Barriers to invasive infilling by Brachypodium sylvaticum in Pacific Northwest forests

Taylor, Laura A.; Hasenkopf, Erik A.; Cruzan, Mitchell B.

doi:10.1007/s10530-015-0871-x

Cited by 9 publications

(5 citation statements)

References 47 publications

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“…Perhaps tilling and mulching in coniferous forests did not change the composition of the plant's growing substrate substantially (especially considering the constant rain of new needles onto the ground), whereas these same actions disturbed deciduous leaf litter enough to provide the seedlings with root access to the soil while keeping enough organic matter present to retain soil moisture (Schramm and Ehrenfeld 2010). In a follow-up study, the abundance of B. sylvaticum seedlings was negatively correlated with deciduous litter cover in both field and controlled microcosm conditions (Taylor et al 2015). Although other environmental influences, such as soil acidity or moisture, may also play a role in abundance of B. sylvaticum in deciduous vs. coniferous forests, these variables most likely covary strongly with forest and leaf litter type and thus would require experiments involving artificial substrate and pH manipulations to disentangle.…”

Section: Resultsmentioning

confidence: 93%

Propagule Pressure and Disturbance Drive the Invasion of Perennial False-Brome (Brachypodium sylvaticum)

Taylor

Cruzan

2015

Invasive plant sci. manag.

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An ecosystem's invasibility is influenced by changes in biotic and abiotic resistances, which often occur due to shifts in the prevailing disturbance regime. The susceptibility of a community to intrusion by nonnative species may interact with propagule pressure to determine the extent of a biological invasion. We examined how propagule pressure, forest community structure, and disturbance interact to influence the invasibility of temperate Pacific Northwest forests by the newly invasive grass, perennial false-brome (Brachypodium sylvaticum). Our goal was to identify factors enabling shifts from establishment to population growth in B. sylvaticum populations at the edge of its expanding range. Ecological sampling methods were used to identify patterns in B. sylvaticum habitat. An inverse relationship between the amount of B. sylvaticum and all perennial vegetation types and soil litter depth was found, suggesting that disturbance might play a role in B. sylvaticum population establishment or growth. An experimental study was then performed to test the effects of disturbance, propagule pressure, and habitat on B. sylvaticum seedling establishment in sites where B. sylvaticum was already naturalized. We found evidence that disturbance of the soil and vegetation led to increased B. sylvaticum seedling recruitment within naturalized sites, especially where conditions of high propagule pressure and deciduous forest canopy existed. In contrast, B. sylvaticum populations dominated by coniferous forest canopy were much more invasible than deciduous forests and did not show increased seedling recruitment in response to our disturbance treatments. Our study shows how propagule pressure and plant community dynamics interact to alter the invasibility of Pacific Northwest forests allowing B. sylvaticum to transition from establishment to population growth thus allowing this weed to cause greater negative impacts on the ecosystem.

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Section: Resultsmentioning

confidence: 93%

Propagule Pressure and Disturbance Drive the Invasion of Perennial False-Brome (Brachypodium sylvaticum)

Taylor

Cruzan

2015

Invasive plant sci. manag.

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“…Slender false brome is ideal for use in this study because its performance and competitive ability has been found to be influenced by mycorrhizal colonization (C. Lee, Portland State University, personal communication; R. Workman, unpublished data). It is also ideal for use in examining invasive infilling processes—the potential for the invasive to invade intact native plant communities—not the likelihood of primary invasion success or how the exotic plant might establish in a new environment (Taylor and Cruzan, 2015; Taylor et al, 2015). Understanding the potential roles of CMN and root interactions on competitive outcomes is important for predicting the infilling success and impacts of B. sylvaticum on native plant communities.…”

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confidence: 99%

Common mycelial networks impact competition in an invasive grass

Workman¹,

Cruzan²

2016

American J of Botany

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“…In the future it would be desirable to include a more mechanistic model of dispersal to explore the possibility of directional dispersal (Caplat et al 2012a). A final limitation of our study is that we only examined infilling population growth, which is when a population spreads into areas within its existing range (Warren et al 2013, Taylor et al 2015), and therefore we did not examine long distance dispersal. Infilling is important and understudied (Johnson et al 2012b), but our approach offers fewer insights about long distance dispersal, another key stage in conifer invasions, and therefore limits the application of this study to the management of infilling or the reduction of density in an invasion.…”

Section: Discussionmentioning

confidence: 99%

“…Thus we decided to examine only the population growth process known as infilling. Infilling can be defined as when the spreading population colonises areas within its existing range, and it occurs because of local dispersal (Warren et al 2013, Taylor et al 2015). We did not gather local demographic data such as birth and death rates at a smaller spatial scale and therefore did not examine directly local demographic dynamics.…”

Section: Methodsmentioning

confidence: 99%

Density dependence and spatial heterogeneity limit the population growth rate of invasive pines at the landscape scale

Sprague

Hulme

Moltchanova³

et al. 2021

Ecography

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Determining population growth across large scales is difficult because it is often impractical to collect data at large scales and over long timespans. Instead, the growth of a population is often only measured at a small, plot-level scale and then extrapolated to derive a mean field estimate. However, this approach is prone to error since it simplifies spatial processes such as the neighbourhood effects of density and dispersal. We present a novel approach that estimates how spatial processes derived from the effects of density and dispersal affect population growth between plot scales and landscape scales. The method is based on a scale transition theory and calculates a transition term to measure the spatial scaling of population growth, which we extend to unstable, expanding populations in order to assess whether landscape-scale population dynamics are different from those estimated at smaller spatial scales. We illustrate this approach using aerial imagery of eight locations in New Zealand experiencing non-native pine invasions. Analyses examined the dynamics at a plot scale (1 ha) and compared this to estimates across entire landscapes (between 24 and 1600 ha), in several cases for more than one time period. We used a Bayesian spatial random effects model to examine population growth and to account for neighbourhood effects and dispersal between plots in a rapidly changing system.We found that the estimates of the scale transition term were typically 10-25% of the mean field estimates, which led to mean field estimates of population growth extrapolated from plots being considerably higher than landscape estimates. The approach we have developed will not only have applications for predicting the populations' growth of invasive species, but also for studies examining the scaling of landscape-scale phenomena.

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Barriers to invasive infilling by Brachypodium sylvaticum in Pacific Northwest forests

Cited by 9 publications

References 47 publications

Propagule Pressure and Disturbance Drive the Invasion of Perennial False-Brome (Brachypodium sylvaticum)

Propagule Pressure and Disturbance Drive the Invasion of Perennial False-Brome (Brachypodium sylvaticum)

Common mycelial networks impact competition in an invasive grass

Density dependence and spatial heterogeneity limit the population growth rate of invasive pines at the landscape scale

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