PLANTS AND ANIMALS INTRODUCTION BY HUMANS

Introduction of Plants and Animals Introduction by Humans

The purpose of this post is to review the introduction of plants and animals, non-native species by humans into new region, the impact of it, whether it is advantageous or disadvantageous to native plants and animals. Foremost, the introduction of them is not noticeable and do not cause damage to the native species until they appear in large quantity that is uncontrollable. Next, the introduction of plants and animals has to concern about its successfulness, the process that lead to invasion of exotics, the detrimental effects of exotics and the criteria that should be met before exotics are intentionally introduced to new areas. To look the consequences of the introduction of plants and animals, the difference impacts on island and on the mainland are compared.

Introduction of plants and animals which are non-native species, is a type of invasive or exotics species to the native species. Introduced animals and plants threaten the ecology, disrupted the food chain as well as food web, and bring some extinction to the native species. Humans as dispersal agents have been proved to be more disadvantages compared to the pros of it. We can see many plants and animals introduction by humans are due to the continuous supply of food, ornament, biological control and by accidental. Of course, the percentage covered by accident is the smallest among all but the effect of it is very large.

In a new region, the non-native species colonies it in a slow pathway. It is often not noticeable by the human and when it does, it may already compete with the native species, which will cause ecological and economic damage to the local place. This will then change the composition of species in that region. Over a period of time, it may affect the genetic flow of the native species.

The suitability of plants and animals to new region much met its ecological niche and habitat. The biotic condition such as competitor and vegetative structure must be suitable to the non-native species, while the abiotic condition such as temperature, humidity, salinity and substrate condition must be met to succeed in new area. Besides, adequacy of introduction unit must accomplish these characteristics, which are sufficient in health, behavior and simple number. Lack of resistance of red fox in the Alligator River National Wildlife Refuge, North America to bacterial infections, made them hard to survive. When the introduction of plant and animals to new place, the degree of escape from disease, parasites and predators also dependent in successfulness of the non-native species, where counteradaptation must be met. Also, the new region give the opportunity to the non-native species, where there is less competition, especially in islands, the successfulness of introduction is higher.

The Factor and Effect of Introduction of Plants and Animals by Humans

The introduction of plants into the new region is good when the region is destroyed by the catastrophe or by deforestation. This is because the native species need a longer time to recover, while the non-native plants can colonise the region in shorter time as the number of competitor is minimized and the different climate they met is suitable for them to grow. Forest restoration can be done quickly by wise selection of native plants or exotic species. This is to restore the soil fertility and stabilize soil. However, the non-native species should be gradually replaced from time to time with native trees that can promote carbon sequestration and produce hardwood (Patrick L.O. 2012). This can be seen in the Australia tree (Acacia spp.), along the road of UMS, they can grow at a faster rate as well as absorbing water at a greater amount. This circumstance may interrupt grows of native tree such as Kapur paji, Seraya kuning and Gagil. In another country like South Africa’s largest cities in the region has a direct effect on the runoff of watershed.

          Another process for introduced animals into new region is to control the exotic species. This can be seen in the introduction of predator red fox to the European rabbit population in Australia and mongooses to control rats on various oceanic islands. On the other hand, the introduction of these predators also brings another effect to the environment. Introduction of it is to the total reduction in viable seed by Larinus planus will reduce the potential for recruitment and will likely lead to a quantitative decrease in the density and persistence of this native species in these stands over time. However, the potential side effect of biological control is rare.

In addition to the above statement, the African giant snail (Achatina fulica), that are previously introduced to some island like the island of French Polynesia, Tahiti and Saipan as a source of food. In contrary, the mass production of it has made the loss of native vegetation and crops. The predatory Wolf Snail (Euglandia rosea), was introduced to overcome this situation. In spite of that, the native species was the victim of the predatory snail, especially the genera Partula and Samoana (S. attenuata), and they are disappeared in the wild. In Hawaii, where the E. rosea has also introduced, the condition of the subfamily Achatinellinae, is thought to be unlikely to survive much longer in the wild (Hadfield, 1986).

          Next, the introduction of water hyacinth (Eichhornia crassipes), as an ornament or decorative item has make Lake Victoria a mass problem and contributed to the buildup of eutrophication. Water hyacinth is native from Southern United State of America to Argentina and West Indies. Due to the mass production of it, the living organism under the lake will die eventually as there is low penetration of sunlight that obstruct the photosynthesis of plant, and low oxygen level that inhibit the respiration of fish and other organism. It cost a lot of money to collect it to produce fuel. Then, some scientists from South African have used the biological control. They imported the some insects, which include two beetles, namely Neochetina eichhorniae and Neochetina bruchi, to control the number of the water hyacinth. These bugs are natural enemies to water hyacinth in the Amazon Basin and feed on different parts of the plants and different ways.

For animal, the red-eared slider turtles (Trachemys scripta elegans), were originated from Southern United as favorite pets. After it was banned in USA in 1975, some turtle farms turned their production toward exportation, mainly to Europe and Asia. They get their names because they got red patch of skin near their ears. In European, these turtles compete with the native species, European pond turtle, Emys orbicularis for basking site and survival, which they utilize the same habitat with greater efficiency. The Trachemys were able to survive in most winters in western Europe and success in breeding is the factors that outcompete the native turtles in term of densities and space.

Cocoa pod borer is a serious pest to cocoa and rambutan. 

          Furthermore, the next incidence is caused by accidental introduction by humans. This happened in some animals and plants that have unintentionally been carried with ship or other forms of transport. For example, the brown tree snake (Boiga irregularis) that carried accompany with the shipments of fruit from Southeast Asia to Guam around 1940s or during World War II (Rodda et al. 1992). They not only affect the distribution of native bird but also the tree around Guam. This is due to the fact that birds are one type of pollinator to the native tree in the area of Guam. The dispersal of native mangrove tree, Bruguiguiera gymnorrhiza by the bird pollinators have led to a reduced seed set and seedling recruitment. Some native species also went to extinction due to the introduction of brown tree snake. In contrary, the web-building spiders were becoming abundant compared to other due to smaller number of the bird species preying on them.

In Sabah, the dandelion (Taraxacum spp.) is believed to be brought by foreigners that climbed to Mount Kinabalu. It was quite unnoticeable for the first few years and it was quite attractive when it was found. Few year after the colonization of the dandelion, it was found that it has effect on the native species, where they compete for nutrient, water, light and space. It was found that non-native species have better breeding systems and fecundity as well as the attractiveness that make pollinators prone to make non-native dandelion like T. officinale reduce the grown of T. japonicum in Japan. The introduction of dandelion has made a loss of money, estimate about $500 million in controlling them.

Dandelion in Mt. Kinabalu.

     Furthermore, the hybridization of non-native species with the native species has brought to the extinction of the native species and has potential for genetic swamping, where the loss of both genetic diversity and locally adapted population, especially the rare and threatened one. The introduction of mallard duck (Anas platyrhynchos) into New Zealand has interbreed effectively with the native grey duck (Anas superciliosus), that less than 5% of the combined population of these two forms is representive of the pure grey duck(Gillespie, 1985). If this proceed, it is unlikely for the grey duck to survive in the wild.

         The hybridization of plants between the native species and introduced species are not noticeable until they are abundance in nature. Hybridization is the interbreeding of individuals from distinct species or occasionally from genetically distinct population (Julie et al.). This can bring to the concern of the conservation biology on the maintaining the genetic flow of the small population of native species before it came to an extinction. For example, cactus Opuntia littoralis and the introduced Opuntia ficus-indica produce the Opuntia occidentalis in southern Carlifornia. However, these hybrids are favored and good for the species because they occupy a less inflammable habitat than parental species.

      If compared the island with the mainland, the invasive species will lead to the extinction of the native species as can be seen in the introduction of the brown tree snake to Guam. According to the Theory of Island Biogeography, at any given time, the number of species on an island is the result of a balance between two processes, that is immigration or colonization and extinction. The mainland have a numerous resource to discover, when one species is decrease in number or almost diminish, the predator can switch to other preys to eat, whereas on the island, the limitation of the colonization can make it to eat their prey until they extinct. This situation is very dangerous as the genetic flow will cease especially the endemic species and the threatened one. The Galapagos Island and Madagascar has banned some trade that halts the dispersal of invasive species to this area to prevent the extinction of the endemic species.

Conclusion

In conclusion, the introduction of plants and animals by human has many cons rather than it pros. The introduction of them can make the area less resource to use, the predation on the native species will bring to the trophic cascade, in which top down influence affect from the predator to the nutrients absorb by plants. There should be some considerable criteria like doing some laboratory experiment on the effect of the introduction of plants and animals to a new region before they are bring to another region. Moreover, the introduced form should measure it should not have any bad impact on the native species. The impact should, at least, has the basic ecosystem characteristics that does not disrupt the specified or introduced region.

                                                                       Mimosa pudica

Recommendation: To read more about this, you all can refer to these books!

"Read more, Gains more"

George W. Cox. (1997). Conservation Biology. 2^nd Edition. Wm. C. Brown. Page 202-210.

Glen MacDonald. (2003). Biogeography: Introduction to Space, Time and Life. John Wiley and Sons. Page 368-372.

Johnathan E.M. Baillie, Craig Hilton-Taylor, Simon N. Stuart. (2004). 2004 IUCN Red List of Threatened Species^TM: A Global Species Assessment. IUCN, Gland, and Cambridge, UK. Page 93.

Julie L. Lockwood, Martha F. Hoopes and Michael P. Marchetti. (2007). Invasive Ecology. Blackwell. Page 13-266.

 

Neil A. Campbell, Jane B. Reece. Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson. (2009). Biology. 8^th Edition. Pearson Benjamin Cummings. Page 1233-1255.

Patrick L. Osborne. (2012). Tropical Ecosystems and Ecological Concepts. 2^nd Edition.    Cambridge University Press. Page 172, 182-184, 196-198, 234, 243, 308, 403-423.

Source for invasice species: Invasive species

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