1. 1 CfE Higher Biology 3.8 Threats to Biodiversity

2. 2 Key areas: 8. Threats to Biodiversity a) exploitation and recovery of populations and the impact of biodiversity. Small populations may lose the genetic variation necessary to enable evolutionary responses to the environmental change (bottleneck effect). b) habitat loss, habitat fragmentation and their impact in species richness. Habitat fragments suffer from degradation at their edges and this may further reduce their size; species adapted to the habitat edges (edges species) may invade the habitat at the expense of interior species. To remedy widespread habitat fragmentation, isolated fragments can be linked with habitat corridors allowing species to feed, mate and recolonise. c) introduced, naturalised and invasive species and their impact on indigenous species. d) climate change and its impact in biodiversity.

3. 3 Threats to biodiversity Exploitation: The over-exploitation of natural resources uses them up at a rate that is greater than they can be replaced. Fishing and harvesting are good examples of how humans can utilise natural resources for raw materials and food. However, quotas in fishing for example, are in place to protect the population of fishes from 'over-exploitation' as some species have become depleted and are at risk of extinction. Quotas are in place to allow the population to recover. Research: 1. Over-exploitation of Cod and fishing quotas that are in place. 2. The suspension placed on commercial whaling.

4. 4 Terminology Bottleneck effect: When many genes in a population are lost and the few remaining survivors struggle to adapt to changes in the environment due to lack of genetic capacity. Natural disasters like tsunamis, earthquakes and forest fires (density Independant factors) are the most likely causes. Habitat fragmentation: Human activity or geographical divides can break up habitats into 'fragments.' Species living at different parts of the fragments compete for the same resources. This is most likely caused by man utilising habitats for motorways, bridges, agriculture or housing. Habitat corridors: When fragments of a habitat have been created, a 'corridor' between the fragments to connect them can also be created. This allows species to feed, live and reproduce with less competition and more saftety. Habitat corridors don't create new habitats or increase biodiversity- they only overcome the problem of isolation created by fragmentation. Hedgerows in agriculture, motorway underpasses, or man planted forests between farms are good examples.

5. 5 Introduced, naturalised and invasive species Introduced species: Non- native species that have been introduced by humans (intentionally or accidentally) to a new geographical location. Naturalised species: Non-native species that become established in their new location in the ‘wild.’ This happens as they do not have the normal threats of predators, competitors or parasites from their natural habitat. Invasive species: Non-native species that threaten the success of native species and out-compete them from resources and may possibly show a population explosion due to this.

6. 6 Research tasks Describe the how the following non-native species found themselves in new geographical locations and the impact this had on the environment and/or humans? 1. Japanese Knotweed to Britain. 2. Lionfish in the Atlantic Ocean. 3. Grey Squirrels to Britain.

7. 7 Climate change and its impact on biodiversity Use the following slide to describe how humans contribute to climate change and how this can impact on biodiversity. Think about: Deforestation; fossil fuels; combustion; agricultural processes; greenhouse gas production; How we measure biodiversity; adaptations to climate change to match a climatic shift.

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9. 9 Modelling climate change http://www.sciencemuseum.org.uk/ClimateChanging/ClimateScienceInf oZone/Exploringwhatmighthappen/2point4/2point4point3.aspx Use the website to: 1. Explore Earths climate change. 2. Explore what might happen.... 3. Explore our future choices!