Galápagos waters are naturally acidified and nutrient-rich due to upwelling from deep ocean currents (Manzello, 2010). Anthropogenic increases in environmental carbon dioxide will lead to ocean acidification throughout the tropics in the following decades (Manzello et al., 2014). Corals are particularly susceptible to acidification, with impacts on skeletal density (Mollica et al., 2018), growth, and diversity (Thompson et al., 2022). Manzello et al. (2014) observed that corals struggled to recover from stressful events in the face of acidified and nutrient-dense waters. In addition, corals show limited ability to adapt to acidification over time (Thompson et al., 2022). Galápagos waters thus provide a model for studying the effects of global warming, eutrophication, and ocean acidification on coral reefs (Manzello et al., 2014). The GNPD has established an underwater coral nursery to facilitate monitoring of coral health and contribute to coral restoration efforts on islands affected by coral loss. Ocean acidification also has impacts on fish (Chung et al., 2014), marine microbial communities (Guevara, 2015), invertebrates (Chan et al., 2011) and phytoplankton (Litchendorf, 2006).

Galápagos mangroves are estimated to store over 778,000 tons of inorganic carbon (Tanner et al., 2019). This carbon can be utilized to buffer coastal waters, thus mitigating ocean acidification (Sippo et al., 2016). Mangrove deforestation has been estimated at 1-2% per year; if this trend continues, mangrove forests may disappear within the century (Alongi, 2002). While mangroves can withstand increased humidity and rainfall, they are predicted to decline in areas where climate change results in a more arid environment (Alongi, 2015).

Fishing is a major contributor to the Galápagos economic landscape. Fisheries can be broadly classified as benthic or demersal-pelagic (Castrejón, 2011). Benthic invertebrates include sea cucumbers (pepino del mar) and spiny lobsters (langosta espinosa), which generate a large proportion of revenue, as well as species that are typically incidental catches, such as slipper lobsters (langostino) (Scyllarides astori), chitons (canchalangua) (Chiton goodallii and Chiton sulcatus), octopus (pulpo) (Octopus oculifer), and snails (churo) (Hexaples princeps and Pleuroploca princeps) (Castrejón, 2011). Demersal-pelagic fish include approximately 68 species; important members have been outlined by Castrejón (2011). Of the demersal fish, the sailfin grouper (bacalao) is the primary fishing target; other important members include other species of grouper (Epinephelus spp.), ocean whitefish (blanquillo) (Caulolatilus princeps), and the endemic white-spotted sand bass (camotillo) (Paralabrax albomaculatus). Coastal pelagic fish include the wahoo (Acanthocybium solandri), Thoburn’s mullet (Mugil thoburni), and the endemic Galápagos mullet (M. galapagensis). Deep sea fishing operations typically target large pelagic fish, such as yellow tuna (Thunnus albacares), Bigeye tuna (Thunnus obesus), swordfish (Xiphias gladius), and mahi-mahi (Coryphaena hippurus) (Castrejón, 2011).

In many cases, the fishing industry continues to be at-odds with conservation efforts, and overexploitation of marine resources represents a significant pressure on wildlife populations in the region. Illegal, unreported, and unregulated (IUU) fishing is a major threat to marine ecosystems, food security, and economic stability worldwide. Despite the efforts of local authorities, residents, and conservationists, the illegal wildlife trade still persists in the region (Galápagos Conservancy, 2021; Frazier, 2021). Illegal fishing is a major threat to endemic Galápagos species, perpetrated by international commercial fleets, illegal sportfishing operations, and even local fisheries. Illegal fishing includes poaching of protected species or fishing of commercial species in violation of regulations on fishing season, quotas, or life stage. Schiller et al. (2013) reported that between 1994 and 1999, 3,000 tons of sea cucumbers (Isostichopus fuscus) were caught illegally in Galápagos waters. In 2017, thousands of dead sharks were intercepted by the Ecuadorian Navy and Galápagos National Park (Bale, 2017). Unregulated fishing refers to fishing of stocks that are not covered under explicit regulations or when occurring by foreign vessels in areas managed by a regional fisheries management organization (RFMO), an international consortium of countries that collaboratively manages fishing stocks. In 2023, to mitigate IUU fishing, multinational cooperation via the United Nations produced measures for the preservation of biodiversity in waters outside of national borders, such as much of the ocean surrounding the Galápagos Islands, and development of procedures for the boarding and inspection of vessels in the South Pacific Ocean (United Nations General Assembly, 2023; South Pacific Regional Fisheries Management Organisation, 2023).

While the preservation of aquatic biodiversity confers long-term economic benefits, these are largely overlooked by poachers in the interest of short-term profits. For example, the northern Islands of Darwin and Wolf are home to the largest reef fish biomass ever recorded, comprised primarily of sharks (Salinas-de-León et al., 2016). The tourism value of a single live shark throughout its lifetime in the Galápagos Islands has been estimated at 5.4 million USD (Lynham et al., 2015). Nevertheless, poaching and bycatch pressure are ongoing and significant threats to marine life in the GMR. From 2001-2007, Ecuadorian authorities seized 29 sharks caught within the GMR (Carr et al., 2013). In addition, commercial fishing ships still often operate at GMR boundaries, waiting for whale sharks (Rhincodon typus) and scalloped hammerhead sharks (Sphyrna lewini) to exit protected areas (Alava and Paladines, 2017; United Nations, 1982).

We define overfishing as legal fishing activities that are still ultimately unsustainable, impacting the resilience and biodiversity of marine ecosystems. These impacts have been documented in many Galápagos species, including sailfin grouper (Usseglio et al., 2016), brown sea cucumbers (Wolff et al., 2012; Ramírez-González et al., 2020), spiny lobsters (Szuwalski et al., 2016), and slipper lobsters (Hearn, 2006; Castrejón, 2011). Prior to 1998, less than 1% of Galápagos waters were protected from fishing. The 1990s saw a rapid rise in artisanal fishing, coinciding with growth of the sea cucumber fishery and expansion of tourism, both stimulating immigration from mainland Ecuador (González et al., 2008; Castrejón and Charles, 2013; Bremner and Perez, 2002). Over 5 million sea cucumbers were harvested over a 3-month timespan in 1994 (Bremner and Perez, 2002). The consequent increase in pressure on marine resources led to accelerated ecosystem degradation. In response, the Special Law for Galápagos was established in 1998, designating 133,000 square-kilometers of marine, coastal, and inland waters as the GMR and prohibiting industrial fishing, while still allowing artisanal and theoretically “small-scale” fishing.

To regulate fisheries, the GMR Management Plan (GMRMP) was implemented in 1999. The GMRMP was designed as an ecosystem-based spatial management (EBSM) plan (Castrejón and Charles, 2013), which accounts for the effects of fishing on the entire marine habitat, including both target and off-target species, and the impacts of other anthropogenic activities such as tourism, marine transport, and energy use (Castrejón and Charles, 2013). EBSM strategies have been effective at promoting ecosystem resiliency and economic sustainability in other regions, such as the Great Barrier Reef (Day, 2008). However, EBSM in the GMRMP faced several challenges, which will be discussed in Section 2.4.5.

Although densities of chitons have declined in coastal fishing areas and a legal minimum harvest size has been proposed (Herrera et al., 2003), there are currently no regulations on the seasonality or capture size for chitons, octopus, or snails (Castrejón, 2011; Riofrío-Lazo et al., 2021). Further research on the impacts of fishing on these less studied benthic invertebrates is warranted.

By implementing more stringent limits on fishing, we can expect to increase commercial stocks, protect marine ecosystems by reducing trophic cascades and habitat degradation, and decrease pollution and carbon emissions from fishing vessels (Sumaila and Tai, 2020). In addition, an increase in fish biomass would increase blue carbon sequestration within marine life (Sumaila and Tai, 2020). A collaborative approach to fisheries management is necessary to effect lasting change in Galápagos waters (Castrejón et al., 2013; Usseglio et al., 2016). Appropriately balancing participatory management from local stakeholders with top-down reform, however, is challenging.

In a recent study, computational modeling was used to evaluate the impact of fishing on ecosystem stability in the southeastern GMR, and concluded that overall, current fishing practices are sustainable and that ecosystem is resilient (Riofrío-Lazo et al., 2021). In that study, the authors also noted that ecosystem balance was promoted by marine mammals, sharks, and certain birds and fish, including the sailfin grouper, suggesting that this latter fish of commercial interest may merit more protection as an ecosystem stabilizer. While these findings are encouraging, the authors acknowledge the inherent limitations of modeling a system using incomplete data on illegal fishing and bycatch (Riofrío-Lazo et al., 2021). Continued reassessment of both target and non-target species in commercial fisheries is necessary to ensure that fisheries management plans in the GMR operate sustainably, particularly while the ecosystem remains under threat from other concurrent marine pressures, such as illegal fishing, marine pollution, and climate change.

Contamination with plastics, persistent organic pollutants, and heavy metals are concerns stemming from anthropogenic activities and disturbances. In several studies, beach plastics were most abundant on the windward eastern coasts of the Galápagos Islands (Jones et al., 2021; Muñoz-Pérez et al., 2023), although Galápagos beaches had lower levels of plastic debris than Ecuador beaches (Mestanza et al., 2019). Plastic pollution affects the ecophysiology and health of a wide variety of species (Alava et al., 2023). Through citizen science efforts, Muñoz-Pérez et al. (2023) reported plastics pollution in 52 animal species on the Galápagos Islands, including mammals, birds, reptiles, fish, and invertebrates. Macroplastic contamination of the environment can lead to morbidity and mortality in wildlife via ingestion, leading to impaction, gastrointestinal disease, or starvation, or entanglement with subsequent constricting injuries or drowning (Muñoz-Pérez et al., 2023). These impacts have been documented with particularly high risk in green sea turtles (Chelonia mydas), marine iguanas (Amblyrhynchus cristatus), giant tortoises (Chelonoidis spp.), Galápagos sea lions, medium-billed ground finches (Geospiza fortis), whale sharks (Rhincodon typus), spine-tailed mobulas (Mobula japonica), and black-striped salemas (Xenocys jessiae) (Muñoz-Pérez et al., 2023).

Plastic pieces less than 5 mm in diameter are considered microplastics. Microplastics originate from the breakdown of beach litter, synthetic clothing, plastic films from packaging, and microbeads from toothpastes and body washes. Microplastics have been identified in multiple Galápagos beach sites (Jones et al., 2021) and were ubiquitous in seawater (Alfaro-Núñez et al., 2021). Microplastics have also been identified in invertebrates (Jones et al., 2021) and hundreds of marine organisms commonly consumed by humans (Alfaro-Núñez et al., 2021), as well as Galápagos penguin guano (McMullen, 2023). Microplastics can result in intestinal impaction in birds (Carlin et al., 2020; Wang et al., 2021) and alter gut microbial composition (Fackelmann et al., 2023). Microplastics also absorb polycyclic aromatic hydrocarbons (PAHs), thus facilitating their ingestion and bioaccumulation (Rochman, 2015). Microplastics and marine debris at turtle nesting sites may result in obstruction, toxin exposure, and affect temperatures of nesting sites, a determining factor for sex in some species (Beckwith and Fuentes, 2018; Garrison and Fuentes, 2019). Microplastics also have the potential to promote biofilm formation and select for different populations of microorganisms (Qiang et al., 2021), posing a risk to the balance of aquatic and coastal ecosystems and potentially serving as an avenue for pathogen acquisition. In the interest of combatting plastics pollution, the Galápagos Special Regime Government Council (Consejo de Gobierno de Régimen Especial de Galápagos – CGREG) enacted Resolution 05-CGREG-2015 in 2018 to restrict the consumption of single-use plastics in the archipelago (CGREG, 2015, CGREG, 2018). Nonetheless, many products can still serve as sources of microplastics pollution.

The use of Galápagos waterways for fuel and oil transportation also confers a risk for wildlife. In 2001, the oil tanker Jessica ran aground on a reef at San Cristóbal Island (Sanderson et al., 2001). The resulting spill of nearly 800,000 gallons of oil led to a 62% mortality in marine iguanas over the following year (Wikelski et al., 2002). For seabirds, oil results in feather matting and loss of waterproofing, resulting in hypothermia and impairing buoyancy. Sea lions are similarly at risk, with conjunctivitis, burns, and death documented in association with exposure to oil (Salazar, 2003). Inhalation of oil particles also results in respiratory distress and can lead to long-term effects such as diminished reproductive success. Smaller spills were recorded in 2019 on San Cristóbal Island (UNESCO, 2019) and 2022 on Santa Cruz Island (Meyer, 2022); in both cases, rapid cleanup measures occurred in collaboration with authorities, conservationists, and volunteers, with the GNPD ultimately reporting no lasting effects from these two incidents.

Accumulation of heavy metals also poses a threat to human and animal health. Classically, heavy metals accumulate within biological systems and reach higher concentrations among species at the top of the food chain. Franco-Fuentes et al. (2021) documented high concentrations of heavy metals in demersal and pelagic fish in the Galápagos Islands. Lead levels in Galápagos birds vary by species and are higher than those in birds from other oceanic islands (Jiménez et al., 2020). The main natural sources of heavy metals are volcanic activity and the erosion of rock formations (Tchounwou et al., 2012). Upwelling currents can also affect heavy metal accumulation (Franco-Fuentes et al., 2021; Jiménez et al., 2020). El Niño events can also cause nutritional stress and increases vulnerability to pollutants (Alava et al., 2023). No clear association between human activities and heavy metal concentrations in Galápagos birds has been determined (Jiménez et al., 2020; Jiménez-Uzcátegui et al., 2017). However, Dinter et al. (2021) reported high levels of cadmium, cobalt, chromium, copper, nickel, and zinc in agricultural topsoil in the Galápagos, most likely due to agrochemical use (Dinter et al., 2021), which could lead to environmental contamination and runoff. Other potential anthropogenic sources of heavy metals include the use of lead shot or fishing line sinkers; byproducts of coal-burning plants and gas combustion; and corrosion of water or sewage pipes (Tchounwou et al., 2012). Runoff from metal foundries, mines, refineries, and chemical plants are significant contributors in other regions, (Tchounwou et al., 2012), but are less likely play a role in the Galápagos Islands.

A variety of human activities can result in accidental traumatic injury to wildlife. In the marine environment, bycatch, fishing gear entanglement or ingestion, and propeller injuries and other vessel strikes may occur (García-Parra and Tapia, 2014). Macroplastic ingestion or entanglement is also a major concern, as discussed in Section 2.4.3.

Galápagos waters are traversed by a variety of vessels, including commercial and small-scale fishing boats, ferries between islands, tour boats, and dive boats. Vessel collisions with marine mammals and fish are a major concern worldwide, with the potential to cause trauma or death to the animal, injury to passengers, and damage to the boat itself (Schoeman et al., 2020). Boat strikes are a documented risk to sea turtles in the GMR, affecting both nesting and foraging sites (Denkinger et al., 2013). Fast boat speeds increase the risk of collision and incidence of mortality in sea turtles, therefore speed limits and “go-slow zones” and area closures have been suggested as key management points (Denkinger et al., 2013; Fuentes et al., 2021). Boat propeller injuries have also been documented in Galápagos sea lions (Denkinger et al., 2015), a social species that frequents coastal areas and beaches of inhabited islands. Vessel collisions also affect whale sharks, who frequent shallower waters and whose movements frequently overlap with large vessel traffic (Womersley et al., 2022). The Galápagos Islands are an important waypoint for seasonal migration of pregnant female whale sharks (Hearn et al., 2016); injury to these individuals thus has further downstream population impacts.

Marine zoning in the GMR was meant to allow sustainable economic activities in designated areas while maintaining protected regions for the recovery and preservation of threatened species, thus decreasing conflict and competition between different sectors (Review: Castrejón and Charles, 2013; Galápagos National Park Directorate, 1998; Edgar et al., 2008). Deep waters were designated as “multiple use zones,” for fishing, tourism, and other GNP-approved activities, while “limited use zones” near coastal areas were subdivided for conservation, tourism, and fishing (Review: Castrejón and Charles, 2013). The GMRMP resulted in an increase in large grouper, white-spotted sand bass, and Galápagos grunts (Orthopristis forbesi) in no-take zones compared to fishing areas (Banks, 2007). Nonetheless, Pontón-Cevallos et al. (2020) predicted that establishment of additional no-take zones and protection of grouper nurseries in mangroves would still be necessary to prevent population collapse of this species.

Ultimately, the success of the GMRMP zoning strategy was hindered by several factors. The co-management strategy was intended to promote local stakeholders advocacy and participation (Castrejón and Charles, 2013; Edgar et al., 2004). However, special interest lobbying during the delineation of no-take zones resulted in de facto prioritization of economic activities over environmental interests (Castrejón and Charles, 2013). For instance, sea cucumber fishermen advocated for no-take zones in areas with already low sea cucumber density, while tour guides lobbied to continue operating in areas with large populations of endangered sharks (Edgar et al., 2004). Between 2000-2001, sea cucumber density was three-fold higher in fishing areas and shark density was five-fold higher in tourist areas, compared to corresponding no-take zones (Edgar et al., 2004).

In addition, because the GMR is spatially heterogeneous with regards to population density and species composition, implementation of a total allowable catch (TAC) quota may be ineffective at preventing overexploitation (Castrejón and Charles, 2013). For example, sea cucumber reproduction requires high population density, thus depletion of one high-density area has higher population-level impacts compared to collecting from multiple less dense regions, even if total numbers fall within TAC quotas. Seasonal fishing limitations, therefore, may provide benefits over TAC for certain species (Castrejón and Charles, 2013). In the past three decades, several periods of quota-regulated sea cucumber fishing have alternated with harvest moratoriums, attempting to satisfy the fishing industry while mitigating population-level impacts (Bremner and Perez, 2002; Ramírez-González et al., 2020). Nonetheless, current strategies appear to be insufficient at preventing sea cucumber overexploitation (Ramírez-González et al., 2020).

Education of local stakeholders is key to achieving buy-in and adherence to regulations, including reporting of observed illegal activities by fishermen in the field. Artisanal fishermen hold most of the fishing permits for the GMR, and thus should be key targets for education. For instance, fishermen seeking rapid economic benefits of harvesting sea cucumbers from high-density areas may initially disagree with zoning regulations, but increased education could lead to recognition that short-term gains may imperil the entire industry and ultimately threaten long-term economic sustainability. In addition, fishermen that buy into fishing regulations may be more likely to report observations of illegal activities.

While GMRMP zones were approved in 2000, it took another six years for physical demarcation of boundaries, further complicating enforcement and adherence to no-take zones (Castrejón and Charles, 2013) and boundaries have yet to be clearly demarcated by the Global Positioning System (GPS). Similarly, in 2004, the Eastern Tropical Pacific Marine Corridor (CMAR) was established as a protected region between Costa Rica, Panama, Colombia, and Ecuador (Enright et al., 2021). This corridor is home to many endemic species and serves as a migratory route for rays, sea turtles, sharks, and whales. However, as of 2021, the exact geographic boundaries of the CMAR had yet to be delineated (Enright et al., 2021). These disconnects between protected area designation and implementation hinder both application and enforcement.

Castrejón and Charles (2013) detailed recommendations for improvements to the zoning strategy for the GMRMP, including integrating input of local stakeholders, regional and federal authorities, and independent experts; considering the enforcement capabilities of local institutions on no-take zones; and incorporating economic incentives, restrictions on fishing gear, and seasonal fishing quotas. Moreover, a monitoring plan is essential to re-assess and revise management strategies. In 2014, the GNPD began a re-zoning project, which included a period for input from local stakeholders (Viteri et al., 2020). However, in 2016, a presidential decree designated a subset of the GMR around Darwin and Wolf islands as a marine sanctuary, off-limits to all fishing activities. This unilateral decision was seen by some to undermine the prior two years of re-zoning negotiations (Viteri et al., 2020). In 2022, another presidential decree further expanded the GMR by 60,000 square kilometers, creating the Hermandad Marine Reserve (HMR) – a wildlife migratory corridor across Ecuadorian, Costa Rican, Panamanian, and Colombian waters that prohibits all extractive activities (Galápagos Conservation Trust, 2022). White et al. (2023) documented an 88% decrease in fishing within the HMR within the year following its implementation. However, it remains to be determined whether the GMR can be appropriate patrolled to enforce these protections long term. These zones of protection are indicated in Figure 2 .

Climate change and industrial fishing remain key threats to the marine environment. The challenges faced in enforcement of the GMRMP should serve as lessons towards future development plans for the CMAR and HMR. Appropriate management of fisheries has the potential to reduce illegal fishing and bycatch of protected species. Regulation of tourism in the GMR and implementation of go-slow zones or protected ocean corridors would also reduce propeller injuries and marine pollution. There continues to be a disconnect between federal and regional authorities with regards to a co-management versus top-down approach for protected areas. Sufficient personnel, regulatory oversight from local authorities, appropriate penalties for infractions, and local stakeholder buy-in are all required for boundaries drawn on paper to have practical and long-lasting positive impacts for marine protection.

Land areas outside of the GNP are designated for human use as either urban or rural zones. The rural zone includes 250.5 square kilometers of land, 76% of which are agricultural production units (APUs) on Santa Cruz (47%), San Cristóbal (34%), Isabela (17%) and Floreana (2%) Islands. APU composition includes pastures (58%), non-invasive forests (22%), invasive vegetation cover (5%), permanent crops (8%), fallow land (4%), and transient crops (1%). Geenhouses, sheds, and corrals comprise another 2%. The remaining 24% of the rural zone is non-agricultural, including forests, areas taken over by introduced species, or residential areas (CGREG, 2016).

Agricultural land is inevitably subject to changes in vegetation composition and density, with downstream ecosystem impacts. Land bird diversity in the Santa Cruz Island agricultural zone (SCIAZ) was significantly lower in pastures compared to forests, although forest patches and corridors ameliorated the negative impacts of farmland (Geladi et al., 2021). The SCIAZ is surrounded entirely by protected areas and intersects with giant tortoise migratory routes, providing a setting for potential human-wildlife interactions or conflict (Benitez-Capistros et al., 2018). Pike et al. (2022a) found that over two-thirds of tortoises spend a mean of 150 days in the SCIAZ before returning to the GNP. Farmers that reported tortoise-associated damage to crops or property were also more likely to report implementing fencing and/or taking physical actions against tortoises (such as harassing, displacing, or upending) (Benitez-Capistros et al., 2018). Various strategies have been suggested to mitigate human-wildlife conflict, extrapolated from cases in other regions (Benitez-Capistros et al., 2019). Providing farmers with economic compensation to account for damage caused by wildlife can inadvertently promote expansion of agricultural areas and livestock grazing with negative downstream ecosystem effects (Benitez-Capistros et al., 2019). Strategies to reduce crop and property damage, such as creation of wildlife corridors that maintain habitat connectivity, may be more viable long-term solutions (Benitez-Capistros et al., 2019). Regardless, communication and cooperation between various stakeholders is critical to develop viable long-term solutions.

Pike et al. (2022a) documented that tortoise density on Santa Cruz Island was lowest in abandoned farmland and highest in tourist areas. Agricultural land abandonment, leading to uncontrolled proliferation of invasive plants, is a major challenge for terrestrial ecosystems and neighboring farms (Benitez-Capistros et al., 2014; Watson et al., 2010). 84% of Galápagos farmers that reported abandoning their property did so due to invasive species impacting production (Brewington, 2011). Abundant ground cover, short vegetation, few shrubs, and presence of ponds were all positively correlated with giant tortoise presence. These habitat features could be utilized to support tortoise conservation on farms, or to create preferred corridors that circumvent farmland to mitigate crop destruction (Pike et al., 2022a, Pike et al., 2022b). Interestingly, tortoises preferred pasture over native vegetation, and most fences in the studied areas did not significantly limit tortoise movement (Pike et al., 2022c); these findings are not necessarily intuitive, highlighting the importance of research to inform conservation recommendations.

Development of the agricultural and livestock sector is complex and controversial, as it requires changes in land use. This sector faces various obstacles, including scarce or unreliable water resources, ineffective irrigation, stony soils, and lack of labor. From the perspective of sustainable development, increasing local food production would promote food security while reducing impacts associated with imports, such as introduced species and fuel use. However, agriculture can negatively impact ecosystem health through unsustainable land/water use, monoculture cultivation, environmental pollution, land abandonment, and run-off. Since the ecosystem is the main attraction and capital of the archipelago, natural resource preservation is essential from both economic and conservation standpoints. Agroproductive development would thus require a participatory approach in management with integration of multisectoral viewpoints and long-term planning to balance these concerns (Khatun, 2018). Development also relies on external economic factors (Burbano et al., 2022). Among Galápagos farmers, a shortage of hired help was a major concern, with most immigrants more interested in the tourism sector (O’Connor, 2014; Brewington, 2011; Lu et al., 2013). Economic diversification to avoid excessive dependence on tourism would thus also benefit agroproductive development. Restoration actions following ecosystem deterioration require investments hundreds of times larger than those for protection (Khatun, 2018), highlighting the importance of prospectively balancing agroproductive and conservation interests before implementing developmental plans.

Organic pesticides used to prevent crop destruction by invertebrates or invasive plants can improve agroproduction, but also result in environmental pollution, off-target killing of endemic pollinators, and neurologic, carcinogenic, or endocrine impacts on vertebrates. 100% of surveyed highland farmers on Santa Cruz Island reported concern over invasive species, and 67% reported using pesticides (O’Connor, 2014). The majority (85%) sold crops primarily to local markets. Higher rates of pesticide use were associated with education below the secondary level, as well as with larger property size, regardless of education level (O’Connor, 2014).

Although Dichlorodiphenyltrichloroethane (DDT) and other World Health Organization (WHO)-designated Class IA and IB pesticides have been prohibited in the Galápagos Islands since 2010, their use may have continued due to illegal import or use of residual stocks (O’Connor, 2014). Most farmers purchase pesticides from local shops, with only 7.5% using imported products. Ecuador’s Agriculture Quality Assurance Agency (La Agencia de Regulación y Control Fito y Zoosanitario (AGROCALIDAD)) monitors vendors to enforce regulations on chemical use, but some shops still carry prohibited pesticides and medications. Farmers have also been documented to inquire about prohibited pesticides at shops, presumably due to past positive experiences (O’Connor, 2014).

The residues of sixteen pesticides, including three persistent organic pollutants (POPs), were detected in coastal waters bordering urban areas of Santa Cruz and Isabela Island (Riascos-Flores et al., 2021). POPs such as DDT have also been identified in Galápagos sea lion pups, increasing over time and reaching clinically significant concentrations, indicating that relay toxicosis and biological accumulation are relevant outcomes of pesticide use in this region (Alava and Gobas, 2012; Alava and Ross, 2018; Alava et al., 2011). Due to persistent use of DDT worldwide, it is possible that atmospheric and oceanic currents lead to DDT residues in the Galápagos Islands, although to the authors’ knowledge, no studies have evaluated this possibility. Galápagos seabirds have been found to have lower levels of POPs in uropygial gland secretions compared to birds from other areas; upwelling waters may decrease local POP concentrations in seabirds foraging areas (Yamashita et al., 2021).

Addressing the overuse of pesticides is a complex challenge that requires creative approaches. Historically low-income regions that undergo rapid economic growth lack management or regulatory infrastructure to mitigate accelerated habitat degradation associated with rapid increases in pesticide use, as in a case study in Thailand (Praneetvatakul et al., 2013). Prior work has suggested that conservation education leads to more environmentally conscious decision-making among farmers (Glynn et al., 1995; Napier et al., 1986; Lynne et al., 1988). It is crucial to enhance education for farmers on the importance of identifying and avoiding prohibited pesticides, increase access to biologically sustainable products, and provide training on sustainable farming techniques to demonstrate that farmers can improve production and combat invasive species without the use of illegal products. O’Connor-Robinson et al. (2018) additionally suggested that farmers could be incentivized to participate in organic farming through a “participatory guarantee system,” in which farms with an organic certification can access specific markets. However, with the exception of coffee, most Galápagos agricultural products lack large export markets (O’Connor, 2014); therefore, incentivizing organic production would most likely require targeting tourism markets, further centralizing economic interests. Development of local infrastructure to address waste and runoff is also necessary as a complementary approach to limiting the impact of POPs.

Historical exploitation of giant tortoises by whalers and mariners led to precipitous population decline. Poaching of wildlife for meat, trophies, traditional medicine, and sale at wet markets unfortunately remain major problems for Galápagos wildlife, particularly for long-lived and slowly reproducing species such as giant tortoises (Márquez et al., 2007). From 1995 to 2004, field personnel on Isabela and San Cristóbal Islands recorded observations of 190 giant tortoise carcasses (Márquez et al., 2007), presumably killed for meat.

Due to the ongoing threat of poaching and wildlife trafficking, the GNPD started a program in 2014 aimed at identifying trafficking networks (Auliya et al., 2016). Unfortunately, identifying and sentencing wildlife smugglers still poses a significant challenge, and poaching continues to occur. On Isabela Island, 4 giant tortoises were killed in 2021 and another 15 were killed in 2022 (Galápagos Conservancy, 2022). In March 2021, 185 live juvenile giant tortoises were recovered from traffickers attempting to transport them in suitcases out of Baltra Airport (Jones, 2021). Iguanas have also been targets of smuggling (Auliya et al., 2016; Gentile et al., 2013). On June 25, 2022, the Ecuadorian Navy seized two vessels carrying 5 live golden land iguanas and 84 juvenile San Cristóbal giant tortoises (State Attorney General’s Office, 2022). Because of the high demand for these species in Europe, Asia, and the United States, the black market prices of golden land iguanas is up to 20,000 USD (State Attorney General’s Office, 2022) while giant tortoise juveniles and adults can garner 5,000 USD and 60,000 USD, respectively (Pacífico Libre, 2021).

In addition, even when traffickers intend to keep wildlife alive for sale, morbidity and mortality still occur (State Attorney General’s Office, 2022) and animals recovered from poachers may not survive to be released. Furthermore, marine iguanas and giant tortoises have genetically distinct subspecies based on their island of origin, and thus live animals recovered from poachers must also be returned to the correct location. Genetic repositories are crucial in enabling wildlife forensic scientists to determine the origins of animals reclaimed from traffickers (Quinzin et al., 2023; Auliya et al., 2016).

Trauma is also key cause of wildlife mortality in the Galápagos Islands and can occur due to interactions between endemic wildlife and domestic animals or invasive species, or secondary to human activities (Kruuk and Snell, 1981; Gottdenker et al., 2008). Populations of endemic rodents in the Galápagos Islands were decimated following introduction of the invasive black rat (Rattus rattus), brown rat (R. norvegicus), and house mouse (Mus musculus) (Dowler et al., 2000). Rodent predation of eggs and chicks is a documented driver of population decline in the endangered Galápagos petrel (Pterodroma phaeopygia) (Cruz and Cruz, 1987a, Cruz and Cruz, 1987b; Riofrío-Lazo and Páez-Rosas, 2015). Domestic cats have a major impact on wildlife worldwide, with predation directly affecting population mass and fecundity, and resource competition and disease transmission posing further threats (Medina et al., 2013; Trouwborst et al., 2020). In the Galápagos Islands, cats have been documented to consume lava lizards, iguanas, and birds (Carrión and Valle, 2018). Similarly, populations of giant tortoises, land iguanas, Galápagos sea lion, Galápagos fur seal, and several bird species have been negatively impacted by nest predation from domestic dogs (Barnett and Rudd, 1983; Kruuk and Snell, 1981). The giant tortoise is particularly vulnerable to the effects of nest predation due to their small clutch sizes.

Accidental vehicular trauma has been reported to affect land iguanas (García-Parra and Tapia, 2014), giant tortoises (García-Parra and Tapia, 2014), lava lizards (Microlophus spp.) (Tanner and Perry, 2007; Medrano-Vizcaíno et al., 2023), and birds (Medrano-Vizcaíno et al., 2023; García-Carrasco et al., 2020) in the Galápagos Islands. Tanner and Perry (2007) analyzed the incidence of dead lava lizards on roads on Santa Cruz Island and found that vehicular trauma disproportionately affected juvenile and adult male lizards. Further, they documented a higher proportion of fatalities in proximity to a particular long, straight road, where speeding was common, and recommended that barriers and underpasses should be considered as a management strategy.

In addition, intentional injuries can be caused by humans during human-wildlife conflict (García-Parra and Tapia, 2014). In 2008, 53 Galápagos sea lion carcasses were found on Pinta Island with skull trauma (Soto, 2008). Denkinger et al. (2015) observed injured and dead sea lions at Wreck Bay on San Cristóbal Island, and reported that 5% of sea lion deaths and 65% of non-lethal injuries were human-caused. Of human-caused injuries, 43% were due to lacerations or blows, 40% to entanglement in plastic or debris, 14% to propeller injuries, and 8% to fishing gear. Causes of human-wildlife conflict are complex and multifactorial, including unintentional injuries as wildlife interact with manmade constructs, such as fences; intentional illegal harvest of animal parts (such as turtle shells, shark fins, or sea lion penises) for sale on the black market; and perception of wildlife as a nuisance due to their interaction with farmland or livestock. Injuries that result from these interactions may be difficult to identify, particularly if they do not lead to death; in addition, active human-wildlife conflict may not be observed, particularly in remote areas. Mitigation of these conflicts thus requires determining and addressing the underlying cause of the conflict, as discussed throughout this review.

From 2011 to 2012, the monthly average income of a Galápagos resident was $1,901 USD, while the monthly expenditure was $1,522 USD (National Institute of Statistics and Census (INEC), 2017). For comparison, the average monthly family income of an Ecuadorian household was $735.47 in 2019 and $746.67 in 2021 (Macías et al., 2022). The higher average income in the Galápagos Islands is somewhat offset by a higher basic cost of living; the “Basic Food Basket” is 80% more expensive in the archipelago compared to the mainland (National Institute of Statistics and Census (INEC), 2017). Because Galápagos food production is not self-sustaining, there is still heavy reliance on imported products. As of 2016, 4,000-5,000 tons of goods per month were imported from mainland Ecuador, including 38% of fresh fruits and vegetables and most dry food products, bringing the total proportion of imported supplies close to 70-75% (Viteri and Vergara, 2017; Pizzitutti et al., 2016; Sampedro et al., 2020). With rising demand for consumer goods, imports are likely to increase, necessitating corresponding expansion of ports (Pizzitutti et al., 2016). Without changes in food policy, Sampedro et al. (2020) predicted that imports would increase to 95% by 2037. In 2014, the profit margin of intermediaries in the Galápagos Islands was estimated to reach 30%, further contributing to the high cost of living (Llive-Cóndor, 2017). Reliance on imported products therefore influences economic resilience and contributes to ecosystem deterioration, given the relationship between cargo shipping, invasive species, and fossil fuel use.

Tourism is the most rapidly growing industry in the Galápagos Islands, encompassing an estimated 51% of the economic landscape in 2007 (Watkins and Cruz, 2007) and 80% as of 2016 (Pizzitutti et al., 2016). The Central Bank of Ecuador estimated that tourism is responsible for 64% of gross value added (Galaípagos Government Council, 2021). Nonetheless, prior studies have estimated that only 7.6-15.5% of revenue generated from tourism directly reaches Galápagos residents, with most revenue absorbed by companies based on mainland Ecuador (de Miras, 1995; Taylor et al., 2009; Watkins and Cruz, 2007). However, Taylor et al. (2003) highlighted the importance of considering not only the direct effects of tourist expenditures, such as revenue generated by hotels, eateries, and travel agencies, but also the indirect effects of tourism. For instance, tourism stimulates production from the fishing, agriculture, livestock, forestry, and drinking water industries, although these sectors do not typically sell products directly to tourists but rather to intermediaries (Taylor et al., 2003). The increased demand for production from these sectors translates to increased income for residents (Taylor et al., 2003). The widening wage gap between the Galápagos Islands and mainland Ecuador could further increase the attractiveness of migration to the archipelago (Taylor et al., 2003).

Addressing deficits in the Galápagos educational system was a key goal cited by UNESCO in 2007 and factored into the decision to include the Galápagos Islands in the List of World Heritage in Danger (UNESCO, 2007). UNESCO called for training and assessment of students and teachers, curriculum reform to incorporate environmental management, and improved vocational training and funding to empower residents to meet local professional needs. Fifteen years later, the Galápagos public education system is still lacking in several areas, including curricular deficiencies, inadequate facilities and infrastructure, poor access to print and digital resources, and outdated teaching practices that favor rote memorization rather than active learning. Cotner and Moore (2018) documented that biology teachers lack expertise to adequately teach the core principles of Darwinian evolution. In addition, many Galápagos residents lack sufficient understanding of sustainable practices necessary for natural resource stewardship. Improvement in the quality of primary and secondary education would increase conservation awareness in the next generation (Jones, 2013). In addition, increased bilingual education and improvement in special needs programs is necessary. Access to education for all Galápagos residents remains one of the key goals of the 2023 Vision. In January of 2023, the Galápagos Conservancy’s Education for Sustainability Program, a collaborative effort with international, national, and regional stakeholders, made headway towards a new curriculum for Galápagos students that incorporates principles of environmental sustainability.

The public school system also lacks information access due to a deficit of public libraries and limited internet connectivity. The COVID-19 pandemic further highlighted issues in education access, with 33% of students having insufficient internet connectivity to attend virtual classes (Galaípagos Government Council, 2021). The CDF initiated a traveling library program in 2019 to deliver books to schools, naturalist guides, and GNP employees (Charles Darwin Foundation, 2023, Charles Darwin Foundation, 2020). Until 2022, satellite internet connectivity was expensive and slow, with limited utility for education (Urquizo et al., 2019). High-speed internet was implemented in 2022, but is not yet available in all sites. In 2019, Urquizo et al. (2019) developed a community intranet system to increase local connectivity between schools on San Cristóbal Island (Urquizo et al., 2019). In addition, the CDF hosts a digital platform for information access, Galapagueana, that provides access to a subset of library archives. However, many older scientific publications of regional research are still only accessible in print, hindering access to the wider scientific community.

Educational opportunities for Galápagos residents must also be developed. Professional training, particularly in vocations focused on the environment, science, and research, would better equip residents to meet the needs of industries in the archipelago, allowing more economic revenue to be conserved locally. In addition, continuing education (CE) programs should be encouraged for residents with tourist-facing professions. For example, in a survey of GNP naturalist guides, most accepted the concept of evolution but expressed interest in learning more (Cotner et al., 2017). Because tourists visiting protected areas must be accompanied by a guide, guides can disseminate knowledge to tourists, encouraging conservation-minded decisions and compliance with regulations. In addition, guides are an important source of monitoring of tourist activity.

Access to clean and affordable energy is crucial for sustainability development and is linked to many other areas of human development (WHO, 2022). The Energy Balance of the Province of Galápagos, prepared by the Geological and Energy Research Institute (IIGE), provides an overview of energy use and production. As of 2018, approximately 90% of energy consumed in the Galápagos Islands was imported, primarily as petroleum derivatives (IIGE, 2018). The archipelago is thus still heavily reliant on fossil fuel consumption. In 2018, the transportation sector was responsible for 84% of energy consumption overall, including 99% of diesel and 100% of gasoline (IIGE, 2018). The remaining energy consumption was divided between residential (8%), public service (5%), construction (3%), and industry (<1%) uses (IIGE, 2018). The residential sector was responsible for the greatest consumption of liquid gas (82%) (IIGE, 2018). Of the 160,900 tons of greenhouse gas emissions produced in the Galápagos Islands in 2018, diesel was responsible for 74% and gasoline for 22% (IIGE, 2018).

In 2022, according to the Agency for the Regulation and Control of Non-Renewable Energy and Natural Resources (ARC), more than 13,000 clients were registered with the Gálapagos electric company (Agency for the Regulation and Control of Non-Renewable Energy and Natural Resources (ARC), 2022), representing nearly 99.7% coverage of the public network (National Institute of Statistics and Census (INEC), 2015). Santa Cruz Island utilizes 60.7% of the electrical energy supply, followed by San Cristóbal (30%), Isabela (8.7%), and Floreana (0.6%) (IIGE, 2018). The public sector (43%) and residential sector (39%) account for most of the electric use (IIGE, 2018).

Pizzitutti et al. (2016) predicted that to meet rising demand for energy due to population growth and increased use of air conditioning, electrical appliances, and personal electronic devices, installation of more diesel-powered generators and importation of fossil fuels will likely occur. As previously highlighted in this review, the risk of marine pollution due to fuel and oil spillage is a major risk to the region. Research on the replacement of fossil fuels is thus a high priority for the region.

Of the energy produced locally, 84% is of thermal origin, 12% wind, and 4% solar (IIGE, 2018). There are currently two wind turbine plants in the Galápagos Islands, and solar panel installation is increasing (Pizzitutti et al., 2016). From 2013 to 2018, solar energy production steadily increased, accounting for approximately 30% of primary energy produced in in 2018 (IIGE, 2018). However, neither wind nor solar are yet viable alternatives to diesel in terms of fully meeting energy needs (Pizzitutti et al., 2016). Without implementation of new renewable energy resources, the proportion of clean energy in the archipelago may drop to only 5% of total energy by 2033 (Pizzitutti et al., 2016).

Llerena-Pizarro et al. (2019) proposed a hybrid solar/biogas energy generation system, with the goal of improving energy efficiency, diversifying the energy matrix and promoting sustainable local development. Based on a computer model, Arévalo et al. (2022) proposed that the archipelago had the potential to fully convert to renewable energy systems by 2031, through a combination of photovoltaic, wind, hydroelectric, and battery systems, with diesel utilized solely for backup generators. Further research into these alternative energy systems is crucial.

A major milestone of sustainable development outlined by the WHO is water availability and its sustainable management, which implies safe drinking water, water resource development, wastewater management, and protection of aquatic biological resources (WHO, 2022). Poor water quality is a threat to public health, associated with respiratory and gastrointestinal disease (Liu and d’Ozouville, 2011), and poses barriers to agriculture, economic sustainability, and aquatic ecosystem health. Human and animal water and waste management are inextricably intertwined; mismanagement of sewage or failure to appropriately treat drinking water contributes to infectious disease outbreaks across species boundaries.

The municipal water and irrigation supply in the main urban areas of the Galápagos Islands are provided primarily via aquifers, cisterns, or rooftop tanks (Mateus et al., 2020, Mateus et al., 2019). Aquifers contain primarily brackish water derived from seawater invasion. A desalinization plant has been present on Isabela Island since 2014, but does not function optimally. There are two drinking water plants on San Cristóbal Island. Municipal water on Santa Cruz Island is primarily untreated brackish water, considered non-potable by national and international standards (Reyes et al., 2015). Gerhard et al. (2017) reported that 90% of point-of-use water access sites on Santa Cruz Island had high levels of microbial contamination. In a survey of 453 households on Santa Cruz Island, 0% of respondents reported drinking water directly from the tap, while 13.1% of households treated tap water before consumption, and 90.1% purchased carboys of drinking water (Vásquez et al., 2021). In some cases, residents use cisterns or roof tanks to store treated drinking water (Grube et al., 2020). Overall, potable water supplies are derived predominantly from bottled water (Reyes et al., 2015; Houck, 2017). However, municipal water is commonly used for household washing and food preparation, resulting in exposure to fecal coliforms and development of waterborne gastrointestinal illnesses (Houck, 2017).

An official report on wastewater management in the archipelago states that the three municipalities utilize public sewerage systems (National Institute of Statistics and Census (INEC), 2017). However, Mateus et al. (2020) reported that on Santa Cruz Island, 97.2% of households use septic tanks, and just 1.9% utilize public sewerage. Thus, in practice, there is virtually no functional sewerage network. So far, evidence suggests that inefficient budget management inhibits the development of sanitary systems and implies a lack of transparency, misallocation of funding, disregard of research data, and lack of prioritization, coordination, and local participation (Mateus et al., 2020). Insufficient and ineffective wastewater treatment plants contribute to poor water quality and groundwater contamination, which can then flow into coastal waters.

Human activities are responsible for contamination of both ground and coastal water in the Galápagos Islands (Liu and d’Ozouville, 2011; Walsh et al., 2010; Overbey et al., 2015; Mateus et al., 2019), with malfunctioning septic tanks implicated as a major contributor (Liu and d’Ozouville, 2011). Fecal contamination of coastal areas led to regulations on recreational activities (Stumpf et al., 2013). Population growth also contributes to water contamination, as the basal aquifer on Santa Cruz Island is located beneath dense urban areas (López and Rueda, 2010). Interestingly, population changes were more strongly correlated with changes in water quality at coastal than inland sites (Mateus et al., 2019). Coastal waters are additionally contaminated by fuel from marine vessels (Walsh et al., 2010).

There have been multiple documented breaches in sanitation with regards to livestock management – particularly swine and poultry – posing risks to human and wildlife populations, including infectious diseases and antimicrobial resistance (AMR). At the national level, the Organic Health Law prohibits the use of rivers, canals, lagoons, lakes, seas, and other natural aquatic sites for discharge of sewage or wastewater produced from animal husbandry or agricultural activities, without proper treatment (Secretariat of Water (SENAGUA) and Agency for Water Regulation and Control (ARCA), 2016). While the Santa Cruz municipality treats effluents from food processing, manufacturing plants, and a hotel using artificial wetland systems, these actions are not generalized to all sources of wastewater, and waste-water treatment plants (WWTPs) have limitations (Liu and d’Ozouville, 2011). Animal waste consisting of manure or viscera is sometimes directly discharged from farms, leading to soil and groundwater contamination (Chiriboga et al., 2006). New data from Ecuador’s National Agricultural Register (Registro Nacional Agropecuario (RENAGRO)) indicates that 45.2% of animal waste is untreated and 47.4% is used as fertilizer, while agricultural residues are mostly incorporated into the soil (57.5%) (Ministry of Agriculture and Livestock, 2022). While there are mandatory biosecurity protocols for livestock farms, their implementation is minor (Puente-Rodríguez et al., 2019). Pathogen introduction via imported feed is also a potential threat, although this has not been definitively documented in the region. The Management Framework for the Program about Climate Change in Galápagos determined that safeguards/investments should be established for environmental problems related to livestock waste, agroprocessing plants, and the coffee industry (Development Bank for Latin America and the Caribbean, 2022). Adequate sanitary conditions and disease prevention go hand in hand with both ecosystem and economic sustainability (Chiriboga et al., 2006).

Several efforts to improve water quality in the Galápagos Islands have been implemented in the last decade. Drinking water treatment plants were associated with a significant decrease in coliform contamination on San Cristóbal Island compared to pre-treatment levels; however, coliforms were still identified in 66% of points of use (Gerhard et al., 2017). In that study, researchers found that E. coli contamination of drinking water did not appear to be associated with human waste contamination, but was likely linked to environmental sources (Gerhard et al., 2017). In 2021, fog catchers were installed on Isabela Island as part of the “Harvesting Water” project, with the goal of establishing a fresh water supply and contributing to sustainable agriculture (Charles Darwin Foundation, 2021). Filtration technologies have been implemented to re-use treated wastewater (Galápagos Conservation Trust, 2021). Groasis Waterboxx^®, a water-saving technology, has been implemented on several islands to augment irrigation practices for growth of several crops (Jaramillo Díaz et al., 2022).