Alien species pathways to the Galapagos Islands, Ecuador

Abstract

Alien species, one of the biggest threats to natural ecosystems worldwide, are of particular concern for oceanic archipelagos such as Galápagos. To enable more effective management of alien species, we reviewed, collated and analysed all available records of alien species for Galápagos. We also assembled a comprehensive dataset on pathways to and among the Galápagos Islands, including tourist and resident numbers, tourist vessels, their itineraries and visitation sites, aircraft capacity and occupancy, air and sea cargo and biosecurity interceptions. So far, 1,579 alien terrestrial and marine species have been introduced to Galápagos by humans. Of these, 1,476 have become established. Almost half of these were intentional introductions, mostly of plants. Most unintentional introductions arrived on plants and plant associated material, followed by transport vehicles, and commodities (in particular fruit and vegetables). The number, frequency and geographic origin of pathways for the arrival and dispersal of alien species to and within Galápagos have increased over time, tracking closely the increase in human population (residents and tourists) on the islands. Intentional introductions of alien species should decline as biosecurity is strengthened but there is a danger that unintentional introductions will increase further as tourism on Galápagos expands. This unique world heritage site will only retain its biodiversity values if the pathways for invasion are managed effectively.

Corrigendum to: A collaboratively derived environmental research agenda for Galápagos

“…Tourism in Galápagos grew at an annual rate of 9% between 1995 and 2011 (Pizzitutti et al 2014). This increase has led to growth in local resident populations and cargo imports (Causton et al 2008;Toral-Granda et al 2017).While tourism generates some financial support for conservation, there is evidence that high levels are responsible for deleterious impacts on species and ecosystems (Burger and Gochfeld 1993;Romero and Wikelski 2002). It is difficult to disentangle the specific (and cumulative) impacts of different types of tourist visits (e.g.…”

“…At visitor sites on uninhabited islands the direct impacts of increased numbers of tourists and residents have been fairly well managed by the Directorate of the Galápagos National Park, but indirect impacts in the inhabited portions of the archipelago have been much more pronounced. Increased numbers of tourists and residents has resulted in a rapid growth in physical infrastructure (not always subjected to adequate environmental assessment), ever-increasing demands for public services, and a continuous growth of the risk of alien species introductions Brandt 2015, 2017;Toral-Granda et al 2017). It is generally agreed that, to reduce environmental impacts and risks, improvements in tourist management are required, along with a reduction in the dependence on labour and fresh food coming from the mainland.…”

“…As permanent and temporary resident populations and tourist numbers have increased, the amount of food required has surpassed the capacity of local farms. There is heavy reliance on goods transported on cargo ships from the mainland, which cause problems such as boats running aground, oil spills and introductions of alien species (Toral-Granda et al 2017). Agricultural productivity on the islands is limited by a lack of workers, alien invasive species and challenging climate.…”

“…Although important steps have been taken to manage the issue of alien species in Galápagos, the number of possible pathways to the islands for new arrivals is still high and continues to increase (Toral-Granda et al 2017). This is mainly due to the growing number of tourists (Viteri-Mejía and Brandt 2017) and the ever-increasing number of goods and services arriving on the islands (Toral-Granda et al 2017).…”

“…As with many other island systems, Galápagos faces many serious environmental challenges including invasive species (Causton et al 2006;Trueman et al 2010;Toral-Granda et al 2017), managing El Niño-Southern Oscillation variability and long-term climate change, tourism (Viteri-Mejía and Brandt 2015), overfishing (Hearn 2008;Toral-Granda 2008), and land-use changes (Trueman et al 2014).…”