6.3.2 populations and sustainability Flashcards
What is a sustainable resource
A renewable resource that is being economically exploited in a way that 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 less economically developed countries to develop through exploiting their natural resources
- create a more even balance in the consumption of these resources between more economically developed countries and LEDCs
Sustainable small-scale timber production
Coppicing - tree trunk cut close to the ground. New shoots form from the cut surface and mature. Eventually the shoots are cut + in their place, more are produced.
Rotational - maintains biodiversity as the trees never grow enough to block out the light - succession cannot occur + more species can survive.
Pollarding - similar to coppicing. The trunk is cut higher up so deer + other animals cannot eat the new shoots as they appear.
Sustainable large-scale timber production
- Selective felling - removing only the largest trees
- Replace trees through replanting rather than waiting for natural regeneration. Helps ensure that the biodiversity + mineral + water cycles are maintained
-Plant trees an optimal distance apart to reduce competition - higher fields, more wood produced per tree - Manage pests an pathogens to maximise yields
- Ensure hat areas of forest remain for indigenous people
Sustainable fishing
- Use of nests with different mesh sizes - immature fish can escape, only mature fish are caught - allows breeding to continue
- Allowing commercial and recreational fishing only at certain times of the year - protects the breeding season + allows fish levels to increase back to a sustainable level.
- Fish farming to maintain the supply of food, while preventing the loss of wild species - some regions, fish are placed in rice fields at planting time where they grow to edible size when the rice is ready to harvest.
Interspecific competition
When two or more different species of organism compete for the same resource.
Results in a reduction of the resource available to both populations.
If one of the species competing for the same food source is better adapted, the less well adapted species is likely to be outcompeted - decline in number - competitive exclusion principle
Intraspecific competition
When members of the sane species compete for the same resource
The availability of the resource, determines the population size
Stage 1: When a resource is plentiful in a habitat, all organisms have enough to survive and reproduce - increase in population
Stage 2: Increased population > many more individuals that share the food + space available - resources are limited - not enough available for all organisms to survive = population decreases in size.
Stage 3: Less competition due to smaller population - more organisms survive + reproduce = population growth
Predator-prey relationships
All predator-prey relationships follow the same pattern
Stage 1: Increase in prey population provides more food for predators, allows more to survive and reproduce. Results in an increase in the predator population
Stage 2: Increased predator population eats more prey organisms, causing a decline in the prey population - death rate of the prey population is greater than its birth rate
Stage 3: Reduced prey population can no longer support the large predator population. Intraspecific competition for food increases, resulting in a decrease in the size of the predator population.
Stage 4: Reduced predator numbers result in less of the prey population being killed - more prey organisms survive and reproduce - increasing the prey population - cycle begins again
Conservation
Maintenance of biodiversity through human action or management - so the natural resources in them can be used without running out - sustainable development.
Reclamation - process of restoring ecosystems that have been damaged or destroyed - may involve controlled burning of areas of a forest, can halt succession + increase biodiversity
Is dynamic and needs to adapt to constant change
Preservation
Protection of an area by restricting or banning human interference so that the ecosystem is kept in its original state.
Most commonly use when preserving sensitive resources, which can be easily damaged or destroyed by disturbances.
Visitation is not allowed, except by those who monitor and manage such areas
Importance of conservation
Economic - provide resources that humans need to survive and to provide an income - rainforest species provide medicinal drugs, clothes and food that can be traded
Social - many people enjoy the natural beauty of wild ecosystems + using them for activities which are beneficial to health by providing a means of relaxation and exercise
Ethical: all organisms have a right to exist, most play an important role within their ecosystem. Many believe we should not have the right to decide which organisms can survive + which we could live without.
