S3 BGE BIOLOGY Part 1 BIODIVERSITY1I: Impact of Natural Hazards on Biodiversity

You will study the following topic at Level 4. A. Biodiversity, Ecosystems & Investigating Abiotic Factors (L3/4/5) B. Biomes (L4/N4) C. Investigating Distribution of Organisms: Sampling Techniques (L3/4/5) D. Identifying Organisms which have been Collected: Keys (L3/5) E. Interdependence, Food Chains & Webs (L4/5) F. Energy in Ecosystems - Pyramids (L5) G. Interdependence -Niche & Biotic factors (L4/5)H. Impact of Population Growth on Biodiversity (L4/5)I. Impact of Natural Hazards on Biodiversity (L4)J. Conservation of Endangered Species (L4)

L4/N4 Learning Outcomes: You should be able to… Understand that threats to biodiversity can be caused by

natural hazards.

(L4) Natural threats to biodiversity.There are many natural threats to biodiversity, these include

1. Forrest & bush fires2. Earthquakes3. Tsunamis4. Volcanic activity5. Floods

They have always taken their toll on plant and animal populations and will continue to do so in the future. These natural events have contributed to extinctions in the past. Some mass extinctions are thought to be caused by climate change or a meteor strike on Earth

1. Forrest FiresDISADVANTAGESForrest fires can be uncontrolled and violent infernos, travelling at high speeds and are capable of destroying everything in their path. The perfect conditions for wildfires include drought, heat and frequent thunderstorms. Once these fires start, they can burn for weeks and do great damage to the ecosystem that they travel through. After wild fires heavy rain can flush soot, ash and charred tree debris into rivers, this threatens the water supply and the biodiversity of water-living organisms

Level 4 Planet Earth: Biodiversity and interdependence SCN 4-01a; Topical Science SCN 4-20a I can predict the impact of population growth and natural hazards on biodiversityNational 4: Unit 3: Key Area 3.2 Natural hazards such as forest fires, earthquakes, tsunamis, floods and volcanic activity will also reduce biodiversity.

ADVANTAGESDespite the initial destruction of habitats, wildfires play an integral part in rejuvenation an ecosystem by consuming decaying matter, destroying diseased trees and related vegetation, creating conditions for new seedlings to germinate and by returning nutrients to the forest floor.

2. EarthquakesNatural disasters such as earthquakes have profound effects on the earth’s biodiversity.

Immediate effects of earthquakes include Landslides and avalanches: these can

be huge and can destroy an entire forests (e.g. pine) or villages.

Biodiversity and forest loss: Forest, plants and wildlife can be affected directly during an earth quake or after. Biodiversity can be affected due to the loss of habitat, food or water supplys.

Change to water sources: Earthquakes can cause natural springs to dry up or new ones to apperar. Changes to water flow can occur (with more or less flow). There can be changes in water quality which affects biodiversity as species compete for this essential resource.

Solid waste and hazardous materials Air pollution

3. TsunamisUnderwater landslides, earthquakes and volcanic eruptions can all cause tsunamis. A tsunami is an extremely high wave of water that moves from out at sea towards land. Because of the enormous volume of water and energy that travels inland, extended areas along the coast are immediately devastated as they strike the coastal ecosystems. As coral reefs, mangrove forests and wetlands are all dependent upon each other for nutrient supplies, the destruction of one will ultimately affect the overall coastal ecosystem. The destruction of coral reef fish populations leads to the elimination of other species that depended on them as a food source, while on land, the soil that was exposed to salt sedimentation, becomes infertile, resulting in the loss of biodiversity in the form of coastal forests and the animal life that they supported.

4. VolcanosDISADVANTAGESVolcanoes can cause lava flows and ejection of ash; however, they also trigger mudflows, avalanches, and cracks or fissures in the Earth's surface. Large-scale volcanic activity may last only a few days, but the massive outpouring of gases and ash can influence climate patterns for years. In addition,

the eruption of volcanoes and subsequent lava flow has an immediate negative effect on surrounding ecosystems and biodiversity.

ADVANTAGESVolcanic eruptions change the natural world in dramatic ways and reshapes ecosystems. As molten rock escapes the Earth it creates rock formations or mountains. In addition, the soil near volcanoes is said to be rich and fertile which is why some people actually set up home on the slopes! Certain birds (e.g. maleo birds) use the heat from volcanoes to help hatch their eggs. After volcanic activity most habitats begins the process of re-colonization almost immediately.

5. Floo ds Flooding is the unusual presence of water on land to a depth which affects normal activities. Flooding can arise from overflowing rivers, heavy rainfall over a short duration (flash floods), or an unusual inflow of seawater onto land (ocean flooding). Ocean flooding can be caused by storms such as hurricanes (storm surge), high tides (tidal flooding), seismic events (tsunami) or large landslides.

DISADVANTAGESIf a flood is large enough flood waters can wash away animals, plants and their habitats. The land animals that are left can either relocate or are forced to stand in polluted water until rescued. This may reduce the level of biodiversity, habitat potential and food present in the ecosystem, creating long-term impacts for surviving wildlife. Flooding can also directly cause riverbank erosion and sedimentation; the dispersal of nutrients and pollutants; changes to surface and groundwater supplies; and local landscapes and habitats.

ADVANTAGESFlooding is a natural ecological process that plays an integral role in ensuring biological productivity and diversity in the flood plain.