History of Land Cover Change on Santa Cruz Island, Galapagos

Abstract

Islands are particularly vulnerable to the effects of land cover change due to their limited size and remoteness. This study analyzes vegetation cover change in the agricultural area of Santa Cruz (Galapagos Archipelago) between 1961 and 2018. To reconstruct multitemporal land cover change from existing land cover products, a multisource data integration procedure was followed to reduce imprecision and inconsistencies that may result from the comparison of heterogeneous datasets. The conversion of native forests and grasslands into agricultural land was the principal land cover change in the non-protected area. In 1961, about 94% of the non-protected area was still covered by native vegetation, whereas this had decreased to only 7% in 2018. Most of the agricultural expansion took place in the 1960s and 1970s, and it created an anthropogenic landscape where 67% of the area is covered by agricultural land and 26% by invasive species. Early clearance of native vegetation took place in the more accessible—less rugged—areas with deeper-than-average and well-drained soils. The first wave of settlement consisted of large and isolated farmsteads, with 19% of the farms being larger than 100 ha and specializing in diary and meat production. Over the period of 1961–1987, the number of farms doubled from less than 100 to more than 200, while the average farm size decreased from 90 to 60 ha/farmstead. Due to labor constraints in the agricultural sector, these farms opted for less labor-intensive activities such as livestock farming. New farms (popping up in the 1990s and 2000s) are generally small in size, with <5 ha per farmstead, and settled in areas with less favorable biophysical conditions and lower accessibility to markets. From the 1990s onwards, the surge of alternative income opportunities in the tourism and travel-related sector reduced pressure on the natural resources in the non-protected area.

Habitat restoration to conserve the Little Vermilion Flycatcher Pyrocephalus nanus on Santa Cruz Island, Galapagos

“…In the Galapagos Islands, declines of insectivorous birds are becoming more common (Dvorak et al 2012(Dvorak et al , 2017(Dvorak et al , 2020. The original habitat of landbirds on several islands in the Galapagos has changed dramatically since colonisation by humans (Alomía et al 2022;Geladi et al 2022;Lundh 2006;Watson et al 2010), altering food sources and adding further pressure on many vulnerable species.…”

“…Small population sizes favour the mating of genetically close individuals, leading to inbreeding and increased hatching failure (Kruuk et al 2002), which could add more stress to this population. Santa Cruz has the largest human population in the Galapagos and large areas of native forest have been cleared for agriculture (Alomía et al 2022; Benitez-Capistros et al 2014; Espinoza De Janon 2013, Geladi et al 2022). The remaining LVF population in Santa Cruz has taken refuge in the forest in the humid zone (550–720 m a.s.l.)…”

Potential model of Scalesia pedunculata carbon sequestration through restoration efforts in agricultural fields of Galapagos

“…Historically, the original vegetation formations in the highland areas have been prone to more pressure to transform them into arable soils to sustain this growth [ 8 ]. Land in the agricultural zone of Santa Cruz for example, has increased over 67% since 1961, with a rampant increase in the 1960s and 1970s [ 9 ]. This replacement meant the reduction of the native forests and grasslands from 94% cover, to only 7% in 2018 in the non-protected areas [ 9 ].…”

“…Land in the agricultural zone of Santa Cruz for example, has increased over 67% since 1961, with a rampant increase in the 1960s and 1970s [ 9 ]. This replacement meant the reduction of the native forests and grasslands from 94% cover, to only 7% in 2018 in the non-protected areas [ 9 ].…”