IndexCharacteristics of invasive alien species and causes of invasionTwo types of IAS introductions: intentional and unintentionalIntentional introductionsUnintentional introductionsEffects of invasive alien speciesEnvironmental impactsEconomic impactsDiseases/health problemsControl and management of invasive aliens SpeciesConclusionReferencesWhat are invasive species? An alien species is a species that is exotic and not native to an area into which it has been introduced, whether intentionally or unintentionally. As its name suggests, it does not belong to the ecosystem into which it was introduced. When we add the term “invasive,” it clarifies that this species would now exhibit negative impacts in the area of ​​its introduction. In recent years there has been a strong trend towards debate and publications on the topic of invasive alien species (IAS). As a result, the term alien species or IAS has been described in different ways by different agencies/experts. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get Original Essay An alien species refers to a species, subspecies, or lower taxon, introduced outside its natural past or present distribution; including any parts, gametes, seeds, eggs or propagules of such species which may survive and subsequently reproduce. Kolar and Lodge point out that invasive species are non-native species that spread from the point of introduction and become abundant. According to di Castri, a biological invader is a species that is usually transported inadvertently and spreads to new territories. Similarly, according to the IUCN, invasive alien species are plants or animals that are introduced by humans, accidentally or intentionally, outside their natural geographic range into an area where they do not naturally occur. A similar sense of understanding has been proposed by Birdlife International which defines IAS as species of animals and plants that are accidentally or deliberately introduced into a natural environment where they are not normally found. The definition proposed by the ISSG highlights the impacts of invasive species also defining the meaning of invasiveness. In other words, according to the ISSG, an invasive species is a species that has established and spread or has the potential to do so outside its natural distribution range, and which therefore threatens ecosystems, habitats and/or other species, potentially causing economic harm and/or environmental harm or harm to human health. Simply put, IAS are exotic species that can have harmful impacts on the ecosystem into which they are introduced. Which taxonomic groups are most invasive? It is very difficult to predict which group of organisms will show more, less, or no invasiveness. In other words, any species has the potential to become invasive if it is removed from its native environment. This can be understood from the fact that IAS are found in all taxonomic groups, including mammals, aquatic and terrestrial plants, fish, birds, insects, amphibians, molluscs, reptiles, mosses, ferns, algae, fungi, and viruses. Alien species do not always pose a threat as in most cases they find it difficult to survive in new ecosystems/conditions and therefore their introduction becomes unsuccessful. However, studies suggest that approximately 1 in 1000 organisms introduced into a new environment has great potential to thrive and become invasive. It is interesting to note that in their native range IAS are kept in check by environmental factors and predators; whereas, in new environments, the lack of such controlling factors provides them with sufficient opportunities to thrive and proliferate. Characteristics of alien speciesInvasives and Causes of Invasion As previously mentioned, there is no specific methodology for predicting the potential of any species to become invasive. However, there are few characteristics that can increase our understanding of a species to determine its invasiveness. Common obvious characteristics of IAS may include a broad native range, rapid rate of reproduction and growth, strong dispersal and competitive abilities, ability to physiologically adapt to new conditions, broad reproductive capacity, and ability to survive with a wide range of types of food with wide tolerance in different conditions. environmental conditions. According to McNeely et al., trade, travel and transportation (3T) are the main drivers of biological invasion. Initially, there were natural barriers in the form of oceans and mountains that prohibited the movement of species from their native range elsewhere. However, human progress in the form of global seaborne trade has opened avenues for the movement of species around the world. Furthermore, globalization has increased its pace considerably. According to the World Resources Institute and the World Bank, the globalization of the economy is demonstrated by the increase in the value of total imports from $192 billion in 1965 to $5.4 trillion in 1998, a 28-fold increase. in just over 30 years. As a result, globalization has shifted the trend of trade, where even the most developed country is now economically dependent on other countries for goods and services. However, globalization has become a source of a new challenge in the form of movement of species outside their native range. Experts believe that the sea/water route is potentially responsible for the IAS problem due to various routes such as shipping, shipping channels, aquaculture and aquarium. trade. Among the various factors responsible for the introduction of IAS, ballast water has often been held responsible since much of global trade occurs via sea. Two types of IAS introduction: intentional and unintentional - existing nature of human movements around the world. Apart from food, there are several defined purposes for which humans introduce exotic species such as aquaculture, forestry, fishing, agriculture, wild game, biological control agents, prevention of soil erosion, research subjects etc. There are cases where alien species have no guarantee of survival unless they are treated. Therefore, humans do their best to ensure the greatest chances of proliferation. As a result, there are some species that do not perform according to the expectations of those who care for them. For example, the targeted introduction of African tilapia into Lake Nicaragua in the 1980s went awry as it showed adverse consequences in the form of destruction of native fish populations along with other impacts. Other causes include cases where alien species are deliberately released from captivity such as in zoos or botanical gardens. Additionally, smuggling endangered or less concern species increases the risk of introducing IAS into newer environments. Unintentional Introductions In this category, we consider cases where exotic species are introduced into newer areas of the world as a byproduct of human activities such as trade, travel, and transportation. In other words, two or more countries are often connected to each other in the form of financial affairs, disaster relief projects or military operations, which become the cause of the inadvertent introduction of IAS. The escape of exotic species from captivity also falls into this type of introduction. Furthermore, climate change can also facilitateinvasion by making habitats more challenging for native species and more hospitable for invasive alien species. Effects of invasive alien species The severity of the disastrous impacts of IAS can be understood from the IUCN notion, which cites the impacts of IAS as immense, insidious and usually irreversible. In the current scenario, the IAS problem is being addressed globally and almost all countries are paying the high costs. It appears that the impacts of IAS can be measured in economic terms, but the problems of unemployment, ecological imbalance, food shortages, decline in biodiversity, disasters, epidemics and loss of life are closely related to IAS and therefore they cannot be ignored. Impacts The disastrous impacts of IAS on the receiving environment are well documented. For example, IAS have been held responsible for the extinction of numerous native species, as well as the disruption of ecological balance, alteration of predator-prey, competition, nutrient dynamics, community structure and ecosystem services , the spread of pathogens and the irreversible loss of the native environment worldwide. the globe. According to Villamagna and Murphy, thick mats of water hyacinth lead to a decrease in phytoplankton, an increase in water turbidity, and a decrease in dissolved oxygen. There are examples where the introduction of predators such as rats, mongooses, snakes or fish has driven endemic bird, reptile, snail and aquatic insect species towards extinction or local extinction. The Convention on Biological Diversity highlighted biological invasion as a major driver of biodiversity decline and the second biggest threat after habitat destruction and ecosystem degradation. The Millennium Ecosystem Assessment also recognized biological invasions as one of the five main causes of biodiversity decline. According to BirdLife International, species such as rats, cats and mice have driven more than 70 bird species to extinction over the past 500 years. Economic impacts The economic impacts of IAS are very costly. According to Birdlife International, for example, IAS cause around 12.5 billion euros in damage every year in Europe alone. A study conducted in the United States estimates costs of $137 billion per year due to invasive species. The costs of IAS for agriculture in the United States have been estimated at over $120 billion per year and for invasive insects globally at over $70 billion per year. According to Bright, losses to agriculture have been estimated at between $55 billion and nearly $248 billion per year globally. Furthermore, a nation faces economic losses when its tourism is affected by IAS. There are reports that IAS can cause degradation of several habitats important for recreational activities in the form of snorkeling, scuba diving, and recreational fishing. It is surprising to note that the impact and costs of running a single IAS can cost millions. For example, the golden apple snail (Pomacea canaliculata), introduced from Latin America as a high-protein food source, caused losses to Philippine rice crops during the 1980s of approximately $1 billion. Understanding the patterns and processes involved in the IAS issue, governments must invest large sums of money in research activities that further add economic burdens to national funds. For example, since 2000 the European Union has funded forty-nine major projects to address different aspects of biological invasions. Diseases/health problems Some alien species have been reportedthey transmit diseases to native populations. Vibrio cholerae and some other microorganisms that can cause harmful algal blooms are transferred and released into ballast water carried by large ships. Gaffkemia, caused by Aerococcus viridans, was introduced into European waters by American lobsters (Homarus americanus) and infected European lobsters (H. gammarus). In some cases IAS have also become dangerous for humans. For example, the African honeybee Apis mellifera has invaded parts of the southern United States, where due to its aggressive and deadly nature it has killed numerous people and animals so far and is popularly known as the killer bee. According to Firehun et al., malaria is one of the major fatal diseases caused by the hindering effect of water hyacinth. This herb has been linked to increased cases of diseases such as cholera and typhoid. Furthermore, chemicals such as pesticides used to kill invasive alien species then find their way into the food chain and cause harmful effects on humans, animals and the environment. Control and management of invasive alien species It is true that not all exotic species transform into invasive species. However, if this were to happen, it would show multi-scale harmful impacts on the environment, economy, human health, tourism, culture and other important aspects. Once an IAS has established itself, it becomes very difficult or economically expensive to eradicate it. Goals for addressing IAS include prevention, early detection, eradication and control of IAS. Below are some suggested methods for IAS control and management along with other strategies: Mechanical control includes the direct, physical removal of IAS manually or with other machinery. However, it requires a significant investment of time and human resources and carries risks due to the presence of animals such as snakes and crocodiles if the target IAS is an aquatic weed. Mechanical control has been identified as an effective method for the removal of many invasive alien species, including water hyacinth (Eichhornia crassipes). For example, the use of machinery to remove water hyacinth from water bodies has proven to be an effective and non-polluting control method. Its main advantage is the simultaneous removal of nutrients and pollutants from the water body. Chemical control involves the use of different chemicals such as herbicides or insecticides. For example, glyphosate and 2,4-D [(2,4-dichlorophenoxy) acetic acid] have been considered effective and safe herbicides to control water hyacinth blooms. However, the chemical method is an expensive affair and requires repeated applications along with the potential development of resistant IAS strains over time and the threat of biological magnification. Biological control involves the intentional introduction of natural enemies of target IAS in the form of predators. or parasite. It often brings the IAS population to a tolerable level and is seen as an environmentally friendly and cost-effective method. In the case of water hyacinth, for example, the biological control method that uses a natural predator (the weevil species Neochetina eichhorniae, N. bruchi or the moth species Sameodes abligullatis) or a pathogen (the fungus Alternaria eichhornia) it proved effective. There are studies that indicate the advantageous use of some exotic species also to control other IAS. However, complete eradication of IAS by this method takes a long time. Please note: this is just an example. Get a custom paper from our expert writers now. 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