Darwin's Naturalization Hypothesis Research Articles

Phylogenetic Relationships and Disturbance Explain the Resistance of Different Habitats to Plant Invasions.

Invasive alien plants have invaded various habitats, posing a threat to biodiversity. Several hypotheses have been proposed to explain the mechanisms of invasion, but few studies have considered the characteristics of the invaded communities and the effects of human interference in the invasion. In this study, we compared the invasibility of three different habitats: abandoned land, eucalyptus plantations, and natural secondary forests. We explored the effects of species diversity, phylogenetic diversity, and disturbance factors on the invasibility of different habitats. The results showed that the invasibility of abandoned land was the highest and the invasibility of the natural secondary forest was the lowest. Phylogenetic indicators affected the invasibility of abandoned land and eucalyptus plantations, and disturbance factors affected the invasibility of all three habitats, while the characteristics of the invaded communities had a weak impact. Our research provided supporting evidence for Darwin's naturalization hypothesis and his disturbance hypothesis but found no relationship between biotic resistance and invasibility. This study indicated that the differences among habitats should be considered when we prove Darwin's naturalization hypothesis in nature reserves.

Darwin's naturalization conundrum reconciled by changes of species interactions.

Although phylogenetic distance between native and exotic species has a close link with their interactions, it is still unclear how environmental stresses and species interactions influence the relationship between phylogenetic distance and biological invasions. Here we assessed the effect of invader-native phylogenetic distance on the growth of the invader (Symphyotrichum subulatum) under three levels of drought (no, moderate, or intense drought). Under no drought, interspecific competition between close relatives was the dominant process and native communities more closely related to the invader showed higher resistance to invasion, supporting Darwin's naturalization hypothesis. In contrast, under intense drought, facilitation between close relatives by mutualism with arbuscular mycorrhizal fungi (AMF) became more important, and the invader became more successful in their more closely related native communities, supporting the preadaptation hypothesis. The colonization rate of AMF of the invader was higher in more closely related native communities regardless of the drought treatment, but it was only positively related to invader biomass under intense drought. Therefore, the shift of species interactions from competition to facilitation may be ascribed to the promotion of AMF to invasion occurring under intense drought, which leads to the effect of closely related natives on the invader shifting from negative to positive. Our results provide a new angle to resolve Darwin's naturalization conundrum from the change of species interactions along a stress gradient, and provide important clues for invasion management when species interactions change in response to global climatic change.

The role of phylogenetic relatedness on alien plant success depends on the stage of invasion.

Darwin's naturalization hypothesis predicts successful alien invaders to be distantly related to native species, whereas his pre-adaptation hypothesis predicts the opposite. It has been suggested that depending on the invasion stage (that is, introduction, naturalization and invasiveness), both hypotheses, now known as Darwin's naturalization conundrum, could hold true. We tested this by analysing whether the likelihood of introduction for cultivation, as well as the subsequent stages of naturalization and spread (that is, becoming invasive) of species alien to Southern Africa are correlated with their phylogenetic distance to the native flora of this region. Although species are more likely to be introduced for cultivation if they are distantly related to the native flora, the probability of subsequent naturalization was higher for species closely related to the native flora. Furthermore, the probability of becoming invasive was higher for naturalized species distantly related to the native flora. These results were consistent across three different metrics of phylogenetic distance. Our study reveals that the relationship between phylogenetic distance to the native flora and the success of an alien species changes from one invasion stage to the other.

The role of phylogenetic scale in Darwin's naturalization conundrum in the critically imperilled pine rockland ecosystem

AbstractAimWe expand on community phylogenetic approaches to Darwin's Naturalization Conundrum by considering phylogenetic scale, comprised of phylogenetic grain and extent. We assess relatedness between invasive, non‐native and native plant species at multiple depths in the phylogeny (i.e. phylogenetic grain) and across multiple clades (i.e. phylogenetic extents) at regional and local spatial scales in the highly fragmented, critically imperilled pine rockland ecosystem.LocationMiami‐Dade County, Florida, USA.MethodsWe used two metrics differing in phylogenetic grain to determine whether invasive or non‐native species were more closely related to native species in the regional pool and at 33 habitat fragments. At both spatial scales, we altered phylogenetic extent from all vascular plants to four smaller phylogenetic domains (Monilophyte, Gymnosperm, Monocotyledon and Dicotyledon) and assessed whether the interpretation of relatedness changed.ResultsFor the regional pool and at a broad phylogenetic grain, non‐native species were more closely related to the native community than invasive species were for all phylogenetic extents (i.e. support for Darwin's Naturalization Hypothesis, DNH), and at a fine phylogenetic grain for only two phylogenetic extents. At the local scale, there was limited support for DNH across all phylogenetic extents. In Monocotyledons, support for DNH was more prevalent at the fine phylogenetic grain, while Dicotyledons showed support for DNH at the broad phylogenetic grain.Main conclusionsIn the pine rockland flora, we found either support for DNH or no difference in relatedness between non‐native‐to‐native and invasive‐to‐native species. However, patterns of relatedness varied across spatial and phylogenetic grain and, critically, this variability is highly dependent on the phylogenetic extent considered. By explicitly assessing the interactions between spatial scale and phylogenetic scale, we show that support for DNH was context dependent, and findings at smaller phylogenetic extents rarely agreed with findings at the larger phylogenic extent.

A habitat‐based assessment of the role of competition in plant invasions

Abstract Many invasion theories invoke resource competition as the primary mechanism of invader advantage. These include Darwin's naturalization hypothesis (DNH), which treats phylogenetic similarity as a proxy for niche overlap and competitive intensity, and the evolutionary imbalance hypothesis (EIH), which suggests the phylogenetic diversity (PD) of an introduced species’ native range is an indicator of its competitive ability. Few tests of invasion theory, however, consider habitat characteristics associated with the role of competition in community assembly. In particular, plant invasions of habitats characterized by high environmental stress and disturbance levels should rarely be driven by competition. This suggests tests of EIH and DNH are habitat dependent, and their relative importance in invasiveness models should be predictable based on habitat qualities related to competitive intensity. Using a dataset of plant invasions in New Zealand (NZ) natural areas that distinguishes naturalized species according to both habitat type and community impact, we evaluated the predictive ability of factors related to EIH, DNH and covariates including year of introduction, introduction mode and life history attributes, in driving species invasiveness. We hypothesized that EIH and DNH would be more important predictors of invasiveness in forested habitats and decline in importance as communities shifted towards those more dominated by herbaceous species and/or more sparsely vegetated. We found mixed support for the role of competition linked to DNH and EIH as a driver of invasions in relation to habitat type. Native range PD was among the best predictors of invasiveness in forests, and declined in importance in more disturbed habitats, supporting EIH. In contrast, phylogenetic nearest neighbour distance (PNND) of invaders to native communities was more important in disturbed environments, suggesting competition does not drive DNH. Further, for most habitats and across all of NZ, neither PD nor PNND was as important as year of introduction or life history and growth form attributes in predicting invasiveness. Synthesis. Although both native range PD and PNND predict the invasiveness of naturalized plants in NZ, the results of our habitat‐specific models indicate that only PD is consistent with an invasion mechanism based on competitive ability. Effects of PNND were greatest in grasslands that have been extensively modified by fire and grazing, suggesting they are more likely driven by invader pre‐adaptation to modified habitat conditions. Due to the importance of matching species' traits to environmental context, invasiveness risk assessments perform better when applied to invaders of particular habitats.

Darwin's naturalization hypothesis does not explain the spread of nonnative weed species naturalized in México.

BackgroundDespite numerous tests of Darwin’s naturalization hypothesis (DNH) evidence for its support or rejection is still contradictory. We tested a DNH derived prediction stating that nonnative species (NNS) without native congeneric relatives (NCR) will spread to a greater number of localities than species with close relatives in the new range. This test controlled the effect of residence time (Rt) on the spread of NNS and used naturalized species beyond their lag phase to avoid the effect of stochastic events in the establishment and the lag phases that could obscure the NCR effects on NNS.MethodsWe compared the number of localities (spread) occupied by NNS with and without NCR using 13,977 herbarium records for 305 NNS of weeds. We regressed the number of localities occupied by NNS versus Rt to determine the effect of time on the spread of NNS. Then, we selected the species with Rt greater than the expected span of the lag phase, whose residuals were above and below the regression confidence limits; these NNS were classified as widespread (those occupying more localities than expected by Rt) and limited-spread (those occupying fewer localities than expected). These sets were again subclassified into two groups: NNS with and without NCR at the genus level. The number of NNS with and without NCR was compared using χ2 tests and Spearman correlations between the residuals and the number of relatives. Then, we grouped the NNS using 34 biological attributes and five usages to identify the groups’ possible associations with spread and to test DNH. To identify species groups, we performed a nonmetric multidimensional scaling (NMDS) analysis and evaluated the influences of the number of relatives, localities, herbarium specimens, Rt, and residuals of regression. The Spearman correlation and the Mann–Whitney U test were used to determine if the DNH prediction was met. Additionally, we used the clustering objects on subsets of attributes (COSA) method to identify possible syndromes (sets of biological attributes and usages) associated to four groups of NNS useful to test DNH (those with and without NCR and those in more and fewer localities than expected by Rt).ResultsResidence time explained 33% of the variation in localities occupied by nonnative trees and shrubs and 46% of the variation for herbs and subshrubs. The residuals of the regression for NNS were not associated with the number or presence of NCR. In each of the NMDS groups, the number of localities occupied by NNS with and without NCR did not significantly differ. The COSA analysis detected that only NNS with NCR in more and fewer localities than expected share biological attributes and usages, but they differ in their relative importance.DiscussionOur results suggest that DNH does not explain the spread of naturalized species in a highly heterogeneous country. Thus, the presence of NCR is not a useful characteristic in risk analyses for naturalized NNS.

It takes one to know one: Similarity to resident alien species increases establishment success of new invaders

AbstractAimDarwin's naturalization hypothesis states that dissimilarity to native species may benefit alien species establishment due to empty niches and reduced competition. We here add a new dimension to large‐scale tests of community invasibility, investigating the role that previously established alien species play in facilitating or hindering new invasions in plant communities.LocationPermanent grasslands across France (including mainland and Corsica), as a receding ecosystem of great conservation importance.MethodsFocusing on 121 alien plant species occurring in 7,215 vegetation plots, we quantified biotic similarity between new invaders and resident alien species (i.e., alien species with longer residence times) based on phylogenetic and trait distances. Additionally, we calculated distances to native species for each alien species and plot. Using multispecies distribution models, we analysed the influence of these biotic similarity measures and additional covariates on establishment success (presence/absence) of new invaders.ResultsWe found that biotic similarity to resident alien species consistently increased establishment success of more recently introduced species. Phylogenetic relatedness to previous invaders had an equally strong positive effect as relatedness to native species. Conversely, trait similarity to natives hindered alien establishment as predicted by Darwin's naturalization hypothesis. These results highlight that various mechanisms may act simultaneously to determine alien establishment success.Main conclusionsOur results suggest that, with greater similarity among alien species, invasion success increases. Such a pattern may arise either due to actual facilitation among invaders or as a result of weaker competitive interactions among invaders than between native and alien species, leading to an indirect facilitative effect. Alternatively, recent environmental changes (e.g., eutrophication, climate change) may have added new environmental filters. Determining how initial invasions might pave the road for subsequent invasions is crucial for effective multispecies management decisions and contributes a new aspect to our understanding of community assembly.

Impact of an Invasive Longhorned Beetle, Tetropium fuscum (Coleoptera: Cerambycidae), on Community Structure of Subcortical and Wood-Associated Insects in Eastern Canada.

Tetropium fuscum (Fabricius) (Coleoptera: Cerambycidae), a phloem-feeding and wood-boring beetle introduced from Eurasia, attacks spruce in eastern Canada alongside its native congener Tetropium cinnamopterum Kirby. We reared phloem- and wood-feeding insects (and their predators) from bolts of red and Norway spruce (Picea rubens and Picea abies) in Nova Scotia, comparing insect communities between bolts with added eggs of T. fuscum or T. cinnamopterum and bolts without added Tetropium (controls). We tested for impacts of each Tetropium on insect community structure (Simpson's diversity, richness, and evenness). We also asked whether, consistent with Darwin's Naturalization Hypothesis, Tetropium spp. would have greater impacts on emergence of its closer relatives (which might be most likely to compete and/or share natural enemies). Addition of Tetropium eggs (either species) to bolts lowered insect diversity in both host trees. Both richness and evenness components of diversity were always lower in +Tetropium treatments, although different components reached statistical significance in different Tetropium species × host combinations. Addition of Tetropium spp. significantly reduced emergence of some species: Evodinus monticola (Randall) (Coleoptera: Cerambycidae) was reduced by T. fuscum on both hosts and by T. cinnamopterum on Norway spruce; Hylobius congener Dalla Torre, Schenkling, and Marshall was reduced by T. fuscum on red spruce; and Xylophagus sp. (Diptera: Xylophagidae) was reduced by T. cinnamopterum on Norway spruce. However, there was no relationship between Tetropium's impact on a community member and their phylogenetic relatedness, and the overall impacts of Tetropium presence were not very different between T. fuscum and T. cinnamopterum.

Limiting similarity and Darwin's naturalization hypothesis: understanding the drivers of biotic resistance against invasive plant species.

Several hypotheses have been proposed to explain biotic resistance of a recipient plant community based on reduced niche opportunities for invasive alien plant species. The limiting similarity hypothesis predicts that invasive species are less likely to establish in communities of species holding similar functional traits. Likewise, Darwin's naturalization hypothesis states that invasive species closely related to the native community would be less successful. We tested both using the invasive alien Ambrosia artemisiifolia L. and Solidago gigantea Aiton, and grassland species used for ecological restoration in central Europe. We classified all plant species into groups based on functional traits obtained from trait databases and calculated the phylogenetic distance among them. In a greenhouse experiment, we submitted the two invasive species at two propagule pressures to competition with communities of ten native species from the same functional group. In another experiment, they were submitted to pairwise competition with native species selected from each functional group. At the community level, highest suppression for both invasive species was observed at low propagule pressure and not explained by similarity in functional traits. Moreover, suppression decreased asymptotically with increasing phylogenetic distance to species of the native community. When submitted to pairwise competition, suppression for both invasive species was also better explained by phylogenetic distance. Overall, our results support Darwin's naturalization hypothesis but not the limiting similarity hypothesis based on the selected traits. Biotic resistance of native communities against invasive species at an early stage of establishment is enhanced by competitive traits and phylogenetic relatedness.

Correction to 'Different effects of invader-native phylogenetic relatedness on invasion success and impact: a meta-analysis of Darwin's naturalization hypothesis'.

Darwin's naturalization hypothesis (DNH), which predicts that alien species more distantly related to native communities are more likely to naturalize, has received much recent attention. The mixed findings from empirical studies that have tested DNH, however, seem to defy generalizations. Using meta-analysis to synthesize results of existing studies, we show that the predictive power of DNH depends on both the invasion stage and the spatial scale of the studies. Alien species more closely related to natives tended to be less successful at the local scale, supporting DNH; invasion success, however, was unaffected by alien-native relatedness at the regional scale. On the other hand, alien species with stronger impacts on native communities tended to be more closely related to natives at the local scale, but less closely related to natives at the regional scale. These patterns are generally consistent across different ecosystems, taxa and investigation methods. Our results revealed the different effects of invader-native relatedness on invader success and impact, suggesting the operation of different mechanisms across invasion stages and spatial scales.

Different effects of invader-native phylogenetic relatedness on invasion success and impact: a meta-analysis of Darwin's naturalization hypothesis.

Darwin's naturalization hypothesis (DNH), which predicts that alien species more distantly related to native communities are more likely to naturalize, has received much recent attention. The mixed findings from empirical studies that have tested DNH, however, seem to defy generalizations. Using meta-analysis to synthesize results of existing studies, we show that the predictive power of DNH depends on both the invasion stage and the spatial scale of the studies. Alien species more closely related to natives tended to be less successful at the local scale, supporting DNH; invasion success, however, was unaffected by alien-native relatedness at the regional scale. On the other hand, alien species with stronger impacts on native communities tended to be more closely related to natives at the local scale, but less closely related to natives at the regional scale. These patterns are generally consistent across different ecosystems, taxa and investigation methods. Our results revealed the different effects of invader-native relatedness on invader success and impact, suggesting the operation of different mechanisms across invasion stages and spatial scales.

Fungal communities as an experimental approach to Darwin's naturalization hypothesis

Darwin's naturalization hypothesis suggests that the success of an invasive species will be lower when colonizing communities are formed by phylogenetically related rather than unrelated species due to increased competition. Although microbial invasions are involved in both natural and anthropogenic processes, factors affecting the success of microbial invaders are unknown.A biological invasion assay was designed using Trichoderma cf. harzianum as the invader and two types of recipient communities assembled in microcosm assays: communities phylogenetically related to the invader, and communities phylogenetically unrelated to it. Both types of communities were invaded by T. cf. harzianum, and the success of colonization was monitored by qPCR; its effect on the genetic structure of recipient fungal communities was then assessed by DGGE profiles. T. cf. harzianum established itself in both communities, reaching 1000–10,000 times higher copy numbers in the non-related communities. However, invader establishment does not affect the structure of the invaded communities. These results suggest that the composition of recipient communities and their phylogenetic relationship to the invader affect the success of colonization by T. cf. harzianum. While this approach represents a very simplified assay, these microcosms enable an experimental test of Darwin's hypothesis in order to understand the biological invasion process in microbial communities.

Retraction—Alien spiders in Chile: evaluating Darwin's naturalization hypothesis

Darwin's naturalization hypothesis (DNH) states that the successful establishment of alien species is favored when the phylogenetic relationship between the colonizer and the recipient community is distant. From a population perspective, the establishment involves both the progressive increase in size and spatial distribution of the invasive population. In this study, we focused our attention on the spatial component of establishment, assessing the role of phylogenetic relatedness as a determinant of its extension. Following DNH, it is expected that alien species closely related to the native spiders would show narrower distribution ranges than alien taxa less related to the native species. We found 18 alien spider species in Chile; all of these are synanthropic and most are of African origin. Our results indicate a difference in range size between related and unrelated species but it was not statistically significant. Consequently, the results do not support DNH as an explanation of the distributional component of establishment of alien spider species in Chile. We conclude that ecological constraints do not affect the process of invasion of spiders; therefore, it is only time that determines the spread of alien spiders in this country.

Retraction—Alien spiders in Chile: evaluating Darwin's naturalization hypothesis

Retraction—Alien spiders in Chile: evaluating Darwin's naturalization hypothesis

Why close relatives make bad neighbours: phylogenetic conservatism in niche preferences and dispersal disproves Darwin's naturalization hypothesis in the thistle tribe.

The number of exotic plant species that have been introduced into the United States far exceeds that of other groups of organisms, and many of these have become invasive. As in many regions of the globe, invasive members of the thistle tribe, Cardueae, are highly problematic in the California Floristic Province, an established biodiversity hotspot. While Darwin's naturalization hypothesis posits that plant invaders closely related to native species would be at a disadvantage, evidence has been found that introduced thistles more closely related to native species are more likely to become invasive. To elucidate the mechanisms behind this pattern, we modelled the ecological niches of thistle species present in the province and compared niche similarity between taxa and their evolutionary relatedness, using fossil-calibrated molecular phylogenies of the tribe. The predicted niches of invasive species were found to have higher degrees of overlap with native species than noninvasive introduced species do, and pairwise niche distance was significantly correlated with phylogenetic distance, suggesting phylogenetic niche conservatism. Invasive thistles also displayed superior dispersal capabilities compared to noninvasive introduced species, and these capabilities exhibited a phylogenetic signal. By analysing the modelled ecological niches and dispersal capabilities of over a hundred thistle species, we demonstrate that exapted preferences to the invaded environment may explain why close exotic relatives may make bad neighbours in the thistle tribe.

Resident-invader phylogenetic relatedness, not resident phylogenetic diversity, controls community invasibility.

A central goal of invasion biology is to elucidate mechanisms regulating community invasibility. Darwin's naturalization hypothesis, one of the oldest hypotheses in invasion biology, emphasizes the importance of phylogenetic relatedness (PR) between resident and invader species for predicting invasibility. Alternatively, a recent extension of the diversity-invasibility hypothesis predicts that phylogenetic diversity (PD) of resident communities influences invasibility. Neither of these hypotheses has undergone rigorous experimental testing, and the relative contributions of PR and PD to community invasibility are unknown, in part because their effects tend to be confounded with each other. Here we consider both perspectives together by independently manipulating PR and PD in laboratory bacterial assemblages. We found that, although invader abundance decreased significantly as PR increased, it was unaffected by PD. Likewise, we found that resident-invader functional similarity, not functional diversity of resident communities, was a significant predictor of invader abundance. Nevertheless, invader abundance was better predicted by PR than by functional similarity. These results highlight the importance of considering species evolutionary relationships, especially the PR between resident and invader species, for the prediction, prevention, and management of biological invasions.

Alien spiders in Chile: evaluating Darwin's naturalization hypothesis

Darwin's naturalization hypothesis (DNH) states that the successful establishment of alien species is favored when the phylogenetic relationship between the colonizer and the recipient community is distant. From a population perspective, the establishment involves both the progressive increase in size and spatial distribution of the invasive population. In this study, we focused our attention on the spatial component of establishment, assessing the role of phylogenetic relatedness as a determinant of its extension. Following DNH, it is expected that alien species closely related to the native spiders would show narrower distribution ranges than alien taxa less related to the native species. We found 18 alien spider species in Chile; all of these are synanthropic and most are of African origin. Our results indicate a difference in range size between related and unrelated species but it was not statistically significant. Consequently, the results do not support DNH as an explanation of the distributional component of establishment of alien spider species in Chile. We conclude that ecological constraints do not affect the process of invasion of spiders; therefore, it is only time that determines the spread of alien spiders in this country.

Darwin's hypotheses to explain colonization trends: evidence from a quasi‐natural experiment and a new conceptual model

AbstractAimWe examined fish establishment trends in the aftermath of the connection of two Neotropical freshwater ecoregions. Darwin's conundrum was used to examine whether taxonomic and functional relatedness would explain establishment or whether the establishment of new populations was driven by ecological interactions (Darwin's naturalization hypothesis, DNH) or by shared environmental requirements (adaptation hypothesis, AH).LocationParaná River, south‐eastern South America.MethodsTaxonomic relatedness was investigated using a one‐tailed Fisher exact test, considering all species and monophyletic groups. Functional traits were used to estimate niche dissimilarities among non‐native species and across the entire set of native species, generating distributions that were fitted to exponential or logarithmic curves, based on a new conceptual model.ResultsOf the 213 species from the Lower Paraná River that had the opportunity to reach the Upper Paraná River, 25% – 53 spp. – were successfully established. The ratios of unshared to shared genera for both successful and unsuccessful non‐native species were not different, but 7% of type I error probability for Characiformes and 8% for all species, would favour DNH. Our results indicate that both DNH and AH could explain successes but that DNH was more likely to explain failures in establishment.Main conclusionDarwin's naturalization hypothesis is more likely to explain the non‐native establishment in invasion processes. Both the DNH and AH explain successful colonization, but DNH provided the best explanation for failed non‐native establishments. Non‐native species that were functionally similar to native species (i.e. with similar traits) were more likely to fail, suggesting that biotic resistance was directly linked to ecological similarity. Biotic resistance could be the most important mechanism for explaining establishment or failure of non‐native species. The conceptual model proposed here can be used to predict which non‐native species are least likely to establish, based on the functional traits of species in the native community.

A phylogenetic analysis of the British flora sheds light on the evolutionary and ecological factors driving plant invasions.

Darwin's naturalization hypothesis predicts that invasive species should perform better in their novel range in the absence of close relatives in the native flora due to reduced competition. Evidence from recent taxonomic and phylogenetic-based studies, however, is equivocal. We test Darwin's naturalization hypothesis at two different spatial scales using a fossil-dated molecular phylogenetic tree of the British native and alien flora (ca. 1600 species) and extensive, fine-scale survey data from the 1998 Countryside Survey. At both landscape and local scales, invasive species were neither significantly more nor less related to the native flora than their non-invasive alien counterparts. Species invasiveness was instead correlated with higher nitrogen and moisture preference, but not other life history traits such as life-form and height. We argue that invasive species spread in Britain is hence more likely determined by changes in land use and other anthropogenic factors, rather than evolutionary history. Synthesis. The transition from non-invasive to invasive is not related to phylogenetic distinctiveness to the native community, but instead to their environmental preferences. Therefore, combating biological invasions in the Britain and other industrialized countries need entirely different strategies than in more natural environments.

Evaluating Darwin's naturalization hypothesis in experimental plant assemblages: phylogenetic relationships do not determine colonization success.

Darwin’s naturalization hypothesis (DNH) proposes that colonization is less likely when the colonizing species is related to members of the invaded community, because evolutionary closeness intensifies competition among species that share similar resources. Studies that have evaluated DNH from correlational evidence have yielded controversial results with respect to its occurrence and generality. In the present study we carried out a set of manipulative experiments in which we controlled the phylogenetic relatedness of one colonizing species (Lactuca sativa) with five assemblages of plants (the recipient communities), and evaluated the colonizing success using five indicators (germination, growth, flowering, survival, and recruitment). The evolutionary relatedness was calculated as the mean phylogenetic distance between Lactuca and the members of each assemblage (MPD) and by the mean phylogenetic distance to the nearest neighbor (MNND). The results showed that the colonization success of Lactuca was not affected by MPD or MNND values, findings that do not support DNH. These results disagree with experimental studies made with communities of microorganisms, which show an inverse relation between colonization success and phylogenetic distances. We suggest that these discrepancies may be due to the high phylogenetic distance used, since in our experiments the colonizing species (Lactuca) was a distant relative of the assemblage members, while in the other studies the colonizing taxa have been related at the congeneric and conspecific levels. We suggest that under field conditions the phylogenetic distance is a weak predictor of competition, and it has a limited role in determining colonization success, contrary to prediction of the DNH. More experimental studies are needed to establish the importance of phylogenetic distance between colonizing species and invaded community on colonization success.