Plant invasion and speciation along elevational gradients on the oceanic island La Palma,Canary Islands

Ecosystems that provide environmental opportunities but are poor in species and functional richness generally support speciation as well as invasion processes. These processes are expected not to be equally effective along elevational gradients due to specific ecological, spatial, and anthropogenic filters, thus controlling the dispersal and establishment of species. Here, we investigate speciation and invasion processes along elevational gradients. We assess the vascular plant species richness as well as the number and percentage of endemic species and non‐native species systematically along three elevational gradients covering large parts of the climatic range of La Palma, Canary Islands. Species richness was negatively correlated with elevation, while the percentage of Canary endemic species showed a positive relationship. However, the percentage of Canary–Madeira endemics did not show a relationship with elevation. Non‐native species richness (indicating invasion) peaked at 500 m elevation and showed a consistent decline until about 1,200 m elevation. Above that limit, no non‐native species were present in the studied elevational gradients. Ecological, anthropogenic, and spatial filters control richness, diversification, and invasion with elevation. With increase in elevation, richness decreases due to species–area relationships. Ecological limitations of native ruderal species related to anthropogenic pressure are in line with the absence of non‐native species from high elevations indicating directional ecological filtering. Increase in ecological isolation with elevation drives diversification and thus increased percentages of Canary endemics. The best preserved eastern transect, including mature laurel forests, is an exception. The high percentage of Canary–Madeira endemics indicates the cloud forest's environmental uniqueness—and thus ecological isolation—beyond the Macaronesian islands.     

Island properties dominate species traits in determining plant colonizations in an archipelago system

The extrinsic determinants hypothesis emphasizes the essential role of environmental heterogeneity in species’ colonization. Consequently, high resident species diversity can increase community susceptibility to colonizations because good habitats may support more species that are functionally similar to colonizers. On the other hand, colonization success is also likely to depend on species traits. We tested the relative importance of environmental characteristics and species traits in determining colonization success using census data of 587 vascular plant species collected about 70 yr apart from 471 islands in the archipelago of SW Finland. More specifically, we explored potential new colonization as a function of island properties (e.g. location, area, habitat diversity, number of resident species per unit area), species traits (e.g. plant height, life-form, dispersal vector, Ellenberg indicator values, association with human impact), and species’ historical distributions (number of inhabited islands, nearest occurrence). Island properties and species’ historical distributions were more effective than plant traits in explaining colonization outcomes. Contrary to the extrinsic determinants hypothesis, colonization success was neither associated with resident species diversity nor habitat diversity per se, although colonization was lowest on sparsely vegetated islands. Our findings lead us to propose that while plant traits related to dispersal and establishment may enhance colonization, predictions of plant colonizations primarily require understanding of habitat properties and species’ historical distributions.     

Potential impacts of the invasive flatworm Platydemus manokwari on arboreal snails

The introduction of the snail-eating flatworm Platydemus manokwari (Tricladida: Rhynchodemidae) has been considered a cause of the extinction of native land snails on several Pacific islands. Although P. manokwari is known to attack land snails on the ground, whether P. manokwari attacks snails on trees remains unclear. To clarify the effect of P. manokwari on arboreal snails, we examined survival rates of land snails experimentally placed on tree trunks (0.5–2.0 m above the ground) in a forest on Chichijima, Ogasawara (Bonin) Islands, in the northwestern Pacific Ocean. The survival of snails experimentally placed on tree trunks with artificially created snail scent trails rapidly decreased for 7 days, and the mortality was caused by P. manokwari predation. However, snails placed on tree trunks without snail scent trails were not attacked by P. manokwari. Therefore, P. manokwari climbed tree trunks, likely tracking the snail scent. We found that over 40% of the snails placed on tree trunks with snail scent trails were eaten by P. manokwari within 7 days. This experiment supports the hypothesis that P. manokwari predation is an important cause of the rapid decline or extinction of native arboreal snails on Pacific islands.     

Predation of insects by feral cats (<Emphasis Type="Italic">Felis silvestris catus</Emphasis> L., 1758) on an oceanic island (La Palma,Canary Island)

Predation of insects by feral cats (Felis silvestris catus) on a heterogeneous oceanic island (La Palma, Canary Islands) was studied. A total of 127 invertebrates were identified in the analysis of 500 scats (100 from each habitat of the Island). Invertebrates appear in 18.00% of the scats, representing an insignificant percentage of the total consumed biomass by feral cats on La Palma Island (0.05%). Insects were the most common invertebrate prey both in percentage of occurrence (90.6%) and invertebrate biomass (93.53%), with a total of 115 prey items. Orthoptera, Lepidoptera and Coleoptera were the main prey groups. Among the five main habitats present in La Palma Island, the temperate forest shows the lowest consumption of invertebrates, although insect consumption did not show statistical differences. However Orthoptera and Lepidoptera were more frequently preyed on in the pine forest and in the xerophytic shrub, respectively. Moreover, applying the Simplified Morisita index, a different insect composition of the diet was observed among habitats. Although, none of insects predated by feral cats are threatened, the identification of invertebrate component of the feral cats’ diet is an important tool for the correct understanding of predation significance and to prevent damage to endangered insect species.     

Species richness, environmental heterogeneity and area: a case study based on land snails in Skyros archipelago (Aegean Sea, Greece)

Aim To test the performance of the choros model in an archipelago using two measures of environmental heterogeneity. The choros model is a simple, easy‐to‐use mathematical relationship which approaches species richness as a combined function of area and environmental heterogeneity. Location The archipelago of Skyros in the central Aegean Sea (Greece). Methods We surveyed land snails on 12 islands of the archipelago. We informed the choros model with habitat data based on natural history information from the land snail species assemblage. We contrast this with habitat information taken from traditional vegetation classification to study the behaviour of choros with different measures of environmental heterogeneity. R² values and Akaike's information criterion (AIC) were used to compare the choros model and the Arrhenius species–area model. Path analysis was used to evaluate the variance in species richness explained by area and habitat diversity. Results Forty‐two land snail species were recorded, living in 33 different habitat types. The choros model with habitat types had more explanatory power than the classic species–area model and the choros model using vegetation types. This was true for all islands of the archipelago, as well as for the small islands alone. Combined effects of area and habitat diversity primarily explain species richness in the archipelago, but there is a decline when only small islands are considered. The effects of area are very low both for all the islands of the archipelago, and for the small islands alone. The variance explained by habitat diversity is low for the island group as a whole, but significantly increases for the small islands. Main conclusions The choros model is effective in describing species‐richness patterns of land snails in the Skyros Archipelago, incorporating ecologically relevant information on habitat occupancy and area. The choros model is more effective in explaining richness patterns on small islands. When using traditional vegetation types, the choros model performs worse than the classic species–area relationship, indicating that use of proxies for habitat diversity may be problematic. The slopes for choros and Arrhenius models both assert that, for land snails, the Skyros Archipelago is a portion of a larger biogeographical province. The choros model, informed by ecologically relevant habitat measures, in conjunction with path analysis points to the importance of habitat diversity in island species richness.     

Island biogeography of bats in Baja California, Mexico: patterns of bat species richness in a near-shore archipelago

Aim We studied the relationship between the size and isolation of islands and bat species richness in a near‐shore archipelago to determine whether communities of vagile mammals conform to predictions of island biogeography theory. We compared patterns of species richness in two subarchipelagos to determine whether area per se or differences in habitat diversity explain variations in bat species richness. Location Islands in the Gulf of California and adjacent coastal habitats on the Baja California peninsula in northwest Mexico. Methods Presence–absence surveys for bats were conducted on 32 islands in the Gulf of California using acoustic and mist‐net surveys. We sampled for bats in coastal habitats of four regions of the Baja peninsula to characterize the source pool of potential colonizing species. We fitted a semi‐log model of species richness and multiple linear regression and used Akaike information criterion model selection to assess the possible influence of log₁₀ area, isolation, and island group (two subarchipelagos) on the species richness of bats. We compared the species richness of bats on islands with greater vegetation densities in the southern gulf (n = 20) with that on drier islands with less vegetation in the northern gulf (n = 12) to investigate the relationship between habitat diversity and the species richness of bats. Results Twelve species of bats were detected on islands in the Gulf of California, and 15 species were detected in coastal habitats on the Baja peninsula. Bat species richness was related to both area and isolation of islands, and was higher in the southern subarchipelago, which has denser vegetation. Log₁₀ area was positively related to bat species richness, which increased by one species for every 5.4‐fold increase in island area. On average, richness declined by one species per 6.25 km increase in isolation from the Baja peninsula. Main conclusions Our results demonstrate that patterns of bat species richness in a near‐shore archipelago are consistent with patterns predicted by the equilibrium theory of island biogeography. Despite their vagility, bats may be more sensitive to moderate levels of isolation than previously expected in near‐shore archipelagos. Differences in vegetation and habitat xericity appear to be associated with richness of bat communities in this desert ecosystem. Although observed patterns of species richness were consistent with those predicted by the equilibrium theory, similar relationships between species richness and size and isolation of islands may arise from patch‐use decision making by individuals (optimal foraging strategies).     

Habitat filtering not dispersal limitation shapes oceanic island floras: species assembly of the Galápagos archipelago

Remote locations, such as oceanic islands, typically harbour relatively few species, some of which go on to generate endemic radiations. Species colonising these locations tend to be a non‐random subset from source communities, which is thought to reflect dispersal limitation. However, non‐random colonisation could also result from habitat filtering, whereby only a few continental species can become established. We evaluate the imprints of these processes on the Galápagos flora by analysing a comprehensive regional phylogeny for ~ 39 000 species alongside information on dispersal strategies and climatic suitability. We found that habitat filtering was more important than dispersal limitation in determining species composition. This finding may help explain why adaptive radiation is common on oceanic archipelagoes – because colonising species can be relatively poor dispersers with specific niche requirements. We suggest that the standard assumption that plant communities in remote locations are primarily shaped by dispersal limitation deserves reconsideration.     

The application of environmental ethics in biological conservation: a case study from the southernmost tip of the Americas

Biological conservation is not only about facts and technical measures concerning ecology, rather it must also consider values. This pertains to both the balancing of various human interests and also to the ethical evaluation of human actions towards nature. Here we discuss how environmental ethics can be incorporated into conservation decisions, and what implications the inclusion of ethical valuation has for the practice of conservation biology. While this is done mostly on a rather abstract level, we illustrate this here by applying ethical theory to a case study: the options for management of the introduced North American beaver (Castor canadensis) in the very south of Chile (Navarino Island). The beaver is an exotic species to the area and has substantially altered the ecological systems of the region. We discuss different options for dealing with the beaver (eradicate, control, tolerate, promote) from the viewpoint of anthropocentric environmental ethics and biocentric ethics. The results of our analysis demonstrate the value of ethical discussions in clarifying and underpinning arguments for and against specific actions. At the same time, they also show that ethical arguments do not decrease the need for sound scientific data but, on the contrary, may even increase this demand. We also highlight that the conclusions regarding adequate actions to be taken vary depending on the specific ethical theory embraced.

Diversity of Saint Helena Island and zoogeography of zoantharians in the Atlantic Ocean: Jigsaw falling into place

Diversity surveys in isolated sites, such as oceanic islands, provide biogeographic data that can improve our analyses and knowledge of evolutionary processes in the oceans. Zoantharians (Cnidaria: Anthozoa) are common and widespread components of shallow-water reefs, but distributional analyses are scarce for this group. In this study, we collected Zoantharia specimens from around Saint Helena Island (STH) in the mid-Atlantic and identified species using external morphology and molecular data. Moreover, we compiled and analysed the most comprehensive distributional data for zoantharian species in the subtropical and tropical Atlantic Ocean to date. Our results show eight zoantharian species in STH, which includes seven new records for STH waters. Furthermore, all families and genera of the suborder Brachycnemina recorded are widespread in the Atlantic Ocean, including at least four amphi-Atlantic species. The Caribbean is the richness centre in the Atlantic Ocean for zoantharian species, a pattern similar to that observed for many other subtropical/tropical marine taxa. However, Zoantharia may have a lower endemism rate in some areas than other common reef animals, for example zooxanthellate scleractinian corals and reef fishes. Moreover, zoantharian species have a more extensive distribution than close-related taxa such as zooxanthellate scleractinian corals and hydrocorals in the Atlantic Ocean.     

Demography of the cycad Ceratozamia mirandae (Zamiaceae) under disturbed and undisturbed conditions in a biosphere reserve of Mexico

The cycad Ceratozamia mirandae is endemic to Chiapas, Mexico. Demographic studies were made in two of its populations in the Sepultura Biosphere Reserve under different conservation conditions; in the nucleus zone “Tres Picos” (conserved) and buffer zone “La Sombra” (disturbed and under management). Spatial distribution of C. mirandae was aggregated, showed a clumped local distribution on shallow soils on steep slopes and male and female cones appear to be synchronous in both populations. The population structure was of type I (Bongers) for both sites. Individuals between the sites showed differences in growth pattern. The oldest plants (80–90 cm tall) were estimated to be about 490 years at “La Sombra”. The finite growth rate () in the buffer zone population showed a tendency for decrease whilst in the nucleus zone this estimate remained stable. The highest elasticity values lied in the transition of the first three classes of the “La Sombra” population, in “Tres Picos” this corresponded to adult plants between 20 and 30 cm tall. Given the above, it is proposed that in the nucleus zone, reproductive adults should be of highest conservation priority, whereas in the buffer zone seedling reintroduction should be carried out regularly until the population increases. We recommend an IUCN Red List category of Vulnerable (VU C, 2a), largely due to difficult-to-control destructive annual forest fires that occur in this Reserve.     

Genetic analysis and conservation of the endangered Canary Island woody sow-thistle, Sonchus gandogeri (Asteraceae)

Sonchus gandogeri, a woody sow-thistle, is an endangered Canary Island endemic with only two known populations, one in the El Golfo and another in the Las Esperillas of El Hierro. Amplified fragment length polymorphism (AFLP) markers were used to assess the genetic variation within and among populations. The mean genetic diversity of two populations was estimated to be 0.380, and the El Golfo population (0.380) had higher genetic diversity than the southeastern one (0.268). The unbiased Neis genetic identity between the two populations was 0.846. The mean genetic diversity of S. gandogeri was much higher than that of the other endangered plant species. This is perhaps due to breeding system, life form, extinction, and/or introgressive hybridization and hybrid origin of the taxon. This study also indicates that the two populations are not strongly differentiated (G_ST=0.149). This study suggests that S. gandogeri is more likely to become extinct due to environmental or demographic forces than genetic factors, such as inbreeding depression. More strict control of introduced herbivores is necessary to protect these populations, and germplasm collection for ex situ conservation is needed.     

Assessing the areas under risk of invasion within islands through potential distribution modelling: The case of Pittosporum undulatum in São Miguel, Azores

Non-indigenous plant species have been frequently reported as successful invaders in island environments, changing plant community composition and structure. This is the case of the sweet pittosporum (Pittosporum undulatum), native from Australia, which is one of the most successful plant invaders in the Azores archipelago. Data extracted from recent forestry inventories were used to model and map the potential distribution of P. undulatum in São Miguel, the larger island of the Azores. Current distribution of P. undulatum is related to climate, altitude and some human activity effects. Further analysis of the areas under risk of invasion showed that protected areas are under potential threat, although only a few native forest remnants seem to be threatened due to future expansion of P. undulatum, since the current distribution of these native communities has been reduced due to clearing and competition with invasive plants. We discuss the threats that any further expansion of the species will represent for low-altitude native forests, as well as the utility of species distribution models in the assessment of the areas under risk of invasion.     

Re-established mutualism in a seed-dispersal system consisting of native and introduced birds and plants on the Bonin Islands,Japan

The disruption of plant–animal interactions such as seed dispersal is one of the most critical effects of biological invasions. To understand the role of introduced species in current seed-dispersal systems, we conducted fecal analyses of the most common resident land birds on the Bonin Islands, Japan, and estimated their relative importance as seed-dispersal agents. Two native birds, the brown-eared bulbul and the Bonin Islands white-eye, and the introduced Japanese white-eye were the primary seed dispersers in secondary forest sites. Because the seed species composition in the feces of native and introduced white-eyes was similar, the latter may be replacing the former as a seed-dispersal agent. Introduced plants did not decrease the number of seed-dispersal opportunities for native species through competition for seed dispersers. Because some bird species have already become extinct on the Bonin Islands, their ecological functions may also have been permanently lost; however, the introduced white-eye may be compensating for this loss of function. In addition, new mutualistic relationships involving native and introduced birds and plants have already been established. In order to control introduced species while having the least impact on the native biota, interspecific interactions must be thoroughly understood before initiating control efforts.     

When North and South don’t mix: genetic connectivity of a recently endangered oceanic cycad,Cycas micronesica,in Guam using EST‐microsatellites

Subject to environmental changes and recurrent isolation in the last ca. 250 Ma, cycads are often described as relicts of a previously common lineage, with populations characterized by low genetic variation and restricted gene flow. We found that on the island of Guam, the endemic Cycas micronesica has most of the genetic variation of 14 EST‐microsatellites distributed within each of 18 genetic populations, from 24 original sampling sites. There were high levels of genetic variation in terms of total number of alleles and private alleles, and moderate levels of inbreeding. Restricted but ongoing gene flow among populations within Guam reveals a genetic mosaic, probably more typical of cycads than previously assumed. Contiguous cycad populations in the north of Guam had higher self‐recruitment rates compared to fragmented populations in the south, with no substantial connection between them except for one population. Guam’s genetic mosaic may be explained by the influence of forest continuity, seed size, edaphic differences, and human transport of cycads. Also important are the extent of synchrony among flushes of reproductive female seed‐bearing sporophylls and restricted pollen movement by an obligate mutualist and generalist insects. An NADH EST‐locus under positive selection may reflect pressure from edaphic differences across Guam. This and three other loci are ideal candidates for ecological genomic studies. Given this species’ vulnerability due to the recent introduction of the cycad aulacaspis scale, we also identify priority populations for ex situ conservation, and provide a genetic baseline for understanding the effects of invasive species on cycads in the Western Pacific, and islands in general.     

Island population,land area,and climate: A case study of the Marshall Islands

A major difficulty in the study of the relationship between human population size and the environment has been placing the problem in a testable framework. Using data from the Marshall Islands, this article tests the proposition that population size and density are highly correlated with environmental variables, including rainfall and land area, through a complex series of socially mediated regulatory mechanisms. This analysis thus supports the population-resources disequilibrium theory of culture change.Deceased.     

Ecological and morphological variation of Canary Island blue tits, Parus caeruleus (Aves: Paridae)

Canary Island blue tits have differentiated within the last million years. Compared with mainland populations they have short wings, large beaks and tarsi, and tend to be less variable in these parameters. Within the archipelago the eastern populations have the shortest wings and tarsi but the widest and deepest beaks. The eastern populations may have been derived from central island ones, following extinction of the original eastern populations during a warm period in the last Ice Age. New measurements have been used to test contrasting predictions of hypotheses that explain inter-island morphological variation in terms of either climatic or ecological influences. Neither hypothesis is sufficient to explain the variation. A model which combines mem is proposed as follows. Mild winter temperatures have selected for small body size and wing length, especially on the hot, dry, eastern islands. On the other pine-forested, islands, selection has favoured relatively long tarsi and long, slender, beaks for efficient foraging among pine foliage. The absence of die pine-dwelling coal tit from the islands has facilitated mis evolutionary shift. It is shown that blue tits in pines forage more in the needles and cones on the Canary Islands than they do on die North African mainland.     

The Arctic charr (<Emphasis Type="Italic">Salvelinus alpinus</Emphasis>) populations of Windermere,UK: population trends associated with eutrophication,climate change and increased abundance of roach (<Emphasis Type="Italic">Rutilus rutilus</Emphasis>)

The north and south basins of Windermere in the English Lake District, UK, support autumn- and spring-spawning populations of Arctic charr, Salvelinus alpinus, which have been studied since the 1930s. Continuous investigations of the population dynamics of Arctic charr at this lake have involved gill netting since 1939, collection of fishery catch-per-unit-effort data since 1966, and hydroacoustic surveys since 1990. Analysis of these and associated long-term data on the abiotic environment and other components of the fish communities revealed recently contrasting fortunes of the Arctic charr populations of the north and south basins, the latter of which has been significantly impacted by eutrophication while both basins have shown elevated water temperatures and increasing roach, Rutilus rutilus, populations. Despite the introduction of phosphate stripping in 1992 and some subsequent initial improvement, the hypolimnion of the south basin still remains significantly eutrophicated and the fishery catch-per-unit-effort in this basin is now at record low levels. In addition, the spatial distribution of roach has expanded to form significant components of the fish communities of inshore and offshore surface habitats, where this cyprinid may compete with Arctic charr for zooplanktonic prey. It is concluded that the Arctic charr populations of Windermere, particularly those of the south basin, currently face a number of significant environmental pressures and continued management action is required to ensure their survival.     

Cospeciation of figs and fig-wasps: a case study of endemic species pairs in the Ogasawara Islands

The interactions between figs (Ficus, Moraceae) and fig-wasps (Agaonidae, Chalcidoidea, Hymenoptera) are special plant-pollinator relationships that are highly species-specific, in that each fig species is pollinated by a single fig-wasp species that can breed only in that particular fig species. This study examined the degree of pre-mating isolation and genetic differentiation for three fig/fig-wasp pairs endemic to the Ogasawara Islands. Simple Y-tube tests revealed that fig-wasps from Ficus nishimurae and Higashidaira type chose their own host figs significantly more often, while fig-wasps from F. boninsimae did not. Based on RAPD markers, the genetic differentiation among the fig species was low, but F. boninsimae formed a cluster within the F. nishimurae cluster. The Higashidaira type has been derived from a subpopulation of F. nishimurae. Five mitochondrial DNA haplotypes were found in the fig-wasps and each haplotype correlated well with the fig species on their island of origin. These results led to a three-step hypothesis on the cospeciation process: (1) spatial separation of fig/fig-wasp populations arises; (2) gene flow is restricted and character differentiation of fig-wasps occurs; (3) there is further restriction of gene flow and genetic and character differentiation of figs.     

Timberline and alpine vegetation on the tropical and warm-temperate oceanic islands of the world: elevation, structure and floristics

In the oceans of the tropical and warm-temperate zone (40° N–40° S), only a small number of islands are high enough to show timberline and alpine vegetation. Excluding large islands with a more continental climate, only the following oceanic islands are relevant: Pico (Azores), Madeira, Tenerife, Gran Canaria and La Palma (Canary islands), Fogo (Cape Verde islands), Fernando Poo (Bioko) and Tristan da Cunha in the Atlantic Ocean, Réunion and Grande Comore (Ngazidja) in the Indian Ocean, Yakushima (Japan), Maui and Hawaii (Hawaiian islands), and Mas Afuera (Juan Fernandez islands) in the Pacific Ocean. Timberline and alpine vegetation exist here under a unique combination of a highly oceanic climate and a marked geographic isolation which contrasts with the tropical alpine vegetation in the extended mountains of South America, Africa and Southeast Asia.This review seeks to identify common physiognomic patterns in the high elevation vegetation that exist despite the fact that the islands belong to different floristic regions of the world. Based on the existing literature as well as personal observation, an overview of the elevation, physiognomy and floristics of the forest (and tree) line and the alpine vegetation on 15 island peaks is given.The forest line ecosystems are dominated either by conifers (Canary islands, Yakushima), heath woodland (Azores, Madeira, Réunion, Grande Comore, Fernando Poo) or broad-leaved trees (Hawaiian islands, Juan Fernandez islands, Tristan da Cunha). In the subalpine and alpine belts, dry sclerophyllous scrub occurs on island mountains that are exposed to the trade winds (Canary islands, Cape Verde islands, Hawaiian islands, Réunion, Grande Comore). These peaks are more or less arid above the forest line because a temperature inversion restricts the rise of humid air masses further upslope. In the summit regions of the remaining islands, which are located either in the wet equatorial and monsoonal regions or in the temperate westerly zones without an effective inversion layer, mesic to wet vegetation types (such as grassland, alpine heathland and fern scrub) are found.Compared to mountains at a similar latitude in continental areas, the forest line on the islands is found at 1000 to 2000 m lower elevations. The paper discusses four factors that are thought to contribute to this forest line depression: (1) drought on trade-wind exposed island peaks with stable temperature inversions, (2) the absense of well-adapted high-altitude tree species on isolated islands, (3) immaturity of volcanic soils, and (4) an only small mountain mass effect that influences the vertical temperature gradient.     

Raccoon (Procyon lotor) in Iberia: Status update and suitable habitats for an invasive carnivore

Raccoons are American carnivores, considered invasive across several countries worldwide, especially in Europe. In the Iberian Peninsula, previous studies on raccoons documented several breeding populations in Spain a decade ago and only two confirmed records from isolated individuals in Portugal. Given the need for updating its Iberian distribution and identifying suitable areas with higher invasion risk, we compiled presence records from established breeding populations and isolated individuals. By using a Maxent approach based on breeding records, we forecasted the suitable habitats in Iberia with higher invasion risk for raccoons and identified the related environmental drivers. Overall, we collected 1039 records of raccoon presence throughout the Iberian Peninsula, including 980 records from established breeding populations. Their origin is probably linked to escapes from captivity. Climatic conditions, linked to both drier and wetter environments, and proximity to water bodies were the main predictors of suitable areas for raccoon’s expansion from the currently established breeding nuclei in Iberia. The forecasted high probability areas showed a wide, but fragmented distribution concentrated on four main areas: central, central-north, central-east, and north-west Iberia. NW Portugal seems to be the area with higher invasion risk in the country, although field surveys showed no evidence of raccoon presence yet. However, there are several records in Spain near the Portuguese border, comprising isolated individuals and breeding populations. Therefore, it is crucial to ensure regular monitoring of areas with high invasion risk, particularly those near facilities with captive raccoons that often act as a source of feral individuals, to assure early detection and effective control for the expansion of this invasive carnivore.