The Galapagos Islands contain some of the most diverse and unique environments on the planet. This fact is reflected in the many endemic species that are found on the islands, with nearly all of the birds, mammals, and reptiles present in the Galapagos being found nowhere else in the world. However, many of these species have become endangered in recent years or have even been driven to extinction. The driving causes behind this environmental damage has been human interaction. Throughout the years, human visitors to the islands have introduced many non-native species, such as feral pigs and cats. These new species wreaked havoc on the islands’ ecosystems and native species due to their invasive nature and destruction of the native species’ offspring. Humans have also directly contributed to the endangerment of Galapagos tortoise species through hunting and have harmed other species due to industrial accidents. Future damage to the Galapagos environment and its species is all but guaranteed by the growing threat of climate change. Many of the species on the islands have adapted to suit their small niches within the Galapagos. Changes in weather patterns, such as the changing frequency and intensity of El Nino’s, have caused damage to several plant species and the nests of egg-laying species. Continued climate change could potentially drive many of the currently endangered endemic species in the Galapagos into extinction as the conditions they have spent centuries adapting to disappear.
HOW SPECIES ARRIVED AT THE GALAPAGOS:
When looking at the present-day species diversity of the Galapagos Islands, the relative imbalance between the different categories of species living on the islands is startling. For example, the Galapagos Islands are home to hundreds of reptile and bird species, but almost no mammals or amphibians. This imbalance is the result of the island chains’ formation millions of years ago. Due to be being well over 600 kilometers from mainland South America, the islands were geographically isolated and supported very little life. The enormous distance separating the islands from mainland South America meant that only species that could travel great distances, either through the air like birds or by swimming like reptiles, would be able to colonize the islands. Plants arrived on the islands through a combination of being resilient to the salty conditions of the ocean, being deposited by migratory sea birds after being eaten on the mainland, or simply being light enough to be blown to the islands by the wind. The desolate and inhospitable conditions of the early Galapagos made sure that only the hardiest and most well-adapted species would be able to gain a foothold. Having never traveled outside the East Coast, I am excited to finally be able to all of the species that make the Galapagos their home. The conditions on the islands are completely unlike any other place I have traveled to and I am expecting to be awed by unique ways that these species have adapted to survive and thrive there. SPECIES ERADICATION EFFORTS:
While the Galapagos Islands may not receive a large number of visitors, human activity has greatly impacted the islands through the introduction of invasive species. These non-native species can cause significant environmental destruction through overconsumption of plants and destroying vital habitats. The primary invasive species behind this destruction are feral pigs, donkeys, and goats. These species appeared on the Galapagos between the time of Darwin’s visit and the late 19th century, having exploded in number since their introduction. In order to limit environmental damage and stop continued unchecked population growth, groups of hunters have eradicated these species from the islands. This eradication was the result of successful hunting campaigns, involving armed hunters and poisoned traps, that occurred during the latter half of the 20th century and the beginning of the 21st. Due to the hunters’ success, many native species have since rebounded and their number continue to grow. While it is regretful that such a large number of animals had to be killed, their removal is ultimately for the best. Many of the species on the Galapagos Islands are endemic, making them much more important to conserve than a handful of invasive species that are abundant across the globe. I am curious about what unintended consequences may arise from their eradication as these species could have possibly kept other invasive species in check, as the donkey report mentions in regard to a non-native shrub making a comeback.
GEOLOGY OF THE GALAPAGOS ISLANDS:
The Galapagos Islands were formed over the course of millions of years through volcanic and tectonic activity. This activity is driven by a “mantle plume” located in the nearby area. Mantle plumes are columns of heated rock that make their way through the Earth’s mantle before melting at the surface. This melting process and the fact that they originate so far within the Earth means that plumes can continue to deposit new material on the surface despite changes in tectonic plates. As the melted rock, or magma, rises to the surface it will begin to pool before eventually causing a volcanic eruption. While some island chains may form in noticeable lines that are dictated by the movement of the tectonic plate, the Nazca plate in regard to the Galapagos, they are located on, the Galapagos do not directly follow this pattern. The area where the mantle plume pushed magma to the service has come to be referred to as the Galapagos Spreading Center as the islands radiate out from this area. Moving along the islands, they get progressively older the closer you are to the southern edge of the chain. Some of the oldest islands have sunk and become sea mounts due to the contraction that occurs when they cool. Given that the Galapagos Islands where formed through a series of magma eruptions and tectonic activity, it is not surprising that there are many active volcanoes in the Galapagos. Many of the volcanoes within the island chain belong to the shield category or have the somewhat unique “inverted soup-bowl” shape. The difference between these two categories of volcanoes is due to the varying thicknesses of the Earth’s crust where they formed. These volcanoes have been instrumental in producing the wide variety of environments found on the Galapagos Islands that support the biodiversity within them. The constant but small output of the volcanoes appears to be instrumental in circulating more nutrients into the ecosystems on the islands. The ash their eruptions produce makes great soil for plants, which in turn attract more species to feed off them. Without these volcanoes, it seems that the incredible diversity found within the Galapagos would not be possible. I am looking forward to being able to visit these volcanoes and observing firsthand the environments that they have created.
LIFE IN THE MANGROVES:
Mangroves are trees and shrubs that have adapted to survive in saltwater and live in areas with large tidal differences. This is accomplished through the use of their roots to take in oxygen or prevent the uptake of salt. There are 35 species of mangroves, with 80 more species being associated with them, and they can be found in coastal areas in the tropics. These species serve important roles within their ecosystems as they provide nutrients and breeding grounds for the aquatic species that live around them. For example, nearly three quarters of commercially sold fish will grow and live within mangroves within their life cycles. Mangroves also provide a wide variety of ecosystem services to humans, acting as buffers for storm surges and filtering pollution from waterways. Despite the vast array of benefits that mangroves provide to humans and animals alike, these forests have been devastated by continuous human development. As stated previously, mangroves provide breeding grounds for many commercial aquatic species, such as shrimp. This has resulted in the clear cutting of forests in order to replace them with shrimp farms and other commercial aquaculture facilities. Human activity has also disturbed many of the local species that use the areas for nesting grounds, resulting in the death of many young birds. Shoreline development has been the driving factor behind the loss of mangrove ecosystem, as the forests are removed for construction purposes. I personally find the destruction of mangrove forests to be reprehensible given the wide range of benefits these ecosystems provide to both humans and animals alike. The areas that mostly contain mangroves are often subject to tropical storms and hurricanes, making the dampening effect that mangroves have extremely beneficial to the long-term survival of these communities. Removing them to build more structures that will only be subject to worsening storm conditions and potential destruction is short sighted and repugnant.