Life-History Traits & Invasion
In SBI201 Introductory Ecology you were introduced to the concept of life-histories - an organism's lifetime pattern of growth and reproduction.
For example, some plant species put reproductive effort into producing many small seeds (e.g. dandelion), whereas others put their effort into producing fewer, larger seeds (e.g. coconut palm). Some species may have one reproductive event in their lives (e.g. north Australian bamboo) whereas others will have many reproductive events (e.g. rabbit).
Each strategy has advantages and disadvantages. Many ecologists believe that an understanding of life-history strategies will help identify species likely to be invasive, and can contribute to developing effective management strategies.s
In the following table, list the type of life history traits that you would expect successful invaders to have? For example, will they have a high or low reproductive rate?
Click here to complete the Life History table.
You will recognise that most of the traits that characterise invaders are typical of r-selected life histories (for a refresher on r- and K-selection, refer to you SBI201 lecture notes or Stilling, pages 59 - 61 on SBI201 E Reserve).
A range of ecologists have looked for patterns in life-history traits of successful invaders, in order to predict future invasive species (Readings 3.1 - 3.3). These have been done both within taxonomic groups and across taxa. However, these generalisations often are found to have many exceptions.
We'd now like you to start exploring these issues by starting work on Assessment item 2
Assignment 2
This is your second assessment item. You are required to write an essay.
Studies of the population ecology of invasive species can assist in both understanding and managing invaders. Read the review paper by Sakai et al. (2001), conduct your own literature review, and then write an essay on the following topic:
Essay Topic: How do the ecology and life-history traits of introduced species affect their chances of success in a new environment and also their management?
Hints- Some of the questions to consider while you are reading the literature include:
- How can an understanding of life-history traits of successful invaders help in predicting future invasive species? Which life history traits are the best predictors of invasion success in plants, and which ones are not? Are there limitations to this approach?
- What stages are necessary for the successful establishment and invasion by new species? Why is there commonly a time lag between the time of introduction of a species and its establishment and spread in the new environment? How can multiple introductions of a species increase invasion success?
- How can an understanding of life-history traits assist in the successful management of species invasions? Is there a vulnerable stage(s) in the invasion process, where invasive plants and animals are more susceptible to control?
You should support your answers with references from the readings and other literature sources.
Reading
Reading 3.4 Sakai et al. (2001). The population biology of invasive species. Annual Review of Ecology and Systematics 32: 305-332.