Table 1 Land cover description of the four sampling areas on San Cristóbal Island, Galapagos, surveyed during the study

Urban area

Three sampling points in green urban areas of the town of Puerto Baquerizo Moreno, lowlands of San Cristobal Island.

The coastal town of Puerto Baquerizo Moreno covers an area of 7.5 km² surrounded by deciduous forests that are within the Galapagos National Park. Most of the town’s nearly 7000 inhabitants reside in a concentrated urban area of 1.53 km² [54]. Urban green areas are situated adjacent to residential neighbourhoods, often along the town borders, and feature a combination of native and non-native xeric scrub vegetation.

Agricultural area

Two sampling points in silvopasture areas in the highlands of San Cristobal Island.

The agricultural area is in the humid highlands of the island. Our sampling sites were in a silvopasture landscape [28, 29] covered by cultivated grasses for cattle, predominantly Brachiaria or Paspalum, interspersed with Citrus and Psidium guajava trees. These points were located a few kilometres away from the border of the national park.

Deciduous forest

Three sampling points at the localities of Playa Carola, La Lobería and Playa Ochoa, lowlands of San Cristobal Island.

These sampling points were in the arid zone of the island, where deciduous scrub and forest grow on lava soils [28, 29]. The vegetation was dominated by native species, such as Vachellia spp., Bursera graveolens, Piscidia carthagenensis, Croton scouleri, and Opuntia spp. These three points were in touristic beach trails, two close to the town of Puerto Baquerizo Moreno, Playa Carola and Playa Loberia, and a more distant and less touristic beach, Playa Ochoa.

Seasonal evergreen forest

Two sampling points in forested remnants on the highlands of San Cristobal Island.

These sampling points were in the humid zone of the island, where cloud-forest-type vegetation grows in small patches preserved by the national park [28, 29]. The habitat includes native species such as Volkameria mollis, Cordia lutea, Chiococca alba, Psidium galapageium and Tournefortia spp., usually within a matrix with non-native species.