M6, C24 Populations and Sustainability Flashcards
define conservation
the maintenance of biodiversity through human action or management
define preservation
protection of an ecosystem by restricting or banning human interference
define sustainability
Using the Earth’s natural resources in a
way which preserves the environment and
ensures the resource is available for future generations.
what are the benefits to being sustainable
It helps to prevent finite resources being used up too quickly
Aims to allow humans in all societies to live comfortably, creating a balance between MEDCs and LEDCs
what is coppicing
Tree trunk is cut close to the ground
New shoots can form from the cut surface and mature
what is rotational coppicing
Woodland divided into sections.
One small area is coppiced at a time.
You move on to different areas until the first area has re-grown and ready to be re-coppiced
what is pollarding
Trunk cut higher than in coppicing
Prevent animals eating new shoots
how can large scale timber production become more sustainable
Involves clearing large areas Can be made more sustainable by….. Selective cutting - only cutting largest trees Replanting trees Planting trees at a good distance apart Killing pests + pathogens
describe the ecosystem of Masai Mara
Savannah (grassland)
Divided by the Mara river
-Fertile regions close to the river = rich grassland + woodlands
-Further from the river = open plains, with scattered scrubs and trees
Famous for the annual zebra and wildebeest migration
The region was dominated by the acacia bush
Also home to the tsetse fly which carries African trypanosomiasis (sleeping sickness)
Many acacia bushes have since been removed to stop the spread
how does cultivation work in Masai Mara
Grassland converted to cropland
Natural vegetation is removed
Nutrients in the soil are used up
Leads to a reliance on fertilisers to grow crops
what is ecotourism
what does it aim to do
tourism directed towards natural environments, to support conservation efforts and observe wildlife
It aims to
-reduce the impact tourism has
-Ensure tourism doesn’t exploit the environment
-Consult + engage local communities
-Ensure infrastructure benefits locals + visitors
Repeated use of hiking trails, mechanical transport is contributing to soil erosion and habitat change
how is conservation and research being used in Masai Mara
An active conservation and protection programme was established
They’ve employed reserve rangers and provided communication equipment, vehicles and infrastructure
This has deterred the poachers from entering
eg. Black rhino are endangered due to poaching for the horn – they are on the IUCN critically endangered list
What balance is created in Masai Mara between the growing population and conservation
Elephants trample on crops and grazers feed off them so land is fenced off but this threatens natural migration
Legal hunting culls excess animals which maintains the population but numbers have to be constantly monitored to balance the ecosystem
Migratory wildlife threatens livestock as they compete for food but disease spreads as both species eat the vegetation
Human population is increasing which means more land is needed for housing but this leaves less land for wildlife
what are virgin caves
an example of preservation
humans can’t enter these newly discovered caves
they’re sensitive so humans walking around them would affect them
how is grazing controlled in Masai Mara
- tribes used land for livestock grazing
- tribes move depending on climate or presence of tsetse fly
- allows vegetation to recover
- grazing is limited to the edge of the reserve as local tribes can’t enter park
- populations have grown in size so herds are larger and more trees have to be removed for fuel
- vegetation is removed, risk of soil erosion increases
what are the pros and cons of ecotourism
pros: educational, profit, employment, aesthetically pleasing, protection of areas and sustainable
cons: soil erosion, damaging environment, expensive
give two reasons why a population would increase and two reasons why it would decrease
increase: births, immigration
decrease: deaths, emigration
define limiting factor
an environmental resource that limits population growth
what are abiotic factors of population size and give some examples
non-living factors that affect population size
air water light wind humidity inorganic nutrients soil pH temperature salinity (salt)
what are biotic factors
give some examples
living factors that affect population size
other organisms competition predation symbiosis - mutualism and parasitism disease
how do you work out population growth as a percentage
(population change during period / population at the start of the period) X 100
what is the percentage increase of the world population from 5,306,425,000 habitants to 6,895,889,000?
(6895889000 - 5306425000) / 530642500
X100
= 30.0%
describe the features of a graph showing the population growth (3 parts)
1) slow growth (lag) - there are few widely dispersed individuals. limits sexual reproduction as mates are hard to locate
2) rapid growth (exponential) - population grows at its maximum rate, its biotic potential. birth rate is higher than death rate and there is little competition
3) stable/no growth - population reaches maximum size that its ecosystem can sustain. This is called the CARRYING CAPACITY (k) where the population remains roughly stable
define carrying capacity
maximum population size of the species that the environment can sustain indefinitely, given that food, habitats, water and other necessities are available in the environment
define ecosystem
A biological community of interacting organisms and their physical environment
describe the Tarai region of Nepal
- Hot and humid
- Fertile soil, rich in plant nutrients
- High biodiversity
- Many plants such as pipal and bamboo
- Large areas of thick forest
- Contains the Bengal tiger, sloth bear, Asian Elephant and Indian Rhinoceros
how does the Tarai region in Nepal use sustainable forest management
national legislation
local groups which set harvesting rules, set rates and prices and determine how income is distributed
aims to provide livelihood for local people, conserve forest and provide income for development
in Nepal, what are the successes of community forestry groups (6)
- increased area and improved density of forests
- improved soil and water management
- increase in retail price which means greater economic growth
- employment and income generated through non-timber products produced
- sustainable wood fuel sources which 3/4 of household energy comes from
- securing biodiversity
in Nepal, how do they promote sustainable agriculture (6)
- promote production of fruit&veg in the hills to avoid further intensification
- enhance crop production by improving irrigation facilities (moving water from area to area)
- growing more than one crop on a piece of land (multi-cropping
- enhance fertility of the soil by growing nitrogen-fixing crops
- growing crop varieties resistant to various soil, climates or biotic challenges (biotechnology and genetic engineering)
- enhancing crop yields by improving fertilisation techniques (using manure to improve soil)
describe an ecosystem of a peat bog
Wet
Spongy ground
Boggy
Mosses, heathers, many insects, so many nesting birds
how do peat bogs form
- An area is wet, acidic and often due to waterlogged soil, the soil lacks oxygen.
- Plants that can survive these conditions grow here; eg. Mosses, sedges and shrubs.
- When these die, the wet, acidic and anaerobic conditions mean the dead plant material cannot fully decay.
- The partly decomposed plant material is called peat.
why are peat bogs being destroyed
- to be mixed with soil to improve soil structure and water retaining properties of soil
- to make space for commercial crops
- they can be dried and burnt to be used as fuel
why is it important to conserve peat bogs
- peat is a carbon store so when you burn it you release carbon dioxide into the atmosphere
- peat bogs take thousands of years to form so they won’t reappear if you destroy them
- they are habitats
- they are a food source for insects which feed nesting birds which feed birds of prey so without them the food chain would be disrupted
what methods are being used to conserve peat bogs
1) removing trees and tree seedlings from the area to allow the peat bog to have maximum water because the trees require water which would leave the peat bog dehydrated
2) use controlled grazing which ensures diverse wetland surface for structure and species composition. provides a range of habitats for rare insects
3) block any ditches around the peat bog to raise the water table to the bog surface
how are humans damaging / have damaged the Galapagos islands
- Explorers/sailors visited in 19th Century affected animal population by eating them
- Non-native animals introduced and ate the native species (decrease in population) eg. dogs, cats, rats eat young tortoises, pigs destroy nests, goats eat plant life.
- Non-native plants introduced, compete with native plants
- Quinine trees taller than native plants, block out sunlight
- Fishing has decreased population of sea life eg. Sea cucumbers and hammerhead sharks reduced due to over fishing
- Increases in tourism (41 000 in 1991 to 210 000 in 2014)
- Population increase due to more opportunities
what things have been put in place to stop the human damage to the Galapagos islands
- Galapagos National Park established in 1959
- Park rangers introduced across the islands
- Human access limited to specific islands of parts of islands and need a licenced guide
- Controlling migration to and from islands
- Eradication of wild goats/dogs
- Marine protection area established – limits on fishing
- Quinine trees kept in check by herbicides and uprooting young trees
- Rules for visitors i.e. no live plants/animals
- Strict controls on movement of domestic and livestock (introduced animals)
how are humans damaging / have damaged Antarctica
Some scientists have specialised labs there
- Tourism has risen in the past 100 years
- Specifically the Antarctic Peninsula, where the climate is milder and wildlife is present
- Hunting whales and seals, and depleting fish populations
- Soil contamination around scientific settlements
- Human sewage
- Pollution
- Rubbish
- Shipping accidents – oil spills
what measures have been put in place to stop human damage to Antarctica
- Antarctic treaty established in 1961 to protect the -Scientific cooperation between nations
- Conservation of plants and animals
- Tourist restrictions
- Waste (food/sewage) must be taken away by ship for disposal
- Ships using thick oil are now banned
define interspecific competition
define intraspecific competition
interspecific - competition between different species
intraspecific - competition between members of the same species
describe the example of red and grey squirrels for interspecific competition
grey squirrels were introduced to Britain from North America
there numbers decreased but red squirrel numbers decreased
grey squirrels can eat a wider range of food so chance of survival increased
food supply for red squirrels decreased as grey squirrel population increased
what are the 3 stages on the graph showing intraspecific competition
1) population increases as there is a lot of resources but this means more competition for food, space etc.
2) Resources become limiting so population starts to decline
3) smaller population means less competition so population starts to grow again
cycle then repeats
what is the competitive exclusion principle
more overlap between 2 species’ niches would result in more intense competition
if 2 species have exactly the same niche, one would be out-competed by the other and would die out or become extinct in that habitat
define niche
the way in which an organism fits into an ecological community or ecosystem
how does the predator-prey relationship work? (the 4 stages)
1) as prey population increases, there is more food for predators so their population increases also
2) prey population declines as more are eaten. the death rate exceeds birth rate
3) the reduced prey population can no longer support the large predator population. Intraspecific competition for food increases which decreases size of predator population
4) reduced predator numbers result in less of prey population being killed. more prey survive and reproduce, increasing prey population.
cycle repeats
