Isole Eolie (Aeolian Islands)

Fishing is mostly small-scale and artisanal, however, some illegal practices are being implemented by using fishing aggregating devices (FAD). These devices are a threat to cetaceans and sea turtles, which are often caught in them as well as in fishing nets and hooks (Blasi and Mattei, 2017; Leone et al., 2019; Sechi et al., 2023). During the last years, the cases of cetaceans killed by illegal nets in the Aeolian sea have increased. Two sperm whales (Physeter microcephalus) were found trapped in these nets only during July 2020 (IUCN Consultation, 2020a; Sea Shepherd Global, 2020). Fishing is also significantly reducing the population of the protected deep-sea coral Corallium rubrum. Trawling activities affect numerous benthic species such as the protected bivalve Pinna nobilis. There is a certain risk of overfishing (which is a threat not only for target species, but also for their predators, such as cetaceans and shearwaters), mainly due to an absence of a marine protected areas, which does not allow defining the restocking areas needed to compensate for fishing pressure (Ministero dell'Ambiente, 2010; IUCN Consultation, 2014; Ruta, 2017). Although the Law 244/2007 designated all the islands and the marine area as a National Park (terrestrial and marine), it is not known why this protected area has not been effectively established (IUCN Consultation, 2020a). Research has been conducted to support the designation of a Marine Protected Area at the Aeolian Islands (Álvarez et al., 2019), which would in part respond to this threat, but the process for its establishment still seems in pause (Notiziario Eolie, 2024). According to local news, following a participatory process started in 2021, the three local municipalities of the Island of Salina approved the resolution to establish a Marine Protected Area of Salina (Giornale di Sicilia, 2024a; Il Corriere, 2024; Altreconomia, 2024). The process of its establishment is ongoing and local stakeholders hope it will lead to the extension to the rest of the archipelago.

There is significant (although heavily seasonal) maritime traffic which, despite being outside the World Heritage site, negatively impacts some bird species, such as the European storm petrel (Hydrobates pelagicus), the Scopoli's shearwater (Calonectris diomedea) and the Eleonora's falcon (Falco eleonorae). Boat and vessel traffic reach the maximum intensity during the breeding season in the proximity of the only two reproductive sites of Hydrobates pelagicus so far detected in the Aeolian Islands, and especially one of them seems to be seriously threatened by direct and indirect human disturbance (Ministero dell'Ambiente, 2010; Lo Cascio, 2016). Maritime traffic also directly affect several species of cetaceans and the loggerhead sea turtle (Caretta caretta) by collision with vessels (Blasi and Mattei, 2017, Leone et al., 2019).

Habitat fragmentation by roads occurs mainly on the islands of Salina, Vulcano and Lipari, where these infrastructures overlap with ecologically sensitive areas. The consequent habitat loss and associated disturbances (sound, light and chemical pollution) are adversely affecting numerous protected species, including endemic invertebrates and plants (Ministero dell'Ambiente, 2010). Recent studies have shown that infrastructure such as roads facilitate the spreading of the invasive Italian wall lizard (Podarcis siculus), which is already common on Vulcano Island, successfully outcompeting and hybridizing with the Aeolian wall lizard (D'Amico et al., 2018).

The incidence of fires during the last years in Lipari has reached worrying proportions: just in July 2017, more than 15% of the island surface was destroyed by arsons (Il Giornale di Lipari, 2017b; Notiziario Eolie, 2017). In 2019, a fire destroyed most part of the northern slope of Lipari Island, including the old landfill that was closed in 2007, but never reclaimed. That produced significant pollution in a wide area (Monte Pilato, Monte Chirica) inside the World Heritage site boundaries, with the risk of dioxin contamination (IUCN Consultation, 2020a). On the other hand, fires on Stromboli are mostly due to volcanic activity (Ministero dell'Ambiente, 2010), such as Stromboli eruption in 2019 which caused a fire damaging up to 39% of the total area of the island (Turchi et al., 2020). However, in May 2022, due to recklessness during the filming of a television drama, the island of Stromboli suffered a severe arson that burned almost half of
the vegetated area of Stromboli. The fire partly damaged the local natural reserve “Riserva Naturale Orientata Isola di Stromboli e Strombolicchio”, which lies within WH site boundaries and Natura 2000 site (ITA030026) boundaries (Copernicus, 2022; Guarino et al., 2024). Fires are threatening bird species such as the protected Dartford’s warbler (Sylvia undata), Cetti's warbler (Cettia cetti), the tortoise Testudo hermanni, and the extremely rare garden dormouse (Eliomys quercinus liparensis) (nowadays considered extinct, see Lo Cascio, 2017), but also a not measurable number of endemic invertebrates and many other species of fauna. Fires are also threatening the few island forests and the xeric grasslands that are identified as priority habitat (6220) in the Habitat Directive 43/92/EU (Ministero dell'Ambiente, 2010). Fires also accelerate the erosion of the slopes and the instability of the terraces, determining a strong impact on the structure of the semi-natural landscapes.
These impacts where detectable in Stromboli´s fire in May 2022.The fire considerably damaged the native plant communities, hosting many species of high biogeographic interest, such as Cytisus aeolicus, one of the rarest and most emblematic endemic plant species of the Aeolian archipelago (Vettore et al., 2024; Zaia et al., 2020), in favour of perennial grass of alien origin (Saccharum biflorum) that instead showed a very high vegetative performance after burning (Guarino et al., 2024). This event had also devastating consequences for the inhabitants and infrastructures on the island. Furthermore, in August 2022 due to the reduced hydro-geological stability caused by the fire, the occurrence of an extreme rainfall event induced extensive sliding and debris flow also affecting the island’s villages (Vettore et al. 2024).
The Regional Forestry Police, responsible for surveillance, is only present on Lipari during summer, and is lacking for most part of the year (IUCN Consultation, 2020a). It is therefore difficult to contain the phenomenon of intentional fires, in most part of the cases presumably caused by illegal hunters (IUCN Consultation, 2017).

Quite a few of the reforestation projects on the islands have made use of non-native species, such as acacia and eucalyptus, negatively affecting the growth of autochthonous populations. In addition, some invasive species such as eucalyptus make an already acidic soil even more acidic, preventing the growth of native species. Another problem concerns the invasive plant Carpobrotus edulis, which recently seems to have extended its distribution on coastal habitats (for instance, on Vulcano Island). Recently, the expansion of other invasive plants, such as the Cape wattle (Paraserianthes lophantha) has been observed (Lo Cascio, 2017). Especially exposed to exotic invasive species are the endemic species living on islands which, due to their geographical isolation, have no escape routes when a non-native species appears in their territory taking over their ecological niche. This is the well-known case of the Italian wall lizard (Podarcis siculus) that, once settled on the Aeolian Archipelago, caused the almost total extinction of the endemic Aeolian wall lizard (Podarcis raffoneae) (D'Amico et al., 2018). The last populations of Aeolian wall lizards survive, paradoxically, precisely because of their extreme isolation, entrenched in some rocks and stacks that have not yet been reached by its competitor, but suffer a severely impoverished genetic diversity (Ministero dell'Ambiente, 2010; Salvi, 2023). The last population on Vulcano Island (the only main island still inhabited by the species) has perhaps recently been extinct and now Aeolian wall lizards occurs only on three tiny islets and a promontory of Vulcano Island (Lo Cascio and Ficetola, 2016; D'Amico et al., 2018; Salvi 2023). Some introduced predators probably contributed to the extinction of the Aeolian wall lizard on the main islands of this archipelago, still having potential impacts on the last individuals on Vulcano Islands. For example, the western whip snake (Hierophis viridiflavus) is an introduced snake on the Aeolian Islands (Avella et al., 2017), and domestic/feral cats and dogs are common on the main islands (additionally establishing a reservoir for some parasite species potentially affecting humans: Brianti et al., 2017; Greco et al., 2019; Otranto et al., 2017).

Marine pollution and, in particular, oil slicks and micro-plastic particles, are threatening the Storm-petrel (Hydrobates pelagicus), the rare Mediterranean shearwater (Puffinus yelkouan), the Scopoli’s Shearwater (Calonectris diomedea) and several marine organisms, such as the fan mussel (Pinna nobilis) and the loggerhead sea turtle (Caretta caretta). The quality of subterranean waters throughout the islands is also jeopardized by the uncontrolled use of herbicides in agriculture as well as by organic pollution from sites used for the dumping of solid urban waste. Although these sites are no longer used, they have not witnessed any restoration projects. This, coupled with the high permeability of the volcanic terrain, which permits extensive percolation and leaching, has led to groundwater pollution (Ministero dell'Ambiente, 2010; Renzi et al., 2018, 2020).
For most of the Aeolian isalnds there seems to be no wastewater treatment system, and it is therefore assumed that the discharges are poured directly into the sea. Sewage treatment systems exist for the islands of Lipari and Vulcano but information about them remain mostly incomplete (Isole sostenibili, 2020). Concerns remain regarding the condition of the sewage treatment on Lipari Island, as the previous infrastructure was considered dated and replaced with a new plant (2012) that, however, has not yet been taken into operation. It remains uncertain whether the sewage of Lipari is adequately treated or released into the sea without any, or only after partial, treatment. It has not been possible to obtain documentation or reliable information from the public offices of the Municipality in order to verify the situation. This has significant implications for the marine fauna and flora, but also for the level of quality of the seawater. It should also be noted that the uncertainness regarding the effectiveness of sewage treatment does not allow to establish whether this should be considered a Low or High Threat (IUCN Consultation, 2020a).

Mass tourism has been the answer for local communities seeking economic growth (Ministero dell'Ambiente, 2010), and it still seems to be the only type of tourism encouraged by local tourist operators (IUCN Consultation, 2013a). Tourism is highly seasonal (Ministero dell'Ambiente, 2010), notwithstanding the promising push in 2007 in support of de-seasonalizing of the industry, which was supported by many local stakeholders (UNESCO and IUCN, 2007). In fact, everything is geared towards a summer seaside tourism comprised of brief visits, intensive consumption and exploitation of resources with a high environmental impact (IUCN Consultation, 2013a). Except for Salina, where the walks within the Natural Reserve are already easily accessible and well indicated, a better management of several old trails existing in the islands and promotion of a new local identity through the National Park proposed in 2007 may instead help de-seasonalize tourism. The increasing number of tourists and their lack of environmental sensitivity is a high threat to the delicate ecological balance of the islands, as well as to specific species such as Eleonora's Falcon (Falco eleonorae) (Ministero dell'Ambiente, 2010), as revealed by the recent decline of the colony on Salina Island. Also, the occurrence of excessive nautical tourism (for instance, in the Pollara Bay, Salina Island) represents the main threat that affects the reproductive success of the local population of Mediterranean storm petrel (Hydrobates pelagicus) (Lo Cascio, 2016). Uncontrolled tourism has led to the re-settlement of people on some islands, such as Vulcano and, in some areas, the population doubles in the summer, such as in the Malfa municipality on the island of Salina (Ministero dell'Ambiente, 2010; Corso et al., 2009). Smaller islands lack the necessary regulations to manage the daily influx of tourists (IUCN Consultation, 2013b). In other cases, legislation exists but is not enforced. For example, the protected Strombolicchio Reserve receives daily visits from unauthorized tourists who are unaware of the fragility of the islet´s ecosystems and who consequently threaten its endemic species (IUCN Consultation, 2013a; Ministero dell'Ambiente, 2010). Additionally, the large seagrass meadows of Posidonia oceanica, which are already limited to a few areas of sandy seabed, have been severely impoverished over the last few decades due to excessive and uncontrolled anchoring by tourist boats (Ministero dell'Ambiente, 2010).

A new sewage treatment plant for Vulcano Island was built on the slopes of the active La Fossa crater in 2012, and despite it should came into operation in 2020 (Isole Sostenibili, 2020), it is stil inactive. The new plant dramatically disrupts the natural geometry and morphology of the valley formed by pyroclastic and sand deposits at the base of the crater. Also, a water pump belonging to this plant was built a short distance from the coastal lagoon of the Isthmus (priority habitat of 43/92/EU directive, code 1150). The Isthmus pump represents a remarkable threat for several bird species included in 147/09/EU directive and for the whole integrity of the Natura 2000 Site ITA030044 (IUCN Consultation, 2014). The sewage treatment infrastructure is very close to the last population of Aeolian wall lizard (Podarcis raffonei) inhabiting Vulcano Island (on Capo Grosso Promontory), and recent studies have shown that human activities facilitate the spreading of the Italian wall lizard (Podarcis siculus), which is already common in the area, successfully outcompeting with the Aeolian wall lizard (D'Amico et al., 2018; Ficetola et al., 2021).

Landslides on the Aeolian Islands can occur due to volcanic activity (Baena et al., 2019; Di Traglia et al., 2018; Gamberi et al., 2024), and they can cause tsunamis (Fornaciai et al., 2019; Macias et al., 2018; Gamberi et al., 2024). These events can be a threat for endemic plants and invertebrates inhabiting the islands' slopes, to protected seabirds and raptors nesting on cliffs and islets, and for the Critically Endangered Aeolian wall lizard, which nowadays is inhabiting mostly small islets (D'Amico et al., 2018). On Vulcano, landslides can also threaten specific slopes of the volcanic structure (Ministero dell'Ambiente, 2010).

Non-toxic algal blooms are common in the summer months when the pressures of tourism are highest, breaking the ecological balance of marine ecosystems (Ministero dell'Ambiente, 2010).

Waste (from building materials, abandoned cars and construction machinery) is filling up a vast volcanic beach on Stromboli (IUCN Consultation, 2013a). On Lipari, the Vallone fiume Bianco riverbed is still used as an illegal dumping ground for old cars, refuse from an olive oil press and other garbage (Ministero dell'Ambiente, 2010). Open landfills are also a threat to local bird species, although decreasingly so due to the closure and decommissioning of public landfills (Ministero dell'Ambiente, 2010). Illegal landfills continue playing a role as sources for the dispersal of several nitrophilous and/or ruderal alien and invasive plants, such as Paraserianthes lophanta and Carpobrotus sp. (Lo Cascio, 2017; Giornale di Sicilia, 2024b).

Numerous protected species living on the Aeolian Islands are threatened by the use of pesticides and herbicides, such as the Eleonora's Falcon (Falco eleonorae) and many other protected bird species. Of particular concern are chlorine-based pesticides, which are particularly dangerous to the Aeolian birds of prey as they are the most susceptible to the negative effects of bio-accumulation (Ministero dell'Ambiente, 2010). During recent years, a gradual decline was also detected for many invertebrate species within the surrounding areas near to vineyards and cultivated fields, that could be due to the widespread use of pesticides and herbicides in local agriculture (IUCN Consultation, 2025).

In recent decades, most of the islands have suffered the consequences of agricultural abandonment, which have increased erosion and caused geological instability. The cessation of cultivation activities has led to the progressive deterioration of slopes, which had been previously modified through water channelling, furrowing, terracing, and the construction of dry stone walls. In some islands, such as Filicudi, Alicudi, Panarea, Salina, terraced landscapes cover between 50% and 70% of the island surface (Barbera et al., 2009). In the terraces, vegetation structure may differ in relation to the age of abandonment of the agricultural use, and often there is interesting shrub formations (with Erica arborea, Arbutus unedo and other woody species). The progressive erosion of dry stonewalls may determine strong changes in the whole landscape structure with dramatic consequences for the local biodiversity, but this issue has not yet claimed the attention from local municipalities and/or protected area managers. These uncultivated areas only have thin vegetation coverage, leading to widespread runoff and a consequent increase in the loss of useful surface soil (Ministero dell'Ambiente, 2010). Another case concerns the northeastern part of Lipari, where the progressive stripping of land has been aggravated by extensive pumice stone extraction (Ministero dell'Ambiente, 2010). Illegal pumice stone extraction activities have still occurred, namely in the Vallone bianco locality of Lipari where activities falling in an area subject to landscape and environmental constraints have been documented from 2019 until July 2023 (Tempostretto, 2024). Currently, Lipari's abandoned quarry and its old mining spoil banks are suffering serious erosion problems, threatening the area's hydrogeological balance (IUCN Consultation, 2013b). This hydrogeological instability is creating serious safety hazards, especially given that even basic security measures have not yet been employed (Legambiente, 2011). The integrity of the geological values that merited inscription on the World Heritage list does not seem to be threatened (IUCN Consultation, 2013b), although it would be interesting to understand whether there is a risk of crater instability in Monte Pelato as alluded to by the State of Conservation report in 2006 (UNESCO, 2006). There are considerations of a pumice geomineral park (Municipality of Lipari, 2018). Between 2015 and 2017, the Municipality of Lipari involved the University of Milan (Politecnico) in a session of preliminary projects to design a future for the area of pumice quarries (PGP, 2017; Il Giornale di Lipari, 2017a). However, after the presentation of results in 2018, nothing seems to have happened (IUCN Consultation, 2020a). Although the plan is only conceptual, it may pose a pathway towards improving conditions at other abandoned mines. The bankruptcy trustee of Pumex S.p.A. is selling ferrous material from the quarries to cover the company’s debt. In 2021, the Sicilian’ regional administration took steps forward for the redevelopment of Campo Bianco - Porticello area as a geosite and “Museum of the pumice”, as previously suggested by IUCN. However, the proposal of the Sicilian region to acquire the area did not materialize and the historical and ethno-anthropological constraint was judged lawless in 2022 by the Sicilian Administrative Court (TAR) (Vettore et al., 2024). In 2024, procedures for the purchase of the former Pumice quarries of Pumex by the private company “Mt Project srl” have been initiated (QdS, 2024). That risks nullifying the possibility of using the existent structures in view of a future geo-mineral park. At the same time, part of the coastal belt of pumice quarries are now used as summer “lido” for local entertainment during the tourist season (IUCN Consultation, 2020a). Another old abandoned quarry, that of caolino (on the northwestern side of Lipari Island), was purchased in 2018 by the winery Tenuta di Castellaro. The new ownership organizes a private (but freely accessible) geomineral park without public financial support.

Despite the ban on helicopter flying over the Natura 2000 sites of the Aeolian Islands, in force under the regulations of the Natural Reserves (RNO) of Alicudi, Filicudi, Panarea, Salina and Stromboli (D.A. n° 484 0f 25/07/1997, D.A. n° 485 of 25/07/1997, D.A. n° 483 of 25707/1997, D.A. n° 87 of 14/03/1987 and D.A. n° 819 of 20/11/1997) and reiterated by the Regional Council of Territory and Environment (Assessorato regionale Territorio e Ambiente) with the note n° 64408 of 28/08/2009, helicopter flights continue in absence of any effective control. The local company “Air Panarea” has now increased the flights by using more than one helicopter. A pragmatic solution, in absence of any control, could be to design special flight corridors that allow to approach the island from the other side (east) instead of the current approach (from the uninhabited cliffs of the western slopes), in order to minimize the impact on bird colonies (IUCN Consultation, 2020a). The reproductive season of the Eleonora’s falcon (Falco eleonorae) coincides with the peak of flights (summer). A decline of the Panarea population of this species and a strong reduction of the number of breeding pairs has been documented during the last decade (Corso and Gustin, 2009; Massa et al., 2015; Lo Cascio, 2016; Il Giornale di Lipari, 2015; Mount City, 2015; Gruppo d'Intervento Giuridico onlus, 2011), and confirmed from more recent data (IUCN Consultation, 2020a). Some pairs, probably belonging to this population, have been observed to use the adjacent islet of Basiluzzo as nesting site (IUCN Consultation, 2020a). The same concerns other islets where nesting pairs have been found during recent years (Lo Cascio & Massa, 2023)