Populations and sustainability

Animal that hunts another animal for food

Predation

When resources aren’t present in adequate amounts to satisfy needs of all individuals requiring them

Competition for resource

Decreases as fewer organisms have enough resources to reproduce

Increases as fewer have enough resources to survive

Intraspecific

Interspecific

Competition between individuals of same species

As factors become limiting = competition - individuals best adapted to obtaining food survive and reproduce, not so well die

Slows down population growth so pop eneters stationary phase

If size drops, comp reduces and size increases

If size increases, comp increases, size drops

Competition between individuals of different species

Population size and distribution of species in ecosystem

Mechanism of one plant interferring with physiology of neighbouring by releasing chemicals into their habitat

Stops neighbours using resources in their habitat

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

Overlaps between 2 species niches results in more intense competition

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)

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

Keeping things ‘natural’ and eliminating human effects on ecosystems

Active managemnt process involving human intervention

When habitats/ecosystems no longer ‘natural’ as result of human activity so preservation not appropriate

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

Species harvested at faster rate than they can replenish themselves

Consideration of social and economical costs to local community

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

Every species has value and humans have ethical responsibility to look after

Shouldn’t kill - playing god

Wellbeing and mental health

Leads to tourism - ecotourism

Maintains biodiversity

Adapts to change/stability

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

Coppicing

Pollarding

Rotational coppicing

Managing woodland

Stem of decidous tree cut close to ground, once cut, new shoot grows from surface and mature into narrow stems

Provides sustainable supply of wood

Prevents deers eating new shoots

Cutting stem of tree higher upso new shoots grow away from ground

Splitting woodland into areas and cutting one area each year going in a rotation

Good for biodiversity - different areas of woodland provide diff habitats

Lets more light in which increases number and diversity of species

Left unmanaged = succession which block sunlight to woodland floor hence reducing number species living there

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)

Removing only largest anad most vulnerable trees

Marine Stewardship Council - 3 principles

1. Fisheries must adapt to change and comply with local, national and international regulations

2. Fishing managed to no permanent damage to habitats or populations

3. Fishing takes place at level which allows it to continue indefinitely - overfishing avoided

Raising fish stocks in aquaculture restricts impact on oceanic fish stocks

The Terai Region

Maasai Mara

South of Nepal

Under pressure from expansion of agriculture, grazing of animals, over-exploitation of resources

Sustainable source of fuel, animal feed, food, medicines, building materials

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

Kenya

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

Land-owners move livetsock during tourist season - leads to increased stocking densities outside where noone recieves PWC money

Habitat destruction, natural resource competition, hunting, pollution

Habitat disturbance

Over exploitation of resources

Introduction of alien species

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

Fishing of exotic species has depleted populations

Out compete local species, eat native, destory native species habitats, bring disease

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

Food for whales, seals and squid

Used to make nutritional supplements and animal feed

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

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

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

Block ditches wiht haybales

Causes poor water quality in rivers and increases flood risk

Dry out land and roads built to carry away wood

Trees cut, less branches to block ditches, keep land moist