6.3.2 Populations and sustainability

Question 1

lag phase features

Answer 1

reproductive rate is slow
population size is small
takes time for dispersed individuals to find each other to mate
acclimatising to habitat

Question 2

exponential phase (log) phase features

Answer 2

reproductive rate > death rate
pop. size increases rapidly
plenty of resources e.g. food (little competition)
little disease
few predators
no overcrowding
low environmental resistance (biotic and abiotic factors which limit population growth)

Question 3

stationary phase features

Answer 3

reproductive rare = death rate (population size remains stable)
habitat cannot support larger population
reached carrying capacity (k)

Question 4

carrying capacity definition

Answer 4

maximum number of individuals in a population supported by a particular habitat, determined by limiting factors
(k)

Question 5

factors limiting population growth and effect

Answer 5

food
water
space
light
oxygen
predation
disease
competition
prevents populations from exceeding carrying capacity

Question 6

r-strategists features

Answer 6

higher reproductive rate
quicker development of population
earlier reprodutive age
shorter life span
smaller body mass

Question 7

k-strategists features

Answer 7

lower reproductive rate
slower development
later reproductive age
longer life span
large body mass

Question 8

boom and busts method

Answer 8

some species exceed their carrying capacity due to rapid reproductive rate
once exceeded, insufficient resources to maintain the population and some die
death also caused by build up of waste products

Question 9

predator-prey relationship

Answer 9

prey population increases when predator numbers are low and low environmental resistance with few limiting factors
more prey = more food for predators
population of predator increases after a long time
more prey eaten by predators = prey numbers decrease
less food for predators, fewer survive and predator numbers decrease
cycle repeats
prey population reach higher than predators

Question 10

intraspecific competition features

Answer 10

within species
as environmental pressures increase (factors become limiting), competition increases
those best adapted survive, reproduce and pass on their genes (others die)
keeps stationary phase stable

Question 11

interspecific competition features

Answer 11

between 2 or more different species
competitive exclusion (when differenr species populations grow together but one dies out due to competition)
or
species fill out slightly different niches (both persist populations grow much slower than when grown alone)

Question 12

conservation definition

Answer 12

using nature in a sustainable manner

active management of ecosystem

Question 13

preservation definition

Answer 13

protection of ecosystem from interference so that it remains in its original state

Question 14

how increasing human populations threatened biodiversity

Answer 14

over-exploitation of wild populations for food
disrupting habitats with urbanisation and pollution
introduicng non-native spcies which competitively exclude native species

Question 15

dynamic conservation definition

Answer 15

preservation of organisms and environments that are at risk from human activity
requires management and the creation of new habitats, which may need reclamation of land

Question 16

ecosystem management strategies examples

Answer 16

reclaim ecosystem by reversing effects of human activity
raise carrying capacity by providing more food
introduce more individuals to enlarge populations
create corridors which connect fragmented habitats (allow species to move between them)
restrict dispersion of individuals by fencing
control predators and poachers
vaccinate individuals against disease
preservatipn of habitats by protecting against pollution or disruption or restrict succession (copping, grazing, etc.)

Question 17

what is clear-felling and why it’s bad

Answer 17

clear-felling = completely cutting down all of the trees in an area
trees take up water from soil and stops soil erosion, which pollutes rivers
trees keep nutrient levels in balance in carbon and nitrogen cycle
clear-felling leads to opposite

Question 18

sustainable production definition

Answer 18

harvesting in amounts which leave sufficient organisms to grow and replenish what has been harvested and can be carried on indefinitely

Question 19

sustainable forestry features

Answer 19

woodland must be able to maintain its ecological function of biodiversity, climate, mineral and water cycles
local people should benefit from forest
balance is needed between making money, supplying plenty of wood and maintaining biodiversity

Question 20

how to ensure each tree yields maximum amount of wood

Answer 20

control pests and pathogens
only plant tree species that grow well in an area
plant trees optimal distances apart to prevent too much competition for light, water and minerals

Question 21

coppicing features

Answer 21

cuts tree trunk close to ground to encourage new, thinner stems to grow
thin wood can be used to furniture, firewood etc. but trees don’t die and no replanting needed

Question 22

rotational coppicing method

Answer 22

woodland divided up and different sections coppicing on different years
coppicing can be done continuously to provide continuous supply of wood
standards = trees left uncoppiced and cut to produce larger timber for planks (more value)

Question 23

pollarding definition

Answer 23

cutting higher up the tree to prevent herbivory

Question 24

aquaculture features

Answer 24

breeding, rearing and harvesting of plants and animals in all types of water environments
restricts impact on oceanic fish stocks

Question 25

fisheries economic feature

Answer 25

high economic value (sales + jobs)

Question 26

marine stewardship council principles for sustainable management

Answer 26

overfishing must be avoided to stop extinction of species (aim to maintain population at its carrying capacity and only harvest excess numbers) no permanent damage to local habitats (maintains structure and function of ecosystems) always comply with local, national and global regulations (be flexible with these)

Question 27

adv of aquaculture over capture fisheries

Answer 27

restricts impact of fishing on oceanic fish stocks | cheap and plentiful protien source for increasing human population

Question 28

disadv of aquaculture over capture fisheries

Answer 28

populations susceptible to pests and pathogens | possible cause of pollution

Question 29

what is a fishery

Answer 29

area of water where fish are caught for recreational or commercial purposes

Question 30

Terai region of Nepal ecosystem

Answer 30

made up of marshy grasslands, savannah and forests | densely populated and home to endangered species (Bengal tiger, one-horned rhinoceros)

Question 31

how humans use forests in Terai region of Nepal

Answer 31

``` locals depend on forests for: fuel animal feed/food building materials agricultural and household tools medicine ```

Question 32

how sustainable forestry is being used in Terai region to maintain biodiversity and meeting needs of locals

Answer 32

WWF worked with Nepalese government introduced community forestry initiatives (gives locals rights to exploit forest and responsibility to look after it) that: -built forest corridors between national parks (essential for dispersal and survival of tigers) -counteracts poachers and illegal felling -developed forestry work, diversified on/off-farm activity, stimulated small credit and marketing schemes introduced biogas plants and wood-efficient stoves to reduce demand for firewood constructed waterholes monitored endangered species eradicating invasive species

Question 33

Masai Mara ecosystem

Answer 33

``` savannah divided by Mara river close to river = grasslands + woodland further from river = open plains contains large mammals e.g. buffalo, elephants, black rhinos ```

Question 34

how sustainable agriculture is being used in Terai

Answer 34

improve irrigation facilities (enhances crop production) multiple cropping (more than one crop grown on a piece of land each growing season) growth of nitrogen-fixing plants (legumes/pulses) to enhance fertility of soil improving fertilisation techniques to enhance crop yields e.g. use manure

Question 35

how humans use lands of Masai Mara

Answer 35

grazing of livestock (semi-nomadic farming) trees for fuel cultivation of crop (leads to reliance on fertilisers for effective crop growth) ecotourism (raises funds but tourist movements contribute to soil erosion and habitat changes) conservation and research (helps understand animal behaviour and physiology and monitor their populations)

Question 36

balance examples in Masai Mara

Answer 36

human land uses in Masai Marai is incompatible with wildlife survival and vice versa e.g. - elephants threaten trampling so land may be fenced, which -ve affects natural migration - legal hunting culls excess animals but animal populations need to be constantly monitored to maintain natural balance in ecosystem - livestock and migratory wildlife compete against each other for grass - more homes and land for agriculture for increasing human population = lowered wildlife density

Question 37

case studies for conservation

Answer 37

``` Masai Mara (Kenya) Terai region (Nepal) ```

Question 38

case studies for preservation

Answer 38

Galapagos Islands Antarctic Lake District Snowdonia National Park

Question 39

habitat disturbance in Galapagos Islands

Answer 39

human population size increased increased demand for water, energy, oil, sanitation services -> more waste and pollution produced building and conversion of land for agriculture causes destruction and fragmentation of habitats

Question 40

over-exploitation of resources in Galapagos Islands

Answer 40

fur traders and whaling boats killed 200,000 tortoises in less than 50 years depletion of sea cucumber populations has drastic effect on underwater ecology international market for shark fins led to 150000 shark deaths each year

Question 41

effects on introduced species on Galapagos Islands

Answer 41

alien species can out-compete local species, eat them. destroy their habitat and bring disease e.g. cats hunt lava lizard and young iguanas goats trample and disrupt giant tortoise food supplies nesting sites red quinine spreads rapidly due to wind-dispersed seeds and outcompete native trees, and shrubs so Galapagos petrel lost its nesting sites

Question 42

managing effects of human activity on Galapagos Islands

Answer 42

search arriving boats and tourists for foreign species introduction of natural predators of invasive species to eradicate them e.g. ladybird wiped out a scale insect that damaged plant communities at least 36% of coastal zones designated "No-Take" areas, no extraction of resources allowed Galapagos marine reserve provides model of how local stakeholders can work together for sustainable management of resources

Question 43

how Antarctic is governed

Answer 43

countries with research stations there under Antarctic treaty actively protect the ecosystem and its biodiversity

Question 44

krill in Antarctic

Answer 44

food for whales, seals, penguins used for nutritional supplements and animal feed new technology means large amounts of krill can be harvested very quickly and easily natural predators cannot adapt/migrate to find krill elsewhere krill fisheries should fish evenly across all areas

Question 45

protected areas in Antarctic

Answer 45

Southern Ocean Whale Sanctuary covers summer feeding grounds for 80-90% of all whales also International Whaling Commission moratorium it is illegal to hunt and kill whales in these areas whaling activity also monitored

Question 46

albatrosses and petrels in Antarctic

Answer 46

threatened by pollution, hunting and poaching for eggs, habitat destruction and introduction of non-native predators, long-line fishing (long fishing line trailed behind fishing boats) to reduce bird catches, boats use: -bird-scaring lines and streamers -weighted lines that sink quickly out of reach of birds -lines at night to avoid bird feeding, breeding and nesting times

Question 47

Lake District ecosystem and how it’s maintained

Answer 47

rich diversity of species and habitats (native woodland, wetland, chalk downland, hay meadows) maintained by grazing causing deflected succession to prevent climax community of oak woodland also financial incentives for farmers to reduce chemical use, safeguard hedges and take care of habitats

Question 48

spruce and pine in conifer plantations in Lake District

Answer 48

support limited biodiversity recent initiatives generated more varied planting and felling patterns causing mosaic of smaller stands of different aged trees

Question 49

invasive species escaped from gardens into Lake District

Answer 49

spread into woodland and outcompeting native species as dense canopy reduces light reaching woodland floor roots produce toxic chemicals, stopping other plants growing they are physically removed by conservation workers

Question 50

limestone pavement in Lake District

Answer 50

solid blocks with fissures between them (unique habitat for rare ferns to grow and butterflies to thrive in) legally protected through Limestone Pavement Orders

Question 51

hay meadows in Lake District

Answer 51

occur in neutral grassland and support rich diversity of flowers and grasses under threat due to preference of silage production farmers paid to maintain hay meadows

Question 52

silage production feature

Answer 52

use of artificial fertiliser and earlier cut

Question 53

heathland in Lake District

Answer 53

could be under threat by overgrazing | financial incentives provided to farmers to prevent overgrazing

Question 54

mire in Lake District

Answer 54

internationally scarce under threat from burning, grazing and drainage managed more sympathetically some rewetted with artificially controlled water levels grazing controlled

Question 55

cliff, rock and scree communities in Lake District

Answer 55

easily damaged by climbers and walkers seasonal restrictions on walking when birds nesting walkers more educated to be more aware paths well maintained to prevent people walking off paths

Question 56

Snowdonia ecosystem

Answer 56

habitats: moorland, bogs, mountain | provide nesting sites for rare birds and home to rare butterflies

Question 57

why and how paths are maintained in Snowdonia

Answer 57

so rare plants dont get trodden on gutters take water from paths but get blocked by rubbish dropped by walkers workers clear rubbish

Question 58

why sheep and goat grazing reduced

Answer 58

sheep graze very low to ground so leaves landscape barren National Park and farmers work together gives rare plants better chance of survival

Question 59

farmers digging open drainage ditches in Snowdonia

Answer 59

dries land but causes poor water quality in rivers and rain flows quickly through habitat, increasing flood risk drainage ditches blocked by hay bales to reduce this

Question 60

conifers planted in Snowdonia

Answer 60

cash crops but dries out moorland as trees absorb water roads have to be built to carry wood away, compacting land when trees cut down, branches used to block drainage ditched to slow water flow and keep land moist

Question 61

old heathers in Snowdonia

Answer 61

burn easily and accidental fires at high risk | burning controlled fires before heathers gets too old and dry prevents such damage

Question 62

why preservation of habitats is not viable sometimes

Answer 62

preservation leaves ecosystems untouched without human interference sometimes not viable as area is damaged already and requires management and restoration

Question 63

conserving lowland bogs

Answer 63

peat and vegetation of bog surface is wet as possible (less trees, block ditches) control grazing (maintain biodiversity of peatland) no/less burning (could lead to death of organisms from rare species)

Question 64

measures in preventing permanent damage to oceans

Answer 64

``` fishing quotas mesh size species restriction days at sea penalties and sanctions monitoring and surveillance public education ```

Question 65

difficulties in preventing permanent damage to oceans

Answer 65

``` area too large expense of monitoring monitoring hampered by weather false reporting of catches death of fish caught but not kept ```