Laura A. Hyatt

Publications (2)5.79 Total impact

• Article: Flexible N uptake and assimilation mechanisms may assist biological invasion by Alliaria petiolata

  Daniel B. Hewins, Laura A. Hyatt
  [show abstract] [hide abstract]
  ABSTRACT: Although nitrogen has historically limited terrestrial plant productivity in the northern hemisphere, accelerated industrial activity is changing the availability of N, with consequences for ecosystem properties including altered susceptibility to biological invasion. Alliaria petiolata (Bieb.) Cavara & Grande is an increasingly problematic invader in forests of eastern North America. Population growth rate of this species is especially high in N-rich habitats, and it produces a variety of N-based compounds that have been shown to interfere with the growth and reproduction of native plants. To investigate how increases and shifts in forms of N will impact A. petiolata, seedlings were transplanted to the greenhouse from the field and grown in sand culture. We applied three concentrations of N (0.25, 1 and 2mM) using five different ratios of NH4 + and NO3 − (100/0, 75/25, 50/50, 25/75, 0/100) in a crossed design to yield fifteen different treatments. Plants were measured throughout the growing season and a final harvest yielded measures of biomass and tissue quality. Plant growth increased significantly in response to increased concentration of total N. These increases were similar for all combinations of N. This flexibility in uptake ability may facilitate the invasion of this species, not only by increasing the range of habitats A. petiolata can occupy but also by enhancing N uptake that can lead to the production of secondary compounds disrupting other species’ belowground mutualisms. We suggest that this species’ ability to respond rapidly to changes in N availability, regardless of its form, may modify competitive interactions with natives and intensify its negative impacts. KeywordsAmmonium-Nitrate-Sand culture-Uptake-Invasive-Brassicaceae-Growth
  Biological Invasions 04/2012; 12(8):2639-2647. · 2.90 Impact Factor
• Article: The Disturbed Resource-Flux Invasion Matrix: A New Framework for Patterns of Plant Invasion

  Anna A. Sher, Laura A. Hyatt
  [show abstract] [hide abstract]
  ABSTRACT: Attempts to classify certain habitats as vulnerable to invasion or plant traits as invasive have met with limited success and applicability. Clearly, not all plant invaders are able to exploit all habitats and not all habitats are equally susceptible to invasion. Here we argue that it is critical for a successful model for invasions to incorporate both environmental and species traits and present just such a framework. Although disturbance has been targeted as a crucial event which renders habitats vulnerable to invasion, disturbances are often integral parts of ecosystems (e.g. floods, tree-falls, fire, etc.) and are not always associated with invasion events. We argue that disturbances that are associated with invasions alter historical patterns of turnover, or flux, of resources in an ecosystem. Given this perspective on the relationship between invasions and disturbances, and the need to integrate species traits with those of invaded ecosystems, we have developed an approach to characterize plant invasion patterns that we call the Disturbed Resource-Flux Invasion Matrix or DRIM. This is a 16-cell matrix that classifies habitats by the quality of changes in physical and chemical resource flux either increasing or decreasing flux relative to historical patterns. Within each matrix cell, it is then possible to apply basic ecological principles to target species traits that can facilitate successful invasion of habitats experiencing that particular kind of disturbance. We present examples from the literature of how habitats and species can be classified according to the DRIM, and demonstrate the application of this theoretical model.
  Biological Invasions 05/1999; 1(2):107-114. · 2.90 Impact Factor