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UNIT 1: THE NATURE OF WEEDS
1 The
nature of weeds
1.1 What is a weed?
1.2 The definition of a weed
1.3 Weeds and human nature
1.4 Weedy traits
1.5 The origins of weeds
1.5.1 Weeds, planting and crop domestication
1.5.2 Biogeographic prehistory of agriculture
1.5.3 Pre-agricultural preadapted wild colonizing species
1.5.4 Wild-crop-weed complexes
1.6 World origins and centers of agriculture, crop
domestication and cultivation
1.7 World crop-weed species groups
UNIT 2: THE EVOLUTION OF WEED POPULATIONS
Introduction
2
Evolution, natural selection and weedy
adaptation
2.1 Introduction
2.2 Evolution
2.2.1 Micro- and macroevolution
2.2.2 Units of evolution and natural selection
2.3 Natural selection and elimination
2.4 The process of natural selection
2.4.1 Population formation:
Precondition to natural selection
2.4.2 Generate variation:
Process of natural selection, step 1
2.4.3 Survival and reproduction: Process of natural selection, step 2
2.5 Adaptation
3
Formation of the local weed
population (deme): Precondition to natural
selection
3.1 Introduction: opportunity
and the formation of the local deme
3.2 The structure of local weedy opportunity
3.2.1 Weedy habitats
3.2.2 Niches in the local community
3.2.3 The niche hypervolume
3.3 Habitat heterogeneity and dynamics
3.3.1 Spatial heterogeneity and patchiness
3.3.2 Temporal division of the environment
3.3.3 Disturbance
3.4 Limiting resources and pervasive conditions in
local opportunity
3.4.1 Limiting resources
3.4.1.1 Light
3.4.1.2 Water
3.4.1.3 Mineral nutrients
3.4.1.4 Gases
3.4.2 Pervasive conditions in the environment
3.4.2.1 Heat
3.4.2.2 Terroir
3.4.3 Environmental signal spacetime
3.5 The nature of plant invasions of local opportunity
3.5.1 The plant invasion process: seizing, exploiting and occupying opportunity
spacetime
3.5.2 Dispersal
3.5.3 Colonization
3.5.4 Enduring occupation of a locality
3.5.5 Extinction
3.5.6 The perception of plant invasion
4.2 Generate genetic variation
4.2.1 Sources of genetic diversity
4.2.1.1 Forces increasing population variability
4.2.1.2 Forces decreasing population variability
4.2.2 Speciation
4.2.2.1 Process of speciation
4.2.2.2 Reproductive isolating mechanisms
4.2.2.3 Modes of speciation
4.3 Generate phenotypic variation
4.3.1 Phenotypic plasticity
4.3.2 Somatic polymorphism
5
Survival, reproduction and
inheritance: Second process of natural
selection
5.1 Survive, avoid mortality
5.2 Reproduce the fittest, eliminate the others
5.2.1 Timing of reproduction
5.2.2 Plant age and stage structure
5.2.3 Reproductive value
5.2.4 Risk of death determines life history
5.2.5 Influences of plant density on mortality
5.2.6 Modes of selection and population diversity
5.3 Inheritance: transmit
parental traits to offspring
5.4 Mating system and inheritance
5.4.1 Mating system and opportunity
5.4.2 Evolution of mating systems
5.4.3 Sex classification systems
5.4.4 Types of mating systems
5.4.4.1 Self-pollenating species
5.4.4.2 Out-crossing species
5.4.4.3 Apomictic species
5.4.4.4 Vegetative clone reproducing species
UNIT 3: ADAPTATION IN WEED LIFE HISTORY
6 Weed
life history
6.1 Introduction to life history
6.1.1 Phenotypic life history traits
6.1.2 Processes of life history adaptation
6.2 Plant life history classification systems
6.2.1 Life span
6.2.2 Growth and life form
6.2.3 Life history strategies
6.3 Representing weed life history
6.4 The ecological demography of plant population life
history dynamics
6.4.1 Weed life history models
6.4.2 Demographic weed life history population dynamics
models
6.4.3 Representation and information, inference and
prediction
6.4.3.1 Representation and information
6.4.3.2 Inference
6.4.3.2.1 The deme
6.4.3.2.2 Life history development and behavior
6.4.3.2.3 Model formalization and measurement metrics
6.4.3.3 Predicting weed population dynamics
6.5 Evolutionary, trait-based, weed life history
population dynamics
7
Reproductive adaptation
7.1 Introduction
7.2 Flowering, anthesis, fertilization and birth
7.2.1 Parental plant architecture
7.2.2 Mating systems
7.3 Embryo adaptation:
embryogenesis and dormancy induction
7.3.1 Induction of seed dormancy
7.3.2 The evolutionary ecology of seed dormancy
7.3.3 Weed seed dormancy variability and somatic
polymorphism
7.3.4 Evolutionary ecology of seed heteroblasty
7.3.5 Weed species seed heteroblasty examples
7.3.6 Observable seed dormancy-germinability regulation
life forms
7.3.6.1 Non-dormant
7.3.6.2 Vegetative, perinating buds
7.3.6.3 Environmental seed germination control mechanisms
7.3.6.4 Hard, gas- and water-impermeable, seed envelope
germination inhibition
7.3.6.5 Light-phytochrome and nitrate stimulated
germination
7.3.6.6 Species with multiple interacting germination
control mechanisms
7.3.6.7 Other seed germination control mechanisms
7.3.7 Experimental weed seed science
7.4 Propagule adaptation:
post-abscission fecundity
7.4.1 Five roles of seeds
7.4.2 Principle of strategic allocation
7.4.3 Trade-offs among seed roles
7.4.4 Seed size trade-offs
7.4.4.1 Seed size plasticity and stability
7.4.4.2 Relationship of seed size to habitat
8
Propagule dispersal in space
and time
8.1 Introduction
8.1.1 The evolutionary ecology of dispersal structures
8.1.2 Seed dispersal trade-offs
8.1.3 Cost of dispersal
8.1.4 Space-time dimensions of dispersal
8.2 Dispersal in space
8.2.1 Dispersal and post-dispersal processes
8.2.2 Seed flux at a locality
8.2.3 Modes of seed and propagule dispersal
8.2.3.1 Gravity
8.2.3.2 Wind and air
8.2.3.3 Water
8.2.3.4 Animal, non-human
8.2.3.5 Human
8.2.3.6 Other modes of dispersal
8.3 Dispersal in time:
formation of seed pools in the soil
8.3.1 Adaptative roles of soil seed pools
8.3.2 Population dynamics in the soil seed pool
8.3.2.1 Life history of a seed
8.3.2.2 Seed states, fates and seed state transition
processes
8.3.2.3 Seed pool additions, losses and continuity
8.3.3 Structure of soil seed pools
8.3.3.1 Spatial distribution in the soil profile
8.3.3.2 Floral seed community compostion
8.3.3.3 Seed pool size
8.3.3.4 Seed longevity in the soil
8.4 Propagule germination and recruitment
8.4.1 Introduction
8.4.2 Process of recruitment
8.4.3 Germination micro-sites and safe sites
8.4.4 Patterns of seedling emergence
8.4.5 Relationship between seed heteroblasty and
recruitment timing
Weed-crop communities
as complex adaptive systems
9 Neighbor
interactions in local plant communities
9.2 The nature of neighbor interactions in the
community
9.2.1 Patterns of neighbor interactions
9.2.2 Interference interactions between neighbors
9.2.2.1 Competition
9.2.2.2 Amensalism
9.2.2.3 Antagonism
9.2.3 Facilitative interactions between neighbors
9.2.3.1 Mutualism
9.2.3.2 Commensalism
9.3 Strategic roles and traits of interference and
facilitation with neighbors
9.3.1 Strategic roles and traits of interference with
neighbors
9.3.1.1 Spatial foraging for local opportunity
9.3.1.2 Temporal foraging for local opportunity
9.3.2 Strategic roles and traits of facilitation with
neighbors
9.3.2.1 Escape and avoid neighbors
9.3.2.2 Co-exist with neighbors
9.3.2.3 Co-operate with neighbors
9.4 Effects of neighborhood interactions on plant
density, growth and form
9.4.1 Space, neighborhoods and plant density
9.4.2 Plant density and productivity per unit area
9.4.3 Plant density and plant size
9.4.4 Plant density and plant form
9.4.5 Dangers in plant density demography
10.2 Weed community structure
10.2.1 The origins of weeds:
wild-crop-weed plant complexes
10.2.2 Biogeographical population genetic structure
10.2.3 Genotype structuring: species association for weedy colonization
10.2.3.1 Species-groups
10.2.3.2 Polyploid species clusters
10.2.3.3 Aggregate species
10.2.4 Genotype structuring:
pre-adaptive coloninzing achetypes
10.2.4.1 Generalist-specialist genotypes
10.2.4.2 Genetic-reproductive colonizing types
10.3 Exploiting opportunity: weed community dynamics
10.3.1 Ecological roles-guilds-trades in weed-crop plant
communities
10.3.1.1 Guild structure and community organization
10.3.1.2 Parameters of weed species ecological role and
niche
10.3.1.3 Trait guild: relative
seedling/bud emergence order
10.3.2 Changes in plant community structure
10.3.2.1 Weed population shifts
10.3.2.2 Plant community ecological succession
10.4 Weed community biodiversity
10.4.1 Scales of weedy biodiversity
10.4.2 Biodiversity encountered by interacting neighbors
10.4.3 Weed community biodiversity: complexity, stability
and equilibrium
10.4.3.1 Community complexity
10.4.3.2
Community stability
10.4.3.3 Equilibrium in the community
10.4.4 Conclusions
