Red Quinine

The Red Quinine tree (Cinchona pubescens) is one of the most invasive plant species on Santa Cruz Island in Galapagos. Other islands remain free of Red Quinine. It has spread to occupy almost the entire highlands of the island, and its eradication is a high priority for the Charles Darwin Foundation (CDF).

Contents 1 Arrival in Galapagos 2 Impact on Galapagos 3 CDRS research activities 4 For the future 5 References

Arrival in Galapagos

Red Quinine (local name: Cascarilla) originated from tropical South America. Settlers introduced it to the agricultural zone in 1946, possibly for its anti-malarial qualities, or as a shade tree.

Impact on Galapagos

Dense stands of Red Quinine trees now cover approximately 12,000 hectares (30,000 acres) of land on Santa Cruz. Wind-dispersed seeds, vegetative reproduction, and shade tolerance of seedlings contribute to the rapid spread.

Vegetation in the highlands has changed from low open scrub and grasslands to a closed forest canopy up to 8 m tall. Red Quinine may also affect soil chemistry, impeding the growth of native plants.

Many endemic species are affected by the presence of Red Quinine, including:

• The endemic Cacaotillo shrub (Miconia robinsoniana) which normally grows in the highlands.
• The endemic Galapagos petrel (Pterodroma galapagensis) nests in burrows on craters in the highlands. A Red Quinine tree-dominated forest might cause changes to burrow structure or limit access for the birds to reach their nests.

CDRS research activities

Scientists at the Charles Darwin Research Station (CDRS) have been involved in studies to examine the effects of Red Quinine on the native vegetation, aspects of its reproductive biology, and its distribution.

The scientists have found that the Red Quinine seed is quite short-lived. They are optimistic that once adult seed-producing trees are killed, the soil seed bank can be exhausted rapidly.

After many trials, researchers have discovered an effective herbicide control technique for Red Quinine.

For the future

Although less than 2% of the total infested area has been controlled, the CDF and the Galapagos National Park Service (GNPS) are optimistic about the possibility of Red Quinine eradication, because:

• Red Quinine trees are easily identifiable.
• There is a 2-3 year period between germination and reproduction when the effective control measures can be used.

CDRS estimates that the total eradication of Red Quinine on Santa Cruz will take 10-15 years at an estimated cost of $6-8 million.

Whilst this undertaking is huge, the relief this will provide to the natural ecosystems of Galapagos will make the effort and expense involved worthwhile. The eradication of Red Quinine will help restore the balance in favor of the endemic flora and fauna on the highlands, preserving the beauty of this area for future generations.

References

Buddenhagen, C., and Yánez, P. 2005. The cost of quinine Cinchona pubescens control on Santa Cruz Island, Galapagos. Galapagos Research 63:32-36.

Buddenhagen, C.E., Rentería, J.L., Gardener, M., Wilkinson, S.R., Soria M., Yánez, P., Tye, A., and Valle, R. 2004. The Control of a Highly Invasive Tree Cinchona pubescens in Galápagos. Weed Technology 18:1194-1202. Weed Science Society of America, Lawrence, Kansas, USA.