An essay on some topics concerning invasive species

There is a tendency for both scientists and lay people to regard invading alien species as inherently ‘bad’ and native species as inherently ‘good. ’ Past invasions occurred commonly without human assistance. They rarely caused large, lasting decreases in species richness or ecological damage. Current invasions provide opportunities for scientific study. They are unintentional, uncontrolled experiments, which can provide insights into attributes of successful colonists, relationships with native species, and impacts on the structure and function of ecological systems. Key words: Biogeography, biological invasions, colonization, exotic species, invasive species, species richness