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2 pages, 199 KiB

Open AccessEditorial

Plant Invasion Ecology

by Alexander P. Sukhorukov

Plants 2023, 12(22), 3887; https://doi.org/10.3390/plants12223887 - 17 Nov 2023

Viewed by 554

Abstract

This article belongs to the Special Issue “Plant Invasion Ecology” [...] Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

Research

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13 pages, 2397 KiB

Open AccessArticle

Increased Plasticity in Invasive Populations of a Globally Invasive Cactus

by Yohannes B. Tesfay, Annika Blaschke, Nathan Ashley, Liberato Portillo, Alessio Scalisi, Benziane Adli and Juergen Kreyling

Plants 2023, 12(18), 3287; https://doi.org/10.3390/plants12183287 - 17 Sep 2023

Cited by 1 | Viewed by 913

Abstract

Biological invasions pose global threats to biodiversity and ecosystem functions. Invasive species often display a high degree of phenotypic plasticity, enabling them to adapt to new environments. This study examines plasticity to water stress in native and invasive Opuntia ficus-indica populations, a prevalent [...] Read more.

Biological invasions pose global threats to biodiversity and ecosystem functions. Invasive species often display a high degree of phenotypic plasticity, enabling them to adapt to new environments. This study examines plasticity to water stress in native and invasive Opuntia ficus-indica populations, a prevalent invader in arid and semi-arid ecosystems. Through controlled greenhouse experiments, we evaluated three native and nine invasive populations. While all plants survived the dry treatment, natives exhibited lower plasticity to high water availability with only a 36% aboveground biomass increase compared to the invasives with a greater increase of 94%. In terms of belowground biomass, there was no significant response to increased water availability for native populations, but plants from the invasive populations showed a 75% increase from the dry to the wet treatment. Enhanced phenotypic plasticity observed in invasive populations of O. ficus-indica is likely a significant driver of their success and invasiveness across different regions, particularly with a clear environmental preference towards less arid conditions. Climate change is expected to amplify the invasion success due to the expansion of arid areas and desertification. Opuntia ficus-indica adapts to diverse environments, survives dry spells, and grows rapidly in times of high-water supply, making it a candidate for increased invasion potential with climate change. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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13 pages, 3874 KiB

Open AccessArticle

The General Trends of Genetic Diversity Change in Alien Plants’ Invasion

by Han Jiang, Yi Zhang, Wenqin Tu, Geng Sun, Ning Wu and Yongmei Zhang

Plants 2023, 12(14), 2690; https://doi.org/10.3390/plants12142690 - 19 Jul 2023

Cited by 2 | Viewed by 1122

Abstract

Genetic diversity is associated with invasion dynamics during establishment and expansion stages by affecting the viability and adaptive potential of exotics. There have been many reports on the comparison between the genetic diversity of invasive alien species (IAS) in and out of their [...] Read more.

Genetic diversity is associated with invasion dynamics during establishment and expansion stages by affecting the viability and adaptive potential of exotics. There have been many reports on the comparison between the genetic diversity of invasive alien species (IAS) in and out of their native habitats, but the conclusions were usually inconsistent. In this work, a standard meta-analysis of the genetic diversity of 19 invasive plants based on 26 previous studies was carried out to investigate the general trend for the change of IASs’ genetic diversity during their invasion process and its real correlation with the invasion fate. Those 26 studies were screened from a total of 3557 peer-reviewed publications from the ISI Web of Science database during the period of January 2000 to May 2022. Based on the selected studies in this work, a general reduction of IASs’ genetic diversity was found in non-native populations compared to that in native ones, while the difference was not significant. This finding suggested that regardless of the change in genetic diversity, it had no substantial effect on the outcome of the invasion process. Therefore, genetic diversity might not serve as a reliable indicator for risk assessment and prediction of invasion dynamic prediction in the case of IASs. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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10 pages, 2355 KiB

Open AccessArticle

The Plant Invader Alternanthera philoxeroides Benefits from Clonal Integration More than Its Native Co-Genus in Response to Patch Contrast

by Wenhua You, Ningning Li, Jin Zhang, Ao Song and Daolin Du

Plants 2023, 12(12), 2371; https://doi.org/10.3390/plants12122371 - 19 Jun 2023

Cited by 2 | Viewed by 840

Abstract

Different connected parts of clonal plants often grow in different patches and the resource contrast between patches has an important effect on the material transfer between the connected ramets. However, it is unclear whether the effect of clonal integration differs between the invasive [...] Read more.

Different connected parts of clonal plants often grow in different patches and the resource contrast between patches has an important effect on the material transfer between the connected ramets. However, it is unclear whether the effect of clonal integration differs between the invasive clonal plant and the related native species in response to patch contrast. To explore this, we grew the clonal fragment pairs of plant invader Alternanthera philoxeroides and its co-genus native species A. sessilis under high contrast, low contrast, and no contrast (control) nutrient patch environments, respectively, and with stolon connections either severed or kept intact. The results showed that, at the ramet level, clonal integration (stolon connection) significantly improved the growth of apical ramets of both species, and such positive effects were significantly greater in A. philoxeroides than in A. sessilis. Moreover, clonal integration greatly increased the chlorophyll content index of apical ramets and the growth of basal ramets in A. philoxeroides but not in A. sessilis under low and high contrast. At the whole fragment level, the benefits of clonal integration increased with increasing patch contrast, and such a positive effect was more pronounced in A. philoxeroides than in A. sessilis. This study demonstrated that A. philoxeroides possesses a stronger ability of clonal integration than A. sessilis, especially in patchy environments with a higher degree of heterogeneity, suggesting that clonal integration may give some invasive clonal plants a competitive advantage over native species, thus facilitating their invasion in patchy habitats. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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13 pages, 1913 KiB

Open AccessArticle

Impact of Prosopis velutina Wooton on the Composition and Diversity of Native Woody Species in a Semi-Arid Zone along the Molopo River, South Africa

by Makuété A. P. Tiawoun, Pieter W. Malan, Alvino A. Comole and Moleseng C. Moshobane

Plants 2023, 12(7), 1561; https://doi.org/10.3390/plants12071561 - 05 Apr 2023

Cited by 1 | Viewed by 1229

Abstract

Invasive alien species represent one of the main threats to biodiversity and species extinction. This is the case for the genus Prosopis, among which Prosopis velutina is the most invasive and common tree species along the Molopo River in the North-West Province, impacting [...] Read more.

Invasive alien species represent one of the main threats to biodiversity and species extinction. This is the case for the genus Prosopis, among which Prosopis velutina is the most invasive and common tree species along the Molopo River in the North-West Province, impacting native plant communities. However, its impact on the composition and diversity of native woody species remains poorly investigated in the area. Thus, this study aimed to assess the impact of P. velutina on native woody plant composition and diversity across three sites along the Molopo River. At each site, five quadrats of 20 × 20 m² were randomly established in invaded and adjacent uninvaded stands. A comparative methodological approach was adopted, and the woody plants in invaded and uninvaded stands with similar site conditions were sampled. The results showed that native woody species density differed significantly (p < 0.05) between invaded and uninvaded stands, except for Bray sites, where there was a marginal difference (p = 0.6). The overall native woody species density decreased by 79.7% in the invaded stand. However, non-metric multidimensional scaling (nMDS) and analysis of similarity (ANOSIM) indicated significant differences in native tree composition between invaded and uninvaded stands at all sites. In all three sites, all ecological indices had significantly lower values in invaded stands compared to uninvaded stands. The decrease in all ecological indices in invaded over uninvaded stands indicated that P. velutina invasion reduced the diversity of native woody plant species. Due to the incessant spread of P. velutina, it may become a long-term dominant species with an increasing impact on the native vegetation. Therefore, the findings of this study call for urgent management and appropriate control measures against the ongoing spread of this invader within the riparian zones of the Molopo River in North-West Province. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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12 pages, 1112 KiB

Open AccessArticle

Wrack Burial Limits Germination and Establishment of Yellow Flag Iris (Iris pseudacorus L.)

by Jesús M. Castillo, Blanca Gallego-Tévar and Brenda J. Grewell

Plants 2023, 12(7), 1510; https://doi.org/10.3390/plants12071510 - 30 Mar 2023

Cited by 3 | Viewed by 1048

Abstract

Seed burial under wrack, mats of water-transported plant debris, can limit recruitment of seedlings in wetlands. In a greenhouse experiment, we studied the effects of wrack burial (0, 1, 2, 4, 8 cm depths) on germination and emergence of the macrophyte Iris pseudacorus, [...] Read more.

Seed burial under wrack, mats of water-transported plant debris, can limit recruitment of seedlings in wetlands. In a greenhouse experiment, we studied the effects of wrack burial (0, 1, 2, 4, 8 cm depths) on germination and emergence of the macrophyte Iris pseudacorus, native to Europe, Mediterranean Basin, and western Asia, that has invaded wetlands in nearly every global ecozone. We recorded the percentages of germinating, senescent, and quiescent seeds and evaluated seedling establishment and growth relative to substrate environmental variables. Seedling emergence of I. pseudacorus was reduced from >80% in controls without burial to <40% even at minimal wrack depths of 1 cm. Few I. pseudacorus seedlings were able to emerge from wrack burial of up to 8 cm in depth. We also found greater numbers of both quiescent seeds and germinated seeds that did not emerge from wrack burial. Reduced seedling emergence and increased seed quiescence with wrack burial were primarily explained by a reduction in daily temperature variation within the substrate. No senescent seedlings were observed with any depth of wrack burial. In view of our results, the management of I. pseudacorus invasion will be a long-term challenge, requiring continued control due to persistent seeds in wrack-buried seed banks. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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22 pages, 2906 KiB

Open AccessArticle

A Modeling Framework to Frame a Biological Invasion: Impatiens glandulifera in North America

by Oğuzhan Kanmaz, Tuğçe Şenel and H. Nüzhet Dalfes

Plants 2023, 12(7), 1433; https://doi.org/10.3390/plants12071433 - 24 Mar 2023

Cited by 1 | Viewed by 1644

Abstract

Biological invasions are a major component of global environmental change with severe ecological and economic consequences. Since eradicating biological invaders is costly and even futile in many cases, predicting the areas under risk to take preventive measures is crucial. Impatiens glandulifera is a [...] Read more.

Biological invasions are a major component of global environmental change with severe ecological and economic consequences. Since eradicating biological invaders is costly and even futile in many cases, predicting the areas under risk to take preventive measures is crucial. Impatiens glandulifera is a very aggressive and prolific invasive species and has been expanding its invasive range all across the Northern hemisphere, primarily in Europe. Although it is currently spread in the east and west of North America (in Canada and USA), studies on its fate under climate change are quite limited compared to the vast literature in Europe. Hybrid models, which integrate multiple modeling approaches, are promising tools for making projections to identify the areas under invasion risk. We developed a hybrid and spatially explicit framework by utilizing MaxEnt, one of the most preferred species distribution modeling (SDM) methods, and we developed an agent-based model (ABM) with the statistical language R. We projected the I. glandulifera invasion in North America, for the 2020–2050 period, under the RCP 4.5 scenario. Our results showed a predominant northward progression of the invasive range alongside an aggressive expansion in both currently invaded areas and interior regions. Our projections will provide valuable insights for risk assessment before the potentially irreversible outcomes emerge, considering the severity of the current state of the invasion in Europe. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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12 pages, 1913 KiB

Open AccessArticle

Increased Leaf Bacterial Network Complexity along the Native Plant Diversity Gradient Facilitates Plant Invasion?

by Xiang-Deng Du, Jiang Wang, Congcong Shen, Jichen Wang, Zhongwang Jing, Li-Nan Huang, Zhen-Hao Luo and Yuan Ge

Plants 2023, 12(6), 1406; https://doi.org/10.3390/plants12061406 - 22 Mar 2023

Viewed by 1120

Abstract

Understanding the mechanisms of biological invasion is critical to biodiversity protection. Previous studies have produced inconsistent relationships between native species richness and invasibility, referred to as the invasion paradox. Although facilitative interactions among species have been proposed to explain the non-negative diversity–invasibility relationship, [...] Read more.

Understanding the mechanisms of biological invasion is critical to biodiversity protection. Previous studies have produced inconsistent relationships between native species richness and invasibility, referred to as the invasion paradox. Although facilitative interactions among species have been proposed to explain the non-negative diversity–invasibility relationship, little is known about the facilitation of plant-associated microbes in invasions. We established a two-year field biodiversity experiment with a native plant species richness gradient (1, 2, 4, or 8 species) and analyzed the effects of community structure and network complexity of leaf bacteria on invasion success. Our results indicated a positive relationship between invasibility and network complexity of leaf bacteria of the invader. Consistent with previous studies, we also found that native plant species richness increased the leaf bacterial diversity and network complexity. Moreover, the results of the leaf bacteria community assembly of the invader suggested that the complex bacteria community resulted from higher native diversity rather than higher invader biomass. We concluded that increased leaf bacterial network complexity along the native plant diversity gradient likely facilitated plant invasion. Our findings provided evidence of a potential mechanism by which microbes may affect the plant community invasibility, hopefully helping to explain the non-negative relationship between native diversity and invasibility. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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16 pages, 2554 KiB

Open AccessArticle

Niche Filling Dynamics of Ragweed (Ambrosia artemisiifolia L.) during Global Invasion

by Xing-Jiang Song, Gang Liu, Zeng-Qiang Qian and Zhi-Hong Zhu

Plants 2023, 12(6), 1313; https://doi.org/10.3390/plants12061313 - 14 Mar 2023

Cited by 2 | Viewed by 1706

Abstract

Determining whether the climatic ecological niche of an invasive alien plant is similar to that of the niche occupied by its native population (ecological niche conservatism) is essential for predicting the plant invasion process. Ragweed (Ambrosia artemisiifolia L.) usually poses serious threats [...] Read more.

Determining whether the climatic ecological niche of an invasive alien plant is similar to that of the niche occupied by its native population (ecological niche conservatism) is essential for predicting the plant invasion process. Ragweed (Ambrosia artemisiifolia L.) usually poses serious threats to human health, agriculture, and ecosystems within its newly occupied range. We calculated the overlap, stability, unfilling, and expansion of ragweed’s climatic ecological niche using principal component analysis and performed ecological niche hypothesis testing. The current and potential distribution of A. artemisiifolia was mapped by ecological niche models to identify areas in China with the highest potential risk of A. artemisiifolia invasion. The high ecological niche stability indicates that A. artemisiifolia is ecologically conservative during the invasion. Ecological niche expansion (expansion = 0.407) occurred only in South America. In addition, the difference between the climatic and native niches of the invasive populations is mainly the result of unpopulated niches. The ecological niche model suggests that southwest China, which has not been invaded by A. artemisiifolia, faces an elevated risk of invasion. Although A. artemisiifolia occupies a climatic niche distinct from native populations, the climatic niche of the invasive population is only a subset of the native niche. The difference in climatic conditions is the main factor leading to the ecological niche expansion of A. artemisiifolia during the invasion. Additionally, human activities play a substantial role in the expansion of A. artemisiifolia. Alterations in the A. artemisiifolia niche would help explain why this species is so invasive in China. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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20 pages, 1482 KiB

Open AccessArticle

Characterization of Invasiveness, Thermotolerance and Light Requirement of Nine Invasive Species in China

by Arvind Bhatt, Xingxing Chen, Marcelo F. Pompelli, Aftab Jamal, Roberto Mancinelli and Emanuele Radicetti

Plants 2023, 12(5), 1192; https://doi.org/10.3390/plants12051192 - 06 Mar 2023

Cited by 5 | Viewed by 1361

Abstract

Understanding responsible functional traits for promoting plant invasiveness could be important to aid in the development of adequate management strategies for invasive species. Seed traits play an important role in the plant life cycle by affecting dispersal ability, formation of the soil seed [...] Read more.

Understanding responsible functional traits for promoting plant invasiveness could be important to aid in the development of adequate management strategies for invasive species. Seed traits play an important role in the plant life cycle by affecting dispersal ability, formation of the soil seed bank, type and level of dormancy, germination, survival and/or competitive ability. We assessed seed traits and germination strategies of nine invasive species under five temperature regimes and light/dark treatments. Our results showed a considerable level of interspecific variation in germination percentage among the tested species. Both cooler (5/10 °C) and warmer (35/40 °C) temperatures tended to inhibit germination. All study species were considered small-seeded, and seed size did not affect germination in the light. Yet, a slightly negative correlation was found between germination in the dark and seed dimensions. We classified the species into three categories according to their germination strategies: (i) risk-avoiders, mostly displaying dormant seeds with low G%; (ii) risk-takers, reaching a high G% in a broad range of temperatures; (iii) intermediate species, showing moderate G% values, which could be enhanced in specific temperature regimes. Variability in germination requirements could be important to explain species coexistence and invasion ability of plants to colonize different ecosystems. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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18 pages, 2135 KiB

Open AccessFeature PaperArticle

Cytogeography of Naturalized Solidago canadensis Populations in Europe

by Zhongsai Tian, Jiliang Cheng, Jingxuan Xu, Dongyan Feng, Jian Zhong, Xiaoxiao Yuan, Zheng Zhang, Yu Zhang, Zhiyuan Mao and Sheng Qiang

Plants 2023, 12(5), 1113; https://doi.org/10.3390/plants12051113 - 01 Mar 2023

Cited by 1 | Viewed by 1563

Abstract

Autopolyploidization has driven the successful invasion of Solidago canadensis in East Asia. However, it was believed that only diploid S. canadensis invaded Europe, whereas polyploids never did. Here, molecular identification, ploidy level, and morphological traits of ten S. canadensis populations collected in Europe [...] Read more.

Autopolyploidization has driven the successful invasion of Solidago canadensis in East Asia. However, it was believed that only diploid S. canadensis invaded Europe, whereas polyploids never did. Here, molecular identification, ploidy level, and morphological traits of ten S. canadensis populations collected in Europe were compared with previously identified S. canadensis populations from other continents and S. altissima populations. Furthermore, the ploidy-driven geographical differentiation pattern of S. canadensis in different continents was investigated. All ten European populations were identified as S. canadensis with five diploid and five hexaploid populations. Significant differences in morphological traits existed among diploids and polyploids (tetraploids and hexaploids), rather than between polyploids from different introduced ranges and between S. altissima and polyploidy S. canadensis. The invasive hexaploids and diploids had few differences in latitudinal distributions in Europe, which was similar to the native range but different from a distinct climate-niche differentiation in Asia. This may be attributed to the bigger difference in climate between Asia and Europe and North America. The morphological and molecular evidences proved the invasion of polyploid S. canadensis in Europe and suggest that S. altissima may be merged into a complex of S. canadensis species. Our study may be concluded that geographical and ecological niche differentiation of an invasive plant driven by ploidy depends on the degree of difference in the environmental factors between the introduced and native range, which provides new insight into the invasive mechanism. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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15 pages, 1533 KiB

Open AccessArticle

Suppression of Seedling Survival and Recruitment of the Invasive Tree Prosopis juliflora in Saudi Arabia through Its Own Leaf Litter: Greenhouse and Field Assessments

by Ahmed M. Abbas, Maryam M. Alomran, Nada K. Alharbi and Stephen J. Novak

Plants 2023, 12(4), 959; https://doi.org/10.3390/plants12040959 - 20 Feb 2023

Cited by 2 | Viewed by 1373

Abstract

Many studies have focused on how leaf litter depth affects seed germination and seedling growth because the seedling stage is the most vulnerable portion of a plant’s life cycle. Invasive plants with the most severe ecological consequences are those that modify ecosystems, and [...] Read more.

Many studies have focused on how leaf litter depth affects seed germination and seedling growth because the seedling stage is the most vulnerable portion of a plant’s life cycle. Invasive plants with the most severe ecological consequences are those that modify ecosystems, and this can occur through the formation of thick litter layers which can suppress the emergence, survival, and recruitment of native plant seedlings; in addition, in some cases, these litter layers can suppress invasive plant seedling recruitment. Prosopis juliflora is a thorny shrub that is native to arid and semi-arid portions of North America, parts of South America, and the Caribbean. It has invaded millions of hectares around the world, including Saudi Arabia. The objective of this study is to evaluate whether P. juliflora leaf litter reduces the recruitment of its own seedlings under greenhouse and field conditions in Saudi Arabia. In both the greenhouse and the field, the number of days to first emergence increased and germination percentage decreased with increasing litter depth. With the 1, 2, and 4 cm litter depth treatments, the number of viable seeds generally decreased, with no emergence, germination, or viable seeds detected for the 8 cm litter depth treatment. Results of this study reveal that increasing the depth of P. juliflora leaf litter suppresses the survival and recruitment of its own seedlings. Future search should assess the actual mechanisms through which P. juliflora seeds are suppressed, the role of allelopathic compounds in this process, and whether viable seeds are dormant and will persist in the soil seed bank. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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14 pages, 1251 KiB

Open AccessArticle

Applicability of Point- and Polygon-Based Vegetation Monitoring Data to Identify Soil, Hydrological and Climatic Driving Forces of Biological Invasions—A Case Study of Ailanthus altissima, Elaeagnus angustifolia and Robinia pseudoacacia

by Georgina Veronika Visztra, Kata Frei, Alida Anna Hábenczyus, Anna Soóky, Zoltán Bátori, Annamária Laborczi, Nándor Csikós, Gábor Szatmári and Péter Szilassi

Plants 2023, 12(4), 855; https://doi.org/10.3390/plants12040855 - 14 Feb 2023

Viewed by 1059

Abstract

Invasive tree species are a significant threat to native flora. They modify the environment with their allelopathic substances and inhibit the growth of native species by shading, thus reducing diversity. The most effective way to control invasive plants is to prevent their spread [...] Read more.

Invasive tree species are a significant threat to native flora. They modify the environment with their allelopathic substances and inhibit the growth of native species by shading, thus reducing diversity. The most effective way to control invasive plants is to prevent their spread which requires identifying the environmental parameters promoting it. Since there are several types of invasive plant databases available, determining which database type is the most relevant for investigating the occurrence of alien plants is of great importance. In this study, we compared the efficiency and reliability of point-based (EUROSTAT Land Use and Coverage Area Frame Survey (LUCAS)) and polygon-based (National Forestry Database (NFD)) databases using geostatistical methods in ArcGIS software. We also investigated the occurrence of three invasive tree species (Ailanthus altissima, Elaeagnus angustifolia, and Robinia pseudoacacia) and their relationships with soil, hydrological, and climatic parameters such as soil organic matter content, pH, calcium carbonate content, rooting depth, water-holding capacity, distance from the nearest surface water, groundwater depth, mean annual temperature, and mean annual precipitation with generalized linear models in R-studio software. Our results show that the invasion levels of the tree species under study are generally over-represented in the LUCAS point-based vegetation maps, and the point-based database requires a dataset with a larger number of samples to be reliable. Regarding the polygon-based database, we found that the occurrence of the invasive species is generally related to the investigated soil and hydrological and climatic factors. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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26 pages, 2502 KiB

Open AccessArticle

A Tight Interaction between the Native Seagrass Cymodocea nodosa and the Exotic Halophila stipulacea in the Aegean Sea Highlights Seagrass Holobiont Variations

by Chiara Conte, Eugenia T. Apostolaki, Salvatrice Vizzini and Luciana Migliore

Plants 2023, 12(2), 350; https://doi.org/10.3390/plants12020350 - 11 Jan 2023

Cited by 8 | Viewed by 1842

Abstract

Seagrasses harbour bacterial communities with which they constitute a functional unit called holobiont that responds as a whole to environmental changes. Epiphytic bacterial communities rapidly respond to both biotic and abiotic factors, potentially contributing to the host fitness. The Lessepsian migrant Halophila stipulacea [...] Read more.

Seagrasses harbour bacterial communities with which they constitute a functional unit called holobiont that responds as a whole to environmental changes. Epiphytic bacterial communities rapidly respond to both biotic and abiotic factors, potentially contributing to the host fitness. The Lessepsian migrant Halophila stipulacea has a high phenotypical plasticity and harbours a highly diverse epiphytic bacterial community, which could support its invasiveness in the Mediterranean Sea. The current study aimed to evaluate the Halophila/Cymodocea competition in the Aegean Sea by analysing each of the two seagrasses in a meadow zone where these intermingled, as well as in their monospecific zones, at two depths. Differences in holobionts were evaluated using seagrass descriptors (morphometric, biochemical, elemental, and isotopic composition) to assess host changes, and 16S rRNA gene to identify bacterial community structure and composition. An Indicator Species Index was used to identify bacteria significantly associated with each host. In mixed meadows, native C. nodosa was shown to be affected by the presence of exotic H. stipulacea, in terms of both plant descriptors and bacterial communities, while H. stipulacea responded only to environmental factors rather than C. nodosa proximity. This study provided evidence of the competitive advantage of H. stipulacea on C. nodosa in the Aegean Sea and suggests the possible use of associated bacterial communities as an ecological seagrass descriptor. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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10 pages, 812 KiB

Open AccessArticle

Predictive Modeling of Kudzu (Pueraria montana) Habitat in the Great Lakes Basin of the United States

by Ashley M. Kovach-Hammons and Jordan M. Marshall

Plants 2023, 12(1), 216; https://doi.org/10.3390/plants12010216 - 03 Jan 2023

Cited by 2 | Viewed by 2488

Abstract

Kudzu (Pueraria montana [Lour.] Merr. var. lobata [Willd.] Maesen & S.M. Almeida ex Sanjappa & Predeep) is an invasive woody vine widespread throughout much of the southeastern United States. New occurrences and recent studies using climatic parameters suggest that the Midwestern region [...] Read more.

Kudzu (Pueraria montana [Lour.] Merr. var. lobata [Willd.] Maesen & S.M. Almeida ex Sanjappa & Predeep) is an invasive woody vine widespread throughout much of the southeastern United States. New occurrences and recent studies using climatic parameters suggest that the Midwestern region of the United States is at the greatest risk of kudzu invasion. As there are already multiple reports of kudzu within the Great Lakes basin and no previous landscape models exist specifically for the basin, we developed probability models from existing spatial data (forest type, geology, land cover, precipitation, temperature, and known kudzu locations) by using maximum entropy methods at the national, regional, and basin scales. All three models had relatively high accuracy and strong positive correlation between predicted and observed values. Based on evaluation of the models using a testing data set, we determined a presence threshold and categorized areas within each model as suitable or unsuitable habitat. We pooled the models and calculated mean habitat suitability within the Great Lakes basin. Much of the southern half of the basin was suitable for kudzu. Continuing management and further monitoring of kudzu spread are likely necessary to limit further introduction and mitigate spread of kudzu within the Great Lakes region. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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14 pages, 10675 KiB

Open AccessArticle

Increased Invasion Risk of Tagetes minuta L. in China under Climate Change: A Study of the Potential Geographical Distributions

by Yuhan Qi, Xiaoqing Xian, Haoxiang Zhao, Rui Wang, Hongkun Huang, Yanping Zhang, Ming Yang and Wanxue Liu

Plants 2022, 11(23), 3248; https://doi.org/10.3390/plants11233248 - 26 Nov 2022

Cited by 2 | Viewed by 1323

Abstract

Tagetes minuta L., a member of the Tageftes genus belonging to the Asteraceae family, is a well-documented exotic plant native to South America that has become established in China. In this study, 784 occurrence records and 12 environmental variables were used to predict [...] Read more.

Tagetes minuta L., a member of the Tageftes genus belonging to the Asteraceae family, is a well-documented exotic plant native to South America that has become established in China. In this study, 784 occurrence records and 12 environmental variables were used to predict the potential geographical distributions (PGDs) of T. minuta under current and future climatic changes using an optimized MaxEnt model. The results showed that (1) three out of the twelve variables contributed the most to the model performance: isothermality (bio3), precipitation in the driest quarter (bio17), and precipitation in the warmest quarter (bio18); (2) the PGDs of T. minuta under the current climate covered 62.06 × 10⁴ km², mainly in North, South, and Southwest China; and (3) climate changes will facilitate the expansion of the PGDs of T. minuta under three shared socioeconomic pathways (SSP 1-2.6, SSP2-4.5, and SSP5-8.5) in both the 2030s and 2050s. The centroid of suitable habitats under SSP2-4.5 moved the longest distance. T. minuta has the capacity to expand in China, especially in Yunnan, where there exist no occurrence records. Customs, ports, and adjacent regions should strengthen the quarantine of imported goods and mobile personnel for T. minuta, and introduced seedlings should be isolated to minimize their introduction risk. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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14 pages, 1880 KiB

Open AccessArticle

Climatic Variability Caused by Topographic Barrier Prevents the Northward Spread of Invasive Ageratina adenophora

by Yi Zhang, Ziyan Liao, Han Jiang, Wenqin Tu, Ning Wu, Xiaoping Qiu and Yongmei Zhang

Plants 2022, 11(22), 3108; https://doi.org/10.3390/plants11223108 - 15 Nov 2022

Cited by 1 | Viewed by 1291

Abstract

Ageratina adenophora (Spreng.) R.M.King & H.Rob. is one of the most threatening invasive alien plants in China. Since its initial invasion into Yunnan in the 1940s, it spread rapidly northward to southern Mount Nyba in Sichuan, which lies on the eastern edge of [...] Read more.

Ageratina adenophora (Spreng.) R.M.King & H.Rob. is one of the most threatening invasive alien plants in China. Since its initial invasion into Yunnan in the 1940s, it spread rapidly northward to southern Mount Nyba in Sichuan, which lies on the eastern edge of the Qinghai–Tibet Plateau. During fieldwork, we found an interesting phenomenon: A. adenophora failed to expand northward across Mount Nyba, even after the opening of the 10 km tunnel, which could have served as a potential corridor for its spread. In this work, to explore the key factors influencing its distribution and spread patterns, we used a combination of ensemble species distribution models with the MigClim model. We found that the temperature annual range (TAR), precipitation of driest month (PDM), highway density (HW), and wind speed (WS) were the most predominant factors affecting its distribution. The north of Mount Nyba is not suitable for A. adenophora survival due to higher TAR. The spatial–temporal dynamic invasion simulation using MigClim further illustrated that the northward invasion of A. adenophora was stopped by Mount Nyba. Overall, Mount Nyba may act as a topographic barrier that causes environmental differences between its south and north sides, preventing the northward invasion of A. adenophora. However, other suitable habitats on the northern side of the mountain still face challenges because A. adenophora is likely to invade via other routes. Therefore, long-term monitoring is needed to prevent human-induced long-distance spread events. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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13 pages, 626 KiB

Open AccessArticle

Effects of Elevated Temperature and High and Low Rainfall on the Germination and Growth of the Invasive Alien Plant Acacia mearnsii

by Tshililo Kharivha, Sheunesu Ruwanza and Gladman Thondhlana

Plants 2022, 11(19), 2633; https://doi.org/10.3390/plants11192633 - 07 Oct 2022

Cited by 5 | Viewed by 1881

Abstract

The impact of climate change on the germination and growth of invasive alien plants varies depending on the plant species and invasion process. We experimentally assessed the responses of the invasive alien plant Acacia mearnsii to future climate change scenarios—namely, elevated temperature as [...] Read more.

The impact of climate change on the germination and growth of invasive alien plants varies depending on the plant species and invasion process. We experimentally assessed the responses of the invasive alien plant Acacia mearnsii to future climate change scenarios—namely, elevated temperature as well as high and low rainfall. Acacia mearnsii was grown at an elevated air temperature (+2 °C), high rainfall (6 mm per day), and low rainfall (1.5 mm per day), and its germination and growth performance were measured over five months. We further examined changes in soil nutrients to assess if the above-mentioned climate change scenarios affected soils. Both elevated temperature and high rainfall did not influence A. mearnsii germination and seedling growth. In contrast, we observed reductions in A. mearnsii germination and growth in the low rainfall treatment, an indication that future drought conditions might negatively affect A. mearnsii invasion. We noted that elevated temperature and rainfall resulted in varied effects on soil properties (particularly soil C, N, Ca, and Mg content). We conclude that both elevated temperature and high rainfall may not enhance A. mearnsii invasion through altering germination and growth, but a decrease in A. mearnsii invasiveness is possible under low rainfall conditions. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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22 pages, 1798 KiB

Open AccessArticle

Do Reproductive Traits of Invasive Populations of Scotch Broom, Cytisus scoparius (Fabaceae), Outperform Native Populations?

by Zigmantas Gudžinskas and Laurynas Taura

Plants 2022, 11(16), 2158; https://doi.org/10.3390/plants11162158 - 19 Aug 2022

Cited by 2 | Viewed by 1407

Abstract

Reproductive traits are among the most important factors in determining the success of species establishment and invasion in a new area. Studies on transcontinental invasions have revealed that invasive species perform better in the invasive range than in their native ranges. We assumed [...] Read more.

Reproductive traits are among the most important factors in determining the success of species establishment and invasion in a new area. Studies on transcontinental invasions have revealed that invasive species perform better in the invasive range than in their native ranges. We assumed that the same regularity exists in intracontinental invasions and thus investigated whether the reproductive traits of Scotch broom, Cytisus scoparius, perform better in the alien invasive range in Europe compared to its native range in the same continent. The aim of this research was to reveal the potential and realised fecundity of C. scoparius in its native and invasive ranges, as well as relationships with the size of pods, habitat type, and how these traits vary at the same site in different years. The results of this study were not able to unambiguously confirm our hypothesis that C. scoparius in the invasive range in Lithuania, specifically in the southern part of the Boreal biogeographical region, outperform plants in the native range with regard to the analysed reproductive traits. Potential fecundity of C. scoparius in the native range was significantly higher than in the invaded range; however, realised fecundity was not significantly different between the native and invasive ranges. The pod length was similar in both ranges, whereas the pod width was significantly greater in the invasive range than in the native range. The results suggest that the number of ovules per pod, number of matured seeds, and the size of pods are related with the type of habitat and local environmental conditions in the habitat. Although many studies on other species have confirmed higher fecundity and overall better performance of plants in the invasive range than in the native range on other continents, this rule probably cannot be applied for intracontinental invasive species occurring in relatively close geographical regions to their native ranges. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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22 pages, 3402 KiB

Open AccessArticle

The Genus Kalanchoe (Crassulaceae) in Ecuador: From Gardens to the Wild

by Anahí Vargas, Ileana Herrera, Neus Nualart, Anne Guézou, Carlos Gómez-Bellver, Efraín Freire, Patricia Jaramillo Díaz and Jordi López-Pujol

Plants 2022, 11(13), 1746; https://doi.org/10.3390/plants11131746 - 30 Jun 2022

Cited by 12 | Viewed by 3124

Abstract

The genus Kalanchoe, mostly indigenous from Madagascar and Tropical Africa, is widely traded for ornamental value. In this study, we provided an updated list of wild and cultivated Kalanchoe taxa in Ecuador; we analyzed the temporal–spatial pattern of their records, and we [...] Read more.

The genus Kalanchoe, mostly indigenous from Madagascar and Tropical Africa, is widely traded for ornamental value. In this study, we provided an updated list of wild and cultivated Kalanchoe taxa in Ecuador; we analyzed the temporal–spatial pattern of their records, and we categorized the invasion status for each taxon and its environment preferences. The records of any taxa belonging to this genus were compiled from an extensive search using various information sources. Our results confirmed the presence of 16 taxa of Kalanchoe in the country. Seven species and a hybrid were detected in the wild. Kalanchoe densiflora, K. laxiflora, K. pinnata, K. tubiflora, and K. ×houghtonii were categorized as invasive. We detected invasive records of some of these plants in protected areas. Almost all taxa had at least one record as cultivated, suggesting that the invasion pathway is ornamental trade. Kalanchoe pinnata individuals in the wild were recorded in the four biogeographic regions of Ecuador, which could be associated with the wide range of precipitations and temperatures in which the species may dwell. Our study highlights the importance of reducing the ornamental value and limiting the use of Kalanchoe taxa with invasive potential in horticulture and promoting, instead, the use of indigenous species. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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11 pages, 1069 KiB

Open AccessArticle

Competitive Interactions between Two Non-Native Species (Alliaria petiolata [M. Bieb.] Cavara & Grande and Hesperis matronalis L.) and a Native Species (Ageratina altissima [L.] R.M. King & H. Rob.)

by Kassandra R. Paulus and Jordan M. Marshall

Plants 2022, 11(3), 374; https://doi.org/10.3390/plants11030374 - 29 Jan 2022

Cited by 2 | Viewed by 2217

Abstract

Alliaria petiolata and Hesperis matronalis are wide-ranging non-native species in North America. Ageratina altissima is native to North America but has become a concern as an invasive species in Asia. A replacement series experiment was established to quantify the competitive interactions between these [...] Read more.

Alliaria petiolata and Hesperis matronalis are wide-ranging non-native species in North America. Ageratina altissima is native to North America but has become a concern as an invasive species in Asia. A replacement series experiment was established to quantify the competitive interactions between these three species and to rank their relative competitiveness with each other. We assessed leaf count, chlorophyll content, and aboveground biomass with comparisons between replacement series mixtures and competition species. Overall leaf count and aboveground biomass were greatest in A. altissima and chlorophyll content was lowest in A. petiolata. Chlorophyll content and aboveground biomass were lower for A. altissima in competition with A. petiolata compared to H. matronalis. Leaf count for A. petiolata was lower in competition with A. altissima compared to H. matronalis. Aboveground biomass for H. matronalis was lower in competition regardless of the species compared to monoculture. There were also negative trends in biomass for A. petiolata in competition with increasing neighbors. However, for A. altissima, the negative trend in biomass was with A. petiolata, H. matronalis did not negatively affect A. altissima biomass. Our rank order of competitiveness was A. altissima > A. petiolata >> H. matronalis. Full article

(This article belongs to the Special Issue Plant Invasion Ecology)

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