Characteristics, significance, and human dimension of global invasive weeds - Invasive Plants: Ecological and Agricultural Aspects - page 223

Characteristics, significance, and human dimension
of global invasive weeds
Prasanta C. Bhowmik
Department of Plant and Soil Sciences, University of Massachusetts, Amherst, MA 01003-7245, USA
Introduction
Invasive plant species have potential to damage our crops, our industries, the
environment and public health. Scientists, academics, leaders of industry and
land managers are realizing that invasive species are serious environmental
threats for the 21st century [1, 2]. Also, invasive species are recognized as one
of the leading threats to biodiversity and imposes tremendous costs on agri-
culture, forestry, fisheries, wetlands, roadsides, natural areas, and other human
enterprises, including human health. Invasive species take a heavy economic
toll with costs estimated to be $137 billion every year in the United States [3].
In 1994, the impacts of invasive plants in the United States were estimated at
$13 billion per year [4].
For centuries people have moved plants, animals, and microbes around the
world. Most countries now rely on plants and animals from other regions of the
world in order to meet their dietary needs. People in the US also import plants
and animals, and their products, as ornamental plants and pets. Organisms that
have been moved from their native habitat to a distant location are typically
referred to as “non-native”, “non-indigenous”, “exotic”, or “alien” to the new
environment.
There are fundamental differences in the approaches dealing with invasive
plant species problem depending on the ecosystem being invaded (terrestrial,
forests, and marine). My purpose is to highlight the characteristics and signif-
icance of terrestrial invasive plant species. Also, I link various aspects of the
human dimension to the current status of global invasive weeds.
Invasive plants and biodiversity
Human induced biological invasions are occurring on a global scale and are
beginning to blur the regional distinctiveness of the Earth's biota. That dis-
tinctiveness, which evolved over the past 180 million years as a result of the
isolation of the continents, has produced and maintained biodiversity. When
considered as a single phenomenon, biological invasions probably has had