CHARLES DARWIN RESEARCH STATION NEWS BULLETIN

Score two for the botanists

The CDF's botany staff recently celebrated two unusual events in conservation biology: eradication of two invasive blackberry species - Rubus adenotrichos and Rubus megalococcus - on Santa Cruz Island.

"In Galapagos, where there are no native blackberries, at least five species of this plant have been introduced over the last 40 years," said CDF's Head of Botany, Alan Tye. Blackberries are highly competitive plants, and their spiny brambles quickly alter habitats and destroy agricultural land. In Galapagos, patience, dedication, and meticulousness have cut two species off at the root.

Since 1999, CDF staff and park wardens have conducted extensive surveys on several islands to locate, remove, and monitor blackberry plants and seed banks. Although conservationists are sometimes happy to simply control invasive species, their goal this time was to completely remove all plants of these two species. Eradication is considered a good option on islands, where there is a high chance of preventing re-invasion.

To confirm eradication, data from previous field research on blackberry seed productivity and dispersal patterns was used to guide search plans. "All farms of the Santa Cruz agricultural area were surveyed during our introduced plant inventories. All known and potential invasion sites were covered by field crews in an intense, systematic search of more than 2,000 hectares conducted over several years," said Tye.

Although there is a remote chance that undiscovered R. megalococcus and R. adenotrichos plants still remain in the Santa Cruz agricultural zone, most of the island's farmers have been part of the CDF's invasive species awareness programs, which encourages farmers to identify and report any new infestations.

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Island restoration a reality

Excitement is in the air for everyone who has been involved with the Isabela Project. This ambitious project, undertaken by the Galapagos National Park Service and CDF with the goal of removing all goats from the Santiago and Isabela islands, is nearing completion in northern Isabela. The feral goats that once ran in herds of thousands, wreaking ecological havoc, are almost gone.

The ecological transformation of the landscape is already visible in the form of a rapidly rising green canopy. On Alcedo Volcano, where goats have been ecologically extinct now for nearly a year, hundreds of young Scalesia trees can be seen.

"To think of well-fed tortoises entering the next rainy season with the breeding fervour I first witnessed here in 1970 is indeed a dream come true, an example of Galapagos conservation setting new world standards," said renowned nature photographer Tui De Roy after a recent flight over northern Isabela. In 1995, De Roy's photographs documented the loss of fog-drip trees along the rim of the caldera, and in 2000 her photographs of a rolling landscape with only scattered remnant trees contrasted with earlier shots of lush thickets on the island's outer slopes.

Less than 200 goats are believed to remain on Isabela Island. Aerial and ground sweeps of Santiago Island in late 2005 detected just a single goat. Locating and removing goats was facilitated by the use of "Judas" goats, outfitted with telemetric tracking collars. These goats are released onto the islands to guide aerial and ground hunters to remnant goat populations.

When the Isabela Project ends in June, its team members will look back with satisfaction. In addition to fulfilling their mandate of eradicating goats from northern Isabela, they achieved a drastic reduction in the number of goats and donkeys in southern Isabela, and are close to eradicating goats from Santiago. These are great bonuses for conservation in the Galapagos.

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