There has been a significant increase in the number of plant species that have been moved for agricultural, horticultural, grazing, and medicinal purposes over the course of the last century. Due to international trade, seeds and propagules are dispersing across continents at rates that have never been seen before.
When governments remove obstacles to commerce that are either physically present or administrative in nature, globalisation can take place. Many civilisations value local trade. The increase in the world’s population, the development of more efficient modes of transportation, and the relaxation of travel restrictions have all played a role in the globalisation of business.
Unfair globalisation
Are there globalised floras? In most cases, the extent of ‘alienness’ of a plant can be deduced from the number of native and non-native species that it contains. However, another indicator of success is the degree to which alien species have established a broad presence in the occupied territories. To determine whether or not non-native plant species were common as native plant species, a group of scientists from around the world combed through the most accurate data available from a variety of nations and regions. The evolution of native and exotic floras is very different from one another. Local biodiversity has developed over time to meet the needs of specific ecological niches.
If foreign plant species spread as broadly as native species in a shorter time, it would indicate that their introduction procedures are identical in terms of distributional range. Even if this were the case, the processes in question would have occurred much more quickly than they do in native species. This could be a reflection of the extraordinary dispersal abilities and high competitiveness of aliens when it comes to colonising new habitats, both of which are thought to be major factors in the success of invasive alien species.
If extraterrestrials are more prevalent than native species, then the process of invasion is working in a manner that is distinct from the natural progression of distributional range expansion and occupation. Aliens with smaller ranges than locals either fail to succeed in new habitats or have not reached their distributional boundaries.
The researchers compiled information on the 120 plant species that can be found across the globe in the greatest diversity with respect to the sub-regions in which they are found. The latter, which consisted of plant species brought in by humans, were referred to as “foreign”. The threshold of 120 species was not determined scientifically, but rather based on the frequency distribution of plants.
They looked at the top 120 species because the sample locations varied in terms of both the area and the number of species they included. They were taken aback by their discovery. First, there was a large amount of variation in the proportion of common plant species that were introduced.
Secondly, the alien species that made it to the list of the 120 species that had spread the furthest throughout Europe and North America, were very different from one another. It is possible that some sub-regions have more aliens than others.
Thirdly, regardless of the size of the study region, non-native species were just as common on the list as their local counterparts.
The ranges of many plant species are expanding across the globe. Knowing the global ranges of native and alien species helps scientists study highly invasive species and build effective monitoring and prevention methods. The subsequent invasions illustrate invasions on both a global and a continental scale.
Water hyacinth
It is possible to find water hyacinth on every continent with the exception of Antarctica. Water hyacinth is a perennial plant that grows in water and is free floating. Stolons allow plants to quickly reproduce, resulting in the formation of thick mats (i.e., vegetative runners). Water hyacinth can fully blanket lakes and wetlands, causing native aquatic species to die out, fish to lose oxygen, and disease-carrying mosquitoes to thrive. Water hyacinth infestations can damage bridges, dams, fisheries, and river navigation. Massive populations in waterways harm transportation, fishing, and illness. Despite controls and regional shipping restrictions, it has expanded to many new regions. Worldwide aquarium plant nurseries and internet retailers sell water hyacinth.
Castor plant
Castor oil plants are Euphorbiaceae spurges from Africa and the Middle East. Seeds contain 40-60 per cent oil-rich triglycerides. The tropical shrub or tree grows quickly to 12 metres or more. The crop is grown worldwide in tropical locations. Horticulturists have sold many kinds as landscaping trees and shrubs, spreading them. Wind and ants spread the commercially available seeds of this species far. The castor oil plant may quickly dominate natural regions, making it difficult for land managers to control.
Gatorweed
The South American Amaranthaceae plant alligator weed is amphibious. Like water hyacinth, it rapidly reduces water flow, canopy light, and water column oxygen, lowering the habitat quality of wetland species. Alligator weed can also overtake drylands and farms. It grows swiftly from stem fragments. It is a part of the Hypericaceae family and has been used to treat depression.
For unknown reasons, certain locations are easier to conquer than others. The presence of a high number of native species in an area increases that region’s susceptibility to invasive species due to the great availability of resources and the environmental diversity present. This pattern holds true on scales ranging from the local to the global. Trade and transportation boost dispersal, introduction and species overlap between regions and nations.
Invasion patterns are frequently explicable by factors such as climate, disturbance, length of time from introduction, and trade volume. On the other hand, temperate zones display a wide variety of invasion patterns. The change in land use has a significant impact on these areas. The earliest plant invaders were widely spread across the landscape. It is possible that increased trade and transit, would give rise to problems in the future for other countries. Because of its long relationship with plants, animals and people since the beginning of agriculture 10,000 years ago, the Mediterranean region has been regarded as a supplier of invasive species to other regions.
Plant inventories and databases are required at both the national and regional levels in order to understand invasion patterns. It is possible that the local flora of different locations will lose their particular identities as additional plant species move into an area. It is not out of the question that commerce and mobility will play a role in the formation of future patterns of biodiversity. If the effects of geographic isolation are lessened, there is a possibility that the reorganisation of species will proceed at a faster rate. It is possible for alien assemblages to spread from local to global scales with the assistance of human-assisted migrations as well as the unintended establishment of species, which is then followed by natural dispersal by wind, water and animals. A bio-geographic cascade is the name given to this sequence of occurrences. While scientists are making progress in locating invasive species in various parts of the world, it might be helpful for them to begin researching native species that are widely spread.