are Smooth-billed Anis, Cattle Egrets, Quails, Guinea Fowl, Peacocks, and the Guayaquil Red-masked parakeet. While there are these introduced species there is also six major endemic species which are the Galapagos Penguin, Flightless Cormorant, Waved Albatross, Galapagos Petrel, Lava Gull and Swallow-tailed Gull.
The Galapagos Penguin are the only penguins to live at the equator. Their population is about 2,000 individuals which are located around the colder areas which nutrient-rich waters of Fernandina and Isabela Island. Flightless Cormorants are also endemic to these islands. The thing that distinguishes this species of cormorant from others is that this one has gained the ability to fly. Galapagos Petrels are one of the only seabirds in the islands that is able to breed in the humid climate of the highlands in the islands of Santa Cruz, Floreana, Santiago, San Cristóbal, and Isabela. Lava Gulls are estimated to have a population of 900-1200 individuals which is because they have such a solitary animal in their nesting and day-to-day living.
Other birds of the island include Galapagos Doves, Broad-billed Flycatchers, Vermilion Flycatchers, and Galapagos Rails. There have been six introduced bird species which have become naturalized overtime. These species are Smooth-billed Anis, Cattle Egrets, Quails, Guinea Fowl, Peacocks, and the Guayaquil Red-masked parakeet. While there are these introduced species there is also six major endemic species which are the Galapagos Penguin, Flightless Cormorant, Waved Albatross, Galapagos Petrel, Lava Gull and Swallow-tailed Gull.
The Galapagos Penguin are the only penguins to live at the equator. Their population is about 2,000 individuals which are located around the colder areas which nutrient-rich waters of Fernandina and Isabela Island. Flightless Cormorants are also endemic to these islands. The thing that distinguishes this species of cormorant from others is that this one has gained the ability to fly. Galapagos Petrels are one of the only seabirds in the islands that is able to breed in the humid climate of the highlands in the islands of Santa Cruz, Floreana, Santiago, San Cristóbal, and Isabela. Lava Gulls are estimated to have a population of 900-1200 individuals which is because they have such a solitary animal in their nesting and day-to-day living.
Figure 12: An image of one of Darwin's Finches.
Sea and Shore Birds
There are three main groups of boobies on the Galapagos Islands: the Blue-footed Boobies, Nazca Boobies, Red-footed Boobies. Since the Blue-footed Boobies feed closer to shore, the Nazca Boobies feed more offshore, and the Red-footed Boobies feed out in the open ocean.
It is known that two of the five species of frigate-birds can be found in the Galapagos. These species of birds had received their name from their pirate-like behaviors. They are typically large black birds with long wings with long hooked beaks as well as deeply forked tails. Some shorebirds that are outlined in this tab are the Galapagos flamingo, the many heron species including Great Blue Herons, Yellow-crowned Night Herons, Lava Herons, Black-crowned Herons and Striated Herons, Oystercatchers, White-cheeked pintails, Gallinules, and Common Egrets.
It is known that two of the five species of frigate-birds can be found in the Galapagos. These species of birds had received their name from their pirate-like behaviors. They are typically large black birds with long wings with long hooked beaks as well as deeply forked tails. Some shorebirds that are outlined in this tab are the Galapagos flamingo, the many heron species including Great Blue Herons, Yellow-crowned Night Herons, Lava Herons, Black-crowned Herons and Striated Herons, Oystercatchers, White-cheeked pintails, Gallinules, and Common Egrets.
Figure 13: An image of a Blue-footed Booby.
Marine Life
The Galapagos Islands is the home for many marine species such as marine iguanas, most of the northern-living penguins, coral beds, and fur seals. The Galapagos is one of the only places in which pelagic species can be seen in close proximity to the shore. The geological and biological processes have enabled the islands to support a large variety of habitats which can serve many marine species.
Figure 14: An image of a sea lion from the Galapagos Islands.
Invertebrates
Terrestrial invertebrates were brought to the Galapagos via active flight, passive drift, and transportation from main marine currents. Within this category, the group with the highest species diversity is insects in the order of Coleoptera, Diptera, Hemiptera, Hymenoptera and Lepidoptera. On the other hand, Diplura, Thysanura, Odonata, Mantodea, Embiidina, Zoraptera, Stresiptera are not as represented. There are also marine invertebrates which include molluscs, marine annelids, echinoderms, cnidarians, and sponges.
Figure 15: An image of a crab that can be found in the coastal parts of the Galapagos Islands.
Mangroves and seagrasses
With the increase in the human population on coastlines, seagrass and mangrove areas are negatively impacted. It was noted that seagrasses have decreased in abundance at a rate of nearly seven percent per year. This is concerning when considering the benefits that the seagrasses have on ecosystems as well as the benefits that it has for humans.
Seagrass keeps the amount of erosion that occurs at a minimum, locks sediments into the bottom of a waterway, and removes sediments from the water column. This allows for water to penetrate the water and provide light to more depths of the water rather than it stopping at the sediments. If the sediment remains in the water column, it creates turbid water. Seagrasses also stabilize shorelines and protections against hurricanes. Seagrasses also are beneficial for dealing with nitrogen and carbon. It was noted that a hectare of seagrass is capable of balancing out the amount of nitrogen as treated sewage from 800 people in one year. When calculated this would benefit financially the total of $19,000 for a single hectare of seagrass for nitrogen. With carbon, the seagrass can fix the same amount of carbon per meter squares that would be needed to balance a car’s emissions for a year if it travels 750 miles.
A study is being outlined in this video which allows researchers to collect snapshots of the community that is in close proximity to mangroves and how the ecosystem changes as the water depth increases.
Humans damage the seagrass population with the storm water runoff from coastal communities as well as different recreational activities such as boating. Boating damages the seagrass beads because of the anchors and boat groundings.
In order to combat the negative impacts that human recreation has on seagrass and mangrove ecosystems, proactivity is required. Since the propellers of boats are scarring the sediments of the water floor, individuals need to fill in these areas with very fine sediment to allow for the seagrass to root itself to the sediment. Although this helps for however long one is willing to do it, it might not be the most successful in the long term. Along with this, people are working to educate the public about how to recreate sustainably without harming the ecosystem.
Seagrass keeps the amount of erosion that occurs at a minimum, locks sediments into the bottom of a waterway, and removes sediments from the water column. This allows for water to penetrate the water and provide light to more depths of the water rather than it stopping at the sediments. If the sediment remains in the water column, it creates turbid water. Seagrasses also stabilize shorelines and protections against hurricanes. Seagrasses also are beneficial for dealing with nitrogen and carbon. It was noted that a hectare of seagrass is capable of balancing out the amount of nitrogen as treated sewage from 800 people in one year. When calculated this would benefit financially the total of $19,000 for a single hectare of seagrass for nitrogen. With carbon, the seagrass can fix the same amount of carbon per meter squares that would be needed to balance a car’s emissions for a year if it travels 750 miles.
A study is being outlined in this video which allows researchers to collect snapshots of the community that is in close proximity to mangroves and how the ecosystem changes as the water depth increases.
Humans damage the seagrass population with the storm water runoff from coastal communities as well as different recreational activities such as boating. Boating damages the seagrass beads because of the anchors and boat groundings.
In order to combat the negative impacts that human recreation has on seagrass and mangrove ecosystems, proactivity is required. Since the propellers of boats are scarring the sediments of the water floor, individuals need to fill in these areas with very fine sediment to allow for the seagrass to root itself to the sediment. Although this helps for however long one is willing to do it, it might not be the most successful in the long term. Along with this, people are working to educate the public about how to recreate sustainably without harming the ecosystem.
Figure 16: An image of sea grass.
Life in the mangroves
Mangrove forests are beneficial to many species. In red mangrove forests, new habitats for different marine and estuary species were able to be established. For example, juvenile fish are able to grow up in a safe environment due to the mangrove roots and how difficult they are to navigate if you are a larger predator. The mangrove forests can be homes of sea cucumbers, fish, horseshoe crabs, mangrove snappers, and many birds such as egrets, herons, and many of the warblers. The mangroves provides a nice winter habitat for these birds as well as a nesting area with less predators for the eggs that the birds will lay. Along with providing shelter, the mangroves provide wind cover in addition to resources.
Unfortunately, human activity has been damaging the mangrove forests with boat activity. To combat this issue, places have implemented no wake zones. In the United States, more specifically Florida, legislature was implemented in order to work towards the protection of these mangrove forests. This was called the mangrove trimming and preservation act.
Mangrove forests are beneficial for humans due to the protection they provide from storms and high winds along with the fact that the mangroves improves the water quality which directly impacts all living species in the area. These forests reduce global climate change, but with the increasing sea level, the mangrove forests are put at risk.
Unfortunately, human activity has been damaging the mangrove forests with boat activity. To combat this issue, places have implemented no wake zones. In the United States, more specifically Florida, legislature was implemented in order to work towards the protection of these mangrove forests. This was called the mangrove trimming and preservation act.
Mangrove forests are beneficial for humans due to the protection they provide from storms and high winds along with the fact that the mangroves improves the water quality which directly impacts all living species in the area. These forests reduce global climate change, but with the increasing sea level, the mangrove forests are put at risk.
Figure 17: An image of a mangrove forest.
Resources
“Biodiversity.” Galapagos Conservancy, Inc.,
www.galapagos.org/about_galapagos/about-galapagos/biodiversity/.
Campbell, Karl, and C. Josh Donlan. “Feral Goat Eradications on Islands.” Conservation
Biology, vol. 19, no. 5, 2005, pp. 1362–1374., doi:10.1111/j.1523-1739.2005.00228.x.
Carrion, Victor, et al. “Feral Donkey (Equus Asinus) Eradications in the Galapagos.”
Biodiversity and Conservation, 2007, doi:10.1007/s10531-005-5825-7.
Cruz, Felipe, et al. “Conservation Action in the Galàpagos: Feral Pig (Sus Scrofa)
Eradication from Santiago Island.” Biological Conservation, vol. 121, no. 3, 2005, pp. 473–478., doi:10.1016/j.biocon.2004.05.018.
d’Ozouville , Noémi, et al. “The Galápagos as a Laboratory for the Earth Sciences.”
Chapman Field Trip Guide, July 2011,
www.webpages.uidaho.edu/~dgeist/Chapman/ChapmanFieldTripGuide.pdf.
Howard, Tim. Galapagos. New York Public Radio Popup Player, 17 July 2014,
www.wnyc.org/radio/#/ondemand/388850.
“Waterways Episode 275 - Life in the Mangroves.” Waterways Episode 275 - Life in the
Mangroves, 22 Oct. 2014, www.youtube.com/watch?v=criOuMj1Tcg&t=246s.
White, W.M. “A Brief Introduction to the Geology of the Galapagos.” Galapagos Geology,
1997, www.geo.cornell.edu/geology/GalapagosWWW/GalapagosGeology.html.
www.galapagos.org/about_galapagos/about-galapagos/biodiversity/.
Campbell, Karl, and C. Josh Donlan. “Feral Goat Eradications on Islands.” Conservation
Biology, vol. 19, no. 5, 2005, pp. 1362–1374., doi:10.1111/j.1523-1739.2005.00228.x.
Carrion, Victor, et al. “Feral Donkey (Equus Asinus) Eradications in the Galapagos.”
Biodiversity and Conservation, 2007, doi:10.1007/s10531-005-5825-7.
Cruz, Felipe, et al. “Conservation Action in the Galàpagos: Feral Pig (Sus Scrofa)
Eradication from Santiago Island.” Biological Conservation, vol. 121, no. 3, 2005, pp. 473–478., doi:10.1016/j.biocon.2004.05.018.
d’Ozouville , Noémi, et al. “The Galápagos as a Laboratory for the Earth Sciences.”
Chapman Field Trip Guide, July 2011,
www.webpages.uidaho.edu/~dgeist/Chapman/ChapmanFieldTripGuide.pdf.
Howard, Tim. Galapagos. New York Public Radio Popup Player, 17 July 2014,
www.wnyc.org/radio/#/ondemand/388850.
“Waterways Episode 275 - Life in the Mangroves.” Waterways Episode 275 - Life in the
Mangroves, 22 Oct. 2014, www.youtube.com/watch?v=criOuMj1Tcg&t=246s.
White, W.M. “A Brief Introduction to the Geology of the Galapagos.” Galapagos Geology,
1997, www.geo.cornell.edu/geology/GalapagosWWW/GalapagosGeology.html.