1. Trisha Spanbauer
  2. http://www.igert.org/profiles/3932
  3. Graduate Student
  4. Presenter’s IGERT
  5. University of Nebraska at Lincoln
  1. Trevor Hefley
  2. http://www.igert.org/profiles/3979
  3. Graduate Student
  4. Presenter’s IGERT
  5. University of Nebraska at Lincoln

Judges’ Queries and Presenter’s Replies

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Presentation Discussion
  • Icon for: Leslie Ruyle

    Leslie Ruyle

    Coordinator
    May 22, 2012 | 09:24 a.m.

    What a great example of interdisciplinary collaboration!

  • Icon for: Brian Drayton

    Brian Drayton

    Faculty
    May 22, 2012 | 09:47 a.m.

    Very interesting work! These two data sets are nice and long. How long a time series do you need for your results to be reliable, do you think? I presume that for many species this will best be thought of in terms of generations rather than years…

  • Icon for: Trevor Hefley

    Trevor Hefley

    Co-Presenter
    May 22, 2012 | 02:29 p.m.

    Hi Dr. Drayton,

    In these two examples we could have used shorter time series and successfully predicted the threshold using our indicator. Based on an unpublished simulation, it appears that longer time series data are needed when the population is far from a threshold and approaching it slowly. Intuitively, this result occurs because LSV increases very rapidly just prior to the threshold (see Fig. 2). So, our methods may be highly relevant for populations that are close to and approaching a threshold rapidly.

    With regard to the sample interval, a sampling interval less than a generation would be relatively uninformative, however, any sampling interval more than a generation is informative. The main dynamic is captured when the environmental change driving the extinction is occurring slowly compared to the generation time and sampling interval. For example, the diatom data in our study is an integrated population estimate sampled at 10 year intervals. This interval is many generations of diatoms, but is relatively high resolution sampling with respect to climate change, which occurs over thousands of years.

  • May 22, 2012 | 12:42 p.m.

    Excellent collaborative, applied, integrated, and outreaching research project!

  • Icon for: Valerie Egger

    Valerie Egger

    Coordinator
    May 22, 2012 | 04:03 p.m.

    Nicely done, Trisha and Trevor! I really enjoy seeing real research collaboration come out of the IGERT program that otherwise would not have happened.

  • May 23, 2012 | 04:19 p.m.

    Really nice video and a great introduction to your research. What a great example of collaborative research, too!

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