How does the introduction of new species happen into an area and how does it upset the food web?
New species can be introduced into an area through various means such as accidental or intentional releases, migration, or human activities like transport, trade, and agriculture. When a new species is introduced into an ecosystem, it can upset the existing food web in several ways.
Firstly, the new species may outcompete existing species for resources such as food, shelter, and breeding sites, leading to a decline in native species. For example, the introduction of the invasive species zebra mussels in the Great Lakes of North America led to a decline in native mussel species.
Secondly, the new species may have no natural predators in the new environment, leading to population growth and dominance, which further upsets the food web. For example, the European green crab introduced to the west coast of North America became a predator of native crab and other small species, leading to a decline in their populations and affecting the food chain.
Lastly, new species can introduce diseases or parasites to the native populations, leading to their decline or extinction. For example, the introduction of the fungal disease chytridiomycosis to frog populations in Central and South America has led to a massive decline in amphibian populations and has affected the food web.
Overall, the introduction of new species can have far-reaching ecological impacts, leading to the loss of native species, disruption of the food web, and changes to ecosystem function and services.