Presented To : Dr. Khalid Nawazpresented By: Maryam Ijaz

Bs Botany 4th Semester

Exotic species

Exotic species• Exotic species are those species

living outside of its native home range.• Many botanist refer to alien or

adentive species where as biological invaders introduced species non native species and non indigenous species.• .

So biologist use this term if a species is present outside of its natural geographic range where as non biologist called the exotic species.

There are different ways for transfer of exotic species .Stowaways Subsistence and CommerceRecreation Science Biological controlHabitat /climate change

How species move ?

Stowaways

Large portions of the species that have transferred around the world were stowaways.Species that have greatly left behind.Stowaways often go unnoticed because they are in very small and inconspicuous.Travelling as eggs, pupa spores on food or on roots of plants .

Earthworms

Most deliberate attempts to combine worlds biota have been motivated by our needs for

food.Colonist every where have brought their own domestic plants and animals with them and often sent back new plants and animals to their home range .

Subsistence and Commerce

In Europe colonization results in transportation of potatoes, corn went back to old world on the same ship that were introducing horses, wheat and many other species.Species for food dominate the list of planned introducing but other needs also have introduction.So wild species are important for commercial purposes.

Conti……..

potatoes

Recreation

Support hunters and anglers have been primary catalyst for planned introduction of exotic wild species.In California 50 species out of 133 fresh water fishes are not native to state. people dumped new species of fishes into almost every water body that they visit regularly including both game fishes and smaller fishes for food and gaming

To study closely scientists often establish breeding colonies in their laboratories sometime these species are outside of their native range and sometime they escape.Example : Gypsy moth

Science

Gypsy moth

• When we think of exotic we usually think of species actually transported by people deliberately or accidently but we could include species that are able to expand their home range themselves because of human changes to environment.

Habitat loss/ climate change

• Most exotic species are leaving environment so completely manipulated by people that their direct impacts on native biota are not very severe. Unfortunately there are thousands of exceptions to this organization some of which are following:

Impacts of exotic species

• It is easy to understand the impact of exotic species when an introduces species kills and eats native species.From economic perspective introduced insects that can consume crop plants are among most destructive exotic pests.

Predators and grazers

• Exotic parasites and pathogens have a tremendous potential to effect native predators and parasites feed on the protoplasm of other species.• European colonist killed far more

natives of Australia and Americans with their diseases than their guns.

Parasites and pathogens

• The effects of exotics as Competitors are most prominent with plants and other sessile species.• Some exotic species can become so

extremely abundant that competition for space is closely tied to basic resources such as;• water, nutrients,and light.

Competitors

• Some introduced species are so closely related to the native species that they may interbreed and produce hybrids.

• The genes of one species come to dominent in a common gene pool largely excluding the genes of second species.This process is called gene swamping.

Hybridization

• Impacts of exotic ecosytem can reach far beyond the individual species that must cope with a predator,competitor,pathogens or parasite.• Exotic species can alter a variety of

ecosystem properties such as productivity ,nutrient cycling,soil and vegitation structure.

Impacts on ecosystem

• Exotic plants can also exchange the entire ecosystem in many ways for example nitrogen fixing plants can significantly change the soil chemistry of the environment.• They invade fire prone exotic plants. Exotic plants can allow fire to burn

more exteremly and entirely change ecosystem.