3.3 Human Impact on Diversity

What is an endangered species?

• We are currently in a period of mass extinctions– 1.5 million living species are

endangered• Included birds, fish, plants,

amphibians, mosses etc.

Golden Toad, last seen May 15, 1989

DefinitionAn endangered species is a species of organisms facing a very high risk of extinction. The phrase is used vaguely in common parlance for any species fitting this description, but its use by conservation biologists typically refers to those designated Endangered in the IUCN Red List, where it is the second most severe conservation status for wild populations, following Critically Endangered.

There are currently 3079 animals and 2655 plants classified as Endangered worldwide, compared with 1998 levels of 1102 and 1197 respectively. The amount, population trend, and conservation status of each species can be found in the Lists of organisms by population. (Wikipedia)

The green sea turtle is an endangered species

Species Extinction

• There have been many large and small scale extinctions in Earth’s past. Why is there so much concern now?– Rate of extinction is climbing– Rate of climate change is too fast for species to

adapt– We can be pretty sure that this time humans are the

cause of the extinctions, not a naturally changing cycle of the planet

Threats to Biodiversity

Habitat destruction

Invasive Species -Purple loosestrife

Pollution

Overexploitation – cod fishery

Climate change

Habitat loss

• Endangers 50% of all threatened species– Due to human activities

• Housing, agriculture, industry, obtaining natural resources, transportation, fragmentation etc.

– If species can’t adapt or move they will not survive

Invasive Species

• A species that is introduced to an area where it is not native and has a harmful effect on the habitat– Usually because there are no

natural controls (i.e. predators)– Can be intentional (e.g. kudzu

vine) or accidental e.g. rats, zebra mussels, sea lamprey

Invasive SpeciesEmerald ash borer arrived in packing material from Asia

Kudzu vine imported from Japan to help control erosion

Pollution

• These are all man made effects:– Atmospheric pollution including green house gases

and acid rain– Changing temperatures from green house gasses,

industrial wastes– Toxic wastes (industrial effluent) in water (surface

and groundwater) and soil– Agriculture wastes including fertilizers, pesticides

and herbicides• Bioaccumulation and biomagnification

Overexploitation

• Extinction is forever!• Between 1988 and 1995 the annual cod catch

dropped from 479 141 tons to 12 490 tons– Cod fishery was closed in in 1995 and the cod

stocks have not recovered enough since then to resume fishing

Some Potential effects of Climate Change on Biodiversity

• Organisms cannot adjust to the rate at which climate change is occurring– Disease outbreaks (more insects, warmer winters)– Plant migration (grasslands replace boreal forests)– Animal migration (cold water fish moving)– Extreme weather (flooding, drought etc.)

– Increased CO2 (increased temp., acid oceans)

– Water quality/availability (esp. in arid regions)

Conserving Biodiversity

• Ex-situ conservation– Protecting species by removing them from their

natural habitat when that habitat is threatened or no longer exists, or the population is very small

• Storing seeds, frozen cuttings, living specimens in botanical gardens or reserves

• Zoos (especially for breeding programs), reserves

• In-situ conservation– Protecting species in their natural habitats

• Habitat restoration

How You can help Conserve Biodiversity

• We can all try to reduce our ecological footprint (5.7 for the average Canadian!)

• What else you can do:– Do not release alien plants or animals into the wild– Do not transport fruit, vegetables, plants or animals

across international borders– Clean equipment i.e. fishing equipment, boat trailers– Do not transport wood over long distances– Keep natural habitats on your property