POpulations And Sustainability Flashcards
3 stages of the population growth curve
Slow growth
Rapid growth
Stable state
Slow growth - population growth curve
The small numbers of individuals tat are initially present reproduce increasing the total population.
Birth rate is higher than death rate = population grows in size
Rapid growth - population growth curve
As the number of breeding individuals increases, the total population multiplies exponentially
NO constraints act to limit the population explosion
Stable state -population growth curve
Further population growth is presented by external constraints
The population size flutuates , but overall size remains stable - usually due to limiting factors e.g. Predators
Birth rates and death rates equal
What are limiting factors
Prevent further growth of a population and in some cases cause it to decline
Abiotic factors
Non living
Temperature, light, pH, availability of o2 and h20, humidity
Biotic factors
Living
E.g. Predators, disease and competition
Carrying capacity
Maximum population size that an environment can support
Although individual years will show increases or decreases, they are often SMALL = pop size remains stable
I mmigration VS emigration
Im= into
Em= out of
Density independent factors
Factors that have an effect on the whole population regardless of its size
E..g earthquakes, fires and volcanic eruptions
Types of competition
Interspecific
Intra specific
Inter specific competition
Between different speciies
Intra specific
Between members of the same speciies
Interspecific competition - what happens ?
If 2 speciies are both competition for the same source , but ONE is more adapted - other is out competed
Competitive exclusion principle
F the conditions are the same, the less well adapted with decline in number and non longer exist in habitat adapted species
INTER SPECIFIC competition
2 specific competition for limited resources, the one that uses them more effectively will eliminate the othe
Grey and red squirrels in the UK - competition
Between red and grey squirrels for food and territory in the UK
in the 1870s the grey squirrel( native of North America) was introduced into the wild in the UK
Grey squirrels can eat a wider range of food, is larger ad can store more fat = more likely to survive
Intraspecific competition - stage 1,2,3
Stage 1- wen a resource is plentiful, all organisms have enough to I survive and reproduce- increase in pop size
Stage 2 - increased pop= more individuals that share the food or space available, resources now limited - not enough is available for all organisms to survive POplation will DECREASEin size
Stage 3- less competition exists as the smaller. Population means less organisms come pitting for same resources = more survive and reproduce = population growth
Stages 1-4 for predator prey relationships
Stag 1- increase in prey = more food for predators = increase in predator pop ( survive and reproduce)
Stage 2-increased predator pop eats more prey - they decline
Stage 3- reduced prey population can no longer sport the large predator population. Intraspecific competition for food increase= rdecrease in the size of predator pop
Stage 4- reduced predator = more prey
Limitations of predator pray graph
Often more factors influence population size
Availability of the food plants for the prey or the presence of other predators
Fluctuations in numbers may result also from seasonal changes in abiotic factors
Conservation
Maintenance of biodiversity through human action or management
Mmaintaining diversity, genetic diversity within species and habitats
Management of ecosystems - sustainable development
Reclamation
What is reclamation
Restoring ecosystems that have been damaged or destroyed e..g controlled burning ( halt succession and increase biodiversity
Preservation
Protection of an area by restricting or banning human interference
ORIGNIAL state
Sensitive resorces, easily damaged or destroyed
Visitation NOT allowed
E.g. Virgin caves
Importance of conservation- economic
To provide resources that humans need to survive and produce an income
Medicinal drugs, clothes, timber, paper
Trading
Conservation importance - social
Natural beauty enjoyed by many
Activities beneficial to Heath - relocation and exercise
Ethical - importance of conservation
Right to exist and most organisms have a role in the ecosystem
We don’t have the right to decide which organisms can survive
We have moral responsibility for future generations, to conserve existing natural organisms
A sustainable resource
A renewable resource that is being economically exploited in such a way that it will not diminish or run out
Aims of sustainability
Preserve the environment
Ensure resources are available for future generations
Allow humans in all societies to live comfortably
Enable LEDCS to develop
Creating more even balance in the consumption of these resources between MEDCS and LEDCS
Existing resources should be used more efficiently
Small scale timber production
COPPICING = Tree trunk cut close to the ground =NEw shoots form from the cut surface and mature = these shoots are eventually cut = MANY uses e.g. Fences
Rotational coppicing
Trees are only cut in a particular section until all have been coppicied , then begins in another area meaning the newly coppicied trees can grow
Maintains biodiversity, trees can never grow enough to block out light, no succession =more speciies can survive
Pollarding
SMALL SCALE
- Trunk is cut higher up = deer and other animal cannot eat the shoots as they appear
Large scale timber production
Felling large areas of forest, these are DESTROYED and will not regrow
Replant, selective cutting ( only largest trees), pest management to maximise yields, ensure areas of forest remain for indigenous people = sustainable
Disadvantage of large scale timber production
Habitats destroyed, soil minerals are reduced, soil susceptible to erosion
Trees important for binding soil, removing h20, maintaining nutrient levels through their role in the carbon and nitrogen cycles
4 ways to promote sustainable fishing
- fishing quotas
- Nets with different mesh sizes- so immature cna escape
- Allowing fishing at certain times of year = protecting breeding season a nd fish can grow to a sustainable size
- FIsh farming to maintain supply of protein food while pretending loss of wild speciies
Masai Maria
Savannah ecosystem , large mammals Livestock graving- local tribes - NOW limited to edge of reserve More cultivation Ecotourism Nature reserve
Masai Mara- balance between humans and animals
Elephants threaten cultivation ( stomp on crops), nut this has an effect on migration
Less hunting- cull excess animal but has to be closely monitored
Migration of wild= diseases for domestic animals
Population of humans increases= more homes required as well as land for cattle and agriculture
Ecotourism
Ensure tourism doesn’t exploit
Consult and engage with local communities on planned developments
Ensure that infrastructure improvements benefit local people and visitors
Terrai region of Nepal
Hot and humid in summer months, and is opposed of reptile soil, rich in plant nutrients
Has been some deforestation and monsoon flooding
Improvements in conservation, improved soil and management, increase in retail price of forestry products, employment and income generation through forest protection securing biodiversity ( community forestry groups work)
Promoting sustainable agriculture
Promoting the production of fruit and veg in the hills and mountain regions to avoid further intensification of the terai
- improving irrigation facilities to enhance crop production
- multiple cropping
- Growth on N fixing crops such not as pulses= increases the fertility
- improving fertilisation techniques to enhance crop yields- e.g. Manure
Peat bogs
A region of wet, spongy ground that contains decomposition vegetation
Ensuring that the peat and vegetation of the bog surface is as nudist routed and wet as possible
Controlled grazing. - maintain biodiversity
Removal of seedling trees ( had a high water requirement, removing h20, reducing its ability to support bog vegetation)§
Management techniques- sensitive area
Limiting areas tourists can visit Controlling movement of livestock Anti poaching measures introduced Replanting of forests and native pants Limiting hunting through quotas and seasonal bans
Galapagos -protecting Living and non living parts
Park rangers
Limiting human access
Controlling migration to /form islands
Strict controls over movement of introduced animals e.g. Pigs
Antarctica - controlling effects of human activities
- discharging waste into sea, including sewage
- hunting whales and seals
- global warming
- soil contamination
Antarctic treaty - Antarctica
Scientific cooperation between the nations
Protection of environment
Conservation of plants and animals
Designation and management of protected areas
Management of tourisme
Snowdonia national park, Wales— key purposes of park authority
Conserve and enhance natural beauty, wildlife and cultural heritage of this area
Promote opportunities for the understanding and enjoyment of the special qualities of the park
Enhance the economics and social wel being of communities within the park
Lake District, England - role of authority
Conserve the region while enabling access for many visitors each year
