Controlled experiments to predict horseweed (Conyza canadensis) dispersal distances

Joseph T. Dauer, David Mortensen, Robert Humston

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Controlled-environment experiments were conducted to predict the dispersal distance of horseweed seed. Seed were released from a fixed height and collected at three distances from the introduction point along a 6-m wind tunnel. Dispersal potential was assessed at wind speeds of 8 and 16 km hr-1 and release heights of 50.8 and 76.2 cm. In separate experiments, settlement velocity was determined to be 0.323 m sec-1 (SD = 0.0687). These data were used to parameterize a mechanistic model and compared to a quantile extrapolation (QE) of wind-tunnel results. The QE method predicted a greater mean dispersal distance than the mechanistic model, with large disparities between maximum dispersal distances. Quantile extrapolation predicted dispersal distances over 100 m, whereas the mechanistic model predicted a maximum distance of approximately 30 m. Air turbulence within the wind tunnel and complex dynamics of seed flight may have contributed to the discrepancy between models. Predicting the mean and numerical distribution of seed dispersal distance is crucial when estimating the spread of wind-dispersed seed and for the design of a field-sampling protocol. Although controlled-environment experiments lack the wind variability present in natural systems, predictions from wind-tunnel studies provide a better first approximation of dispersal distance than the mechanistic model. Field experiments designed on the basis of these outcomes are more likely to capture the true dispersal distribution. This should provide more accurate data to inform management decisions for wind-dispersed species.

Original languageEnglish (US)
Pages (from-to)484-489
Number of pages6
JournalWeed Science
Volume54
Issue number3
DOIs
StatePublished - Jan 1 2006

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Conyza canadensis
wind tunnels
mechanistic models
seeds
seed dispersal
wind speed
flight
air
prediction
sampling

All Science Journal Classification (ASJC) codes

  • Agronomy and Crop Science
  • Plant Science

Cite this

Dauer, Joseph T. ; Mortensen, David ; Humston, Robert. / Controlled experiments to predict horseweed (Conyza canadensis) dispersal distances. In: Weed Science. 2006 ; Vol. 54, No. 3. pp. 484-489.
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Controlled experiments to predict horseweed (Conyza canadensis) dispersal distances. / Dauer, Joseph T.; Mortensen, David; Humston, Robert.

In: Weed Science, Vol. 54, No. 3, 01.01.2006, p. 484-489.

Research output: Contribution to journalArticle

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