Parc national de l'Iguazu

The declaration of the Iguazú Falls as one of the Seven Wonders of the World (2011) has been instrumental in positioning the Iguazú National Park, already a World Heritage Site since 1984, as one of the most popular tourist destinations in the world. In 2019, 1.5 million visitors entered the park. After the COVID-19 pandemics between 2020-2022, annual visitation reached again 1.5 million in 2023 and 1.3 million in 2024 (IUCN consultation, 2024). In the first half of 2025, 78,205 people visited, meaning 18.99% more than in 2024 and 7.6% more than in 2023 (7wonders, 2024, 2025). On most days, the total number of visitors is less than 5,500, allowing for a comfortable visit without waiting or crowds considering the established carrying capacity of 6,902 visitors per day (APN, 2020). However, there is an increasing trend of concentration of visitors. In 2014, the number of visitors per day exceeded 8,000 only twice, but in 2018 this happened 14 times. In this scenario, the services and visiting areas collapse, delays and waiting times are recorded in almost all activities performed by visitors. To order and improve the visitation experience in terms of quantity and quality the Iguazú National Park Public Use Management Plan (APN, 2020) was approved in 2021 and the Visitor Load Capacity was established (State Party of Argentina, 2022; IUCN consultation, 2024). Additionally, a system of viewpoints with new interpretation and educational signs and infrastructures has been established along the unpaved section of National Route 101 to decompress the waterfall area (IUCN consultation, 2024).

The Iguazú National Park Management Plan reports 123 non-native plants species including 13 invasive plant species (6 woody and 7 herbaceous), as well as 3 exotic fish species identified in the upper Iguazú river (Coptodon rendalli, Geophagus brasiliensis, Oreochromis niloticus) and one in the lower Iguazú (Clarias gariepinus). Since 2010 they are carrying out control and monitoring activities. The Iguazú National Park Management Plan includes exotic species control activities (APN, 2018). The International Hotel installed inside the visitors area is considered the original focus of irradiation for many of the exotic species (State Party of Argentina, 2022). After a strong initial control phase, the hotel continues exotic vegetation control.

Tourism infrastructure has led to the disruption of natural aesthetic values. For visitors, the most prominent and direct impacts of infrastructure on the visual integrity of the falls are: the Sheraton Iguazú Hotel, the old unused trails to the Garganta del Diablo (Argentina) and the Porto Canoas restaurant and souvenir shop at the edge of the falls, and the Naipi souvenir shop and elevator from the edge of the canyon to the elevated walkways to the Santa María falls and the Hotel das Cataratas (Brazil) (IUCN and UNESCO, 2008). Visitor facilities and trails have also had an impact on the vegetation and wildlife of the waterfall area, which has the greatest biodiversity and the highest number of endemic species.
Increased visitation also led to the habituation of wildlife and associated human-wildlife conflicts. Habituation is mainly caused by tourists feeding wild animals e.g. Capuchin monkeys and coatis. Between 2020 and 2022, enclosure structures continued to be installed in visitation areas. Positive results in dissuading feeding of wild animals have also been obtained through the ongoing program “Your food kills me” (“Tu comida me mata”) (State Party of Argentina, 2022, 2023).

The Itaipu dam (Brazil and Paraguay) on the Parana River and the four Brazilian dams on the Iguazú River have significantly altered the flow of water that feeds the falls, and the flora and fauna of the river, although the details are not known. The fact that much of the river downstream of the dams flows through protected areas contributes significantly to mitigating potential negative impacts (IUCN and UNESCO, 2008; World Heritage Committee, 2010; World Heritage Committee, 2012; UNESCO, 2012). The Baixo Iguaçú hydroelectric plant (Brazil), located on the Iguazú River 70 km upstream from the falls and 500 m from the boundary of the Iguazú National Park, is fully operational (State Party of Brazil, 2019). A group of NGOs identified 53 potential environmental impacts, of which 45 would be negative and 29 irreversible (APN, 2018). The World Heritage Committee recommended that a comprehensive monitoring system of aquatic fauna and water flows be established to monitor the implementation of the requirements and action plans developed for the hydroelectric project and to evaluate their effectiveness in mitigating potential negative impacts on the Outstanding Universal Value of the Iguazu National Park and Iguaçu National Park in Brazil (UNESCO, 2018). No comprehensive overall monitoring system both for aquatic fauna and water flow was developed in cooperation with the Brazilian authorities, however punctual collaborative activities are carried out (State Party of Argentina, 2022). Joint surveillance and control efforts along both sides of the Iguazú River are being successfully carried out, involving national security forces from Brazil and Argentina, as well as Argentina’s national and Misiones province park rangers. A long-term monitoring and research project has been performed since 2019 from the Argentinian side, aiming to study the Iguazú River’s ecosystems, fish communities, and water quality over a 12-year period. In addition, collaborative activities are supporting the research and monitoring of the local jaguar population, which inhabits both sides of the international border. This transboundary cooperation is further strengthened through active participation in COMPARNI, the advisory commission for the Brazilian national park (State Party of Argentina, 2022). Additionally, there is fluent communication on water information between Argentinian and Brazilian management authorities: Brazilian electricity production and dam administration (COPEL), as well as Itaipú Dam authorities inform both countries on potential upstream decisions (IUCN consultation, 2024).

On the unpaved section of the RN 101 road, birds of the Caprimulgidae family are the most affected, and there is also significant intentional run-overs of ungulates for local consumption (APN, 2018). On the paved sections of the RN 1010 and RN 12, speeding causes road-kill of a wide variety of animals, from jaguars to raptors, including both diurnal and nocturnal species, generally run over by passenger vehicles (APN, 2018). Since the last report, new wildlife crossings have been added, vehicle surveillance radars have been installed where approved by federal authorities, and road checks have been improved (State Party of Argentina, 2022; IUCN consultation, 2024).

The Iguazú National Park Management Plan reports an increase in rainfall and temperatures especially during spring and winter, as well as extraordinary floods and droughts. Sensitive species such as amphibians will be affected and changes in the forest composition and physiognomy are expected (APN, 2018). Moreover, a study conducted in Iguazú National Park shows that climate change, particularly increased rainfall linked to El Niño events, has a severe negative impact on the local yacaré population, a key aquatic predator in the ecosystem (Herrera, 2014).
Exceptional floods happened in 2022-2023. In September 2023 flooding destroyed part of the trails catwalks limiting the public access to some main cascades (i.e. Garganta del Diablo). The access has been restored in May 2024 (IUCN consultation, 2024). The National Meteorological Service (SMN) confirmed that the severe floods during the September-October-November 2023 period were caused by El Niño, with its impacts intensified by climate change. Moreover, there is an opportunity to initiate adaptation efforts in the National Park by aligning with the 2023 Provincial Action Plan for Health and Climate Change, particularly its seventh objective, which encourages collaboration with other agencies for implementing such measures (Ministry of Public Health of the Province of Misiones, 2023). Currently, there is a need to develop specific adaptation strategies within the National Park and to strengthen monitoring efforts to better understand and address the cumulative effects of climate change and upstream dams, which together pose increasing risks to the park’s aquatic ecosystems and biodiversity.

Hunting for commercial and recreational purposes continues to be an important threat. Hunting of predatory species (eagles, vipers and carnivores) is also lead by local fears, traditions and to avoid threats to farm animals. Insects trapping (arthropods and butterflies) is carried out for sale. The Iguazú National Park Management Plan includes programs and projects to cut down hunting inside the Park and its surroundings (APN, 2018). Under the ”Proyecto Yaguareté”, a camera trap monitoring system and scientific activities are performed to monitor the jaguar and its preys’ populations as well as hunting activities (State Party of Argentina, 2023).

Fishing takes place mainly in the Iguazú River and its tributaries. The fishing methods vary according to the section of the river. Some of the most fished species are dorado, pacú, surubí (Pseudoplatystoma sp.) and manguruyú (Zungaro zungaro), and in the upper river the moncholo (Steindachneridion melanodermatum), an endemic species of high conservation value (APN, 2018). Monitoring and surveillance of poaching and illegal fishing activities continues. Furthermore, a new SMART surveillance system has been installed in order to improve the threats mapping and field data collection tool, and consequently field surveillance (State Party of Argentina, 2022, 2023; IUCN consultation, 2024).

Commercial species (orchids and ferns, among others), medicinal plants and other species used for crafts are extracted mostly by local people. Extractions were carried out outside Iguazú National Park, overexploitation led to an increasing extraction within the park, especially in the areas close to Puerto Iguazú (APN, 2018). Extraction of palmitos (Euterpe edulies) for local consumption and for sale occurred in the past (APN, 2018), however, since the closure of the local Palmito canning factory, the palm extraction has decreased, but not totally disappeared (IUCN consultation, 2024; State Party of Argentina, 2022).

When seen at a regional scale, there is an area on the eastern boundary of the Park called the “Argentine Peninsula Bottleneck” that is a barrier to genetic flows between the Brazilian and Argentinean National Parks. In the last decades this area has been settled by colonists who have continued over the years to deforest the area for agricultural development and the rearing of livestock. Projects that seek to slow the rate of deforestation have only had marginal success (IUCN and UNESCO, 2008; World Heritage Committee, 2010; World Heritage Committee, 2012; UNESCO, 2012).
To improve the connection between the Argentinian and the Brazilian parks around the “Argentine Peninsula Bottleneck” several measures have been taken: A new park headquarters was built in the center of the city of Andresito, on the eastern edge; the Alto Iguazú Reserve was established at a key point seeking to maintain and improve tree cover in the center of the Andresito Peninsula (Decreto 537/2019; APN, 2018, 2022b).

Water-borne pollutants from agriculture and silviculture in the surroundings of the site include nutrients, toxic chemicals and sediments (APN, 2018). There is limited published information on specific pollutants and their potential impacts on the site’s ecological values. A 2009 study identified major threats to the watershed, including anthropogenic alterations to river flow and a potential salinization process (Gómez, 2009). Moreover, upstream deforestation leads to changes in the water’s physical and chemical properties, altering its transparency after rainfall due to soil runoff (Casciotta, 2016). Rivers from neighbouring municipalities in both Argentina and Brazil are polluted with untreated or partially treated domestic and industrial wastewater, including sewage and grey water from tourism facilities, which flow into the Iguazú River basin and impact its water quality (APN, 2018). There have also been recent reports from local residents since 2024 about untreated wastewater being discharged directly into the river (Voz de las Cataratas, 2024). The combination of inadequate effluent treatment, the high density of dams, and the spread of invasive species highlights the need to better understand cumulative impacts on water quality and to develop transboundary management plans to mitigate harm to the site’s ecological values.