Soil Microbes Alter the Diversity-Invasibility Relationship by Promoting a Complementarity Effect on Community Invasion Resistance

Abstract Background Soil microbes can affect both the invasiveness of exotic plants and the invasibility of native plant communities, but it still remains unclear whether soil microbes can influence the relationship between native plant diversity and community invasibility.Methods We constructed native plant communities with three levels of species richness (one, three, or six species) in unsterilized or sterilized soil (i.e., with or without soil microbes) and either prevented their invasion by exotic plants or allowed them to be invaded by each of three exotic species (Solidago canadensis, Erigeron canadensis or Symphyotrichum subulatum), which are highly invasive in China. The soils conditioned by the native plant communities that were not invaded by the exotic species were used as soil microbe inocula to test whether species richness-induced differences in soil microbes affected the growth of each of the three invasive species.Results Compared with soils containing microbes, the absence of soil microbes weakened the negative species richness-invasibility relationship, indicating that soil microbes can contribute to higher invasion resistance in more diverse native plant communities. In the presence of soil microbes, the higher invasion resistance of more diverse communities was mainly ascribed to the complementarity effect. However, soil microbes from communities with a higher species richness did not have a stronger negative effect on the growth of any of the three invasive species. Conclusion Soil microbes can alter the diversity-invasibility relationship by promoting the complementarity effect on community invasion resistance. Our results highlight the importance of integrating the role of soil microbes when testing the diversity-invasibility hypothesis.

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Exotic plant invasion and understorey species richness: a comparison of two types of eucalypt woodland in agricultural Western Australia

Pacific Conservation Biology ◽

10.1071/pc980021 ◽

1998 ◽

Vol 4 (1) ◽

pp. 21 ◽

Cited By ~ 10

Author(s):

Max Abensperg-Traun ◽

Lyn Atkins ◽

Richard Hobbs ◽

Dion Steven

Keyword(s):

Species Richness ◽

Exotic Species ◽

Plant Species ◽

Plant Invasion ◽

Native Plants ◽

Exotic Plants ◽

Exotic Plant ◽

Native Plant ◽

Road Verge ◽

Exotic Plant Invasion

Exotic plants are a major threat to native plant diversity in Australia yet a generic model of the invasion of Australian ecosystems by exotic species is lacking because invasion levels differ with vegetation/soil type and environmental conditions. This study compared relative differences in exotic species invasion (percent cover, spp. richness) and the species richness of herbaceous native plants in two structurally very similar vegetation types, Gimlet Eucalyptus salubris and Wandoo E. capillosa woodlands in the Western Australian wheatbelt. For each woodland type, plant variables were measured for relatively undisturbed woodlands, woodlands with >30 years of livestock grazing history, and woodlands in road-verges. Grazed and road-verge Gimlet and Wandoo woodlands had significantly higher cover of exotic species, and lower species richness of native plants, compared with undisturbed Gimlet and Wandoo. Exotic plant invasion was significantly greater in Gimlet woodlands for both grazed (mean 78% cover) and road-verge sites (mean 42% cover) than in comparable sites in Wandoo woodlands (grazed sites 25% cover, road-verge sites 19% cover). There was no significant difference in the species richness of exotic plants between Wandoo and Gimlet sites for any of the three situations. Mean site richness of native plants was not significantly different between undisturbed Wandoo and undisturbed Gimlet woodlands. Undisturbed woodlands were significantly richer in plant species than grazed and road-verge woodlands for both woodland types. Grazed and road-verge Wandoo sites were significantly richer in plant species than communities in grazed and road-verge Gimlet. The percent cover of exotics was negatively correlated with total (native) plant species richness for both woodland types (Wandoo r = ?0.70, Gimlet r = ?0.87). Of the total native species recorded in undisturbed Gimlet, 83% and 61% were not recorded in grazed and road-verge Gimlet, respectively. This compared with 40% and 33% for grazed and road-verge Wandoo, respectively. Grazed Wandoo and grazed Gimlet sites had significantly fewer native plant species than did road-verge Wandoo and road-verge Gimlet sites. Ecosystem implications of differential invasions by exotic species, and the effects of grazing (disturbance) and other factors influencing susceptibility to exotic plant invasion (landscape, competition and allelopathy) on native species decline are discussed. Exclusion of livestock and adequate methods of control and prevention of further invasions by exotic plants are essential requirements for the conservation of these woodland systems.

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A century of ecosystem change: human and seabird impacts on plant species extirpation and invasion on islands

PeerJ ◽

10.7717/peerj.2208 ◽

2016 ◽

Vol 4 ◽

pp. e2208 ◽

Cited By ~ 6

Author(s):

Thomas K. Lameris ◽

Joseph R. Bennett ◽

Louise K. Blight ◽

Marissa Giesen ◽

Michael H. Janssen ◽

...

Keyword(s):

Species Richness ◽

Exotic Species ◽

Plant Species ◽

Plant Communities ◽

Soil Depth ◽

Rapid Change ◽

Ecosystem Change ◽

Native Plant ◽

Native Plant Species ◽

Species Cover

We used 116 years of floral and faunal records from Mandarte Island, British Columbia, Canada, to estimate the indirect effects of humans on plant communities via their effects on the population size of a surface-nesting, colonial seabird, the Glaucous-winged gull (Larus glaucescens). Comparing current to historical records revealed 18 extirpations of native plant species (32% of species historically present), 31 exotic species introductions, and one case of exotic introduction followed by extirpation. Contemporary surveys indicated that native species cover declined dramatically from 1986 to 2006, coincident with the extirpation of ‘old-growth’ conifers. Because vegetation change co-occurred with an increasing gull population locally and regionally, we tested several predictions from the hypothesis that the presence and activities of seabirds help to explain those changes. Specifically, we predicted that on Mandarte and nearby islands with gull colonies, we should observe higher nutrient loading and exotic plant species richness and cover than on nearby islands without gull colonies, as a consequence of competitive dominance in species adapted to high soil nitrogen and trampling. As predicted, we found that native plant species cover and richness were lower, and exotic species cover and richness higher, on islands with versus without gull colonies. In addition, we found that soil carbon and nitrogen on islands with nesting gulls were positively related to soil depth and exotic species richness and cover across plots and islands. Our results support earlier suggestions that nesting seabirds can drive rapid change in insular plant communities by increasing nutrients and disturbing vegetation, and that human activities that affect seabird abundance may therefore indirectly affect plant community composition on islands with seabird colonies.

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A century of ecosystem change: human and seabird impacts on plant species extirpation and invasion on islands

10.7287/peerj.preprints.1787 ◽

2016 ◽

Author(s):

Thomas K Lameris ◽

Joseph R Bennett ◽

Louise K Blight ◽

Marissa Giesen ◽

Michael H Janssen ◽

...

Keyword(s):

Species Richness ◽

Exotic Species ◽

Plant Species ◽

Plant Communities ◽

Soil Depth ◽

Rapid Change ◽

Ecosystem Change ◽

Native Plant ◽

Native Plant Species ◽

Species Cover

We used 116-years of floral and faunal records from Mandarte Island, British Columbia, Canada, to estimate the indirect effects of humans on plant communities via their effects on the population size of a surface-nesting, colonial seabird, the Glaucous-winged gull (Larus glaucescens). Comparing current to historical records revealed 18 extirpations of native plant species (32% of species historically present), 31 exotic species introductions, and one case of exotic introduction followed by extirpation. Contemporary surveys indicated that native species cover declined dramatically from 1986 to 2006, coincident with the extirpation of ‘old-growth’ conifers. Because vegetation change co-occurred with an increasing gull population locally and regionally, we also tested predictions from the hypothesis that the presence and activities of seabirds help to explain those changes. Specifically, we predicted we would observe high nutrient loading and exotic plant species richness and cover on nearby islands with versus without gull colonies as a consequence of competitive dominance in species adapted to high soil nitrogen and trampling. As predicted, we found that native plant species cover and richness were lower, and exotic species cover and richness higher, on islands with versus without gull colonies. In addition, we found that soil carbon and nitrogen on islands with nesting gulls were positively related to soil depth and exotic species richness and cover across plots and islands. Our results suggest that gulls have the potential to drive rapid change in insular plant communities by increasing nutrients and disturbing vegetation. Because human activities have contributed to long-term change in gull populations, our results further suggest compelling, indirect links between human management decisions and plant community composition on islands of the Georgia Basin.

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A century of ecosystem change: human and seabird impacts on plant species extirpation and invasion on islands

10.7287/peerj.preprints.1787v1 ◽

2016 ◽

Author(s):

Thomas K Lameris ◽

Joseph R Bennett ◽

Louise K Blight ◽

Marissa Giesen ◽

Michael H Janssen ◽

...

Keyword(s):

Species Richness ◽

Exotic Species ◽

Plant Species ◽

Plant Communities ◽

Soil Depth ◽

Rapid Change ◽

Ecosystem Change ◽

Native Plant ◽

Native Plant Species ◽

Species Cover

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Effects of Urbanization on Plant–Pollinator Interactions in the Tropics: An Experimental Approach Using Exotic Plants

Insects ◽

10.3390/insects11110773 ◽

2020 ◽

Vol 11 (11) ◽

pp. 773

Author(s):

Marie Zakardjian ◽

Benoît Geslin ◽

Valentin Mitran ◽

Evelyne Franquet ◽

Hervé Jourdan

Keyword(s):

Exotic Species ◽

Plant Communities ◽

Urban Areas ◽

Native Species ◽

New Caledonia ◽

Land Use Changes ◽

Exotic Plants ◽

Exotic Plant ◽

Wild Bees ◽

Plant Pollinator

Land-use changes through urbanization and biological invasions both threaten plant-pollinator networks. Urban areas host modified bee communities and are characterized by high proportions of exotic plants. Exotic species, either animals or plants, may compete with native species and disrupt plant–pollinator interactions. These threats are heightened in insular systems of the Southwest Pacific, where the bee fauna is generally poor and ecological networks are simplified. However, the impacts of these factors have seldom been studied in tropical contexts. To explore those questions, we installed experimental exotic plant communities in urban and natural contexts in New Caledonia, a plant diversity hotspot. For four weeks, we observed plant–pollinator interactions between local pollinators and our experimental exotic plant communities. We found a significantly higher foraging activity of exotic wild bees within the city, together with a strong plant–pollinator association between two exotic species. However, contrary to our expectations, the landscape context (urban vs. natural) had no effect on the activity of native bees. These results raise issues concerning how species introduced in plant–pollinator networks will impact the reproductive success of both native and exotic plants. Furthermore, the urban system could act as a springboard for alien species to disperse in natural systems and even invade them, leading to conservation concerns.

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Comparing Effectiveness and Impacts of Japanese Barberry (Berberis thunbergii) Control Treatments and Herbivory on Plant Communities

Invasive Plant Science and Management ◽

10.1614/ipsm-d-13-00004.1 ◽

2013 ◽

Vol 6 (4) ◽

pp. 459-469 ◽

Cited By ~ 12

Author(s):

Jeffrey S. Ward ◽

Scott C. Williams ◽

Thomas E. Worthley

Keyword(s):

Invasive Species ◽

Plant Communities ◽

Initial Treatment ◽

Prescribed Burning ◽

Labor Cost ◽

Native Plant ◽

Minimal Impact ◽

Japanese Barberry ◽

Treatment Type

AbstractTwo factors that can degrade native plant community composition and structure, and hinder restoration efforts, are invasive species and chronic overbrowsing by ungulates such as white-tailed deer. Beginning in 2007, the effectiveness, costs, and impacts of Japanese barberry control treatments and herbivory on nonnative and native plant communities was examined at eight study areas over 4 to 5 yr. Prescribed burning and mechanical mowing by wood shredder or brush saw were utilized as initial treatments to reduce the aboveground portion of established barberry and were equally effective. Without a follow-up treatment, barberry had recovered to 56 to 81% of pretreatment levels 50 to 62 mo after initial treatment. Follow-up treatments in mid-summer to kill new sprouts included directed heating and foliar herbicide applications. Relative to untreated controls, follow-up treatments lowered barberry cover 50 to 62 mo after initial treatment by at least 72%. Although all follow-up treatments were equally effective, the labor cost of directed heating was four times higher than for herbicide applications. Follow-up treatment type (directed heating vs. herbicide) had minimal impact on species other than barberry. White-tailed deer herbivory had a larger impact on other species than did barberry control treatments. Native grass and fern cover was higher outside of exclosures. Areas inside exclosures had higher cover of Oriental bittersweet and multiflora rose, but not Japanese barberry. Thus, recovery of native communities will require more than simply removing the dominant invasive species where deer densities are high. Excellent reduction of Japanese barberry cover can be achieved using either directed heating or herbicides as follow-up treatments in a two-step process, but other invasive plants may become a problem when barberry is removed if deer populations are low.

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Vegetation change in an urban grassy woodland 1974 - 2000

Australian Journal of Botany ◽

10.1071/bt03100 ◽

2004 ◽

Vol 52 (5) ◽

pp. 597 ◽

Cited By ~ 21

Author(s):

J. B. Kirkpatrick

Keyword(s):

Species Richness ◽

Species Composition ◽

Exotic Species ◽

Native Species ◽

Vegetation Change ◽

Structural Changes ◽

Linear Models ◽

Tree Cover ◽

Native Plant ◽

Native Species Richness

Few temporal studies document vegetation change in Australian temperate grassy woodlands. Floristic and structural data were collected from 68 randomly located sites in the Queens Domain, an urban grassy woodland remnant, in 1974, 1984, 1994 and 2000 and a search made for rare species. Species of conservation significance were concentrated at highly disturbed sites, whereas vegetation types of conservation significance decreased in area as a result of increases in the numbers of Allocasuarina verticillata, which caused a change in many unmown areas from Eucalyptus viminalis grassy woodland to E. viminalis–A. verticillata woodland/forest or A. verticillata open/closed forest. Structural changes were associated with changes in species composition and an increase in native-species richness. Increases in tree cover occurred where fires were most frequent, possibly as a result of the lack of mammalian herbivores. The frequencies of herbs and annual grasses were strongly affected by precipitation in the month of sampling. Half of the species that showed a consistent rise or fall through time were woody plants, approximately twice the number expected. In the dataset as a whole, species-richness variables were largely explained by varying combinations of variables related to moisture availability, altitude and the incidence of mowing. The strongest influences on species composition were the same, although slope and time since the last fire also contributed to multiple regression and generalised linear models. Compositional stability was positively related to native-species richness, whereas high levels of exotic-species richness occurred at both low and high levels of native-species richness. The maintenance of native-plant biodiversity on the Domain requires such counterintuitive measures as the maintenance of exotic trees and the control of native trees, demonstrating the contingencies of conservation management in fragmented vegetation that consists of a mixture of native and exotic species.

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The impacts of invasive plant species on the biodiversity of Australian rangelands

The Rangeland Journal ◽

10.1071/rj06014 ◽

2006 ◽

Vol 28 (1) ◽

pp. 27 ◽

Cited By ~ 58

Author(s):

A. C. Grice

Keyword(s):

Invasive Species ◽

Species Richness ◽

Plant Species ◽

Native Species ◽

Invasive Plant ◽

Plant Species Richness ◽

Native Plant ◽

Weed Species ◽

Ecological Processes ◽

Native Plant Species

Most parts of the Australian rangelands are at risk of invasion by one or more species of non-native plants. The severity of current problems varies greatly across the rangelands with more non-native plant species in more intensively settled regions, in climatic zones that have higher and more reliable rainfall, and in wetter and more fertile parts of rangeland landscapes. Although there is quantitative evidence of impacts on either particular taxonomic groups or specific ecological processes in Australian rangelands, a comprehensive picture of responses of rangeland ecosystems to plant invasions is not available. Research has been focused on invasive species that are perceived to have important effects. This is likely to down play the significance of species that have visually less dramatic influences and ignore the possibility that some species could invade and yet have negligible consequences. It is conceivable that most of the overall impact will come from a relatively small proportion of invasive species. Impacts have most commonly been assessed in terms of plant species richness or the abundance of certain groups of vertebrates to the almost complete exclusion of other faunal groups. All scientific studies of the impacts of invasive species in Australian rangelands have focused on the effects of individual invasive species although in many situations native communities are under threat from a complex of interacting weed species. Invasion by non-native species is generally associated with declines in native plant species richness, but faunal responses are more complex and individual invasions may be associated with increase, decrease and no-change scenarios for different faunal groups. Some invasive species may remain minor components of the vegetation that they invade while others completely dominate one stratum or the vegetation overall.

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Species richness, phylogenetic diversity and phylogenetic structure patterns of exotic and native plants along an elevational gradient in the Himalaya

Ecological Processes ◽

10.1186/s13717-021-00335-z ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Kumar Manish

Keyword(s):

Species Richness ◽

Exotic Species ◽

Native Species ◽

Phylogenetic Diversity ◽

Elevational Gradient ◽

Species Assemblages ◽

Native Plant ◽

Phylogenetic Structure ◽

Phylogenetic Overdispersion ◽

The Himalaya

Abstract Background So far, macroecological studies in the Himalaya have mostly concentrated on spatial variation of overall species richness along the elevational gradient. Very few studies have attempted to document the difference in elevational richness patterns of native and exotic species. In this study, this knowledge gap is addressed by integrating data on phylogeny and elevational distribution of species to identify the variation in species richness, phylogenetic diversity and phylogenetic structure of exotic and native plant species along an elevational gradient in the Himalaya. Results Species distribution patterns for exotic and native species differed; exotics tended to show maximum species richness at low elevations while natives tended to predominate at mid-elevations. Native species assemblages showed higher phylogenetic diversity than the exotic species assemblages over the entire elevational gradient in the Himalaya. In terms of phylogenetic structure, exotic species assemblages showed majorly phylogenetic clustering while native species assemblages were characterized by phylogenetic overdispersion over the entire gradient. Conclusions The findings of this study indicate that areas with high native species richness and phylogenetic diversity are less receptive to exotic species and vice versa in the Himalaya. Species assemblages with high native phylogenetic overdispersion are less receptive to exotic species than the phylogenetically clustered assemblages. Different ecological processes (ecological filtering in case of exotics and resource and niche competition in case of natives) may govern the distribution of exotic and native species along the elevational gradient in the Himalaya.

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Meta-Analysis of Exotic Forages as Invasive Plants in Complex Multi-Functioning Landscapes

Invasive Plant Science and Management ◽

10.1614/ipsm-d-14-00076.1 ◽

2015 ◽

Vol 8 (3) ◽

pp. 292-306 ◽

Cited By ~ 12

Author(s):

John Derek Scasta ◽

David M. Engle ◽

Samuel D. Fuhlendorf ◽

Daren D. Redfearn ◽

Terrance G. Bidwell

Keyword(s):

Community Structure ◽

Plant Community ◽

Plant Communities ◽

Invasive Plants ◽

Effect Size ◽

Meta Analysis ◽

Plant Community Structure ◽

Native Plant ◽

Forage Species ◽

Negative Effect

AbstractIntroducing exotic forages in the attempt to enhance livestock and wildlife forage has been practiced widely for over a century. These forage species are selected for traits conferring persistence under stress, potentially yielding invaders that transform native plant communities. Using standardized systematic review guidelines and meta-analytical techniques we quantified effects of exotic forage invasion on change of native plant community structure, and compared the magnitude and direction of change across exotic forage species, plant functional groups, and structure of plant communities. Our study of 13 exotic forage species in North America (six C4 grasses, three C3 grasses, and four legumes) yielded 35 papers with quantitative data from 64 case studies. Nine of the 13 species met our inclusion criteria for meta-analysis. The overall effect of exotic forage invasion on native plant communities was negative (Ē̄ = −0.74; 95% confidence interval [CI]: −0.29 to −0.25). The effect size was most negative for two C4 grasses, Lehmann lovegrass and Old World bluestems. A negative effect was also expressed by C3 and C4 grass functional groups, and these effects were stronger than for legumes. Effect size differed among measures of plant community structure, with the greatest negative effect on native plant biomass and the least negative effect on species evenness. Weighted fail-safe numbers indicated publication bias was not an issue. Exotic forage species are important for agricultural production but may threaten complex multi-functioning landscapes and should be considered as a subset of potentially invasive exotic species. Characteristics making exotic forages different from other exotic plants hinge on pathways of selection and dispersion: selection is based on persistence mechanisms similar to characteristics of invasive plants; dispersion by humans is intentional across expansive geographic regions. Exotic forages present a complex socio-ecological problem exacerbated by disconnected scientific disciplines, competing interests between policy and science, and organized efforts to increase food production.

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