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Title: Combining local, landscape, and regional geographies to assess plant community vulnerability to invasion impact

Invasive species science has focused heavily on the invasive agent. However, management to protect native species also requires a proactive approach focused on resident communities and the features affecting their vulnerability to invasion impacts. Vulnerability is likely the result of factors acting across spatial scales, from local to regional, and it is the combined effects of these factors that will determine the magnitude of vulnerability. Here, we introduce an analytical framework that quantifies the scale‐dependent impact of biological invasions on native richness from the shape of the native species–area relationship (SAR). We leveraged newly available, biogeographically extensive vegetation data from the U.S. National Ecological Observatory Network to assess plant community vulnerability to invasion impact as a function of factors acting across scales. We analyzed more than 1000 SARs widely distributed across the USA along environmental gradients and under different levels of non‐native plant cover. Decreases in native richness were consistently associated with non‐native species cover, but native richness was compromised only at relatively high levels of non‐native cover. After accounting for variation in baseline ecosystem diversity, net primary productivity, and human modification, ecoregions that were colder and wetter were most vulnerable to losses of native plant species at the local level, while warmer and wetter areas were most susceptible at the landscape level. We also document how the combined effects of cross‐scale factors result in a heterogeneous spatial pattern of vulnerability. This pattern could not be predicted by analyses at any single scale, underscoring the importance of accounting for factors acting across scales. Simultaneously assessing differences in vulnerability between distinct plant communities at local, landscape, and regional scales provided outputs that can be used to inform policy and management aimed at reducing vulnerability to the impact of plant invasions.

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Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Ecological Applications
Medium: X
Sponsoring Org:
National Science Foundation
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  1. Abstract Aim

    Native biodiversity is threatened by the spread of non‐native invasive species. Many studies demonstrate that invasions reduce local biodiversity but we lack an understanding of how impacts vary across environments at the macroscale. Using ~11,500 vegetation surveys from ecosystems across the United States, we quantified how the relationship between non‐native plant cover and native plant diversity varied across different compositions of invading plants (measured by non‐native plant richness and evenness) and environmental contexts (measured by productivity and human activity).


    Continental United States.

    Time Period

    Surveys from 1990s‐present.

    Major Taxa Studied

    Terrestrial plant communities.


    We fit mixed effects models to understand how native plant richness, diversity and evenness varied with non‐native cover. We tested how this relationship varied when non‐native cover interacted with non‐native plant richness and evenness, and with productivity and human activity.


    Across the United States, communities with greater cover of non‐native plants had lower native plant richness and diversity but higher evenness, suggesting rare native plants can be lost while dominant plants decline in abundance. The relationship between non‐native cover and native community diversity varied with non‐native plant richness and evenness but was not associated with productivity and human activity. Negative associations were strongest in areas with low non‐native richness and evenness, characterizing plant communities that were invaded by a dominant non‐native plant.

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    Non‐native plant cover provides a first approximation of invasion impacts on native community diversity, but the magnitude of impact depended on non‐native plant richness and evenness. Relationships between non‐native cover and native diversity were consistent in strength across continental scale gradients of productivity and human activity. Therefore, at the macroscale, invasive plant impacts on native plant communities likely depend more on the characteristics of the invading plants, that is the presence of a dominant invader, than on the environmental context.

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    Blue Mountains of the Inland Northwest, USA.


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