Biological invasion happens when an organism, any sort of organism, arrives somewhere beyond its previous range. Nowadays, most invasions come from human actions, deliberate or accidental. But natural invasions happen too, from minor changes of range to major invasions across continents. One reason for studying invasions is that many invasive species have become serious pests. The cumulative losses in the USA from some non-indigenous species were estimated at almost $100 billion by 1991. It has to be noted that most invaders fail and have small effects, but that the cumulative effect of those that succeed has been and will continue to be large. Another important fact is that invasions have been an important component of the evolutionary process throughout geological history. Researchers are therefore not only interested in what makes a successful invader, but also in the ecological as well as the genetic impacts of invasions
Table of Contents
1. Introduction
2. Biological Invasions: General Concepts
2.1 Natural vs. Human-induced Invasions
2.2 The Tens Rule
3. Factors Determining Invasion Success
3.1 Propagule Pressure
3.2 Intrinsic Rates of Increase
3.3 Genetic Characteristics
3.4 Abundance and Range
3.5 Taxonomic Isolation
3.6 Climatic Matching
3.7 Niche Occupation
3.8 Genetic Factors and Species Differences
4. Causes of Invasion Failure
5. Genetic Impacts of Invasions
5.1 Hybridisation and Genetic Fusion
5.2 Genetic Innovation and Loss of Variation
5.3 Speciation as a Consequence
6. Ecological Impacts of Invasions
6.1 Biological Control and Its Risks
6.2 Predation and Grazing Effects
6.3 Pathogens and Tree Diseases
6.4 Competition and Amensalism
6.5 Ecosystem Processes
6.6 Extinction and Biodiversity
Research Objectives and Themes
The work explores the dynamics of biological invasions, aiming to understand the ecological and genetic factors that determine why certain species successfully establish in new environments while others fail. It investigates the mechanisms behind invasion success, the genetic impacts on native and invading populations, and the wide-ranging ecological consequences of such invasions.
- The distinction between natural and anthropogenic invasion pathways.
- Statistical predictors of invasion success, such as propagule pressure and climatic matching.
- The role of genetic variation and hybridisation in the evolution of invasive populations.
- Ecological impacts including competition, predation, and the alteration of ecosystem processes.
- The risks associated with biological control and the threat of species extinction.
Excerpt from the Book
Biological Invasions
Biological invasion happens when an organism, any sort of organism, arrives somewhere beyond its previous range. Nowadays, most invasions come from human actions, deliberate or accidental. But natural invasions happen too, from minor changes of range to major invasions across continents. One reason for studying invasions is that many invasive species have become serious pests. The cumulative losses in the USA from some non-indigenous species were estimated at almost $100 billion by 1991. It has to be noted that most invaders fail and have small effects, but that the cumulative effect of those that succeed has been and will continue to be large. Another important fact is that invasions have been an important component of the evolutionary process throughout geological history. Researchers are therefore not only interested in what makes a successful invader, but also in the ecological as well as the genetic impacts of invasions.
When dealing with invasions one should realise the fact that they can be natural or due to human actions as mentioned above. This will be illustrated by some examples. The Great American Interchange, the progressive exchange of mammalian faunas, and their subsequent evolution, between North and South America, is an example of a major natural invasion. It was the result of tectonic movements that brought these continents close together and formed the Central American bridge between them, a process starting 10 million years ago in the Miocene, and possibly still underway. In the 19th century the pattern of colonisation and trade meant that introductions were predominantly from Europe. European settlers often set about recreating a European agricultural landscape, and started to introduce European species. Nowadays, the flow of commerce is much more widely spread, and faster, and so invasions travel in all directions. One example of this is the flow of marine organisms in ballast in ships.
Summary of Chapters
1. Introduction: Defines biological invasions as the movement of organisms beyond their range, highlighting their evolutionary significance and the distinction between natural and human-mediated events.
2. Biological Invasions: General Concepts: Discusses the nature of invasions and introduces the "tens rule" as a statistical guideline for assessing the probability of establishment and pest status.
3. Factors Determining Invasion Success: Examines predictors like propagule pressure, habitat suitability, genetic traits, and climatic matching in the context of successful establishment.
4. Causes of Invasion Failure: Explores why many introductions fail, focusing on the lack of sustainable resources and the prevalence of natural enemies.
5. Genetic Impacts of Invasions: Analyzes the consequences of invasions on genetic structures, including hybridisation, founder effects, and the potential for speciation.
6. Ecological Impacts of Invasions: Investigates the broader effects of invaders on native ecosystems, including biological control, predation, competition, and extinction events.
Keywords
Biological invasions, non-indigenous species, invasion success, propagule pressure, tens rule, genetic variation, hybridisation, ecological impact, biological control, competition, ecosystem processes, extinction, biodiversity, invasive pests, evolutionary process.
Frequently Asked Questions
What is the central focus of this work?
The work focuses on the ecology and genetics of biological invasions, analyzing how species establish in new environments and the resulting consequences for those ecosystems.
What are the primary thematic areas covered?
Key themes include the drivers of invasion success, genetic impacts like hybridisation, the ecological effects of introduced predators, and the role of human activity in facilitating biological invasions.
What is the main goal of the research presented?
The goal is to understand the mechanisms that allow species to become successful invaders and to evaluate the ecological impacts, ranging from minor biodiversity changes to severe extinctions.
Which scientific methodology is used?
The study utilizes a comparative ecological approach, incorporating statistical observations of invasion patterns, historical data, and analysis of genetic and biological factors influencing invasion outcomes.
What does the main body of the text cover?
The main body details the factors for invasion success, such as climatic matching and propagule pressure, and discusses the environmental impacts of various invasive groups like mammals, insects, and plants.
Which keywords best characterize the study?
Relevant keywords include biological invasions, propagule pressure, ecosystem effects, genetic variation, hybridisation, and ecological impact.
How does the author evaluate the "tens rule"?
The author views the tens rule as a rough but useful general guideline, emphasizing that while it applies to various British and global groups, it must be interpreted with caution due to frequent exceptions.
What is the significance of hybridisation in the context of invasions?
Hybridisation is presented as a mechanism that can lead to rapid genetic change, sometimes resulting in "new" characteristics that allow an invasive plant or animal to thrive in conditions its parents could not tolerate.
- Quote paper
- BA (Oxon), Dip Psych (Open) Christine Langhoff (Author), 2002, Biological Invasions, Munich, GRIN Verlag, https://www.grin.com/document/4692
