3.5: Biodiversity under Attack pg. 92 Extinct: no longer existing on Earth. There are 180 chameleons in this world. 59 different species are only found on the Island of Madagascar. The habitats for chameleons on Madagascar are being destroyed through forestry practices. This will lead to a number of species dying off. Biodiversity Hotspots Area with a large biodiversity, are known as biodiversity hotspots and are found in natural undisturbed ecosystems where many home species rarely seen outside of the ecosystem. There are 25 identified hotspot areas found on Earth, and Madagascar is just but one. Most of these hotspots are threatened by human encroachment and activity. The removal of trees destroys animal habitats, pollution by chemicals; such as, industrial waste or fertilizer reduces water quality, threatening aquatic organisms. Strip mining destroys habitats and removes vital resources important terrestrial organisms. Humans need to take extra care to preserve these hotspots to keep the healthy and sustainable. The Range of Biodiversity in Ontario The greatest biodiversity is found in the tropics and decreases as you move towards the poles. Ontario, have more species in the south and fewer species in the north. Humans populate areas in the same manner based on habitat and food availability. Humans are a greater threat to southern Ontario then the north. - More natural ecosystems are cleared for farming, housing, or road construction. - More pollution I created, which can damage ecosystems and the organism that live in them. Species at Risk Biodiversity is threatened by the extinction of organisms, biodiversity decreases. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) is responsible for monitoring the status of species. The governments, universities, other agencies and Aboriginal groups make up the committee, and they use collected data on existing species to monitor and group species into four categories; special concern, threatened, endangered, extirpated, and extinct. Species Extinction Natural catastrophes or gradual changes to habitat and climate can lead to species extinction if they fail to adapt to their new surroundings. Human Activity and Extinction Rates Human activity is the greatest threat to species, and it occurs over a relative short period of time. Organisms have no time to adapt. Humans disrupt ecosystems; exploit new species as they are found. When humans reached North America 10 000 years ago 80 species were soon extinct; sabre-tooth cat, mammoth, and stellar’s sea cow. Figure 4: Of the 167 species a risk in Ontario’s deciduous forest, 4 species are extinct, 13 are extirpated, 72 are endangered, 39 are threatened, and 39 are of special concern. Species at Risk in Canada There are still species becoming extinct during our lifetime, Blanding turtle is threatened by habitat loss and needs to be protected. Polar bears are of a special concern due to melting sea ice and green house gases increasing the Earth’s temperature. Over 700 species of vertebrates have become extinct in the last 4000 years, 12 were from Canada. Still there are 167 species are at risk (extirpated) of becoming extinct in Ontario’s deciduous forests. Reasons to Protect Biodiversity Ecosystem with high biodiversity are healthy and more stable, therefore it is important to protect them. - ensure ecosystem stability and sustain all life forms. - Provide natural processes to produce oxygen, carbon dioxide, and nitrogen that protect our planet. - Help species adapt to changes in their environment. - Provide raw materials for food, clothing, and medicine. - Enhance our quality of life by adding variety to our surroundings. - Help shape our culture and inspire poets, painters, and writers. Species at Risk Classification Definition Special concern May become threated or endangered b/c of various factors Likely to become endangered if no action is taken In immediate danger of becoming extirpated or extinct No longer exists in the wild in a specific area No longer exists on Earth Threatened Endangered Extirpated Extinct Number Examples of species (2009) Polar bear, great blue heron, Atlantic cod 160 145 244 23 13 Humpback whale, wood bison, Kentucky coffee tree Barn owl, swift fox, northern cricket frog Paddlefish, grey whale Great auk, passenger pigeon, sea mink Check Your Learning: Questions 1 – 10, pg. 95 Wrap Up: - Biodiversity hotspots are under attack by human activity. - COSEWIC categories at risk species as extirpated, endangered, threatened, or of special concern. - Extinction rates have increased due to human disruption of ecosystems. - Protecting biodiversity ensures ecosystems stability ad sustains all life forms.