Lecture 2 - Weed Characteristics

Question 1

what does the evolutionary success of any organism depend on

Answer 1

• # of individuals in existence
• extent of reproductive output
• area of the world’s surface they occupy
• range of habitats they can enter

Question 2

what determines the evolutionary success of a weed

Answer 2

• they are persistent
• they can defy/avoid extermination to a large extent

Question 3

what is a plant’s weediness greatly affected by

Answer 3

affected by the environment in which it grows and the nature of the community where it grows

Question 4

what do weed traits affect

Answer 4

seed dormancy and longevity
phenology
ecophysiology
reproductive biology
fecundity (reproductive success)
response to stress

Question 5

1st principle of weeds

Answer 5

weeds are highly heterogeneous, with considerable variation in traits contributing to their success

Question 6

2nd principle of weeds

Answer 6

while weeds may be inherently competitive and/or invasive, their success is modulated by community structure

Question 7

weeds are often specialized in ________________

Answer 7

non-specialization

Question 8

weeds are widely adapted and able to ……..

Answer 8

• invade new areas
• suppress/displace desirable species
• dominate disturbed sites
• resist eradication or control measures

Question 9

3 general characteristics of weedy species

Answer 9

ability to invade, dominate, persist

Question 10

weed traits contributing to invasion

Answer 10

wind dispersal
high seed production
vegetative spread
good seed survival/viability
ability to germinate on surface

Question 11

weed traits contributing to domination

Answer 11

high competitive ability (rapid growth)
resistant to management practices

Question 12

weed traits contributing to persistence