Example Of Purpose Essay

Identifying Environmental Hazard: The Impact of Invasive Species on Native Species Population

The purpose of the lab is to investigate the population dynamic upon introduction of invasive species. This allows the population to grow seemingly uncontrolled and to displace other native population. Population dynamic in this laboratory observation includes the increase and decrease of invasive species population and the impact of this fluctuation to the ecosystem as a whole.

Introduction

Introduction of aquatic invasive species to an ecosystem has been known to have consequences on the alteration of population dynamics of an ecosystem. The population dynamics are caused by the biotic potential and the effects of environmental resistance. Minimal environmental resistance will create population explosion, as there is no factor that regulates the population. Factors regulating the population include predator decline or resource increases. Another reason for population explosion is the introduction of an invasive species foreign to an ecosystem that is not immediately regulated by the environmental restraints of the particular ecosystem that they invade.
This alteration can have devastating impact on the economy due to the decline in fishery and tourism, as well as increasing cost due to the needs for eradicating/controlling the invasion . Aquatic invasive species will impact the population of native species by increased predation which consequently impacts the overall composition of the ecosystem . Other than predation, the success of invasive species can be attributed to the lack of pathogens than regulate the population size . An example of aquatic invasive species is the introduction of the dressenid mussels known as Zebra (Dressena polymorpha) and Quagga (Dressena rostriformis) mussels. Their introduction has caused the reorganization of the ecosystem as well as an economic hardship. This has led to pollution-causing effects linked to the growth of alga known as Cladophora.

Hypothesis/Predicted Outcome

The hypothesis of this study is: Increase in the population of invasive species will impact the population of native species.
Methods
The data were obtained from a long period of monitoring (20 years) on the aquatic ecosystem of the Great Lakes. The data were collected in year 0, 4, 7, 10, 13, 15, and 20 to allow time series analysis. The population of Zebra and Quagga mussels is expressed as density/m2, the population of phytoplankton and zooplankton as µg/ml, Cladophora biomass as g/m2, and fish population as kilotons.

Results/Outcome

The results of this study are presented in the following table (Table 1).
Data Source: https://class.aiu-online.com/_layouts/MUSEViewer/MUSE.aspx?mid=375400

Discussion/Analysis

The population of phytoplankton negatively correlates with the population of the Zebra and Quagga mussels which can be attributed to predation. Consequently, the population of the phytoplankton impacts the populations of zooplanktons, foraging fish and the Lake Trout. The increase of Cladophora biomass is believed to be associated with the decline in foraging fish species, which is also observed in Hudson River case . The result of the analysis shows that the fluctuation of invasive species impacts the native species. Therefore, this finding supports the hypothesis.
Between the year 13 and 15 the population of the mussel decreased by half, and continued to decrease by year 20. This can be caused by several factors such as eradication strategies , or the increase in natural parasites or pathogens that regulate the population of the invasive species .
Findings from this laboratory exercise and also from other researches show that introduction of invasive species may alter the ecological composition. Invasive species may have advantages over the native species due to the lack of predators and pathogens. However, over a period of time, the success of invasive species will be regulated by changes in biotic and abiotic composition of the ecosystem. Predators and pathogens (e.g., bacteria from bird’s feces) that regulate the invasive species population may be introduced to the ecosystem and cause the decline in the invasive species population. This ecological pattern provides opportunities where biotic and abiotic manipulations can be used to form the basis for establishing strategy for eradicating and controlling the aquatic invasive species .

Works Cited

Culver, C., Lahr, H., Johnson, L., & Cassell, J. (2013). Quagga and Zebra Mussel Eradication and Control Tactics. San Diego: University of California.
Gendron, A. D., Marcogliese, D. J., & Thomas, M. (2012). Invasive species are less parasitized than native competitors, but for how long? The case of the round goby in the Great Lakes-St. Lawrence Basin. Biol Invasions 14, 367–384.
Ricciardi, A., Avlijas, S., & Marty, J. (2012). Forecasting the ecological impacts of the Hemimysis anomala invasion in North America: Lessons from other freshwater mysid introductions. Journal of Great Lakes Research 38, 7-13.
Rosaen, A. L., Grover, E. A., Spencer, C. W., & Anderson, P. L. (2012). The Costs of Aquatic Invasive Species. Chicago: Anderson Economic Group, LLC.
Strayer, D. L., Hattala, K. A., Kahnle, A. W., & Adams, R. D. (2014). Has the Hudson River fish community recovered from the zebra mussel invasion along with its forage base? Canadian Journal of Fisheries and Aquatic Sciences 71(8), 1146-1157.