Understanding intraspecific trait variations, particularly for invasive species that occupy large geographic areas with different resource conditions, can enhance our understanding of plant responses to changes in environmental resources. However, most related studies have focused on aboveground traits, while variations in root traits and responses to changes in resources during biological invasion have not been clarified. To fill this knowledge gap, we compared the root traits of Chromolaena odorata from 10 introduced populations in Southeast Asia and 12 native populations in North and Central America under different soil nutrients. The introduced populations of the invader exhibited greater resource-acquisitive root traits, characterized by reduced fine root diameter but increased proportions of absorbing root length and specific root length, compared to the native populations. Although nutrient addition significantly affected root traits, the introduced populations showed greater phenotypic plasticity in four traits (root / shoot ratio, specific root length, absorbing root length proportion, and branching intensity) than the native populations. Different root trait syndromes were observed between the introduced and native populations. These results indicate that after introduction, C. odorata may shift towards a more soil resource-acquisitive strategy and thus respond more positively to increased soils nutrients, thereby showing better performance in high-resource environments. This study provides a better understanding of how species respond to environment changes and reveals the factors underlying exotic plant invasion success.
{"title":"Variation in root traits and phenotypic plasticity between native and introduced populations of the invasive plant Chromolaena odorata","authors":"Yang-Ping Li, Wei-Tao Li, Yan-Fen Niu, Yulong Feng","doi":"10.3897/neobiota.92.110985","DOIUrl":"https://doi.org/10.3897/neobiota.92.110985","url":null,"abstract":"Understanding intraspecific trait variations, particularly for invasive species that occupy large geographic areas with different resource conditions, can enhance our understanding of plant responses to changes in environmental resources. However, most related studies have focused on aboveground traits, while variations in root traits and responses to changes in resources during biological invasion have not been clarified. To fill this knowledge gap, we compared the root traits of Chromolaena odorata from 10 introduced populations in Southeast Asia and 12 native populations in North and Central America under different soil nutrients. The introduced populations of the invader exhibited greater resource-acquisitive root traits, characterized by reduced fine root diameter but increased proportions of absorbing root length and specific root length, compared to the native populations. Although nutrient addition significantly affected root traits, the introduced populations showed greater phenotypic plasticity in four traits (root / shoot ratio, specific root length, absorbing root length proportion, and branching intensity) than the native populations. Different root trait syndromes were observed between the introduced and native populations. These results indicate that after introduction, C. odorata may shift towards a more soil resource-acquisitive strategy and thus respond more positively to increased soils nutrients, thereby showing better performance in high-resource environments. This study provides a better understanding of how species respond to environment changes and reveals the factors underlying exotic plant invasion success.","PeriodicalId":54290,"journal":{"name":"Neobiota","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140238608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-12DOI: 10.3897/neobiota.92.116392
A. Kortz, M. Hejda, J. Pergl, Josef Kutlvašr, P. Petřík, J. Sádlo, M. Vítková, M. Vojík, Petr Pyšek
Plant invasion science has made a substantial progress in documenting the impacts of aliens, but comparisons with the impacts of native dominants are still rare. Further, the impacts on larger spatial scales remain poorly understood. We recorded the impacts of 10 native and nine invasive dominant plants in the Czech Republic on species richness and Shannon diversity by comparing communities with high vs. low cover of the dominant species. To estimate the impacts at the (i) population level and (ii) between-population level, we compared the Jaccard dissimilarity, nestedness and turnover of high- and low-dominance plots. Further, we calculated the Jaccard dissimilarity, nestedness and turnover between the high- and low-dominance plots within each population to express the impacts on species composition. We tested whether (i) native and invasive dominants affect the population- and between population levels of diversity by making the vegetation more homogenous; (ii) whether these effects differ between the native and alien dominants; and (iii) whether the impacts at different spatial levels are related. At the population level, high-dominance plots (with both native and alien dominants) showed higher nestedness and lower turnover compared to the low-dominance plots. Further, all plots with native dominants, both with high- and low dominance, showed higher similarity but lower nestedness than plots with alien dominants. Most importantly, high-dominance plots with native dominants were more similar to each other but showed marginally significantly lower nestedness compared to high-dominance plots with alien dominants. At the between-population level, high-dominance plots with native dominants showed a marginally significantly lower turnover compared to high-dominance plots with alien dominants. The differences in Jaccard dissimilarity, nestedness and turnover between the low- and high-dominance plots at the population level showed strong positive relations to low- and high-dominance differences at the between-populations level. Further, compositional impacts, expressed as the dissimilarity between high- vs. low-dominance plots, positively related to the plot-level impacts on Shannon diversity. Our results show that (i) both native and invasive dominants tend to reduce the diversity over larger areas and that the effect of native dominants may be even stronger, and (ii) the effects on plot-level richness and diversity cannot be easily extrapolated to larger scales but the impacts at the population- and between-populations levels are positively related.
{"title":"Impacts of native and alien plant dominants at different spatial scales","authors":"A. Kortz, M. Hejda, J. Pergl, Josef Kutlvašr, P. Petřík, J. Sádlo, M. Vítková, M. Vojík, Petr Pyšek","doi":"10.3897/neobiota.92.116392","DOIUrl":"https://doi.org/10.3897/neobiota.92.116392","url":null,"abstract":"Plant invasion science has made a substantial progress in documenting the impacts of aliens, but comparisons with the impacts of native dominants are still rare. Further, the impacts on larger spatial scales remain poorly understood. We recorded the impacts of 10 native and nine invasive dominant plants in the Czech Republic on species richness and Shannon diversity by comparing communities with high vs. low cover of the dominant species. To estimate the impacts at the (i) population level and (ii) between-population level, we compared the Jaccard dissimilarity, nestedness and turnover of high- and low-dominance plots. Further, we calculated the Jaccard dissimilarity, nestedness and turnover between the high- and low-dominance plots within each population to express the impacts on species composition. We tested whether (i) native and invasive dominants affect the population- and between population levels of diversity by making the vegetation more homogenous; (ii) whether these effects differ between the native and alien dominants; and (iii) whether the impacts at different spatial levels are related. At the population level, high-dominance plots (with both native and alien dominants) showed higher nestedness and lower turnover compared to the low-dominance plots. Further, all plots with native dominants, both with high- and low dominance, showed higher similarity but lower nestedness than plots with alien dominants. Most importantly, high-dominance plots with native dominants were more similar to each other but showed marginally significantly lower nestedness compared to high-dominance plots with alien dominants. At the between-population level, high-dominance plots with native dominants showed a marginally significantly lower turnover compared to high-dominance plots with alien dominants. The differences in Jaccard dissimilarity, nestedness and turnover between the low- and high-dominance plots at the population level showed strong positive relations to low- and high-dominance differences at the between-populations level. Further, compositional impacts, expressed as the dissimilarity between high- vs. low-dominance plots, positively related to the plot-level impacts on Shannon diversity. Our results show that (i) both native and invasive dominants tend to reduce the diversity over larger areas and that the effect of native dominants may be even stronger, and (ii) the effects on plot-level richness and diversity cannot be easily extrapolated to larger scales but the impacts at the population- and between-populations levels are positively related.","PeriodicalId":54290,"journal":{"name":"Neobiota","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140249339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-06DOI: 10.3897/neobiota.92.120486
Colin E. Hughes
{"title":"Wattles on the move","authors":"Colin E. Hughes","doi":"10.3897/neobiota.92.120486","DOIUrl":"https://doi.org/10.3897/neobiota.92.120486","url":null,"abstract":"<jats:p />","PeriodicalId":54290,"journal":{"name":"Neobiota","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140261580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-06DOI: 10.3897/neobiota.92.116033
Joanna Grabowska, M. Płóciennik, Michał Grabowski
One of the negative impacts of non-native invasive species on trophic interactions in an invaded ecosystem occurs via increased interspecific competition for food resources between the invader and local species of the same food niche. In freshwaters, there are usually several fish species that feed on similar food resources. Ponto-Caspian gobies are amongst the most successful and widespread invaders colonising European waterways. They have a wide food niche and an opportunistic feeding strategy, with a focus on benthic invertebrates and piscivory occurring occasionally mainly in the case of large individuals. Competition with native percids for food resources is predicted on the basis of high dietary overlap. However, studies published so far provide no unequivocal answer. In order to resolve this question, we conducted a comparative taxonomic analysis of gut content, with an emphasis on chironomids and amphipods, of the invasive monkey goby (Neogobius fluviatilis), racer goby (Babka gymnotrachelus) and the native Eurasian perch (Perca fluviatilis) occurring sympatrically in a large lowland European river, the Bug River in Poland. We found that each species forages in slightly different habitats, as indicated by the different composition of prey species in the gut content. This suggests feeding niche partitioning between the studied species facilitating their co-existence and reduction or avoidance of competition for food resources. Resource partitioning regarding prey types and foraging habitats is a mechanism for permitting the co-existence of closely-related alien gobies with similar food preferences in the invaded waters and co-occurrence with local species. This mechanism can contribute to their invasion success, as observed in European waters during the recent decades. We also demonstrate that precise prey identification to the lowest possible taxon is crucial to reveal the dietary overlap between co-occurring fish species and to predict the impact of alien invaders on native species through interspecific competition, as well as to recommend such an approach in studies upon fish foraging strategies.
{"title":"Detailed analysis of prey taxonomic composition indicates feeding habitat partitioning amongst co-occurring invasive gobies and native European perch","authors":"Joanna Grabowska, M. Płóciennik, Michał Grabowski","doi":"10.3897/neobiota.92.116033","DOIUrl":"https://doi.org/10.3897/neobiota.92.116033","url":null,"abstract":"One of the negative impacts of non-native invasive species on trophic interactions in an invaded ecosystem occurs via increased interspecific competition for food resources between the invader and local species of the same food niche. In freshwaters, there are usually several fish species that feed on similar food resources. Ponto-Caspian gobies are amongst the most successful and widespread invaders colonising European waterways. They have a wide food niche and an opportunistic feeding strategy, with a focus on benthic invertebrates and piscivory occurring occasionally mainly in the case of large individuals. Competition with native percids for food resources is predicted on the basis of high dietary overlap. However, studies published so far provide no unequivocal answer. In order to resolve this question, we conducted a comparative taxonomic analysis of gut content, with an emphasis on chironomids and amphipods, of the invasive monkey goby (Neogobius fluviatilis), racer goby (Babka gymnotrachelus) and the native Eurasian perch (Perca fluviatilis) occurring sympatrically in a large lowland European river, the Bug River in Poland. We found that each species forages in slightly different habitats, as indicated by the different composition of prey species in the gut content. This suggests feeding niche partitioning between the studied species facilitating their co-existence and reduction or avoidance of competition for food resources. Resource partitioning regarding prey types and foraging habitats is a mechanism for permitting the co-existence of closely-related alien gobies with similar food preferences in the invaded waters and co-occurrence with local species. This mechanism can contribute to their invasion success, as observed in European waters during the recent decades. We also demonstrate that precise prey identification to the lowest possible taxon is crucial to reveal the dietary overlap between co-occurring fish species and to predict the impact of alien invaders on native species through interspecific competition, as well as to recommend such an approach in studies upon fish foraging strategies.","PeriodicalId":54290,"journal":{"name":"Neobiota","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140261750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-29DOI: 10.3897/neobiota.91.113801
J. Mulema, Sydney Phiri, Nchimunya Bbebe, Rodwell Chandipo, M. Chijikwa, Hildah Chimutingiza, Paul Kachapulula, Francisca Kankuma Mwanda, Mathews Matimelo, Emma Mazimba-Sikazwe, Sydney Mfune, M. Mkulama, Miyanda Moonga, W. Mphande, Millens Mufwaya, Rabson M. Mulenga, Brenda Mweemba, Damien Ndalamei Mabote, Phillip Nkunika, Isaiah Nthenga, M. Tembo, J. Chowa, Stacey Odunga, S. Opisa, Chapwa Kasoma, Lucinda Charles, F. Makale, I. Rwomushana, N. Phiri
A prioritisation study was conducted to address the lack of adequate information about potential pests likely to be introduced in Zambia and become invasive. The study was conducted by subject matter experts from relevant institutions in and outside Zambia. Although this study focused on major pest categories, this paper only addresses bacteria and Protista. A list of 306 bacterial and 10 Protista species adjudged to affect plants was generated using CABI’s Horizon Scanning Tool. The 316 (total) pest species were refined to focus on pests that affect value chains important to Zambia’s economy. This resulted in a final list of 133 bacteria and eight Protista. Four additional bacteria species considered of phytosanitary interest were added and all 137 bacteria and eight Protista species were subjected to a rapid risk assessment using agreed guidelines. Vectors reported to transmit any of the pathogenic organisms were also subjected to a risk assessment. A proportion of 53% (n = 77 of 145) comprising 73 bacteria and four Protista species were reported as present in Africa. Of these, 42 (57%, n = 73) bacterial species and two (n=4) Protista species were reported in neighbouring countries. Considering a cut-off of 54, the highest scoring pests were 40 bacteria (highest score of 140) and three Protista (highest score of 125). Three actions were suggested for high-scoring pests, a detection surveillance, a pest-initiated pest risk analysis (PRA) or a detection surveillance followed by pest-initiated PRA. A “no action” was suggested where the risk was very low although, for some pathogenic organisms, a “no action” was followed by periodic monitoring. This information will contribute towards proactive prevention and management of biological invasions.
{"title":"Rapid risk assessment of plant pathogenic bacteria and protists likely to threaten agriculture, biodiversity and forestry in Zambia","authors":"J. Mulema, Sydney Phiri, Nchimunya Bbebe, Rodwell Chandipo, M. Chijikwa, Hildah Chimutingiza, Paul Kachapulula, Francisca Kankuma Mwanda, Mathews Matimelo, Emma Mazimba-Sikazwe, Sydney Mfune, M. Mkulama, Miyanda Moonga, W. Mphande, Millens Mufwaya, Rabson M. Mulenga, Brenda Mweemba, Damien Ndalamei Mabote, Phillip Nkunika, Isaiah Nthenga, M. Tembo, J. Chowa, Stacey Odunga, S. Opisa, Chapwa Kasoma, Lucinda Charles, F. Makale, I. Rwomushana, N. Phiri","doi":"10.3897/neobiota.91.113801","DOIUrl":"https://doi.org/10.3897/neobiota.91.113801","url":null,"abstract":"A prioritisation study was conducted to address the lack of adequate information about potential pests likely to be introduced in Zambia and become invasive. The study was conducted by subject matter experts from relevant institutions in and outside Zambia. Although this study focused on major pest categories, this paper only addresses bacteria and Protista. A list of 306 bacterial and 10 Protista species adjudged to affect plants was generated using CABI’s Horizon Scanning Tool. The 316 (total) pest species were refined to focus on pests that affect value chains important to Zambia’s economy. This resulted in a final list of 133 bacteria and eight Protista. Four additional bacteria species considered of phytosanitary interest were added and all 137 bacteria and eight Protista species were subjected to a rapid risk assessment using agreed guidelines. Vectors reported to transmit any of the pathogenic organisms were also subjected to a risk assessment. A proportion of 53% (n = 77 of 145) comprising 73 bacteria and four Protista species were reported as present in Africa. Of these, 42 (57%, n = 73) bacterial species and two (n=4) Protista species were reported in neighbouring countries. Considering a cut-off of 54, the highest scoring pests were 40 bacteria (highest score of 140) and three Protista (highest score of 125). Three actions were suggested for high-scoring pests, a detection surveillance, a pest-initiated pest risk analysis (PRA) or a detection surveillance followed by pest-initiated PRA. A “no action” was suggested where the risk was very low although, for some pathogenic organisms, a “no action” was followed by periodic monitoring. This information will contribute towards proactive prevention and management of biological invasions.","PeriodicalId":54290,"journal":{"name":"Neobiota","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140413243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-27DOI: 10.3897/neobiota.91.110560
Tomos Siôn Jones, A. Culham, B. J. Pickles, John David
It is estimated that there are 30 million gardeners in Britain, who could play a crucial role in being the ‘first contact’ for reporting ornamental plants in gardens with invasive potential. Invasive species are one of the five drivers of the global nature crisis, many of which were originally introduced through ornamental horticulture. Ornamentals confined to gardens and those which have already naturalised, but are not yet shown to be invasive, represent a ‘pool’ of species with invasive potential – ‘future invaders’. An online survey asking gardeners to report ornamentals they had noticed invading or taking over their garden resulted in 251 different taxa being reported (including cultivars). The future invaders were prioritised with a simple yet structured scheme, looking at the domestic and global naturalised and invasive status of each taxon, including in the Global Register of Introduced and Invasive Species (GRIIS) and the Global Naturalized Alien Flora (GloNAF) databases. The structured scheme identified a shortlist of nine ornamentals of concern which should be prioritised for further analysis, such as a formal risk assessment. Identifying and preventing future invaders before they escape gardens is critical, to prevent future threats to nature. There is also a gap in the identification of potentially invasive ornamentals, which are not currently invasive, yet are beyond the scope of formal horizon scanning because they are naturalised. Here we explore whether surveying gardeners can be a suitable approach to prioritising future invaders while also being an opportunity to increase awareness of invasive species. This positive feedback loop between gardeners and invasion scientists could help reduce the risk of future invaders.
{"title":"Can gardeners identify ‘future invaders’?","authors":"Tomos Siôn Jones, A. Culham, B. J. Pickles, John David","doi":"10.3897/neobiota.91.110560","DOIUrl":"https://doi.org/10.3897/neobiota.91.110560","url":null,"abstract":"It is estimated that there are 30 million gardeners in Britain, who could play a crucial role in being the ‘first contact’ for reporting ornamental plants in gardens with invasive potential. Invasive species are one of the five drivers of the global nature crisis, many of which were originally introduced through ornamental horticulture. Ornamentals confined to gardens and those which have already naturalised, but are not yet shown to be invasive, represent a ‘pool’ of species with invasive potential – ‘future invaders’. An online survey asking gardeners to report ornamentals they had noticed invading or taking over their garden resulted in 251 different taxa being reported (including cultivars). The future invaders were prioritised with a simple yet structured scheme, looking at the domestic and global naturalised and invasive status of each taxon, including in the Global Register of Introduced and Invasive Species (GRIIS) and the Global Naturalized Alien Flora (GloNAF) databases. The structured scheme identified a shortlist of nine ornamentals of concern which should be prioritised for further analysis, such as a formal risk assessment. Identifying and preventing future invaders before they escape gardens is critical, to prevent future threats to nature. There is also a gap in the identification of potentially invasive ornamentals, which are not currently invasive, yet are beyond the scope of formal horizon scanning because they are naturalised. Here we explore whether surveying gardeners can be a suitable approach to prioritising future invaders while also being an opportunity to increase awareness of invasive species. This positive feedback loop between gardeners and invasion scientists could help reduce the risk of future invaders.","PeriodicalId":54290,"journal":{"name":"Neobiota","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140426807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-22DOI: 10.3897/neobiota.91.109251
M. Gruntman, U. Segev
The success of invasive species is often attributed to rapid post-introduction evolution, due to novel selection pressures at the introduced range. However, evolutionary shifts in invasion-promoting traits can also take place within the introduced range over time. Here, we first present a review of the proposed hypotheses regarding the selection pressures and trait divergence along gradients of invasion history and the studies that examined them. In addition, we present the results of a meta-analysis aimed to provide a more general overview of current knowledge on trait evolution with time since introduction. Invasion-promoting traits, including growth, competitive ability and dispersal ability, were proposed to decline in more established populations with a long invasion history due to the attenuation of selection pressures, such as enemy release or interspecific competition, while herbivore defence was suggested to increase. Our meta-analysis results reveal a general indication for the evolution of invasive plants with residence time for most of the studied traits. However, this divergence did not have a consistent direction in most traits, except for growth, which, in contrast with our prediction, increased with residence time. The lack of empirical support for the predicted change in most of the studied traits over time suggests trait evolution might be affected by other context-dependent factors such as climatic gradients along invasion routes. Similarly, the increased allocation to size in older and more established populations may be driven by increased conspecific competition pressure experienced in these populations. The general temporal effect found in our meta-analysis stresses the need to consider population age when comparing attributes of invasive plants between native and invasive ranges. Moreover, the increased size of invasive plants in older populations, suggests that the dominance of these plants might not attenuate with time since introduction, thus highlighting the need to further explore the long-term dynamics between invasive plants and their recipient native communities.
{"title":"Effect of residence time on trait evolution in invasive plants: review and meta-analysis","authors":"M. Gruntman, U. Segev","doi":"10.3897/neobiota.91.109251","DOIUrl":"https://doi.org/10.3897/neobiota.91.109251","url":null,"abstract":"The success of invasive species is often attributed to rapid post-introduction evolution, due to novel selection pressures at the introduced range. However, evolutionary shifts in invasion-promoting traits can also take place within the introduced range over time. Here, we first present a review of the proposed hypotheses regarding the selection pressures and trait divergence along gradients of invasion history and the studies that examined them. In addition, we present the results of a meta-analysis aimed to provide a more general overview of current knowledge on trait evolution with time since introduction. Invasion-promoting traits, including growth, competitive ability and dispersal ability, were proposed to decline in more established populations with a long invasion history due to the attenuation of selection pressures, such as enemy release or interspecific competition, while herbivore defence was suggested to increase. Our meta-analysis results reveal a general indication for the evolution of invasive plants with residence time for most of the studied traits. However, this divergence did not have a consistent direction in most traits, except for growth, which, in contrast with our prediction, increased with residence time. The lack of empirical support for the predicted change in most of the studied traits over time suggests trait evolution might be affected by other context-dependent factors such as climatic gradients along invasion routes. Similarly, the increased allocation to size in older and more established populations may be driven by increased conspecific competition pressure experienced in these populations. The general temporal effect found in our meta-analysis stresses the need to consider population age when comparing attributes of invasive plants between native and invasive ranges. Moreover, the increased size of invasive plants in older populations, suggests that the dominance of these plants might not attenuate with time since introduction, thus highlighting the need to further explore the long-term dynamics between invasive plants and their recipient native communities.","PeriodicalId":54290,"journal":{"name":"Neobiota","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140438223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-21DOI: 10.3897/neobiota.91.111628
A. Goetz, E. González-Sargas, Mayra C. Vidal, P. Shafroth, A. Henry, A. Sher
Effective ecological restoration requires empirical assessment to determine outcomes of projects, but conclusions regarding the effects of restoration treatments on the whole ecosystem remain rare. Control of invasive shrubs and trees in the genus Tamarix and associated riparian restoration in the American Southwest has been of interest to scientists and resource managers for decades; dozens of studies have reported highly variable outcomes of Tamarix control efforts, as measured by a range of response variables, temporal and spatial scales and monitoring strategies. We conducted a literature search and review, meta-analysis and vote count (comparison of numerical outcomes lacking reported variances and/or sample sizes) on published papers that quantitatively measured a variety of responses to control of Tamarix. From 96 publications obtained through a global search on terms related to Tamarix control, we found 52 publications suitable for a meta-analysis (n = 777 comparisons) and 63 publications suitable for two vote counts (n = 1,460 comparisons total; 622 comparisons reported as statistically significant) of response to Tamarix control. We estimated responses to control by treatment type (e.g. cut-stump treatment, burning, biocontrol) and ecosystem component (e.g. vegetation, fauna, fluvial processes). Finally, we compared results of the various synthesis methods to determine whether the increasingly stringent requirements for inclusion led to biased outcomes. Vegetation metrics, especially measures of Tamarix response, were the most commonly assessed. Ecosystem components other than vegetation, such as fauna, soils and hydrogeomorphic dynamics, were under-represented. The meta-analysis showed significantly positive responses by vegetation overall to biocontrol, herbicide and cut-stump treatments. This was primarily due to reduction of Tamarix cover; impacts on replacement vegetation were highly variable. We found concordance amongst our varied synthesis approaches, indicating that increased granularity from stricter quantitative techniques does not come at the cost of a biased sample. Overall, our results indicate that common control methods are generally effective for reducing Tamarix, but the indirect effects on other aspects of the ecosystem are variable and remain understudied. Given that this is a relatively well-studied invasive plant species, our results also illustrate the limitations of not only individual studies, but also of reviews for measuring the impact of invasive species control. We call on researchers to investigate the less commonly studied responses to Tamarix control and riparian restoration including the effects on fauna, soil and hydrogeomorphic characteristics.
{"title":"Outcomes of control and monitoring of a widespread riparian invader (Tamarix spp.): a comparison of synthesis approaches","authors":"A. Goetz, E. González-Sargas, Mayra C. Vidal, P. Shafroth, A. Henry, A. Sher","doi":"10.3897/neobiota.91.111628","DOIUrl":"https://doi.org/10.3897/neobiota.91.111628","url":null,"abstract":"Effective ecological restoration requires empirical assessment to determine outcomes of projects, but conclusions regarding the effects of restoration treatments on the whole ecosystem remain rare. Control of invasive shrubs and trees in the genus Tamarix and associated riparian restoration in the American Southwest has been of interest to scientists and resource managers for decades; dozens of studies have reported highly variable outcomes of Tamarix control efforts, as measured by a range of response variables, temporal and spatial scales and monitoring strategies. We conducted a literature search and review, meta-analysis and vote count (comparison of numerical outcomes lacking reported variances and/or sample sizes) on published papers that quantitatively measured a variety of responses to control of Tamarix. From 96 publications obtained through a global search on terms related to Tamarix control, we found 52 publications suitable for a meta-analysis (n = 777 comparisons) and 63 publications suitable for two vote counts (n = 1,460 comparisons total; 622 comparisons reported as statistically significant) of response to Tamarix control. We estimated responses to control by treatment type (e.g. cut-stump treatment, burning, biocontrol) and ecosystem component (e.g. vegetation, fauna, fluvial processes). Finally, we compared results of the various synthesis methods to determine whether the increasingly stringent requirements for inclusion led to biased outcomes. Vegetation metrics, especially measures of Tamarix response, were the most commonly assessed. Ecosystem components other than vegetation, such as fauna, soils and hydrogeomorphic dynamics, were under-represented. The meta-analysis showed significantly positive responses by vegetation overall to biocontrol, herbicide and cut-stump treatments. This was primarily due to reduction of Tamarix cover; impacts on replacement vegetation were highly variable. We found concordance amongst our varied synthesis approaches, indicating that increased granularity from stricter quantitative techniques does not come at the cost of a biased sample. Overall, our results indicate that common control methods are generally effective for reducing Tamarix, but the indirect effects on other aspects of the ecosystem are variable and remain understudied. Given that this is a relatively well-studied invasive plant species, our results also illustrate the limitations of not only individual studies, but also of reviews for measuring the impact of invasive species control. We call on researchers to investigate the less commonly studied responses to Tamarix control and riparian restoration including the effects on fauna, soil and hydrogeomorphic characteristics.","PeriodicalId":54290,"journal":{"name":"Neobiota","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140442035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-19DOI: 10.3897/neobiota.91.111222
Elizabeth M. Oishi, Kiara R. Kattler, Hannah V. Watkins, Brett R. Howard, Isabelle M. Côté
Understanding the density-dependent impacts of an invasive predator is integral for predicting potential consequences for prey populations. Functional response experiments are used to assess the rate of prey consumption and a predator’s ability to search for and consume prey at different resource densities. However, results can be highly context-dependent, limiting their extrapolation to natural ecosystems. Here, we examined how simulated habitat complexity, through the addition of substrate in which prey can escape predation, affects the functional response of invasive European green crabs (Carcinus maenas) foraging on two different bivalve species. Green crabs feeding on varnish clams (Nuttallia obscurata) shifted from a Type II hyperbolic functional response in the absence of substrate to density-independent consumption when prey could bury. Green crabs ate few Japanese littleneck clams (Venerupis philippinarum) under all densities, such that no functional response curve of any type could be produced and their total consumption was always density independent. However, the probability of at least one Japanese littleneck clam being consumed increased significantly with initial clam density and crab claw size across all treatments. At mean crab claw size and compared to trials without substrate, the proportion of varnish clams consumed were 4.2 times smaller when substrate was present, but substrate had a negligible effect (1.2 times) on Japanese littlenecks. The proportion of varnish clams consumed increased with crab claw size and were higher across both substrate conditions than the proportion of Japanese littlenecks consumed; however, the proportion of Japanese littleneck clams consumed increased faster with claw size than that of varnish clams. Our results suggest that including environmental features and variation in prey species can influence the density-dependent foraging described by functional response experiments. Incorporating replicable features of the natural environment into functional response experiments is imperative to make more accurate predictions about the impact of invasive predators on prey populations.
{"title":"Substrate complexity reduces prey consumption in functional response experiments: Implications for extrapolating to the wild","authors":"Elizabeth M. Oishi, Kiara R. Kattler, Hannah V. Watkins, Brett R. Howard, Isabelle M. Côté","doi":"10.3897/neobiota.91.111222","DOIUrl":"https://doi.org/10.3897/neobiota.91.111222","url":null,"abstract":"Understanding the density-dependent impacts of an invasive predator is integral for predicting potential consequences for prey populations. Functional response experiments are used to assess the rate of prey consumption and a predator’s ability to search for and consume prey at different resource densities. However, results can be highly context-dependent, limiting their extrapolation to natural ecosystems. Here, we examined how simulated habitat complexity, through the addition of substrate in which prey can escape predation, affects the functional response of invasive European green crabs (Carcinus maenas) foraging on two different bivalve species. Green crabs feeding on varnish clams (Nuttallia obscurata) shifted from a Type II hyperbolic functional response in the absence of substrate to density-independent consumption when prey could bury. Green crabs ate few Japanese littleneck clams (Venerupis philippinarum) under all densities, such that no functional response curve of any type could be produced and their total consumption was always density independent. However, the probability of at least one Japanese littleneck clam being consumed increased significantly with initial clam density and crab claw size across all treatments. At mean crab claw size and compared to trials without substrate, the proportion of varnish clams consumed were 4.2 times smaller when substrate was present, but substrate had a negligible effect (1.2 times) on Japanese littlenecks. The proportion of varnish clams consumed increased with crab claw size and were higher across both substrate conditions than the proportion of Japanese littlenecks consumed; however, the proportion of Japanese littleneck clams consumed increased faster with claw size than that of varnish clams. Our results suggest that including environmental features and variation in prey species can influence the density-dependent foraging described by functional response experiments. Incorporating replicable features of the natural environment into functional response experiments is imperative to make more accurate predictions about the impact of invasive predators on prey populations.","PeriodicalId":54290,"journal":{"name":"Neobiota","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140451192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-08DOI: 10.3897/neobiota.91.115675
Miao-Miao Zheng, Petr Pyšek, Kun Guo, Hasigerili Hasigerili, Wen‐Yong Guo
Alien species are colonizing mountain ecosystems and increasing their elevation ranges in response to ongoing climate change and anthropogenic disturbances, posing increasing threats to native species. However, how quickly alien species spread upward and what drives their invasion remains insufficiently understood. Here, using 26,952 occurrence records of 58 alien plant species collected over two centuries in the Czech Republic, we explored the elevation range and invasion speed of each alien species and the underlying factors driving these variables. We collected species traits relevant for invasion (e.g., clonality, flowering time, life span, invasion status, height, mycorrhizal type, native range, naturalized range, monoploid genome size, and Ellenberg-type indicator values for light, temperature, and nitrogen), human-associated factors (e.g., introduction pathways and the sum of economic use types), and minimum residence time. We explored the relationships between these factors and species’ elevation range and invasion speed using phylogenetic regressions. Our results showed that 58 alien species have been expanding upward along mountain elevations in the Czech Republic over the past two centuries. A stronger effect of species’ traits than human-associated factors has been revealed, e.g., clonality was a key trait supporting the invasion of alien species into the mountains, while human-associated factors showed no effect. Our findings highlight that the characteristics associated with rapid reproduction and spread are crucial for alien species’ invasion into montane regions. Identifying key drivers of this process is important for predicting the spatiotemporal dynamics of alien species in high-altitude ecosystems and thus employing apposite measures to reduce the threat to native plant species.
{"title":"Clonal alien plants in the mountains spread upward more extensively and faster than non-clonal","authors":"Miao-Miao Zheng, Petr Pyšek, Kun Guo, Hasigerili Hasigerili, Wen‐Yong Guo","doi":"10.3897/neobiota.91.115675","DOIUrl":"https://doi.org/10.3897/neobiota.91.115675","url":null,"abstract":"Alien species are colonizing mountain ecosystems and increasing their elevation ranges in response to ongoing climate change and anthropogenic disturbances, posing increasing threats to native species. However, how quickly alien species spread upward and what drives their invasion remains insufficiently understood. Here, using 26,952 occurrence records of 58 alien plant species collected over two centuries in the Czech Republic, we explored the elevation range and invasion speed of each alien species and the underlying factors driving these variables. We collected species traits relevant for invasion (e.g., clonality, flowering time, life span, invasion status, height, mycorrhizal type, native range, naturalized range, monoploid genome size, and Ellenberg-type indicator values for light, temperature, and nitrogen), human-associated factors (e.g., introduction pathways and the sum of economic use types), and minimum residence time. We explored the relationships between these factors and species’ elevation range and invasion speed using phylogenetic regressions. Our results showed that 58 alien species have been expanding upward along mountain elevations in the Czech Republic over the past two centuries. A stronger effect of species’ traits than human-associated factors has been revealed, e.g., clonality was a key trait supporting the invasion of alien species into the mountains, while human-associated factors showed no effect. Our findings highlight that the characteristics associated with rapid reproduction and spread are crucial for alien species’ invasion into montane regions. Identifying key drivers of this process is important for predicting the spatiotemporal dynamics of alien species in high-altitude ecosystems and thus employing apposite measures to reduce the threat to native plant species.","PeriodicalId":54290,"journal":{"name":"Neobiota","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139790777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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