L15 Invasive Plant Ecology Flashcards
Why do most invasions fail
Inappropriate abiotic conditions
Outcompeted
Natural enemies - herbivores and disease
Lack of species to pollinate, disperse or facilitate
Low density effects (lack of mates)
Lack of genetic diversity
Why do we worry babout invasions if they are rare
The small number that are successful have drastic effects on populations, communities and ecosystems
Cause extinctions
Loss of ecosystem services
What 3 factors determine the impact of an invasive
Size of range
Abundance within range
Effect of each individual plant on the community
When would synergestic effects occur
With multiple invaders
How do you quantify population dispersal over space
Density and distribution
How do you quantify population demographics over time
Age and sexual structure
2 ways to cquantify populations
CSR selection
K-r selected species
How do ramets reproduce
Vegetatively
What reproduction can occur between native and non-native species
Hybridisation
What trade offs occur when producing seeds
Size and number
What factors control germination
Light
Moisture
Temperature
What point in a plants growth has the highest mortality
Emergence and establishment
What determines phenology
Genetics
Biotic and abiotic factors
What does phenotypic plasticity allow
Adaptation
What is the name given to natural deterioration leading to death
Senescence
What resources can be competed over
Light
Nutrients
Water
Above and below ground space
Polliantors
K,,
What is allelopathy
Release of chemicals from roots, shoots, leaves or flowers
How can plants defend against herbivory
Physical - spines or hairs
Chemical - digestibility reducers, phytotoxins (secondary metabolites)
Do herbivores help or reduce invasives
Both
Can assist with spread but can also reduce invasions by browsing on seedlings
If invaders occur layer in succession, do they have more or less of an effect
More
What other terms for non-native are there
Alien
Non-indigenous
Foreign
Exotic
How long ago does it have to be introduced to be a non-native species
A non-native species is anything that has been introduced since the end of the last ice age
How many established aliens are there in the UK
Nearly 2000
What effects can aquatic invasive species have
Form blanket surface on water
Prevent air-breathing invertebrates reaching surface
Loss of oxygen in water
Block waterways
What is eutrophication
Where excessive nutrient input increases algal growth, preventing sun reaching other aquatic plants, which stops oxygen production for other life
