When Can Herbivores Slow or Reverse the Spread of an Invading Plant? A Test Case from Mount St. Helens

Fagan, William F.; Lewis, Mark A.; Neubert, Michael G.; Aumann, Craig; Apple, Jennifer L.; Bishop, John G.

doi:10.1086/497621

Cited by 97 publications

(46 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1). In addition, the extent of range expansion achieved early in an invasion may determine the importance of Allee effects (Kot et al 1996) and the efficacy of biological control agents in slowing the spread of invaders (Fagan et al 2005). For these reasons, it is important to know if management strategies for reducing asymptotic invasion speed are also effective in reducing transient peaks.…”

Section: Parameter Contributions To Asymptotic Vs Transient Peak Invmentioning

confidence: 99%

Contributions of demography and dispersal parameters to the spatial spread of a stage‐structured insect invasion

Miller

Tenhumberg

2010

Ecological Applications

View full text Add to dashboard Cite

Abstract. Stage-structured models that integrate demography and dispersal can be used to identify points in the life cycle with large effects on rates of population spatial spread, information that is vital in the development of containment strategies for invasive species. Current challenges in the application of these tools include: (1) accounting for large uncertainty in model parameters, which may violate assumptions of ''local'' perturbation metrics such as sensitivities and elasticities, and (2) forecasting not only asymptotic rates of spatial spread, as is usually done, but also transient spatial dynamics in the early stages of invasion. We developed an invasion model for the Diaprepes root weevil (DRW; Diaprepes abbreviatus [Coleoptera: Curculionidae]), a generalist herbivore that has invaded citrusgrowing regions of the United States. We synthesized data on DRW demography and dispersal and generated predictions for asymptotic and transient peak invasion speeds, accounting for parameter uncertainty. We quantified the contributions of each parameter toward invasion speed using a ''global'' perturbation analysis, and we contrasted parameter contributions during the transient and asymptotic phases. We found that the asymptotic invasion speed was 0.02-0.028 km/week, although the transient peak invasion speed (0.03-0.045 km/week) was significantly greater. Both asymptotic and transient invasions speeds were most responsive to weevil dispersal distances. However, demographic parameters that had large effects on asymptotic speed (e.g., survival of early-instar larvae) had little effect on transient speed. Comparison of the global analysis with lower-level elasticities indicated that local perturbation analysis would have generated unreliable predictions for the responsiveness of invasion speed to underlying parameters. Observed range expansion in southern Florida (1992Florida ( -2006 was significantly lower than the invasion speed predicted by the model. Possible causes of this mismatch include overestimation of dispersal distances, demographic rates, and spatiotemporal variation in parameter values. This study demonstrates that, when parameter uncertainty is large, as is often the case, global perturbation analyses are needed to identify which points in the life cycle should be targets of management. Our results also suggest that effective strategies for reducing spread during the asymptotic phase may have little effect during the transient phase.

show abstract

Section: Parameter Contributions To Asymptotic Vs Transient Peak Invmentioning

confidence: 99%

Contributions of demography and dispersal parameters to the spatial spread of a stage‐structured insect invasion

Miller

Tenhumberg

2010

Ecological Applications

View full text Add to dashboard Cite

show abstract

“…Ranges of populations contract as habitat is destroyed or developed (Wilcove et al 1986), expand as individuals are introduced into new environments (Johnson et al 2006;Urban et al 2007) or recolonize old ones (Fagan et al 2005;Ortiz-Catedral et al 2009), and change as populations adapt in response to altered climate conditions (Davis and Shaw 2001;Pinsky et al 2013). A key characteristic of these changes is the rate at which a population is able to grow and spread.…”

Section: Introductionmentioning

confidence: 99%

Dispersal Evolution in the Presence of Allee Effects Can Speed Up or Slow Down Invasions

Shaw

Kokko

2015

The American Naturalist

View full text Add to dashboard Cite

Successful invasions by sexually reproducing species depend on the ability of individuals to mate. Finding mates can be particularly challenging at low densities (a mate-finding Allee effect), a factor that is only implicitly accounted for by most invasion models, which typically assume asexual populations. Existing theory on singlesex populations suggests that dispersal evolution in the presence of amate-finding Allee effect slows invasions. Here we develop a two-sex model to determine how mating system, strength of an Allee effect, and dispersal evolution influence invasion speed. We show that mating system differences can dramatically alter the spread rate. We also find a broader spectrum of outcomes than earlier work suggests. Allowing dispersal to evolve in a spreading context can sometimes alleviate the mate-finding Allee effect and slow the rate of spread. However, we demonstrate the opposite when resource competition among females remains high: evolution then acts to speed up the spread rate, despite simultaneously exacerbating the Allee effect. Our results highlight the importance of the timing of mating relative to dispersal and the strength of resource competition for consideration in future empirical studies. abstract: Successful invasions by sexually reproducing species depend on the ability of individuals to mate. Finding mates can be particularly challenging at low densities (a mate-finding Allee effect), a factor that is only implicitly accounted for by most invasion models, which typically assume asexual populations. Existing theory on singlesex populations suggests that dispersal evolution in the presence of a mate-finding Allee effect slows invasions. Here we develop a two-sex model to determine how mating system, strength of an Allee effect, and dispersal evolution influence invasion speed. We show that mating system differences can dramatically alter the spread rate. We also find a broader spectrum of outcomes than earlier work suggests. Allowing dispersal to evolve in a spreading context can sometimes alleviate the mate-finding Allee effect and slow the rate of spread. However, we demonstrate the opposite when resource competition among females remains high: evolution then acts to speed up the spread rate, despite simultaneously exacerbating the Allee effect. Our results highlight the importance of the timing of mating relative to dispersal and the strength of resource competition for consideration in future empirical studies.

show abstract

“…Specific invader success has been attributed to factors such as specific leaf area (5), water use efficiency (6), resistance to disturbance (7), herbivore resistance (8), escape from natural enemies (9), and plant-soil feedbacks (10,11). However, among invasive species, only a few general plant traits, such as vegetative reproduction, self pollination, phylogeny (i.e., other successful invaders in the family or genus) and native geographic range have been identified (12,13).…”

mentioning

confidence: 99%

Species-driven changes in nitrogen cycling can provide a mechanism for plant invasions

Laungani

Knops

2009

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Traits that permit successful invasions have often seemed idiosyncratic, and the key biological traits identified vary widely among species. This fundamentally limits our ability to determine the invasion potential of a species. However, ultimately, successful invaders must have positive growth rates that longer term result in higher biomass accumulation than competing established species. In many terrestrial ecosystems nitrogen limits plant growth, and is a key factor determining productivity and the outcome of competition among species. Plant nitrogen use may provide a powerful framework to evaluate the invasive potential of a species in nitrogen-limiting ecosystems. Six mechanisms influence plant nitrogen use or acquisition: photosynthetic tissue allocation, photosynthetic nitrogen use efficiency, nitrogen fixation, nitrogenleaching losses, gross nitrogen mineralization, and plant nitrogen residence time. Here we show that among these alternatives, the key mechanism allowing invasion for Pinus strobus into nitrogen limited grasslands was its higher nitrogen residence time. This higher nitrogen residence time created a positive feedback that redistributed nitrogen from the soil into the plant. This positive feedback allowed P. strobus to accumulate twice as much nitrogen in its tissues and four times as much nitrogen to photosynthetic tissues, as compared with other plant species. In turn, this larger leaf nitrogen pool increased total plant carbon gain of P. strobus two-to sevenfold as compared with other plant species. Thus our data illustrate that plant species can change internal ecosystem nitrogen cycling feedbacks and this mechanism can allow them to gain a competitive advantage over other plant species.ecosystem feedbacks ͉ plant nitrogen use

show abstract

When Can Herbivores Slow or Reverse the Spread of an Invading Plant? A Test Case from Mount St. Helens

Cited by 97 publications

References 56 publications

Contributions of demography and dispersal parameters to the spatial spread of a stage‐structured insect invasion

Contributions of demography and dispersal parameters to the spatial spread of a stage‐structured insect invasion

Dispersal Evolution in the Presence of Allee Effects Can Speed Up or Slow Down Invasions

Species-driven changes in nitrogen cycling can provide a mechanism for plant invasions

Contact Info

Product

Resources

About