Ecosystems Flashcards
Ecosystem
The interrelationship between communities of plants and animals and the environment in which they live. A balance between abiotic and biotic environments - inputs, outputs, store and flows.
Biome
A large-scale ecosystem such as tropical rainforests or savannah grasslands that are closely allied to climate regions.
Biomass
The total dry mass of all living organisms in a particular ecosystem including plants, animals and microorganism.
Nutrient cycling
The transfer and recycling of plant nutrients between biomass, litter and soil stores. (nutrient uptake by plants, leaf tissues die and fall, nutrients released as litter decomposes to humus)
Inputs
Weathered rock - soil
Dissolved in rain - litter
Outputs
Loss through leaching - soil
Loss through run-off - litter
Reducer organisms
Detritivores (worms) and decomposers (bacteria)
Energy pyramids
90% energy lost at each trophic level due to respiration, movement and excretion and inefficiency at each trophic level - fewer organisms can be supported at each higher trophic level.
Vegetation succession
Progressive development of vegetation community in an environment
Sere
Each stage in a vegetation succession
Climatic Climax Community (CCV)
A state of perfect adaptation to and in equilibrium with the environment at that time - final seral stage
Primary succession
Happens on surfaces that have never had any vegetation growing on them eg bare rock exposed by retreating glaciers
Secondary succession
Happens on surfaces that have once been colonised by vegetation by have since been changed or destroyed eg deforestation
Pioneer community
The first sere of a vegetation succession - hardy to the elements
Dominant species
The main species at each stage or sere in the vegetation succession
Plagioclimax community
Plants whose development is held in check by human intervention eg grazing livestock or burning heather moorland preventing the natural climatic climax being reached
Subclimax community
Vegetation does not reach its climatic climax as a result of interruptions by natural, local factors eg soil changes or flooding
Arresting factor
An interruption that stops a climax community from being reached
Lithosere succession and example
eg Isle of Arran raised beach
- Areas of bare rock will initially be colonised by blue-green bacteria and single-celled photosynthesisers which have no root system and can survive where there are few minerals and nutrients - autotrophs.
- Lichens and mosses also make up the pioneer community. These plants are capable of living in areas lacking in soil, devoid of a permanent supply of water and experiencing extremes in temperature.
- Lichens and various forms of weathering help to break up the rock to form a veneer of soil in which more advanced plant life can grow. As they die, bacteria convert plants to humus, creating a richer soil.
- Seeds, mostly of grasses, then colonise the area. As these plants are taller, they replace the lichens and mosses as dominants - although mosses and lichens still continue to grow.
- As the plant succession evolves over a period of time, the grasses will give way as dominants to fast growing shrubs.
- The fast growing shrubs will be replaces by fast growing trees eg Rowan
- These will eventually face competition from slower growing trees eg Ash and finally Oak - CCV
Temperate deciduous woodland location
40-60 degrees North and South of equator
Temperate deciduous woodland climate
Wide climatic variation - influenced by warm and cold air masses - very changeable weather patterns.
East seaboard and continental +/- 30 degrees C
West margins warmer winters (5degrees) and cooler summers (18degrees)
Long daylight in summer, short daylight and low LI in winter
Precipitation all year - snow in winter, distance from sea influences
+120 days long warm growing season - >5 frost free months
Extreme weather rare
Temperate deciduous woodland characteristics
Stratification - tree canopy, shrub layer, field layer (bracken, ferns and grass) and ground layer (moss and lichen).
Large tree crowns with broad, thin leaves to capture sun and prevent leaching
Thick bark to insulate against winter temps
Leaf fall to prevent frost bite damage, reduce water loss, reduce SA to prevent branches being broken by heavy snowfall
Winter dormancy to reduce transpiration and moisture uptake in frozen soils
Deep, wide roots to maximise soil moisture capture
Has a high productivity due to temperate climate - enough rain/sun for trees and plants to photosynthesise
Most had been cleared for farming due to great soil potential. Only small pockets (
Temperate deciduous woodland soil
BROWN EARTH SOIL
Deep, well-drained, fertile
Well-mixed and aerated by earthworms and rodents
Decomposers break down leaf litter - rich humus
Little nutrient leaching due to tree canopy
Acidic soil idea for plant growth
Efficient nutrient cycling - annual leaf fall rich in nutrients for deciduous tress (decomp slow in winter)
Heather moorland formation
Was once deciduous woodland
Cleared for farming
Soils deteriorated due to naturally efficient nutrient cycling broken - exposing to heavy upland rainfall - soils eroded and leached - thin, acidic, less fertile, peaty podsol
Upland areas then colonised by hardier plants - bracken and heather (moorland vegetation)
Heather moorland management
Carefully controlled by burning on a 10-15 year rotation - 6 patches within 1km2
Keeps as much of the moorland as possible in the most productive, building phase and the amount of edible green shoots at its highest to provide feeding and breeding areas for grouse - unburnt nesting cover.
Tropical rainforest biome location
Within the tropics - 20 degrees north and south of the equator
Tropical rainforest climate
Low diurnal temperature range
Average daily temperature 28 degrees
Rarely falls below 22 degrees at night, while cloud cover restricts daytime temperature to 32 degrees or lower
Annual temperature range = 2 degrees - year round growing season - no defined seasons - insolation evenly distributed throughout year > each day has 12 hour daylight
High humidity - rapid evapotranspiration from swamps, trees and rivers creates a sticky oppressive heat.
High annual rainfall - warm, moist and unstable air forced to rise at inter-tropical convergence zone > daily convection storms > 2000mm/yr
Tropical rainforest characteristics
Most productive biome on the planet - ideal climate and growing conditions > rich biodiversity - almost 50 million species of animals and 480 species of tress per hectare
Permanent green landscape - deciduous trees but all-year growing season means leaf fall can happen any time of the year.
Constant fight for sunlight = stratification: forest floor, shrub layer, understorey, canopy and emergent layer
Tropical rainforest soil
IRON-RICH LATERITE SOIL
Rapid chemical weathering due to hot and humid climate - perfect conditions for rotting and breaking down of leaf litter.
Very fragile - continuous leaf fall for nutrients and thin humus layer.
80% nutrients originate from vegetation - nutrient cycling very efficient
If vegetation is removed, heavy rainfall causes nutrients to leach and fertility of soils is lost
Biomass = largest store
Litter store = limited due to high climate
Plant adaptations in the tropical rainforest
Small herbs with large flat leaves to capture as much sunlight as possible > 1% reaches forest floor
Thick buttress roots rising up to 2m above the forest floor to spread weight of tree. Stilt or prop roots point downwards from main trunk for support - especially in marshy ground
Slender and less substantial trees in understorey are more shade tolerant - only receive hazy light through canopy
Gap between understorey and canopy trees allows understorey to receive a more even spread of sunlight and avoid shadow
Huge mushroom shaped crowns of canopy trees creates and enormous photosynthetic surface - most productive
80% canopy trees grow drip tip leaves to help them shed excess water quickly
Emergent trees are hardy to the elements and have thicker non-drip tip leaves as moisture is soon evaporated
Animal adaptations in the tropical rainforest
Strong, large and lightweight toucan bills to open fruit and crack seeds
Hands and feet cling to branches eg toucan, sloth, tree frogs
Tails to balance in canopy eg spider monkey
What is a symbiotic relationship?
Two species depend on each other for pollination and food eg Euglossine orchid bees pollinate Brazil nut trees - cannot reproduce without specific bees
Reasons for deforestation in the tropical rainforest
- Space for farming and settlements > traditional slash-and-burn wasteful of space, cattle ranching causes soil erosion and low quality meat for TNCs in HICs, plantation of cash-crops - oil palm and soya bean
- Logging for timber > hardwoods for HICs eg mahogany
- Mining of bauxite, iron ore, tin, copper and lead > accessible once forest is cleared - open cast mining eg Carajas
- Road construction supports development of rainforest for other uses > people in and raw materials out eg Trans-Amazonian Highway 6000km and most roads illegal
- Hydroelectric power cheap and plentiful renewable energy > reservoirs flood large areas eg Maderia river
- Settlement growth - population increases - ‘growth corridor’ roads
Economic impacts of human activity on the TRF
Corruption, poor governance and inadequate law enforcement frequently means that locals are exploited and economic benefits of deforestation rarely get to those in most need
Government gives land to those better off and sidelines smaller growers living in harmony with the forest
Foreign transnationals - agribusinesses - also have a large presence
Environmental impacts of human activity on the TRF
20000 tropical equatorial rainforest species become extinct every year
Fragile soils exposed to heavy rainfall causes rapid soil erosion and leaching
Silted watercourses leads to localised flooding
Carbon sink - 20% CO2 released/year > enhanced greenhouse effect
Migrants lack knowledge of successful shifting cultivation
Social impacts of human activity on the TRF
Deforestation clears physical environment, social cohesion, language traditions and culture of Quichua Indians of Tena, Ecuador
Settle along roads - new settlers = heath threats
Impacts of human activity on the TRF case study 1: Cargill
A large US transnational food, agricultural, financial and industrial agribusiness employing 138000 in 67 countries
2009 profits over $3.3 billion
‘Commit’ to: Conducting business with integrity and responsibility, to reduce environmental impact, conserve natural resources, treat people with dignity and respect and invest and engage with communities with which they work.
Soya production around Santarem: 28000 hectares deforested 2002-2004, 10% deforested for soya - feeds animals > cheap meat for Europe > 50% plantations in Mato Grosso
Cargill port at Santarem built in 2003 > export of Soya. Man farmers moved causing conflict with locals and concrete paving of BR-163 highway
Brazilian government justification: 0% deforested for soya in 4 years > punished by NGOs; 0% deforested in the next few years for livestock > satellite monitoring and take away from farm if deforested.
Alley-cropping
The planting of fast-growing saplings of hardy trees eg Inga, in rows.
After 18 months, the canopy is shaded with alleys, killing grass and weeds.
Trees cut and decomposing mulch returns nutrients to soil.
Less common than slash-and-burn as more expensive (Inga trees), takes 18 months, uses up that could be used for soya and education needed.
Impacts of human activity on the TRF case study 2: Batwa Pygmies, Uganda
1992 Bwindi Impenetrable Forest and Mgahinga forest reserves = national parks
Access restricted to protect biodiversity
Tourist industry encourages economic development > negative impact on local tribes - excluded from government decisions and some communities evicted eg Batwa pygmies tribe forced to settle in fringes of existing settlements but ill-prepared for life eg used to hunting in forest, but now no land so have to work to buy local food.
Have become a tourist attraction due to colourful culture.
New sustainable community based projects > Batwa trail
Money raised put back into local pygmy community eg health + education
Impacts of human activity on the TRF case study 3: Sepilok Orang-utan rehabilitation centre, Borneo
Orang-utan numbers have declined > human activities in their native environment
Pressure of development led to 80% loss of habitat in the last 20 years
Deforestation and poaching (for pets) responsible
Centre set up in 1964 to care for orphaned, sick or injured orang-utans
No boundary fences > 80 free to return to wild any other time
Other endangered species eg sunbears taken in
A model of sustainable tourism - visitor access restricted to walkways and can’t touch apes
Sepilok centre for research and education has a global awareness
Urbanisation
The increase in the % of the population that live in towns and cities
Ways in which human activity affects ecosystems
Ecosystems are rapidly changing due to human activity > climate, water supply, air quality
- Water, air and land pollution > waste matter, chemicals and heavy metals > stunts plant growth - only tolerant survive
- Compaction of soil > buildings, foundations, transport > restricts free drainage - water logging and limited soil aeration
- Acidification of soil > acid rain > reduces availability of nutrients
- Creation of watertight surfaces > tarmac roads, concrete > limits soil moisture storage, soil depth and root growth
- Increased in planned vegetation > recreational parks and gardens > non-native invaders
- Buildings > homes, offices, warehouses > provide shelter and shade
Urban niche
A specialist urban habitat > such as around neglected buildings and on wasteland
Colonisation of wasteland succession and example
eg Abandoned Sheffield ski village
- Pioneer species eg lichen and mosses colonise bare surfaces with little soil, moisture of nutrients
- Death of pioneer species adds humus and moisture to soil > seed plants can grow in surface cracks of sheltered locations > moisture available eg Oxford Ragwort, Rosebay willow herb
- Tall herbs eg bramble and hawthorn outcompete smaller species where soils are richer in nutrients
- Taller grasses and bushes eg holly thrive in deeper fertile soils
- Rarely reaches CCV > eyesore and usually redeveloped
Planned invaders
Frequently introduced by gardeners eg for decoration or erosion control
Unplanned invaders
Carrier by animals, birds and the wind. Invasive non-native species not always indigenous to Britain eg Japanese Knotweed brought into the country in Victoria times and has doubles its coverage in the last 20 years in London alone.
Influences on the colonisation of wasteland
Slope Moisture availability Aspect Porosity Surface roughness Pollution levels
Protosoil
The beginnings of a soil (humus)
Ruderal species
Able to tolerate waste ground, rubbish and debris eg Oxford Ragwort and dandelion
Ecosystems along roads and motorway verges
Highways Agency plants grass seed and flower meadow seed, trees and shrubs eg Maple and Beech to screen and deaden noise
Invaded by other species from windblown seeds from surrounding areas, traffic or birds
Halophytes found due to salt spreading in winter > up to 6 months eg Danish Scurvy grass and Sea-Spurrey found on M5
Nitrogen-rich exhaust fumes boost growth of some wild flowers > insects and animals - reduced by mowing
60 sites of Special Scientific Interest along roads - butterflies and small mammals = distinctive ecosystems
Ecosystems along railway lines
Windbourne seeds sucked along by trains eg Oxford Ragwort
Lack of human interference > fenced off > encourages wildlife and nesting cover for birds
Ecosystems along canals
Act like ponds > aquatic plants eg Yellow Flag Iris, Waterfowl - moorhens, ducks and kingfishers, and water loving insects eg dragonflies and damselflies
Ecological Conservation Areas and what they do
Areas of notable environmental interest or importance which is protected by law against undesirable changes
Encourages wildlife back to cities
Make cheap use out of an otherwise derelict area - parks more expensive
Reduce maintenance costs in the area with informal, volunteering work planting, dredging and improving (groups and organisations involved)
Maintain diversity
Ecological conservation area case study: Troopers Hill > locations etc
1956
1km East of Bristol City Centre, North of River Avon
Owned and managed by Bristol City Council but locals also involved
Provides an area of recreation
Ecological conservation area - conserves special ecosystem with several rare species
Jan 2007 new management plan > 5 years, renewed annually
Hillside facing S+W > uneven plateau top
Uneven and steep due to extensive work for minerals (copper and sandstone) led to poor soils and bare rock
Sandstone = acidic soil, rest of Bristol = limestone = alkaline
Ecological conservation area case study: Troopers Hill > What is done to conserve
- Acid Heath and grassland > poorest soils but most important habitats. Only ling and bell heather allowed. Some cut back to encourage regrowth and new seedlings
- Flower meadow > most fertile soils with grasses and flowering plants eg Petunia. Mowed annually in late June and July to allow flowers to bloom and seed before cutting. Limits nutrient content of soil but encourages flower growth
- Trees > no huge trees due to previous industrial use. Most arrived through natural regeneration but only native trees allowed eg oak - non-native removed when young. Gives privacy to adjoining properties, shelter for birds and screens adjacent allotments
- Scrub > a transitional landscape between grassland and woodland - scattered bushes in grassland to closed-canopy vegetation dominated by shrubs and tree saplings less than 5m tall. Spaces maintained between woody plants. If not managed, spaces may disappear and some herbaceous species will be lost and diversity may diminish. But no natural succession.
- Invertebrates > butterflies, crickets and grasshoppers. Local rarities and endangered species eg mining bee, preserved species by maintaining habitat
Negative human influences on the environment
Global warming > climate change > loss of habitats and species Destruction of natural habitats Loss of biodiversity Unsafe water supplies Soil erosion Loss of wild foods (especially fish) Fossil fuel combustion > pollution Toxic chemicals World population growth > limited resources > 9.2 billion by 2050
Fragile environment
An environment that lacks resilience to change in conditions i.e. is vulnerable to change e.g. human activity, foreign species and natural eg flooding and drought
Fragile environments case study 1: Central Amazon Conservation Complex > Location etc.
N/NW of Manaus with watershed of East Rio Negro
More than 6million hectares
Links Jau National Park, Mamiraua Sustainable Development Reserve Focal Zone and Amana Sustainable Development Reserve
2nd largest area of protected rainforest in the world
Sparsely population - a few live close to rivers in small settlements > Ameridians traditionally cultivate small plots of land and collect meat, fish and fruit from the forest > trade in forest products
No major human activity projects affecting the area and little tourism due to isolation = little outside development pressure
Diverse range of wildlife: endangered species eg Puma, average 180 tree species per hectare, nearly 200 mammal species (over 100 species of bat), over 500 bird species and over 300 fish species.
Fragile environments case study 1: Central Amazon Conservation Complex > Management
MANAGEMENT:
3 main functions:
1. Protect land and minimise impact of human activity
2. Research, catalogue and protect biodiversity
3. Manage specific activities eg tourism
Carried out by zoning:
1. Primitive > most protected
2. Extensive use > a little activity
3. Intensive use > previous activity must be sustainably managed
4. Special use > core activities
Fragile environments case study 2: Serengeti > Location and problems
Savanna grassland covering 30000km2 in Tanzania and SW Kenya
PROBLEMS:
1. Hunting and poaching > sport, food, ivory, rhino horn; 1970s and 1980s black rhino population down to 2; 1989 ban on international trade of ivory - still hunted illegally for meat
2. Population increase > land use conflicts - settlement, crops and grazing; colonisation and farming = habitats lost; increased hunting
3. Fire > uncontrolled fires can damage trees and destroy roots - can’t grow back; controlled fires prevent woodland growth, burn off dead grass and allow new shoots to grow
4. Invasive species > eg Mexican Poppy outcompetes native plants and crops - some areas unsuitable for framing; animal species can spread disease eg 1994 canine distemper virus from domestic dogs to 1/3 Serengeti lions and killed them
Fragile environments case study 1: Central Amazon Conservation Complex > Success
SUCCESS:
- Protects surrounding area from major developments
- Improved biodiversity eg Black Caiman population increased by 100% and Piraucu fish by 300%
- Sustainable activities promoted
- Poverty reduced > average household income increased 50-99% > local farmers and craftsmen joined producer’s association allowing them to sell goods directly to buyers without commission
- Ecotourism provides income and promotes conservation
- Local education and health improved > 53% drop in infant mortality, 80 teachers trained to educate about environment = 1800 children
DIFFICULTIES:
- Large and understaffed so difficult to monitor and control illegal activities
- Restricting access is difficult > relies on volunteers
- Population growth is a problem - intensive fishing and hunting
- Deforestation continuous around the edges = habitat loss and fragmented - becomes more accessible = increase in hunting and fishing
Fragile environments case study 2: Serengeti > Management
1951 Serengeti National Park 15000km2 Tanzania
- Aerial wildlife surveys, water quality monitoring and invasive species monitoring
- Protection of priority species eg anti-poaching patrols for black rhino population
- Disease monitoring and vaccination programmes - domestic dogs living near park vaccinated against rabies and canine distemper virus
- Controlled burning stops a build up of dry grass, preventing wild fires
- Conservation education projects > supports 74 conservation clubs in primary schools and teacher training involves locals
- 4 Wildlife Management Areas (WMAs) created > community based conservation approach eg Ikona community WMA 450km2 - 5 villages use resources sustainably
- Tourism brings money with strict regulations eg driving only in permitted areas and access only at certain points
Fragile environments case study 2: Serengeti > Success
SUCCESS:
- WMAs food source, income and reduce illegal poaching
- Poaching declined > elephant population 550 in 1990 > 2100 in 2011 > increased ranger presence
- Money from tourism goes back into National Park to pay for conservation projects > creates jobs and a market for locals
- Disease monitoring prevented outbreaks of disease eg 1996 Rinderpest didn’t enter park > cattle vaccinated close to park
THREATS:
- Human population still growing > more farms and settlements = conflicts?
- Reluctancies for WMAs - what will they gain? Some areas still exploited
- Outside WMAs, poaching is still a problem > 40000 killed each year
- Tourism has a negative impact > road construction, vehicles, planes, pollution, waste disposal (pests), disturbance and distress of animals and an increased demand for water = water shortages
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