Threats to Biodiversity & Restoration Ecology

Considerations about Biodiversity Biodiversity is linked to ecosystem variability The more variable ecosystems we have the greater biodiversity will be on Earth A B Ecotones; Have increased biodiversity Edges; Have increased biodiversity

Habitat Loss Natural Sources Human Activities Volcanic eruptions Wildfires Droughts Severe storms (hurricanes) Deforestation Draining wetlands Damming rivers

Deforestation in the Tropics Deforestation occurs when forests are logged for timber or cleared for agricultural use Tropical forests cover 7% of Earth’s land, but they contain about half of all the species on Earth Tropical rainforests often have biodiversity hotspots What can you infer about the bar graph?

Deforestation in Canada Canada has a vast boreal plains ecosystem stretching across Manitoba, Saskatchewan and Alberta This ecosystem is home to more species of breeding birds than any other forest ecosystem in North America From 1966-1994 forests decreased by up to 55% The number of bird species declined from 105 in 1987 to only 67 in 1995

Wetlands and their importance Areas of land that are covered by water Cover about 6% of Earth’s surface Wetlands provide habitat for many organisms Wetland plants filter sediment and pollution from water

Canadian Wetlands 24% of the world’s wetlands are in Canada Most wetlands are in Manitoba and Ontario They cover about 14% of Canada’s total land area

Alien Species Are species introduced to new parts of the biosphere from other places They are also called introduced species or non-native species or exotic species They usually arrive by accident in shipments of foods and other goods They are harmless or beneficial most times

Invasive Species Invasive species are alien species which can take over the habitat of native species or invade their bodies Many alien species invade aquatic ecosystems through ballast water

Zebra Mussels Introduced into the Great Lakes through the ballast water in the 1980s Zebra mussels are native to Asia Shrimp-like crustaceans have declined since then, because they feed on the same food as the Zebra mussels As the number of crustaceans have declined, so have the numbers of fish

Round Gobies in the Great Lakes The round goby from Asia now lives in the Great Lakes, where it competes with native fish for spawning areas The round goby is also known to eat the eggs of native fish

Overexploitation Overexploitation is the use or extraction of a resource until it is depleted It can lead into the disappearance of a species Examples include the Passenger pigeon, the Yellowfish tuna, and the Atlantic cod

The Passenger Pigeon The Passenger pigeon disappeared in the early 1900s due to overhunting The population of Passenger pigeons was once about 5 billion

The Yellowfish Tuna & the Atlantic Cod The Yellowfish tuna and the Atlantic cod numbers have been reduced by 90% due to overfishing

Can salmon help to keep forests healthy?

Connectivity Across Ecosystems Up to 70% of Nitrogen in organisms that live in the BC forests come via the salmon from the Pacific Ocean Such nutrients help to increase biodiversity in the forest Areas without salmon have lower biodiversity than in areas with salmon Overfishing and habitat destruction from logging and dam construction has resulted into the decline of the salmon population

Extinction of Species Occurs when death rate is higher than birth rate over an extended period of time Background extinction happens over long periods of time. Ecosystems change gradually Mass extinction happens relatively rapidly as ecosystems change suddenly e.g. dinosaurs

Plants at Risk in Ontario Extirpated: Local extinction, species exists elsewhere Endangered: risk of becoming extinct Threatened: vulnerable to endangerment

Biodiversity Crisis? Ecologists estimate that the current rate of extinction is 100-1000 times higher than a normal background rate It appears that biodiversity crisis has resulted from the action of humans Such actions include deforestation, habitat destruction, air and water pollution

Environmental Stewardship Environmental stewardship is the idea that all humans are responsible for looking after a huge piece of property that belongs to all living things; the biosphere Some ecosystems might be more vulnerable than others, and become unsustainable in less time

Restoration Ecology Is the renewal of degraded or destroyed ecosystems through active human intervention E.g. Don valley Brick Works

Restoration Methods; reforestation Reforestation is the re-growth of a forest through natural processes or through planting seeds/trees

Wetland Restoration Process by which a wetland is returned to its natural state in terms of soil quality, water coverage, type of plants grown, and habitat Water control structures are used by wetland conservationists to help restore and maintain water levels

Controlling Alien Species Biocontrol; the use of one species to control the population growth or spread of an undesirable species e.g. Gypsy moths and indiscretus Chemicals; the use of chemicals to control the population of an undesirable species e.g. rats which reduced the colony of ancient murrelets

Bioremediation vs Bioaugmentation Bioremediation involves the introduction of living plants, fungi or bacteria to detoxify soils, or to break down oil from oil spills Bioaugmentation is the use of organisms to add essential nutrients to depleted soil E.g. clover planted to replenish nitrogen levels in soil

The Future of Restoration Ecology Restoration and enhancement of sustainable ecosystem would be essential especially when we consider our exponential population growth and our negative impact to ecosystems The Alberta Tar Sands involves almost total destruction of huge areas of boreal forests and the production of toxic waste The scale of this project promises to be a major challenge for restoration