Contents



Preface

Invasive alien species (IAS) are non-native species to a particular locality and have the tendency to spread very quickly when they have successfully established themselves in the new invaded areas. IAS include plants, insects, birds, nematodes, fish, frogs, cats, snakes, turtles, toads, and pathogens. The stages of invasiveness of these species include introduction pathways, establishment, and dispersal. Invasive species are found in all ecosystems including terrestrial, marine, and other aquatic ecosystems, and they can be introduced into new areas either accidentally or intentionally through anthropogenic activities. Introduction pathways of IAS include agricultural trade and accidental transport of adults and pre-imaginal stages of insects, plant seeds, and vegetative parts in containers and vehicles. Infested fruits and planting materials are the key introduction pathways for several invasive insect species including palm weevils, fruit flies, emerald ash borer (EAB), mealy bugs, spider mites, western flower thrips, tomato pinworm, the brown marmorated stinkbug, the fall armyworm, and others. IAS can spread by cars, trucks, ships, aircrafts, and other means of travel and transportation of goods. Increasing trade through globalization facilitates the spread of invasive species. Climate change also hastens the spread of IAS and renders ecosystems more vulnerable to invasion by non-native or exotic species. Insects are among the most numerous invasive species worldwide and the number of new invasions is increasing exponentially, representing a threat to the economy and the environment. Insects represent about 87% of invasive species and cost the global economy more than 70 billion US\$ annually, according to the International Union for Conservation of Nature (IUCN).

It is extremely difficult and sometimes near impossible to eradicate invasive species completely once they have established themselves in a new habitat. In most cases, exotic species flourish in their new habitat due to prevailing congenital

The impact of IAS on ecosystems may include endangering biological diversity through completion and niche displacement, vectoring of serious human and animal diseases, and increasing the risk of native species extinction. Inter-regional immigration through introduction of alien plant species may lead to hybridization, which is likely to increase the threat of species extinction due to introgression. IAS could also alter phylogenetic diversity across communities, modify trophic chains, and change ecosystem functioning and delivery of ecosystem services by changing

In the time of globalization, invasive species are gaining an increasing economic and ecological significance. There is a need for more research and comprehensive edited volumes on the impact of IAS on global agricultural activities as well as on the different ecosystems, particularly with the increasing evidence of climate change and global warming. This book addresses issues pertaining to invasive insect and plant species with emphasis on their introduction pathways, bionomics, dispersal, risk assessment, economic impact, possible management, and control options.

The book contains nine chapters over two sections; section one is about invasive insect species and includes five chapters, while section two deals with invasive plant

environmental conditions and the absence of their natural enemies.

nutrients and contaminants' cycling.

*by Faten Mannai, Ramzi Khiari and Younes Moussaoui*
