Scientists uncover surprising payoff from invasive pest removal efforts: 'Delivering significant returns'

New research from the University of Hawaiʻi shows that watershed conservation efforts to protect Kauaʻi from invasive species have significantly increased groundwater supplies, helping to ensure water security on the island.

The study analyzed the impact of conservation fence units in Kauaʻi, which were constructed to protect watersheds from invasive plants and animals, such as feral pigs and deer. By analyzing existing and potential fenced areas over a 50-year span, researchers found that these conservation efforts led to "significant returns in groundwater recharge."

Groundwater recharge is the process of water from rain, rivers, or other sources soaking into the ground and replenishing underground aquifers. This water is then used to supply fresh water to local communities. The U.S. Department of the Interior reports that groundwater provides 99% of Hawaiʻi's drinking water and about 50% of all freshwater used in the state.

The study found that every dollar invested in conservation fence units resulted in an average of 593 gallons of recharged groundwater. In some naturally protected regions like Wainiha and Nāmolokama, the return was even higher at up to 2,625 gallons per dollar. Mid-elevation areas were identified as providing the highest groundwater recharge benefits per dollar, as these regions are particularly vulnerable to invasive species.

The researchers proposed that expanding fenced areas through increased conservation efforts could increase total groundwater recharge from 21.4 billion to 34.4 billion gallons over the next 50 years, though the average return per dollar would slightly decrease.

"The findings indicate that existing conservation efforts have been strategically implemented in high-impact areas, delivering significant returns in terms of groundwater recharge," the report said. "Expanding these efforts would further enhance water security for the island."

Watch now: Giant snails invading New York City?

Watershed conservation plays a key role in maintaining both the quality and quantity of freshwater resources by improving groundwater recharge and reducing runoff. According to the study, healthy watersheds also help prevent soil erosion, reduce flood risks, and support biodiversity. These efforts, in turn, benefit local communities by ensuring a more reliable clean water supply for drinking, agriculture, and other essential uses.

Should we be actively working to kill invasive species?

Absolutely 💯