History of invasive species in Hawaii

Timeline of Invasive Species over time

Before Western contact (Pre-1778)

Before Western contact, Hawai‘i’s ecosystems developed in isolation, resulting in highly specialized native plants and animals.

While early Polynesian settlers introduced a limited number of species, land management systems such as ahupuaʻa helped maintain ecological balance.

Large-scale ecosystem disruption had not yet occurred.

​

Western Contact, The Start of Ecological Disruption (Late 1700s–1800s)

The arrival of Europeans in 1778 marked a major turning point.

Ships unintentionally introduced rats, insects, weeds, and mosquitoes, many of which spread rapidly due to the lack of natural predators.

Rats preyed on native birds and eggs, while mosquitoes later became carriers of avian diseases that native birds had no immunity against.

This period represents the beginning of Hawai‘i’s invasive species crisis.

​

Plantation Agriculture & Land Transformation (1800s–Early 1900s)

During the plantation era, invasive species introductions increased dramatically.

Large-scale agriculture required clearing native forests and importing crops, labor, and animals from around the world.

Invasive plants such as strawberry guava, introduced in the early 1800s, spread aggressively and displaced native forests.

These changes weakened watersheds, altered water flow, and reduced biodiversity impacting both ecosystems and Hawaiian communities connected to the land.

​

Globalization & Modern Introductions (Mid-1900s–2000s)

As Hawai‘i became more connected through global trade, tourism, and military transport, new invasive species continued to arrive.

Pests such as little fire ants, coqui frogs, and coconut rhinoceros beetles were introduced through cargo shipments and imported plants.

Hawai‘i’s dependence on imports made prevention increasingly difficult, allowing invasive species to spread across multiple islands.

​

Present Day — Current Local Impact in Hawai‘i

• Environmental Impact

  • Invasive plants like strawberry guava dominate over native species. Invasive animals, including rats and mosquitoes, continue to push native bird species toward extinction. These species deteriorate the ecosystem​

• Cultural Impact

  • Invasive pests such as the coconut rhinoceros beetle threaten coconut and native palm trees, which has great cultural significance in Hawaiian traditions, food systems, and ceremonies. The loss of these species threatens Hawaiian culture and traditional practices.

• Economic & Human Health Impact

  • Little fire ants interfere with farming, and impair residential areas. Invasive species also threaten agriculture and tourism by damaging landscapes and increasing management costs.