scholarly journals Trait-Environment Relationships Reveal the Success of Alien Plants Invasiveness in an Urbanized Landscape

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1519
Author(s):  
Reham F. El-Barougy ◽  
Mohammed A. Dakhil ◽  
Mohamed Abdelaal ◽  
Ali El-Keblawy ◽  
Louis-Félix Bersier
Keyword(s):  
Alien Species ◽  
Urban Areas ◽  
Native Species ◽  
Native Plants ◽  
Plant Traits ◽  
Species Traits ◽  
Alien Plants ◽  
Urbanization Gradient ◽  
Soil Resources ◽  
Species Groups

Urban areas are being affected by rapidly increasing human-made pressures that can strongly homogenize biodiversity, reduce habitat heterogeneity, and facilitate the invasion of alien species. One of the key concerns in invaded urban areas is comparing the trait–environment relationships between alien and native species, to determine the underlying causes of invasiveness. In the current study, we used a trait–environment dataset of 130 native plants and 33 alien plants, recorded in 100 plots covering 50 urban areas and 50 non-urban ones in an urbanization gradient in the arid mountainous Saint-Katherine protected area in Egypt. We measured eleven morphological plant traits for each plant species and ten environmental variables in each plot, including soil resources and human-made pressures, to construct trait–environment associations using a fourth-corner analysis. In addition, we measured the mean functional and phylogenetic distances between the two species groups along an urbanization gradient. Our results revealed strongly significant relationships of alien species traits with human-made pressures and soil resources in urban areas. However, in non-urban areas, alien species traits showed weak and non-significant associations with the environment. Simultaneously, native plants showed consistency in their trait–environment relationships in urban and non-urban areas. In line with these results, the functional and phylogenetic distances declined between the aliens and natives in urban areas, indicating biotic homogenization with increasing urbanization, and increased in non-urban areas, indicating greater divergence between the two species groups. Thereby, this study provided evidence that urbanization can reveal the plasticity of alien species and can also be the leading cause of homogenization in an arid urban area. Future urban studies should investigate the potential causes of taxonomic, genetic, and functional homogenization in species composition in formerly more diverse urbanized areas.

scholarly journals Alien Plants are Less Palatable to Pest Herbivores than Native Plants: Evidence from Cafeteria Experiments in Search of Suitable Plant Species to Restore Degraded Ecosystems

2021 ◽  
Vol 40 (1) ◽  
pp. 16-24
Author(s):  
Mouldi Gamoun ◽  
Mounir Louhaichi
Keyword(s):  
Alien Species ◽  
Plant Species ◽  
Native Species ◽  
Native Plants ◽  
Feeding Preference ◽  
Alien Plants ◽  
General Tendency ◽  
Native Plant ◽  
Evolutionary Potential ◽  
Wide Range

Abstract Nowadays, the ecology and evolutionary potential of alien species are the subjects of several ecological studies. The goal of this study was to compare the feeding preference of Arion ater on seedlings and leaves of alien and native plant species. Seedlings of three native species and one alien species were offered to slugs individually and in combination. Afterward, leaf discs from the native and alien species collected from the same source site of slug’s habitat were offered individually and in combination for slugs. When the new plant emerges, it constitutes a generous source of potential food and slugs would even feed on seedlings, which are not particularly palatable. Nonetheless, when given a choice, slug often preferentially feeds on some food items while ignoring others. Alien plants are more resistant to herbivory than native plants. There is a general tendency for alien species to be less palatable than native species. In general, slugs may eat a wide range of seedlings that are much more attractive than mature plants of the same species. Therefore, the native herbivores were found to attack native plants and promoted alien plants. Consequently, highly unacceptable alien species such as Eucalyptus globulus may play an important role in the restoration process.

scholarly journals Alien woody plants are more versatile than native, but both share similar therapeutic redundancy in South Africa

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260390
Author(s):  
Kowiyou Yessoufou ◽  
Annie Estelle Ambani ◽  
Hosam O. Elansary ◽  
Orou G. Gaoue
Keyword(s):  
Plant Species ◽  
Native Species ◽  
Native Plants ◽  
Invasion Biology ◽  
Alien Plants ◽  
Parasitic Infections ◽  
Alien Plant Species ◽  
Secondary Chemistry ◽  
Alien Plant ◽  
Medicinal Flora

Understanding why alien plant species are incorporated into the medicinal flora in several local communities is central to invasion biology and ethnobiology. Theories suggest that alien plants are incorporated in local pharmacopoeias because they are more versatile or contribute unique secondary chemistry which make them less therapeutically redundant, or simply because they are locally more abundant than native species. However, a lack of a comprehensive test of these hypotheses limits our understanding of the dynamics of plants knowledge, use and potential implications for invasion. Here, we tested the predictions of several of these hypotheses using a unique dataset on the woody medicinal flora of southern Africa. We found that the size of a plant family predicts the number of medicinal plants in that family, a support for the non-random hypothesis of medicinal plant selection. However, we found no support for the diversification hypothesis: i) both alien and native plants were used in the treatment of similar diseases; ii) significantly more native species than alien contribute to disease treatments particularly of parasitic infections and obstetric-gynecological diseases, and iii) alien and native species share similar therapeutic redundancy. However, we found support for the versatility hypothesis, i.e., alien plants were more versatile than natives. These findings imply that, although alien plant species are not therapeutically unique, they do provide more uses than native plants (versatility), thus suggesting that they may not have been introduced primarily for therapeutic reasons. We call for similar studies to be carried out on alien herbaceous plants for a broader understanding of the integration of alien plants into the pharmacopoeias of the receiving communities.

scholarly journals Increases in multiple resources promote plant invasion

2021 ◽  
Author(s):  
Zhijie Zhang ◽  
Yanjie Liu ◽  
Angelina Hardrath ◽  
Huifei Jin ◽  
Mark van Kleunen
Keyword(s):  
Light Intensity ◽  
Alien Species ◽  
Plant Invasion ◽  
Native Plants ◽  
Common Garden ◽  
Alien Plants ◽  
Limiting Factors ◽  
Global Changes ◽  
Multiple Resources ◽  
Common Garden Experiments

Invasion by alien plants is frequently attributed to increased resource availabilities. Still, our understanding is mainly based on effect of single resource. Despite the fact that plants rely on many resources, little is known about how multiple resources affect success of alien plants. Here, with two common garden experiments, one in China and one in Germany, we tested whether nutrient and light availabilities affected the competitive outcomes between alien and native plants. We found that under low resource availabilities or with addition of only one type of resources aliens were not more competitive than natives. However, with a joint increase of nutrients and light intensity, aliens outcompeted natives. Our finding indicates that addition of multiple resources could greatly reduce the number of limiting factors (i.e. niche dimensionality), and that this favors the dominance of alien species. It also indicates that habitats experiencing multiple global changes might be more vulnerable to plant invasion.

scholarly journals The role of biotic factors during plant establishment in novel communities assessed with an agent-based simulation model

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5342 ◽  
Author(s):  
Janina Radny ◽  
Katrin M. Meyer
Keyword(s):  
Survival Rate ◽  
Simulation Model ◽  
Native Species ◽  
Native Plants ◽  
Survival Rates ◽  
Species Traits ◽  
Native Community ◽  
Competition Intensity ◽  
Positive Effects ◽  
Successful Establishment

Background Establishment success of non-native species is not only influenced by environmental conditions, but also by interactions with local competitors and enemies. The magnitude of these biotic interactions is mediated by species traits that reflect competitive strength or defence mechanisms. Our aim was to investigate the importance of species traits for successful establishment of non-native species in a native community exhibiting biotic resistance in the form of competition and herbivory. Methods We developed a trait-based, individual-based simulation model tracking the survival of non-native plants in a native community. In the model, non-native plants are characterized by high or low values of competition and defence traits. Model scenarios included variation of initial number of non-natives, intensity of competitive interaction, density of herbivores and density as well as mixture of the native community. Results Traits related to competition had a much greater impact on survival of non-native species than traits related to defence. Survival rates of strong competitors never fell below 50% while survival of weak competitors averaged at about 10%. Weak competitors were also much more susceptible to competitive pressures such as community density, composition and competition intensity. Strong competitors responded negatively to changes in competition intensity, but hardly to composition or density of the native community. High initial numbers of non-native individuals decreased survival rate of strong competitors, but increased the survival rate of weak competitors. Survival under herbivore attack was only slightly higher for plants with high defensive ability than for those with low defensive ability. Surprisingly, though, herbivory increased survival of species classified as weak competitors. Discussion High survival rates of strong non-native competitors relate to a higher probability of successful establishment than for weak competitors. However, the reduced survival of strong competitors at high initial numbers indicates a self-thinning effect, probably mediated by a strongly competitive milieu. For weak competitors, our model emphasizes positive effects of high propagule pressure known from field studies. General effects of herbivory or defence abilities on survival were not supported by our model. However, the positive effect of herbivory on survival of weak competitors indicated side effects of herbivory, such as weakening resident competitors. This might play an important role for establishment of non-natives in a new community.

scholarly journals Remoteness promotes biological invasions on islands worldwide

2018 ◽  
Vol 115 (37) ◽  
pp. 9270-9275 ◽  
Author(s):  
Dietmar Moser ◽  
Bernd Lenzner ◽  
Patrick Weigelt ◽  
Wayne Dawson ◽  
Holger Kreft ◽  
...  
Keyword(s):  
Alien Species ◽  
Island Biogeography ◽  
Native Species ◽  
Native Plants ◽  
Oceanic Islands ◽  
Tropical Islands ◽  
Large Dataset ◽  
Island Species ◽  
Species Pools ◽  
Natural Dispersal

One of the best-known general patterns in island biogeography is the species–isolation relationship (SIR), a decrease in the number of native species with increasing island isolation that is linked to lower rates of natural dispersal and colonization on remote oceanic islands. However, during recent centuries, the anthropogenic introduction of alien species has increasingly gained importance and altered the composition and richness of island species pools. We analyzed a large dataset for alien and native plants, ants, reptiles, mammals, and birds on 257 (sub) tropical islands, and showed that, except for birds, the number of naturalized alien species increases with isolation for all taxa, a pattern that is opposite to the negative SIR of native species. We argue that the reversal of the SIR for alien species is driven by an increase in island invasibility due to reduced diversity and increased ecological naiveté of native biota on the more remote islands.

scholarly journals Native and non-native plants attract diverse bees to urban gardens in California

2019 ◽  
Vol 25 ◽  
Author(s):  
Gordon Frankie ◽  
Ingrid Feng ◽  
Robbin Thorp ◽  
Jaime Pawelek ◽  
Marissa Helene Chase ◽  
...  
Keyword(s):  
Urban Areas ◽  
Native Species ◽  
Host Plants ◽  
Native Plants ◽  
Ornamental Plants ◽  
Geographic Origin ◽  
Native Plant ◽  
Native Plant Species ◽  
Native Bee ◽  
The University

Bees visit native and non-native plant species for pollen and nectar resources in urban, agricultural, and wildland environments. Results of an extensive survey of bee-flower collection records from 10 California cities from 2005-2011 were used to examine host-plant records of native and non-native ornamental plants to diverse native and non-native bee species; five cities were from northern California and five were from southern California. A total of 7,659 bees and their floral host plants were examined. Of these, 179 were Apis mellifera and 7,390 were non-Apis. Only four other non-native species (all in Megachilidae) were recorded in the survey, and together they accounted for 402 individuals. These bees have been databased in preparation for deposition in the University of California-Berkeley Essig Museum of Entomology. We identified 229 bee species and 42 genera visiting native and non-native plant types in urban areas. Of the 229 species, 71 bee species were collected from only native plants; 52 were collected from only non-native host plants; and 106 were collected from both types of plants. Native bee species were common on native plants and non-native plants, but there were substantially more non-native bee species visiting non-native plants compared to native plants. Flowering periods in months were similar for both types of plants, but non-natives tended to flower later in the year. We propose that using native and non-native plants improves habitat gardening by increasing opportunities for attracting a richer diversity of bee species and for longer periods. Knowing basic bee-flower relationships in an area is key to planning a bee habitat garden with a variety of plant types, regardless of their geographic origin. 

scholarly journals Phylogenetic Diversity of Urban Floras in the Central Urals

2021 ◽  
Vol 9 ◽  
Author(s):  
Alyona S. Tretyakova ◽  
Basil N. Yakimov ◽  
Pavel V. Kondratkov ◽  
Nickolay Yu. Grudanov ◽  
Marc W. Cadotte
Keyword(s):  
Alien Species ◽  
Urban Areas ◽  
Native Species ◽  
Phylogenetic Diversity ◽  
Indigenous Species ◽  
Phylogenetic Distance ◽  
Full Spectrum ◽  
Modern Cities ◽  
Urban Floras ◽  
Central Urals

Modern cities harbor a high diversity of plants, and urban floras are significantly different from non-urban floras especially when considering the proportion of alien species found in cities. However, it is not clear whether urban areas disproportionately select for species from relatively few evolutionary lineages or provide opportunities for species across the full spectrum of plant lineages. Here, we examined the taxonomic and phylogenetic diversity of the floras in four cities (Yekaterinburg, Kamensk-Uralsky, Krasnoufimsk, and Turinsk) in the understudied region of Central Urals (Russian Federation). We classified native species into indigenous and apophytic species, namely, those that are sensitive to anthropogenic disturbance and those that have expanded their range with human activity, respectively. Alien species were classified into archaeophytes and neophytes according to when they were introduced (i.e., before or after than 1800). Phylogenetic diversity was quantified using Faith’s index to reflect total evolutionary history in urban areas and mean phylogenetic distance (MPD) to reflect species dissimilarity. Phylogenetic diversity of native species was higher than that for alien species, and the standardized effect size (SES) of MPD for natives was positive, reflecting their general dissimilarity from one another, while it was very negative for aliens, showing that they were phylogenetically clustered. However, among natives, apophytes were significantly clustered, while indigenous species were overdispersed. For the aliens, MPD was higher for archaeophytes compared to neophytes, though both groups were significantly clustered. These results show that urbanization leads to a non-random selection of plants. Apophytes and alien plants were composed of closely related species, reflecting similar ecological traits and are likely to be pre-adapted to the environmentally altered and highly disturbed urban environment.

scholarly journals Contrasting alien effects on native diversity along biotic and abiotic gradients in an arid protected area

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reham F. El-Barougy ◽  
Ibrahim A. Elgamal ◽  
Abdel-Hamid A. Khedr ◽  
Louis-Félix Bersier
Keyword(s):  
Protected Area ◽  
Arid Regions ◽  
Native Plants ◽  
Alien Plants ◽  
Native Plant ◽  
Native Community ◽  
Soil Resources ◽  
Future Studies ◽  
Resource Limited ◽  
Native Diversity

AbstractAlien impact on native diversity could be a function of both the relatedness of alien species to native community and resources availability. Here, we investigated whether alien plants expand or decrease the functional and phylogenetic space of native plant communities, and how this is affected by alien relatedness to natives and by resources availability. We used a trait-environment dataset of 33 alien and 130 native plants in 83 pairs of invaded and non-invaded plots, covering a gradient of soil resources (organic matter-nitrogen) in Saint-Katherine-Protectorate, Egypt. First, we compared the changes in native composition and calculated alien relatedness to natives within each pair of plots. Second, we tested the effects of resources availability and relatedness on the magnitude of alien impact (defined as a change in native diversity). We found that native composition was phylogenetically less but functionally more diverse in invaded plots compared to non-invaded ones. Moreover, in resources-rich plots, dissimilar aliens to natives significantly increased native diversity, while in resource-limited ones, similar aliens to natives declined native diversity. These results suggest that the assessment of alien impacts in arid-regions is significantly linked to resources-availability and relatedness to natives. Hence, future studies should test the generality of our findings in different environments.

scholarly journals Functional diversity changes in native and alien urban flora over three centuries

2021 ◽  
Author(s):  
Marija Milanović ◽  
Ingolf Kühn ◽  
Petr Pyšek ◽  
Sonja Knapp
Keyword(s):  
Invasive Species ◽  
Alien Species ◽  
Functional Diversity ◽  
Functional Traits ◽  
Urban Areas ◽  
Native Species ◽  
Seed Mass ◽  
Ecological Niches ◽  
Alien Plant ◽  
Over Time

AbstractAlien species in urban areas have a large effect on overall species diversity. A suitable metric of flora’s response to environmental change is functional diversity (FD) that refers to the multivariate space of species’ trait compositions, reflecting their ecological niches. We studied how FD changed over 320 years of urbanization in the city of Halle (Saale), Germany. Selected functional traits (related to stress-tolerance, reproduction, competitiveness and phenology) were examined for the difference in FD between native and alien plant species, the latter specifically for archaeophytes, neophytes and invasive species. Functional diversity for each trait was calculated using Rao’s Q index followed by a linear model to test for changes in Rao’s Q over time between the groups. Over the 320 years, overall FD remained constant despite species turnover, but FD significantly increased for neophytes and invasive species compared to native species. Plant height was the only trait showing increase in FD as main effect, while for the other traits examined FD decreased over time. Considering invasive species separately, the majority of traits exhibit a significant increase in FD except for seed mass where it decreased. Finally, FD of multiple functional traits combined decreased over time. This can be due to homogenization of functional trait between native and alien species, as a consequence of habitats becoming more similar and subsequent habitat filtering. Our results demonstrate that during the last three centuries, urbanization influenced plant FD in various ways and may contribute to future uniformity of urban floras and greater invasiveness.

scholarly journals Alien plants in Central European river ports

NeoBiota ◽  
2019 ◽  
Vol 45 ◽  
pp. 93-115 ◽  
Author(s):  
Vladimír Jehlík ◽  
Jiří Dostálek ◽  
Tomáš Frantík
Keyword(s):  
Alien Species ◽  
Native Species ◽  
River Flow ◽  
Industrial Area ◽  
Global Scale ◽  
Alien Plants ◽  
Central European ◽  
Native Flora ◽  
Number Of Species ◽  
Port Area

River ports represent a special type of urbanized area. They are considered to be an important driver of biological invasion and biotic homogenization on a global scale, but it remains unclear how and to what degree they serve as a pool of alien species. Data for 54 river ports (16 German, 20 Czech, 7 Hungarian, 3 Slovak, and 8 Austrian ports) on two important Central European waterways (the Elbe-Vltava and Danube waterways) were collected over 40 years. In total, 1056 plant species were found. Of these, 433 were alien, representing 41% of the total number of species found in all the studied Elbe, Vltava, and Danube ports. During comparison of floristic data from literary sources significant differences in the percentage of alien species in ports (50%) and cities (38%) were found. The number of alien species was closely related to port size, but the proportion of alien species expressed as a percentage of the total number of species did not depend significantly on port area. The proportion of alien species in both studied waterways decreased with distance from the sea and was highest in the Hungarian ports and lowest in the Czech Republic, Austria and Bavaria. Lower levels of shipping towards inland regions due to decreased river flow are likely the reason for this trend. The dissimilarity in the species composition of alien and native flora between individual river ports increased with increasing inter-port distance. Neophytes presented a stronger distance decay pattern than did either native species or archaeophytes of the Danube inland ports, potentially due to the different cargoes of individual ports, which may affect the introduction of different neophytes from different geographic areas. The results show that river ports in Central Europe should be regarded as a type of industrial area and deserve full attention with regard to the distribution and spread of alien plants.

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