Impact of Alien Plant Invaders on Pollination Networks in Two Archipelagos

Mutualistic interactions between plants and animals promote integration of invasive species into native communities. In turn, the integrated invaders may alter existing patterns of mutualistic interactions. Here we simultaneously map in detail effects of invaders on parameters describing the topology of both plant-pollinator (bi-modal) and plant-plant (uni-modal) networks. We focus on the invader Opuntia spp., a cosmopolitan alien cactus. We compare two island systems: Tenerife (Canary Islands) and Menorca (Balearic Islands). Opuntia was found to modify the number of links between plants and pollinators, and was integrated into the new communities via the most generalist pollinators, but did not affect the general network pattern. The plant uni-modal networks showed disassortative linkage, i.e. species with many links tended to connect to species with few links. Thus, by linking to generalist natives, Opuntia remained peripheral to network topology, and this is probably why native network properties were not affected at least in one of the islands. We conclude that the network analytical approach is indeed a valuable tool to evaluate the effect of invaders on native communities.     

Contrasting effects of invasive plants in plant–pollinator networks

The structural organization of mutualism networks, typified by interspecific positive interactions, is important to maintain community diversity. However, there is little information available about the effect of introduced species on the structure of such networks. We compared uninvaded and invaded ecological communities, to examine how two species of invasive plants with large and showy flowers (Carpobrotus affine acinaciformis and Opuntia stricta) affect the structure of Mediterranean plant–pollinator networks. To attribute differences in pollination to the direct presence of the invasive species, areas were surveyed that contained similar native plant species cover, diversity and floral composition, with or without the invaders. Both invasive plant species received significantly more pollinator visits than any native species and invaders interacted strongly with pollinators. Overall, the pollinator community richness was similar in invaded and uninvaded plots, and only a few generalist pollinators visited invasive species exclusively. Invasive plants acted as pollination super generalists. The two species studied were visited by 43% and 31% of the total insect taxa in the community, respectively, suggesting they play a central role in the plant–pollinator networks. Carpobrotus and Opuntia had contrasting effects on pollinator visitation rates to native plants: Carpobrotus facilitated the visit of pollinators to native species, whereas Opuntia competed for pollinators with native species, increasing the nestedness of the plant–pollinator network. These results indicate that the introduction of a new species to a community can have important consequences for the structure of the plant–pollinator network.     

Pollination patterns and plant breeding systems in the Galápagos: a review

Background

Despite the importance of the Galápagos Islands for the development of central concepts in ecology and evolution, the understanding of many ecological processes in this archipelago is still very basic. One such process is pollination, which provides an important service to both plants and their pollinators. The rather modest level of knowledge on this subject has so far limited our predictive power on the consequences of the increasing threat of introduced plants and pollinators to this unique archipelago.

Scope

As a first step toward building a unified view of the state of pollination in the Galápagos, a thorough literature search was conducted on the breeding systems of the archipelago''s flora and compiled all documented flower–visitor interactions. Based on 38 studies from the last 100 years, we retrieved 329 unique interactions between 123 flowering plant species (50 endemics, 39 non-endemic natives, 26 introduced and eight of unknown origin) from 41 families and 120 animal species from 13 orders. We discuss the emergent patterns and identify promising research avenues in the field.

Conclusions

Although breeding systems are known for <20 % of the flora, most species in our database were self-compatible. Moreover, the incidence of autogamy among endemics, non-endemic natives and alien species did not differ significantly, being high in all groups, which suggests that a poor pollinator fauna does not represent a constraint to the integration of new plant species into the native communities. Most interactions detected (approx. 90 %) come from a single island (most of them from Santa Cruz). Hymenopterans (mainly the endemic carpenter bee Xylocopa darwinii and ants), followed by lepidopterans, were the most important flower visitors. Dipterans were much more important flower visitors in the humid zone than in the dry zone. Bird and lizard pollination has been occasionally reported in the dry zone. Strong biases were detected in the sampling effort dedicated to different islands, time of day, focal plants and functional groups of visitors. Thus, the existing patterns need to be confronted with new and less biased data. The implementation of a community-level approach could greatly increase our understanding of pollination on the islands and our ability to predict the consequences of plant invasions for the natural ecosystems of the Galápagos.     

Native and alien flower visitors differ in partner fidelity and network integration

Globalisation persistently fuels the establishment of non‐native species outside their natural ranges. While alien plants have been intensively studied, little is known about alien flower visitors, and especially, how they integrate into natural communities. Here, we focus on mutualistic networks from five Galápagos islands to quantify whether alien and native flower visitors differ consistently in their pairwise interactions. We find that (1) alien flower visitors have more interaction partners and larger species strengths (i.e. plants are more connected to alien insects), (2) native insects tend to have higher partner fidelity as they deviate more from random partner utilisation, and iii) the difference between native and alien flower visitors in network integration intensifies with island degradation. Thus, native and alien flower visitors are not interchangeable, and alien establishment might have yet unforeseen consequences for the pairwise dynamics between plants and flower visitors on the Galápagos – especially on the heavily disturbed islands.     

Consequences of plant invasions on compartmentalization and species’ roles in plant–pollinator networks

Compartmentalization—the organization of ecological interaction networks into subsets of species that do not interact with other subsets (true compartments) or interact more frequently among themselves than with other species (modules)—has been identified as a key property for the functioning, stability and evolution of ecological communities. Invasions by entomophilous invasive plants may profoundly alter the way interaction networks are compartmentalized. We analysed a comprehensive dataset of 40 paired plant–pollinator networks (invaded versus uninvaded) to test this hypothesis. We show that invasive plants have higher generalization levels with respect to their pollinators than natives. The consequences for network topology are that—rather than displacing native species from the network—plant invaders attracting pollinators into invaded modules tend to play new important topological roles (i.e. network hubs, module hubs and connectors) and cause role shifts in native species, creating larger modules that are more connected among each other. While the number of true compartments was lower in invaded compared with uninvaded networks, the effect of invasion on modularity was contingent on the study system. Interestingly, the generalization level of the invasive plants partially explains this pattern, with more generalized invaders contributing to a lower modularity. Our findings indicate that the altered interaction structure of invaded networks makes them more robust against simulated random secondary species extinctions, but more vulnerable when the typically highly connected invasive plants go extinct first. The consequences and pathways by which biological invasions alter the interaction structure of plant–pollinator communities highlighted in this study may have important dynamical and functional implications, for example, by influencing multi-species reciprocal selection regimes and coevolutionary processes.     

The relative importance of birds and insects as pollinators of the New Zealand flora

Native birds may have been underestimated as pollinators of the New Zealand flora due to their early decline in abundance and diversity on the mainland. This paper reconsiders the relative importance of birds and insects as pollinators to eight native flowering plants, representing a range of pollination syndromes, on two offshore island refuges. Experimental manipulations were made on five of these plant species to assess the relative effectiveness of bird and insect visitors as pollinators. In addition, foraging behaviour and the respective morphologies of flowers and visitors were measured at all eight plants to identify the main pollinators. The experimental measures showed that percentage fruit set was significantly higher in flowers exposed to birds than flowers from which birds were excluded in all manipulated plants. The observational measures revealed that for six of the flowering species (Sophora microphylla, Vitex lucens, Pittosporum crassifolium, Pittosporum umbellatum, Pseudopanax arboreus and Dysoxylum spectabile) the endemic honeyeaters were most likely to meet the conditions necessary for successful pollination. For the remaining two species (Metrosideros excelsa and Geniostoma ligus trifolium) the contribution by honeyeaters and insects to pollination was equivalent. The results suggest that the role of the endemic honeyeaters in pollination of the New Zealand flora, and the subsequent regeneration of native forest ecosystems, should be important considerations in ecosystem management.     

Alien pollinator promotes invasive mutualism in an insular pollination system

The alien predatory lizard, Anolis carolinensis, has reduced the insect fauna on the two main islands of the Ogasawara archipelago in Japan. As a result of this disturbance, introduced honeybees are now the dominant visitors to flowers instead of endemic bees on these islands. On the other hand, satellite islands not invaded by alien anoles have retained the native flower visitors. The effects of pollinator change on plant reproduction were surveyed on these contrasting island groups. The total visitation rates and the number of interacting visitor groups on main islands were 63% and 30% lower than that on satellite islands, respectively. On the main islands, the honeybees preferred to visit alien flowers, whereas the dominant endemic bees on satellite islands tended to visit native flowers more frequently than alien flowers. These results suggest that alien anoles destroy the endemic pollination system and caused shift to alien mutualism. On the main islands, the natural fruit set of alien plants was significantly higher than that of native plants. In addition, the natural fruit set was positively correlated with the visitation rate of honeybees. Pollen limitation was observed in 53.3% of endemic species but only 16.7% of alien species. These data suggest that reproduction of alien plants was facilitated by the floral preference of introduced honeybees.     

A global comparison of plant invasions on oceanic islands

Oceanic islands have long been considered to be particularly vulnerable to biotic invasions, and much research has focused on invasive plants on oceanic islands. However, findings from individual islands have rarely been compared between islands within or between biogeographic regions. We present in this study the most comprehensive, standardized dataset to date on the global distribution of invasive plant species in natural areas of oceanic islands. We compiled lists of moderate (5–25% cover) and dominant (>25% cover) invasive plant species for 30 island groups from four oceanic regions (Atlantic, Caribbean, Pacific, and Western Indian Ocean). To assess consistency of plant behaviour across island groups, we also recorded present but not invasive species in each island group.We tested the importance of different factors discussed in the literature in predicting the number of invasive plant species per island group, including island area and isolation, habitat diversity, native species diversity, and human development. Further we investigated whether particular invasive species are consistently and predictably invasive across island archipelagos or whether island-specific factors are more important than species traits in explaining the invasion success of particular species.We found in total 383 non-native spermatophyte plants that were invasive in natural areas on at least one of the 30 studied island groups, with between 3 and 74 invaders per island group. Of these invaders about 50% (181 species) were dominants or co-dominants of a habitat in at least one island group. An extrapolation from species accumulation curves across the 30 island groups indicates that the total current flora of invasive plants on oceanic islands at latitudes between c. 35°N and 35°S may eventually consist of 500–800 spermatophyte species, with 250–350 of these being dominant invaders in at least one island group. The number of invaders per island group was well predicted by a combination of human development (measured by the gross domestic product (GDP) per capita), habitat diversity (number of habitat types), island age, and oceanic region (87% of variation explained). Island area, latitude, isolation from continents, number of present, non-native species with a known invasion history, and native species richness were not retained as significant factors in the multivariate models.Among 259 invaders present in at least five island groups, only 9 species were dominant invaders in at least 50% of island groups where they were present. Most species were invasive only in one to a few island groups although they were typically present in many more island groups. Consequently, similarity between island groups was low for invader floras but considerably higher for introduced (but not necessarily invasive) species – especially in pairs of island groups that are spatially close or similar in latitude. Hence, for invasive plants of natural areas, biotic homogenization among oceanic islands may be driven by the recurrent deliberate human introduction of the same species to different islands, while post-introduction processes during establishment and spread in natural areas tend to reduce similarity in invader composition between oceanic islands. We discuss a number of possible mechanisms, including time lags, propagule pressure, local biotic and abiotic factors, invader community assembly history, and genotypic differences that may explain the inconsistent performance of particular invasive species in different island groups.     

Evolution of mutualism in plant-pollinator interactions on islands

The evolution and ecology of interactions between plants and pollinators are discussed based on the studies on the Izu Islands and mainland Honshu, Japan. The species assemblage is depauperate, and long-tongued pollinators are absent or rare on the islands. Bumblebees, one of the most important pollinators in Japan, are generally absent. Plants depending strongly on bumblebee pollination are absent on Izu Islands, but those depending on varied pollinators including bumblebees display smaller flower sizes and accommodate smaller pollinators than their mainland counterparts. Breeding systems of these species also shift to partial inbreeding, possibly an evolutionary result of the decrease in pollinator availability. Changes in flowering phenology between mainland and island populations also occur. Plants in the islands tend to reproduce vegetatively less frequently and produce greater numbers of smaller seeds than those in the mainland. The possibility of evolution on the side of island pollinator species is also discussed, although there are few data on this topic.     

The smallest of all worlds: pollination networks

A pollination network may be either 2-mode, describing trophic and reproductive interactions between communities of flowering plants and pollinator species within a well-defined habitat, or 1-mode, describing interactions between either plants or pollinators. In a 1-mode pollinator network, two pollinator species are linked to each other if they both visit the same plant species, and vice versa for plants. Properties of 2-mode networks and their derived 1-mode networks are highly correlated and so are properties of 1-mode pollinator and 1-mode plant networks. Most network properties are scale-dependent, i.e. they are dependent upon network size. Pollination networks have the strongest small-world properties of any networks yet studied, i.e. all species are close to each other (short average path length) and species are highly clustered. Species in pollination networks are much more densely linked than species in traditional food webs, i.e. they have a higher density of links, a shorter distance between species, and species are more clustered.     

Avian translocations restore dual interaction networks in an island ecosystem

Many island bird species have been driven to extinction by introduced predators. Although poorly understood, these extinctions could have a 2-fold impact on bird–plant mutualisms, because island bird species can serve as both pollinators and seed dispersers. We investigated how avian translocations into a mammal-free reserve in New Zealand affected the structure of bird–flower and bird–fruit interactions. We observed bird–fruit and bird–flower interactions over a 9-year period to establish (1) the extent to which native birds are both nectivorous and frugivorous (i.e. “dual mutualists”) and (2) how avian translocations and conservation reestablished nectivory and frugivory networks. Results showed that all but one native bird species were dual mutualists. Pairwise species interaction frequencies were positively correlated between networks. However, overall levels of nectivory by each bird species were unrelated to levels of frugivory. Interaction specialization and species strength also did not differ between networks. The reintroduction of threatened and endangered bird species appeared to have restored both interaction networks, and the sequence of species recovery accelerated restorative changes. Overall results indicate that not only does the extinction of dual mutualists have a 2-fold, negative effect on mutualistic interactions with plants, they can also accelerate the recovery of ecosystem services following restoration efforts.     

Breeding system and pollination ecology of introduced plants compared to their native relatives

Identifying how plant-enemy interactions contribute to the success of introduced species has been a subject of much research, while the role of plant-pollinator interactions has received less attention. The ability to reproduce in new environments is essential for the successful establishment and spread of introduced species. Introduced plant species that are not capable of autonomous self-fertilization and are unable to attract resident pollinators may suffer from pollen limitation. Our study quantifies the degree of autogamy and pollination ecology of 10 closely related pairs of native and introduced plant species at a single site near St. Louis, Missouri, USA. Most of these species pairs had similar capacities for autogamy; however, of those that differed, the introduced species were more autogamous than their native congeners. Most introduced plants have pollinator visitation rates similar to those of their native congeners. Of the 20 species studied, only three had significant pollen limitation. We suggest that the success of most introduced plant species is because they are highly autogamous or because their pollinator visitation rates are similar to those of their native relatives. Understanding and identifying traits related to pollination success that are key in successful introductions may allow better understanding and prediction of biological invasions.     

Threatened pollination systems in native flora of the Ogasawara (Bonin) Islands

• Background and Aims Various alien species have been introducedto the Ogasawara Islands (Japan). A survey was made investigatingwhether the native pollination systems fit an ‘islandsyndrome’ (biasing the flora to dioecy, with subdued,inconspicuous flowers) and whether alien species have disruptedthe native pollination network. • Methods Flower visitors and floral traits were determinedin the field (12 islands) and from the literature. Associationsamong floral traits such as sexual expression, flower colourand flower shape were tested. • Key Results Among the 269 native flowering plants, 74·7% are hermaphroditic, 13·0 % are dioecious and 7·1% are monoecious. Classification by flower colour revealed that36·0 % were white, 21·6 % green and 13·8% yellow. Woody species (trees and shrubs) comprised 36·5% of the flora and were associated with dioecy and white flowers.Solitary, endemic small bees were the dominant flower visitorsand visited 66·7 % of the observed species on satelliteislands where the native pollination networks are preserved.In contrast to the situation on the satellite islands, introducedhoneybees were the most dominant pollinator (visiting 60·1% of observed species) on the two main islands, Chichi-jimaand Haha-jima, and had spread to satellite islands near Chichi-jimaIsland. • Conclusions The island syndrome for pollination systemsin the Ogasawara Islands was evident in a high percentage ofdioecious species, the subdued colour of the native flora andsolitary flower visitors on satellite islands. The shape andcolour adaptations of several flowers suggested native pollinationniches for long-proboscis moths and carpenter bees. However,the domination and expansion of introduced honeybees have thepotential for disruption of the native pollination network inthe two main, and several satellite, islands of the OgasawaraIslands.     

Two invasive acacia species secure generalist pollinators in invaded communities

Exotic entomophilous plants need to establish effective pollinator interactions in order to succeed after being introduced into a new community, particularly if they are obligatory outbreeders. By establishing these novel interactions in the new non-native range, invasive plants are hypothesised to drive changes in the composition and functioning of the native pollinator community, with potential impacts on the pollination biology of native co-flowering plants. We used two different sites in Portugal, each invaded by a different acacia species, to assess whether two native Australian trees, Acacia dealbata and Acacia longifolia, were able to recruit pollinators in Portugal, and whether the pollinator community visiting acacia trees differed from the pollinator communities interacting with native co-flowering plants. Our results indicate that in the invaded range of Portugal both acacia species were able to establish novel mutualistic interactions, predominantly with generalist pollinators. For each of the two studied sites, only two other co-occurring native plant species presented partially overlapping phenologies. We observed significant differences in pollinator richness and visitation rates among native and non-native plant species, although the study of β diversity indicated that only the native plant Lithodora fruticosa presented a differentiated set of pollinator species. Acacias experienced a large number of visits by numerous pollinator species, but massive acacia flowering resulted in flower visitation rates frequently lower than those of the native co-flowering species. We conclude that the establishment of mutualisms in Portugal likely contributes to the effective and profuse production of acacia seeds in Portugal. Despite the massive flowering of A. dealbata and A. longifolia, native plant species attained similar or higher visitation rates than acacias.     

Linking Plant Specialization to Dependence in Interactions for Seed Set in Pollination Networks

Studies on pollination networks have provided valuable information on the number, frequency, distribution and identity of interactions between plants and pollinators. However, little is still known on the functional effect of these interactions on plant reproductive success. Information on the extent to which plants depend on such interactions will help to make more realistic predictions of the potential impacts of disturbances on plant-pollinator networks. Plant functional dependence on pollinators (all interactions pooled) can be estimated by comparing seed set with and without pollinators (i.e. bagging flowers to exclude them). Our main goal in this study was thus to determine whether plant dependence on current insect interactions is related to plant specialization in a pollination network. We studied two networks from different communities, one in a coastal dune and one in a mountain. For ca. 30% of plant species in each community, we obtained the following specialization measures: (i) linkage level (number of interactions), (ii) diversity of interactions, and (iii) closeness centrality (a measure of how much a species is connected to other plants via shared pollinators). Phylogenetically controlled regression analyses revealed that, for the largest and most diverse coastal community, plants highly dependent on pollinators were the most generalists showing the highest number and diversity of interactions as well as occupying central positions in the network. The mountain community, by contrast, did not show such functional relationship, what might be attributable to their lower flower-resource heterogeneity and diversity of interactions. We conclude that plants with a wide array of pollinator interactions tend to be those that are more strongly dependent upon them for seed production and thus might be those more functionally vulnerable to the loss of network interaction, although these outcomes might be context-dependent.     

Exotic species richness and native species endemism increase the impact of exotic species on islands

Aim Exotic species pose one of the most significant threats to biodiversity, especially on islands. The impacts of exotic species vary in severity among islands, yet little is known about what makes some islands more susceptible than others. Here we determine which characteristics of an island influence how severely exotic species affect its native biota. Location We studied 65 islands and archipelagos from around the world, ranging from latitude 65° N to 54° S. Methods We compiled a global database of 10 island characteristics for 65 islands and determined the relative importance of each characteristic in predicting the impact of exotic species using multivariate modelling and hierarchical partitioning. We defined the impact of exotic species as the number of bird, amphibian and mammal (BAM) species listed by the International Union for Conservation of Nature (IUCN) as threatened by exotics, relative to the total number of BAM species on that island. Results We found that the impact of exotic species is more severe on islands with more exotic species and a greater proportion of native species that are endemic. Unexpectedly, the level of anthropogenic disturbance did not influence an island's susceptibility to the impacts of exotic species. Main conclusions By coupling our results with studies on the introduction and establishment of exotic species, we conclude that colonization pressure, or invasion opportunities, influences all stages of the invasion process. However, species endemism, the other important factor determining the impact of exotic species, is not known to contribute to introduction and establishment success on islands. This demonstrates that different factors correlate with the initial stages of the invasion process and the subsequent impacts of those invaders, highlighting the importance of studying the impacts of exotic species directly. Our study helps identify islands that are at risk of impact by exotics and where investment should focus on preventing further invasions.     

Pollinator individual‐based networks reveal the specialized plant–pollinator mutualism in two biodiverse communities

Generalization of pollination systems is widely accepted by ecologists in the studies of plant–pollinator interaction networks at the community level, but the degree of generalization of pollination networks remains largely unknown at the individual pollinator level. Using potential legitimate pollinators that were constantly visiting flowers in two alpine meadow communities, we analyzed the differences in the pollination network structure between the pollinator individual level and species level. The results showed that compared to the pollinator species‐based networks, the linkage density, interaction diversity, interaction evenness, the average plant linkage level, and interaction diversity increased, but connectance, degree of nestedness, the average of pollinator linkage level, and interaction diversity decreased in the pollinator individual‐based networks, indicating that pollinator individuals had a narrower food niche than their counterpart species. Pollination networks at the pollinator individual level were more specialized at the network level (H′₂) and the plant species node level (d′) than at the pollinator species‐level networks, reducing the chance of underestimating levels of specialization in pollination systems. The results emphasize that research into pollinator individual‐based pollination networks will improve our understanding of the pollination networks at the pollinator species level and the coevolution of flowering plants and pollinators.     

Breeding system of the subantarctic plant species Pringlea antiscorbutica R. Br. and search for potential insect pollinators in the Kerguelen Islands

The reproductive biology of Pringlea antiscorbutica R. Br. (Brassicaceae), an endemic species from the southern Indian Ocean islands, is investigated here. Controlled crosses were performed between plants grown in a common garden on the Kerguelen Islands. Searching for potential insect pollinators, we investigated the flying ability of all insects known from the Kerguelen Islands. We showed evidence for self-compatibility, low pollen limitation in the absence of a biotic pollen vector and slight selfing depression in P. antiscorbutica. The insects present on the islands are mostly wingless and are not likely to be efficient pollinators of this species. Since P. antiscorbutica shows morphological adaptations to insect pollination despite the absence of pollinators in its present range, we conclude that this species recently evolved from insect pollination to wind and/or autonomous pollination.     

Resource heterogeneity, diet shifts and intra-cohort competition: effects on size divergence in YOY fish

The pollination syndrome hypothesis has provided a major conceptual framework for how plants and pollinators interact. However, the assumption of specialization in pollination systems and the reliability of floral traits in predicting the main pollinators have been questioned recently. In addition, the relationship between ecological and evolutionary specialization in pollination interactions is still poorly understood. We used data of 62 plant species from three communities across southern Norway to test: (1) the relationships between floral traits and the identity of pollinators, (2) the association between floral traits (evolutionary specialization) and ecological generalization, and (3) the consistency of both relationships across communities. Floral traits significantly affected the identity of pollinators in the three communities in a way consistent with the predictions derived from the pollination syndrome concept. However, hover flies and butterflies visited flowers with different shapes in different communities, which we mainly attribute to among-community variation in pollinator assemblages. Interestingly, ecological generalization depended more on the community-context (i.e. the plant and pollinator assemblages in the communities) than on specific floral traits. While open yellow and white flowers were the most generalist in two communities, they were the most specialist in the alpine community. Our results warn against the use of single measures of ecological generalization to question the pollination syndrome concept, and highlight the importance of community comparisons to assess the pollination syndromes, and to understand the relationships between ecological and evolutionary specialization in plant-pollinator interactions.     

Dispersal ability of island endemic plants: What can we learn using multiple dispersal traits?

Island endemic species are expected to have lower dispersal ability than their non-endemic congeners. Several studies have demonstrated differences in diaspore morphology between endemic species and their non-endemic congeners. It is, however, relatively difficult to translate the differences in morphology of the diaspores into differences in dispersal ability. To avoid this problem, we measured directly dispersal values (anemo-, hydro-, exozoo- and endozoo-chory) of 27 pairs of closely related endemic and non-endemic species from Canary Islands. We did not explicitly support the hypothesis about the loss of dispersal ability of island species. The comparison of pairs of endemic and non-endemic species showed the reduction in dispersal potential only for endozoochory. In many cases, endemic species had, in fact, the same or better dispersal ability than their non-endemic congeners. Higher dispersal ability of endemic species could have been evolved as a consequence of species subsequent dispersal to neighboring islands. As a support for this we found that the endemic species dispersing better than their non-endemic congeners also occupy more islands within the archipelago. We conclude that reduction of dispersal ability of species on islands may not be as general as previously expected and we need to take into account multiple species traits to understand the possible evolution of species dispersal potential.