Invasive species are harmful exotic animals

Species that are nonnative to a specific location are called invasive species. Invasive species have the ability to spread at a level that proves harmful to the human economy, environment, and human health.  

The term that is used to define the species that is not native to a specific location and affect the bioregions and habitat,  they can also affect the environment ecology and economy.   

It may be an animal or a plant that overcrowds a region and disrupt that habitat wilderness area.  Invasive species are defined by the European Union as“ those species that now threaten the biological diversity were firstly out of this area of natural distribution”. ^[1]Invasive Species | SpringerLink 

Causes of Invasive species

Scientists have to include ecosystem factors and species in the mechanisms that cause the introduced species to become invasive species.

Traits of the invasive species

• Fast growth rate
• High rate of reproduction
• The ability of wide dispersal
• High plasticity to phenotype,  which means that they have the ability to change  their growth which suits the present condition
• Can tolerate  environmental conditions on a wide range
• Generalist which means that they can feed on a wide variety of food.
• They have  also Association with humans
• They have  previously successful invasions

Usually and introduce species have to survive at a low population density until in a new location it becomes an invasive species. In a new location to maintain and reproducing itself will be a difficult task for the introduced species.

If an introduced species successfully compete with the native species for resources, for example, light, nutrients, physical space, food, and water, it will allow the introduced species to multiply rapidly.  

A coexistence is present between the native species and an invasive species for a long period of time until the population of the invasive species becomes denser and larger and the invasive species successfully adapt to a new location and competitive abilities become Apparent.  

An invasive species can create a negative or positive effect on native species because it can change the environment by modification of abiotic factors, by the release of chemical compounds, or by the effect of herbivores’ behavior.

Ecosystem-based mechanisms

The available resources amount and their utilization by organisms will determine the effect of invasive species on the ecosystem.  A stable ecosystem has an equilibrium between the use of the resources that are available.  when changes occur in an ecosystem, for example, forest fire it will favor the normal succession of forbs and grasses that are native to that location. 

An introduced species will utilize the resources that were the resources of native species so that introduced species will grow faster and squeeze the native species.  In this situation, Phosphorus and nitrogen are often considered as a limiting factor.  

In an ecosystem each species have its specific niche, so the invasive species will fill the niches that were not occupied by native species by creating new niches.

Edge effects show the disturbance of an ecosystem part when a piece of land is cleared for agricultural use, a distinct habitat is formed between the boundary of a newly cleared piece of land and the remaining undisturbed habitat.

It will create new losers and winners and hopefully host the species that were not survived outside that habitat’s boundary, the populations of newly introduced species have a great rate of adaptations, in this way in a new environment the newly introduced species become invasive.

These Rapid adaptations include the alters in phenology, morphology, plasticity, and Physiology, so their offspring will be fitter and better adapted for this environment,

Effects of invasive species

The invasive species have affected the ecology, geomorphology, and economy.

Ecological effects 

The local areas are pressurized by human habitation and land clearing. The habitats that are disturbed by human activities are very sensitive to invasive species, that have harmful effects on the ecosystem because they can alter the functions of an ecosystem.

Ecosystem functions are changed by the influence of invasive species because invasive species can change the nutrient cycle and the native ecosystem hydrology.

Sometimes hybridization occurs between the native species that are rare in nature and the invasive species that are closely related to that native species creating adverse effects on the native species by causing their extinction.

Geomorphological effects 

Bio protection and bio construction are the geomorphological effects of the plant species that are invasive. While bioerosion,  bioturbation, and bio construction is the primary geomorphological effects of animal species that are invasive.

Economic effects 

Some invasive species create some negative effects on the local area’s economy. Sea lamprey can feed on all types of fishes like Salman and trouts by adding destructive effects on the fish industry. ^[2]THE SCIENCE OF INVASIVE SPECIES (cbd.int) ^[3]Invasive-Species-The-hidden-threat-to-sustainable-development.pdf ^[4]wo_gtr79_83_091.pdf (fs.fed.us) ^[5]https://neobiota.pensoft.net/article/35466/download/pdf/346652

Benefits of invasive species

• The invasive species provide food resources and suitable habitats for other organisms, when native species are endangered or extinct the invasive species fill their place.
•  For the restoration, the invasive species act as a catalyst,  because the invasive species can increase biodiversity and heterogeneity in an ecosystem.
• For an existing engineer of an ecosystem, the non-native species can play the role of a substitute.
• The invasive species can also be introduced to fill a niche that was a niche of native species previously.
• Service is also provided by non-native species e.g  As a pollinator,  in the rainforest the Honey Bee was introduced to pollinate landscapes because the native species cannot do this. ^[6]https://www.gla.ac.uk/media/Media_636086_smxx.pdf ^[7]Redirecting (elsevier.com)

Reviewed by:
Dr. Muhammad Khalid Mukhtar (Ph.D.)
University of Sargodha, Sargodha