Isabella island

Isabela Island is the largest and geologically one of the most fascinating islands of the Galápagos Archipelago, situated in the Pacific Ocean off the coast of Ecuador. It is renowned for its diverse wildlife, volcanic landscapes, and significant ecological importance. The island is both a natural wonder and a vital component of global scientific and conservation research due to its unique combination of geography and biodiversity.

Geography and Formation

Isabela Island covers an area of approximately 4,586 square kilometres, making it larger than all the other Galápagos Islands combined. It lies directly on the equator and stretches across both the northern and southern hemispheres. The island was formed through the merging of six large shield volcanoes — Ecuador, Wolf, Darwin, Alcedo, Sierra Negra, and Cerro Azul — whose lava flows gradually coalesced to create the island’s elongated shape.
The highest peak on the island is Wolf Volcano, reaching about 1,707 metres above sea level, while Sierra Negra is noted for having one of the largest volcanic calderas in the world. Frequent volcanic activity has kept parts of the island geologically young, with fresh lava fields still visible in several regions.
The rugged terrain includes lava tunnels, coastal cliffs, and fertile highlands, creating distinct ecological zones ranging from arid lowlands to humid uplands.

Flora and Fauna

Isabela Island is a sanctuary of biodiversity, home to many species that are endemic to the Galápagos. Its ecosystems vary from mangrove-fringed lagoons to volcanic slopes, supporting unique wildlife populations adapted to specific environments.
Characteristic species include:

• Giant tortoises, representing several distinct subspecies that evolved separately around the island’s volcanic regions.
• Marine iguanas, which are the only sea-going lizards in the world.
• Galápagos penguins, found mainly along the cooler western coast.
• Flightless cormorants, adapted to swimming and diving instead of flying.
• A variety of Darwin’s finches, flamingos, and sea lions.

Vegetation patterns correspond to altitude and moisture. Coastal areas are dominated by cacti and salt-tolerant plants, while the higher zones contain dense forests of guava, Scalesia trees, and moss-covered vegetation.

Human Settlement and Economy

The main human settlement on the island is Puerto Villamil, located on the southern coast. It serves as the administrative and tourism centre of Isabela and is home to around 1,700 to 1,800 residents.
The local economy is based on fishing, small-scale agriculture, and eco-tourism, with strict regulations in place to maintain environmental balance. Tourism provides income and employment, but it is carefully managed to prevent overexploitation of the island’s fragile habitats.

Natural Attractions and Activities

Isabela Island offers some of the most spectacular natural features in the Galápagos:

• Sierra Negra Volcano: Known for its enormous caldera and hiking trails offering panoramic views of volcanic landscapes.
• Wall of Tears (El Muro de las Lágrimas): A historical site built by prisoners during the island’s penal colony period, now a significant cultural landmark.
• Tintoreras Islets and Los Túneles: Famous for snorkelling and observing marine life, including white-tipped reef sharks, rays, sea turtles, and penguins.
• Wetlands and Lagoons near Puerto Villamil: Home to flamingos and migratory birds.

The island’s mix of geological formations and wildlife encounters makes it a preferred destination for naturalists and eco-tourists.

Conservation and Environmental Management

Given its ecological value, Isabela Island is under strict protection as part of the Galápagos National Park and the Galápagos Marine Reserve. Conservation efforts are directed at preserving endemic species, preventing habitat degradation, and controlling invasive animals such as goats, rats, and cats that threaten native fauna.
Projects to restore native vegetation, protect nesting sites, and regulate tourism have been implemented successfully. The eradication of invasive herbivores like goats and donkeys has allowed native ecosystems, particularly tortoise habitats, to recover.
Ongoing research and monitoring programmes aim to balance conservation with sustainable tourism. Environmental awareness among visitors and residents is strongly promoted to ensure the long-term survival of the island’s ecosystems.

Volcanic Activity and Scientific Importance

Isabela Island’s volcanic activity makes it a living laboratory for scientists studying plate tectonics, evolution, and ecology. The island sits on the Nazca Plate, where hotspots beneath the Earth’s crust continue to create new geological formations. Periodic eruptions, such as those of Wolf and Sierra Negra, contribute to scientific understanding of volcanic processes and island formation.
The island’s varied habitats have also been central to studies of evolutionary adaptation, a theme first explored by Charles Darwin during his visit to the Galápagos in 1835. The isolated conditions and diversity of life on Isabela offer crucial insights into natural selection and species diversification.

Climate and Environment

The climate of Isabela Island is influenced by oceanic currents, particularly the Humboldt Current, which brings cool water from the south, and the Panama Current, which introduces warmer conditions. This interplay results in two primary seasons:

• A warm and wet season from December to May, characterised by higher rainfall and lush vegetation.
• A cool and dry season from June to November, marked by the presence of mist (garúa) and cooler sea temperatures.

The western coast is typically cooler and supports marine species that prefer colder waters, while the interior highlands experience higher humidity and denser vegetation.

Challenges and Future Outlook

Despite its protected status, Isabela faces continuing environmental pressures:

• Invasive species threaten endemic wildlife and plant populations.
• Tourism growth risks ecological imbalance if not properly managed.
• Climate change poses a long-term challenge, affecting ocean temperatures, species distribution, and nesting cycles.