Santa Cruz: "Media Luna", "Los Gemelos",
"El Chato", "Zona de Pampa", and the road
to Baltra.

For more information contact with:
Carlos Carvajal, +593 (0)5 252 6189 Ext. 229, ccarvajal@spng.org.ec



Approximately 32% of the flora on Santa Cruz is introduced.

Santa Cruz is the most populated and most visited island in the Galapagos, which makes it the island invaded by the widest variety of introduced plants. The Directorate of the Galapagos National Park works tirelessly to keep them under control, an arduous and expensive job.

	NATIVE AND ENDEMIC FLORA OF THE GALAPAGOS » View presentation:

Like all inhabited islands, Santa Cruz is invaded by plants near agricultural areas.

The island has all the botanical zones found on the Galapagos: coastal, arid, transition, the Scalesia spp. and Miconia spp. areas, and the plains (pampas) area.

The danger of introduced plants.

It is presumed that the introduction of exotic species, mainly plants, began with the arrival of humans in the Galapagos in the seventeenth century, but the greatest introduction occurred in the early nineteenth century, with human colonization of the Islands.

Introduced plants are one of the greatest dangers to the flora of the Galapagos, as many of them are highly invasive, competing with native and endemic plants for light, water, and nutrition.

WORST INVASIVE PLANTS IN GALÁPAGOS* Blackberry (Rubus, 5 varieties) Guava (Psidium guajava) Cascarilla o Quinina (Cinchona pubescens) Cedrela (Cedrela odorata) Supirosa (Lantana camara) Sauco (Cestrum auriculatum) Maracuyá (Passiflo) Pomarosa (Syzygium jambos) Hoja del aire (Bryophyllum pinnatum) Pasto elefante (Pennisetum purpureum) Laurel (Cordia alliodora) Cabuya (Furcraea hexapetala) Sauco macho (Citharexylum gentryi-Verbenaceae) Tulipán africano (Sphatodea campanulata) Zaragoza (Aristolochia odoratisima) Higuerilla (Ricinus communis) Poleo (Hyptis pectinata) Saboya (Panicum maximum) Floripondio (Datura y Brugmansia spp) * Marked in bold, invasive plants of Santa Cruz

It is estimated that there are about 700 introduced plants, 50 of which are highly invasive.

Santa Cruz has a high number of exotic plants. The most aggressive ones are the blackberry (Rubus niveus), Cedrela (Cedrela odorata), elephant grass (Pennisetum purpureum), and "cascarilla" (Cinchona succirubra). Exotic species have good dispersal mechanisms and invade the forests of native species.

The Miconia robinsoniana forest, communities of native Adiantum spp. ferns and Cyathea Weatherbyana tree ferns are invaded by "cascarilla" and elephant grass ("pasto elefante") in the highest parts of the island, such as "Media Luna" and "Cerro Crocker"
(Crocker Hill).

In the lower areas, these plants introduced in the 1950s now cover about 10,000 hectares and have invaded the Scalesia pedunculata area near "Los Gemelos". 

	CONTROL OF INVASIVE PLANTS » View presentation:

These plants change biodiversity, competing with native species such as the "cafetillo" and several species of Lycopodium spp. creeping plants, and displace animal species like the Galapagos rail and the vermillion flycatcher.

In the "El Chato" area, cedrela, introduced in 1950 to be used as timber, proved to be very aggressive and now covers 1,200 hectares in the National Park area and 800 hectares in the farming area. Farm owners continue growing this species, because it is one of the most important timber species in the Galapagos Islands. 

However, cedrela has a higher growth rate than the native species Scalesia pedunculata and guayabillo. It also prevents the growth of Clerodendrum molle ("rodilla de caballo"), Chiococca alba ("espuela de gallo"), Thournefortia pubescens, and Zanthoxilium fagara (uña de gato). Because of the shade and the resin it produces, cedrela trees do not allow coexistence with native species.

	ECOSYSTEM RESTORATION Ecosystems where invasive plants are controlled recover quickly, which is also seen with the return of birds such as the vermillion flycatcher or the Galapagos rail (pictured), a bird endemic to the Galapagos.

The same occurred with other purposely introduced species. Initially these plants were beneficial for humans, because they could obtain fruit such as guava and citrus trees such as passion fruit. Today they are a pest, reducing the agricultural area and requiring a substantial investment for their control.

Elephant grass serves as foliage, but blackberries (Rubus niveus) make the site inaccessible to livestock. On Santa Cruz this species has already covered over 2,500 acres in the high areas.

"Sauco" (Cestrum auriculatum), besides being an invasive plant became a threat to livestock, which can be poisoned by eating its fruit and leaves that are highly toxic.

Results of the control of invasive plants

To protect Miconia spp. and native fern communities, the Directorate of the Galapagos National Park performs the control of invasive plants in specific parts of Santa Cruz, like the Miconia spp. area in "Media Luna" and the pampas zone on Crocker Hill.

Areas infested with "cascarilla", guava, elephant grass, and Saboya (panicum maximum) were controlled.

An area of 180 hectares of blackberries was controlled with the foliar spray technique using Round Up.

After controlling "cascarilla" (a total of 310 hectares on the island) and other species such as guava, elephant grass, and "higuerilla", the natural regeneration of native Miconia spp. and ferns can be observed.

In the Los Gemelos craters, areas infested with blackberries, "cascarilla", passion fruit, "sauco", elephant grass, and "higuerilla" were controlled. After the control of invasive species, the Directorate of the Galapagos National Park has a reforestation program ready for Scalesia pedunculata in this area. Until late 2008, a 13-hectare area was reforested.

In the El Chato area, where the giant tortoise reserve is located, areas infested with cedrela, elephant grass, passion fruit, blackberry, and guava are controlled.

On the road to "Canal de Itabaca" efforts are carried out to control several hectares infested by a range of introduced species, including "supirosa" (lantana), elephant grass, "higuerilla", cedrela, "cascarilla", "sauco", kalanchoe (Bryophyllum pinnatum), and species of limited distribution (Hyptis pectinata and Leucaena leucocephala (Fabaceae).

Eradication of introduced species of limited distribution

It involves preventive control of introduced species that may be invasive in protected and agricultural areas according to the experience on other islands, like Hawaii.

In areas of absolute protection (see the Zoning of the Galapagos) several species were controlled, such as "sauco macho" (Citharexylum gentry - Verbenaceae), Floripondio datura, and Brugmansia spp., various Solanaceae (tamarillo, "naranjilla"), the african tulip tree (Sphatodea campanulata - Bignoniaceae), "poleo" (Hyptis pectinata), various Lamiaceae and "zaragoza" (Aristolochia odoratissima).

In the agricultural zone of Santa Cruz several species such as Andean raspberry (Rubus glaucus), "sauco macho", and "zaragoza" were monitored at several sites totaling approximately 25 hectares.