207 501 Management of Plant and Animal Invasions
Invasions are natural ecological phenomena. Dispersing individuals encounter suitable habitat, establish, spread and evolve. In this way, species have radiated outwards from their origins, colonised distant offshore islands, and species have spread in response to changes in climate. Human-induced invasions of plants, animals and diseases in modern times have dramatically altered the scales of time and distance over which invasions take place. Their impacts can be considerable, wiping out unique communities, endangering rare species, adding considerable costs to agriculture, horticulture and forestry, and having effects on the health, leisure and livelihoods of people. Tools such as pesticides and biological control can often be used to great effect, while for other invaders there are no obvious solutions. There may be unwanted side-effects of control methods on non-target species, they may adversely affect human health, and may cause considerable public concern. Integrated management strategies can be developed using ecological information about the species but these must be implemented in a real world that involves economics, politics, opinions and social interactions. This subject is taught by Roger Cousens |
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