Biology Reference
In-Depth Information
its current pace, the earth's flora could eventually homogenize to only a few highly
successful species (Luken and Thieret 1997; Ewel et al. 1999; McNeely 1999).
Plant invasion is generally divided into a biological component, or the capacity
of a plant to spread beyond the site of introduction ( invasiveness ) and an environ-
mental component, which is the susceptibility of a habitat to the colonization and
establishment of individuals from species not currently part of the local community
( invasibility ) (Rosonsweig 2001 ; Davis et al. 2005; Radosevich et al. 2007).
Environmental differences among habitats and communities contributing to invasi-
bility are often easier to identify than the biological traits associated with invasive-
ness (Lonsdale 1999; Reichard 1997), although certain habitats, such as those of
mature forests and dense grassland, tend to have relatively few exotic plant species
(Richardson et al. 1994; Harrison 1999; Parks et al. 2005). Knowing the suscepti-
bility of different habitats and plant communities to invasion can help design pro-
grams to manage invasive plants or protect native habitats.
17.2
Basis for Management Decisions About Invasive Plants
Land managers use a variety of ways to manage invasive plants. Weeds are invasive
plants that increase in habitat range because of the expansion of human activities
for production (Radosevich et al. 2007). These activities alter the structure and
function of many plant communities around the world. Decisions about weed con-
trol are influenced by the biology of the species, existing technology, and social
considerations that are often represented by people affected by management proce-
dures (Radosevich and Ghersa 1992). These three factors are linked through six
fundamental scientific disciplines (Fig. 17.2), which collectively generate a base of
Sociology
Toxicology
Presticide safety
Environmental
impact assessment
Ethics
Farm worker
displacement
Economics
Farming
systems
Ecology
Thresholds,
cost/benefit
Gene flow
Seedbank
dynamics
Tool efficacy
Interference
Biology
Technology
Applic.
technology
Genetics
Community
population
dynamics
Gene
expression
Mechanics of action
Genetic engineering
Biological
control
Soil/herbicide
relations
Physiology
Morphology
Chemistry
Herbicide
screening
Fig. 17.2 A diagram depicting the interrelationships of six fundamental disciplines in weed
science. Major areas of activity are weed technology, weed biology, and the ethics of weed control
(reproduced from Radosevich and Ghersa 1992)
 
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