Ecosystems

• services of an ecosystem: provisional services (goods), regulating services (air quality, climate, pollution), cultural services, supporting services (soil formation, photosynthesis, nutrient cycling)
• Millenium ecosystem assessment: where the services are derived from
• sustainable management processes of the tropical rainforest:
• An ecosystem


  a community made up of biotic and abiotic components such as air, water and mineral soil.
• Biodiversity


  - variety of all forms of life on earth in terms of species (species diversity)​

  - variations within species (genetic diversity)​

  - interdependence between species (ecosystem diversity).
• Abiotic characteristics


  the non living environment
• Biotic characteristics


  living organisms in an area
• Goods


  physical materials, such as timber from trees or fish caught in a lake. (Things that are of value to us)
• Services


  functions of the biome that help serve the planet. e.g. regulating the composition of the atmosphere, maintaining the health of the soil.
• 4 categories of ecosystem good and services

  - Provisional services (goods): Products obtained from the ecosystem

  - Supporting services: Keep the ecosystem healthy so it can provide other services

  - Regulating services: Services linked to other physical systems and keep areas and the whole planet healthy

  - Cultural services: Benefits people get from visiting or living in a healthy ecosystem
• A biome


  - a large scale ecosystem

  - a large geographical area of distinctive plant and animal groups, which are adapted to that particular environment. ​

  The climate and geography of a region determines what type of biome can exist in that region. ​

  A world map of biomes tends to be a map of the world vegetation zones and the distribution of zonal soils.
• TROPICAL RAINFOREST


  - Hot all year round​

  - 500-1000mm of rainfall per year​

  - Dense forest made up of several - - distinct layers​

  - High in biodiversity​

  - Found around the equator
• TEMPERATE / DECIDUOUS FOREST


  - Forests in cool, rainy areas​

  - Trees that lose their leaves in autumn (deciduous)​

  - Four distinct seasons​

  - Found in the middle latitudes - in the UK!
• BOREAL / TAIGA / CONIFEROUS FOREST

  - Cold woodland or forest​

  - Cold, harsh climate, with low rainfall​

  - trees do not loose their leaves in autumn (coniferous)​

  - Canada, Finland, northern Russia
• TROPICAL GRASSLAND


  - Also known as a Savannah​

  - Plains of grass​

  - Hot, seasonally dry, with a rainy season. ​

  - Large mammals like zebras, gazelles and lions
• TEMPERATE GRASSLAND


  - Plains of grasslands​

  - Hot summers, cooler winters​

  - Large mammals like antelopes and bison​
• HOT DESERTS


  - They cover 1/5 of the Earth's area​

  - Harsh environment with very little rainfall​

  - Extreme temperatures​

  - Defined as an area of <250mm of rainfall​​
• TUNDRA


  - Cold​

  - Treeless​

  - Coldest biome​

  - Very little rainfall​

  - Found towards the extreme north and south.
• latitude


  is a geographic coordinate that specifies the north-south position of a point on the Earth's surface.

  
• Thermohaline circulation


  Thermohaline circulation is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes
• Gulf stream


  - The Gulf Stream is a warm ocean current driven by westerly winds.​

  - It begins in the Gulf of Mexico then blow North East ........where it heads to Europe to become the North Atlantic Drift.
• ocean currents


  - Ocean Currents are surface movements of water, they are caused by prevailing winds. ​

  - Warm currents take water from tropical areas towards the poles. ​

  - Cold currents take water back towards the equator.​

  - They move heat energy around the globe. ​

  
• Factors affecting climate


  - Prevailing wind direction

  - Latitude

  - Ocean currents

  - Sea (distance from)

  - Height (altitude)
• energy transfer


  - An ecosystem depends on two processes: Energy transfer and nutrient cycles

  - Energy cannot be destroyed. It simply changes form

  - Energy is passed through an ecosystem from one element to another.

  - ​At each trophic level, some energy is available as food for the next level

  - Each level decreases in size, 90% of energy lost through life processes-respiration, movement and excretion

  - Only 10% available as food, number of living organisms decreases as trophic levels increase

  
• inefficiency of energy transfer


  No energy transfer is 100% efficient. Energy is lost through respiration, the decay of dead organisms and excreta within each unit of the food chain. Also, heat is given off when energy is passed from one trophic level to the next.​

  Consequently, at each higher level, fewer organisms can be supported than at the previous level, even though their size generally increases.​

  Simple food chains are rare. There is usually a variety of plants and animals at each level, forming a more complicated food web. This range of species is necessary since a sole species occupying a single trophic level in a food chain could be 'consumed' this would adversely affect organisms in the succeeding stages.
• the suns energy


  - Heat energy: cannot be captured, but warms up communities and surroundings​

  - Light energy: captured by green plants and transformed into chemical energy through photosynthesis
• the nutrients cycle


  - Fixation is the process where bacteria convert nitrogen in the air into a form that is used by plants.​​

  - Mineralization is a biological process in which inorganic substances are converted to organic substances by soil microorganisms.​​

  - Leaching is the downward movements of minerals to groundwater stores. ​​

  - Photosynthesis.​​

  - Organic matter is the key driver in the nutrient cycle.
• gersmehl


  - Soil is the top layer of the earth that is composed of disintegrated rock particles, humus, water and air.​

  - Litter is organic matter in and on the soil, it includes humus and leaf litter.​

  - Biomass is the total mass of living organisms, mainly plant tissue, per unit area. It is a store of energy and is also know as standing crop.

  
• NPP


  The two main factors that contribute to the NPP of a biome are:​

  - P to E ratios (Precipitation to Evaporation) ​

  - how far away from the equator they are located (and therefore their proximity to the sun).
• measures of biodiversity Richness

  The number of groups of genetically or functionally related individuals. In most vegetation surveys, richness is expressed as the number of species and is usually called species richness.
• measures of biodiversity Evenness


  Proportions of species or functional groups present on a site. The more equal species are in proportion to each other the greater the evenness of the site and therefore the more bio-diverse. A site with low evenness indicates that a few species dominate the site.
• why biodiversity is good

  - benefits from a mixture of plants:​

  - soils improve with nitrogen fixers, deep rooted plants bring nutrients up from soil layers below other plants roots.​

  - some species work together so that both can survive (called commensalism) and therefore, diverse communities can be more stable.​

  - diverse plant communities generally have all niches filled and are theoretically less likely to be invaded by noxious or opportunistic introduced species

  - Providing forage for a variety of insect and vertebrate species.​

  - Stability resulting from plants in the community that are able to survive drought, insect plagues, and/or disease outbreaks so that the site will have some soil protection/forage/etc. in those years.​

  - Plants containing a variety of genetic material that may be useful in long-term survival and stability of the community.​
• Direct Threats


  Relate to either physical or human actions that cause immediate harm
• Indirect Threats


  Actions that consequently cause harm. For example climate change.
• impact of climate change

  - Flowers in the UK now often have a second 'spring' in autumn as a reaction to warmer temperatures.

  - Early droughts in Europe are reducing toad and frog populations as ponds and other water bodies disappear.

  - As sea levels rise, this is having a negative impact on coral reefs, which cannot survive in deep water.

  - Increasing the frequency and extremity of El Nino - reduction in stocks and variety of fish in Peru.

  - 80% of the remaining ancient woodlands in England and Wales are individual pockets of less than 20 hectares.
• invasive species examples


  - Some have been introduced accidently, some on purpose.​

  - Purple Loosestrife (Purple peril) European wildflower taken to the USA. Spread to all but the Desert states, invades and kills off habitats by outgrowing native species. ​

  - New Zealand - brushtail possum is an ecological nightmare. Protected in Australia, in New Zealand it has no predators. Each night the estimated 70 million possums eat 21,000 tonnes of vegetation.
• impact of pollution


  - New chemicals to the environment added by humans.​

  - Fertilisers containing phosphorus and nitrogen. ​

  - Eutrophication = dead zones in oceans and freshwater ecosystems. ​

  - DDT used to kill mosquitos = effects of it amplified further up the food chain affecting top predators. Ospreys laying thin eggs. ​

  - Acid rain also an issue especially in boreal forests in Sweden Norway Germany and Poland.
• impact of overexp


  - Logging, Hunting and Fishing​

  - Otters hunted to extinction and the sea urchins the otters eat feed on the kelp. Numbers explode and kelp forest destroyed if not kept in check by the otter predators. ​

  - 1 billion people dependent on fish as main source of protein - led to overfishing. Increase in catch and bycatch = lowering of biodiversity. Newfoundland
• Ecosystems most at risk: Coral Reefs


  - Direct: Dynamite fishing, coral mining, unsustainable tourism, pollution, sediment from de-vegetated slopes and damage from boat anchors.​

  - Indirect: Climate change / Ocean acidification - Coral bleaching.
• Ecosystems most at risk: Tropical Rainforests


  - Deforestation for food, minerals, timber and population pressure.​

  - Holds 50% of world biodiversity, so impact is more acute. Land is easily degraded.