What’s a predator?
Animal that hunts another animal for food
__ acts as a limiting factor on population size
Predation
When does competition occur?
When resources aren’t present in adequate amounts to satisfy needs of all individuals requiring them
What will happen if a resource is in short suuply?
Competition for resource
What happens to rate of reproduction as intensity of comp increases and why?
Decreases as fewer organisms have enough resources to reproduce
What happens to death rate as intensity of comp increases and why?
Increases as fewer have enough resources to survive
What are the 2 types of competition?
Intraspecific
Interspecific
What’s intraspecific competition?
Competition between individuals of same species
How does intraspecific competition slow down population growth so it enters stationary phase?
As factors become limiting = competition - individuals best adapted to obtaining food survive and reproduce, not so well die
What’s the advantage of intaspecific competition?
Slows down population growth so pop eneters stationary phase
How does intraspecific competition keep a population stable?
If size drops, comp reduces and size increases
If size increases, comp increases, size drops
What’s interspecific competition?
Competition between individuals of different species
What does interspecific competition affect?
Population size and distribution of species in ecosystem
What’s alleopathy?
Mechanism of one plant interferring with physiology of neighbouring by releasing chemicals into their habitat
Why is alleopathy a form of competition?
Stops neighbours using resources in their habitat
How did G.F Gause research interspecific competition?
Grew 2 species of Paramecium, seperately and togther. When togther = commpetition for food. Pa more effective than Pe over 20 days. Pop of Pe reduced and died out, Pa increased and only species remaining
What did G.F Gause conclude following his research?
Overlaps between 2 species niches results in more intense competition
What’s the competitive exclusion theory?
If 2 species have exact same niches, one is out-competed by other and dies out or becomes extinct in habitat (2 specie can’t occupy same niches)
What are the counterarguments for the competitive exclusion theory?
Extinction not nessecarily inevitable - interspecific comp can lead to one pop smaller than the other
Lab experiment so easily exclude other varibales - in wild, range of variables may act as limiting factor
What does preservation focus on?
Keeping things ‘natural’ and eliminating human effects on ecosystems
What’s conservation?
Active managemnt process involving human intervention
When is conservation used?
When habitats/ecosystems no longer ‘natural’ as result of human activity so preservation not appropriate
What are the threats to biodiversity?
Increasing human pop threatens through:
Over-exploitation of wild populations for food, sport and commerce
Habitat disruption and fragmentation due to more intensive agricultural practices, increased pollution and building
Native species extinction due to out-competition of species introduced by humans
What’s over exploitation?
Species harvested at faster rate than they can replenish themselves
What does successful conservtion require?
Consideration of social and economical costs to local community
Give ways in which we conserve/manage biodiversity
Raising carrying capacity by providing extra food
Control predators and poachers
Vaccinate against disease
Encourage natural dispersion
Add more individuals
Fencing
Restrict succession
Preventing pollution
What are the ethical reasons for conservation?
Every species has value and humans have ethical responsibility to look after
Shouldn’t kill - playing god
What are the aesthetic reasons for conservation?
Wellbeing and mental health
Leads to tourism - ecotourism
What are the ecological reasons for conservation?
Maintains biodiversity
Adapts to change/stability
What are the economic reasons for conservation? (Direct and indirect)
Direct economic value:
plant and animals species provide valuable food source
natural environment valuable source of beneficial organisms - many drugs today
natural predators of pests act as biological agents - preferable to causing pollution with chemicals
Resources- food, timber, medicine
Indirect value:
Insect species responsible for pollinating crops - without harvest may fail = no business for farmers
How can we manage small scale timber production?
Coppicing
Pollarding
Rotational coppicing
Managing woodland
What is coppicing?
Stem of decidous tree cut close to ground, once cut, new shoot grows from surface and mature into narrow stems
How does coppicing help with sustainable management?
Provides sustainable supply of wood
How does pollarding help with sustainable management?
Prevents deers eating new shoots
What’s pollarding?
Cutting stem of tree higher upso new shoots grow away from ground
What’s rotational coppicing?
Splitting woodland into areas and cutting one area each year going in a rotation
How does rotational coppicing help with sustainable management?
Good for biodiversity - different areas of woodland provide diff habitats
Lets more light in which increases number and diversity of species
How does management of woodland help with sustainable management?
Left unmanaged = succession which block sunlight to woodland floor hence reducing number species living there
How can we manage large scale timer production?
Replace and tree harvested
Ensure forest as whole maintains ecological function
Selective cutting
Only plant species that will grow well
Control pests and pathogens
Position trees optimal distance apart (too close = comp, too thin = poor quality timber)
What’s selective cutting?
Removing only largest anad most vulnerable trees
What are some of the ways of managing fisheries?
Marine Stewardship Council - 3 principles
Fisheries must adapt to change and comply with local, national and international regulations
Fishing managed to no permanent damage to habitats or populations
Fishing takes place at level which allows it to continue indefinitely - overfishing avoided
How does aquaculture help with sustainable managament?
Raising fish stocks in aquaculture restricts impact on oceanic fish stocks
Give 2 examples where there is balance between conservation and human needs
The Terai Region
Maasai Mara
Where is the Terai Region?
South of Nepal
What problems are the forests in the Terai Region facing?
Under pressure from expansion of agriculture, grazing of animals, over-exploitation of resources
What human needs do the forests in the Terai Region support?
Sustainable source of fuel, animal feed, food, medicines, building materials
How is the conflict between conservation and human needs being balanced in the Terai Region?
WWF and Governement introduced community forestry initiatives - locals had right to exploit and have responsibilities to look after it
Forest corridors between national parks for dispersal of species - counteracts poachers
Introduced biogas plants and wood efficient stoves to reduce demand for firewood
Constructed waterholes, eradicated invasive species, monitored endagered
Where is the Maasai Mara?
Kenya
How is the conflict between conservation and human needs being balanced in the Maasai Mara?
Partnerships between conservancies and tourism operators developed payment for wildlife conservation (PWC) schemes - conservancies paid PWC revenue proportional to area of land set aside for conservation
What are the negatives of conservancies in the Maasai Mara?
Land-owners move livetsock during tourist season - leads to increased stocking densities outside where noone recieves PWC money
How can human activities affect populations?
Habitat destruction, natural resource competition, hunting, pollution
How have human activites affected the Galapagos Islands?
Habitat disturbance
Over exploitation of resources
Introduction of alien species
How has human activity caused habitat disturbance in the Galapagos Islands?
Pop size increased, increased demand for water, energy and sanitation services means more waste and pollution
Building and conversion of land for agriculture caused destruction and fragmentation
How has human activity in the Galapagos caused over exploitation of resources?
Fishing of exotic species has depleted populations
How has human activity led to invasion of alien species in the Galapagos?
Out compete local species, eat native, destory native species habitats, bring disease
How are the effects of human activities in the Galapagos managed?
Charles Darwin Research Station - 2 strategies: prevent into and dispersion of alien species and treat problems caused by alien species. Search arriving boats and tourists
Natural predators exploited to reduce damage to ecosystems by pest pops
No take areas - no extracction of resources allows, community left undisturbed
What are the uses of krill?
Food for whales, seals and squid
Used to make nutritional supplements and animal feed
How are the effects of human activities controlled in the Antarctic?
Avoid over exploitation - trigger level catch size in areas, when reached must be conducted equally in all areas
Protected areas - Southern Ocean Whale Sanctuary - illegal to kill/hunt within sanctuary (monitoring of whaling activity to ensure effective)
Long line fishing - bird scaring lines, weigthed lies, use lines at night
What threats are there to biodiversity in the lake district and what are the solutions?
Invasive outcompeting native - remove invasive
Limestone pavement habitat for rare butterflies and ferns in fixtures - pavement legally protected
Hay meadows under threat due to preferance away from haymaking and towards silage production - farmers paid to maintain hay meadows
Cliff and rocks damaged by climbers snda walkers (habitats) - Seasonal restrictions when nesting, walkers eduacted, paths well maintained
How are the mountains of Snowdonia National Park maintained to control human activites?
Footpaths maintained so rare plants not trodden on
Gutters to take water from paths
Farmers and employers work togther to reduce animals grazing
Farmers encouraged to plant hedges/fences
What are the solutions to reverse the effects of open drainage ditches?
Block ditches wiht haybales
What are the problems with open drainage ditches?
Causes poor water quality in rivers and increases flood risk
What are the problems with planting conifers as cash crops and what’s the solution to deal with this?
Dry out land and roads built to carry away wood
Trees cut, less branches to block ditches, keep land moist
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