Invasive Species

Invasive species can have detrimental effects on ecosystems. Their presence changes the functions of ecosystems, threaten native species directly through competition for limited resources and predation. Successful invasive species can shift food webs removing keystone organisms and create a species dominated ecosystem. Invasive species have been identified as the second biggest threat to ecosystems. (Vitousek et al. 1996 ). Although not every species that reaches a new region are able to successfully invade. It is only when the non-native species become widespread and abundant that it is likely to cause ecological harm. If the non-native species is unable to set up a self-sustaining population in the new range, the alien population will face …show more content…
The invasion of Lion fish (Pterois volitans and P. miles) have spread rapidly across Western Atlantic, Caribbean and Gulf of Mexico. These predators have a big effect on native fish through predation. Green et el (2012). Showed that between 2008 and 2010 the abundance of lionfish populations increased from 23% to 40% of the total biomass of predators in the study site. Overlapping with a rapid decline in native fish. This produces a number of threats initially reducing the number of native prey fish, leading to a reduction in the availability of food for other predators. Causing competition for the native predator fish. Ernesto and Arias-Gonzàlez et el (2011) showed removal of prey species, which feed on algae present on coral are essential. It is predicted the removal of these fish species would reduce coral population in the Caribbean by 10% within the next decade. Management strategies to control lionfish populations have mainly been on a local scale. Lion fish have been identified as one of the biggest problems to conservation (Sutherland, W. J. 2010). Capable of realising 2 million eggs, even if a few survive they are able to quickly repopulate. One method used to control populations was the use of competitions with the aim of catching as many of these invaders are possible. Competitions of this nature have been used before with varying success. Competitions aimed at salmon have …show more content…
On the other hand this introduction may positively change the ecosystem. Many native fauna are shown to use invasive species as habitats. Crooks (2002). Demonstrated that the arrival of habitat building invasive plants increased the diversity and abundance of native species. This increased abundance is not true for all native species. It is suggested only native fauna with fitness that is equal to or greater than the invading species will survive, meaning that invading species still present a threat to less fit native fauna. (Rodriguez 2006). Even though invasive species have increased the abundance of native species by providing new habitats, these habitats may not allow the native species to thrive, due to the changes in ecosystem processes which generate stress reducing the native species fitness (Posey, Wigand & Stevenson 1993; Crooks 2001). The invasion of species including seaweed, seagrass and oyster into salt marsh environments results in both higher diversity and abundance of native fauna compared to uninvaded salt marshes (Bulleri et al. 2006). The added complexity to habitats these organisms bring allow species to avoid predation. A great benefit to epifauna. However these benefits appear short term. The stresses this change in habitat causes can reduce the fitness of adult organism leading to negative long term effects in overall

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