Threats to Biodiversity

Habitat Loss Deforestation: trees cut and never replanted (for timber or agriculture reasons) Tropical forests only cover 7% of Earth’s land yet contain over half of Earth’s species. Wetland drainage:6% of the earths surface, 24% of all wetlands are in Canada (Manitoba and Ontario) Habitat loss and species loss are one problem but also plants in wetlands help filter out sediment and pollutants from the water helping to keep it clean.

Alien Species Introducing new (non-native) species from a different area into an ecosystem. May be purposeful or an accident through shipments of goods by humans Most alien species are harmless or even beneficial in their new ecosystem

Invasive Species An alien species that takes over the habitat of native species Upset equilibrium (balance) of the ecosystem Many aquatic invasive species are transported in the ballast water of a ship (helps to keep the boat in balance) Ballast water is like a huge aquarium containing fish, and microscopic organisms ZEBRA MUSSELS AND LAKE ERIE GOBIE and the GREAT LAKES

Over Exploitation Taking too much of a resource for human use to the point of resource depletion The cod fishery on the East coast is an example of this

Ecosystem connectivity Several ecosystems are connected through the lifecycle of some of it’s organisms. Ex. Salmon: they hatch in fresh water stream temperate rain forest (B.C.) Spend adult life in Pacific ocean picking up and storing nutrients Return to birth place to spawn (breed) Bears catch salmon bring into the forest and the nutrients from the ocean are released into the forest as its body decays.

Extinction Death rate remains higher than birth rate for a long time= species will go extinct Not necessarily only caused by humans, ecosystems change and species can go extinct because of this Patterns of natural extinction: Background extinction-slow change in ecosystems result in recurring extinction Mass extinction: sudden change in ecosystems on earth result in many species going extinct all at once.

Extinction

Current extinction rates Due to human presence rate is 100 to 1000x higher than normal background rates. This problem has been called the BIODIVERSITY CRISIS Resulted by humans and acts such as deforestation, habitat destruction and air and water pollution changing abiotic and biotic factors

Restoring ecology The renewal of degraded or destroyed ecosystems ( like the TED talks video) Reforestation methods: Seeding efforts and management have shown this works Wetland restoration: Alfred bog is an example Pg. 87 Water control is used to restore water to drained wetlands then replanting native species occurs Controlling alien species: Biocontrol: the use of a species to control the population growth or spread of an undesirable species Problems go with this-sometimes the species it controls can affect native species negatively. Gypsy moth and Parasitoid fly example

Controlling alien species Chemicals: poisons directly presented to the organisms to be controlled can have fairly contained results (e.g. killing rats on an island had big impacts on the rats population and minimal on the bird population of the island) Bioremediation: the use of living organisms to clean up contaminated areas naturally E.g. fungi, plants and bacteria can be used to extract contamination. Bioaugmentation: the use of organism to add essential nutrients to depleted soils E.g. clover planted to restore nitrogen levels naturally

The future of Restoration Ecology Alberta Tar sands result in almost complete habitat and ecosystem destruction The oil spill off the coast of New Mexico