COURSE SUMMARY: 

 

Strategy theories, especially as they relate to weeds

   *     Focus on selective pressures of disturbance and competition

   *     Plant traits (strategies) that are adapted to these pressures

             -     r-K    (trade-offs in reproduction and growth)

             -     Grime's triangle theory      (how quantitative, uses, assumptions)

 

 

Disturbance, types, selective pressure, and succession.

 

 

Reproduction, recovery from disturbance

   *     Vegetative mechanisms

             -     trade-off between dispersal in time or space

             -     advantages and disadvantages compared to seeds

   *     Sexual reproduction

             -     Seed dormancy

             -     Seed bank    (seed longevity, mechanisms of losses, sampling methods, relation to existing vegetation)

             -     Germination  (phytochrome and canopy)

             -     Simple population dynamics (models) related to seeds

 

 

Weed control, in relation to reproduction

 

 

Dispersal

   *     Vegetative mechanisms

   *     Water and biota

   *     Wind  (direction, distance, methods, effects of vegetation)

 

 

Distribution, types, relation to sources, how to estimate

 

 

Competition

   *     Defined, real vs. apparent

   *     What is being competed for?  Competitive mechanisms/traits

   *     Methods of determining and measuring competition

             -     Study objectives

             -     Different methods relate to different objectives

             -     Issues related to setting-up competition studies (i.e. choice of conditions, initial density, etc.)

   *     Competing theories of competition (Tilman and Grime)

   *     Factors that can influence competitive balance

 

Herbivory

   *     Influences on plant competition

   *     Biological control

             -     Definitions and concept

             -     Plant & insect characters suitable for biological control

             -     Issues of controlling native vs. non-indigenous weeds with biological control agents

 

 

Herbicide resistance, definitions, herbicide/plant factors

 

 

Agricultural applications of weed ecology

   *     Economic threshold concept, factors influencing, concerns other than crop yield

   *     Prediction of crop losses to weeds (prediction of weeds?)

   *     Critical periods for weed control

   *     Practical applications (or not) for farmers (e.g. competitive index)

   *     Crop - weed models of population dynamics

   *     Future directions for weed ecology

 

 

Invasions of non-indigenous weeds

   *     Difficulties of applying economic threshold concept to non-crop and natural habitats

   *     Mechanisms of international dispersal, invasion rates

   *     Why problems where introduced but not always where native?

   *     Control options - prevention,   prediction of worst weeds?

 

 

Community structure and diversity

   *     Drivers and measures of community diversity