Populations and Sustainability

What is conservation?

active management of an ecosystem to maintain its species and habitats

reasons for conservation of biological resources

economic reasons

• promotes ecotourism, drug development

social reasons

• provides activity with others

ethical reasons

• prevents extinction of endangered species

• conserves biodiversity for future generations

What is preservation?

Protection of an ecosystem by restricting or banning humans from it to maintain its original state

What is ecosystem management?

Humans use, or manage an ecosystem’s natural resources sustainably

Name the 6 ways timber production is sustainably managed?

1) Coppicing, 2) Clear felling 3) Selective felling 4) Rotational felling 5) Pollarding 6) Strip felling

Explain the concept of coppicing

cuts tree trunk close to ground level stimulating the growth of new shoots which can then be harvested

can be done indefinitely

benefits of coppicing

increases life span of trees

provides a variety of light levels which increases biodiversity of other plant species

stimulates growth of new shoots increasing timber production

explain clear felling

removal of all trees from a forest area chosen for harvesting

danger of clear felling

can reduce plant biodiversity

what are the steps for sustainable clear felling

1) limit size of felled area 2) replant felled trees 3) limit soil erosion 4) keep minimum distance between replanted trees 5) let replanted trees fully regrow before harvesting

how is fishing sustainably managed?

fishing quotas limit number of caught fish

mesh size ensure only adult fish are caught

species restriction protects endangered fish species

trawler sizes reduce number of caught fish

catch inspections to enforce all measures

difficulties with sustainably managing fishing?

area too large

false reporting of caught fish numbers to avoid quotas

expensive catch inspections, threatens measures not to be enforced at all

What is interspecific competition?

competition for resources between individuals of different species

What is intraspecific competition?

competition for resources between individuals of the same species

What is the carrying capacity?

the maximum size a population can maintain for a long period of time

How can abiotic conditions slow or stop the growth of a population and give an example?

abiotic conditions are unfavourable for species so less of population reproduce e.g in cold climates mammals use more energy maintaining their body temperature and less energy is available for reproducing

How can abiotic conditions promote the growth of a population and give an example?

abiotic conditions become favourable so more of the population reproduce e.g. during summer there is more light exposure in a day, more light for photosynthesis so plants have more energy for reproducing

What is succession?

a series of progressive changes in the composition of an ecological community over time

examples of management techniques for succession

Grazing - animals graze to prevent growth of vegetation

Burning - burning kills vegetation and allows secondary succession to take place

how are heather moors managed?

Heather moors are where red grouse live

they feed on heather shoots and make homes in longer heather

if left to succession, heather would be unsuitable

so heather moorland is burnt approximately every 12 years to manage succession

What are the two main threats humans pose to biodiversity?

POPULATION GROWTH

RESOURCE EXPLOITATION

list methods of conservation

protected areas (e.g. national parks) - protect habitats

seedbanks - store seeds to avoid extinction

protected species - avoid extinction

fishing quotas - prevent overfishing

problems with Tourism in the Masai Mara Kenya and solutions

home to many safari animals

tourism demand has led to the construction of numerous camps in reserve, polluting landscape and increased number of people visiting lanf

disrupt wildlife behaviour

legislation has been introduced to limit human activity in reserve but rules are not adhered to

conservation trusts employing local people to work on conservation projects

employing local people to monitor lions and locations allowing farmers to move livestock away before they arrive instead of poisoning lions

Problems in Terai Nepal

population receive low income and rely on local forest for food and duel

destruction of forest for resources is leading towards an ecological disaster for both wildlife and locals

solution: conservationists in Nepal are enabling local people to have management rights over the forests in which they live, educating them on conservation

what measures have been introduced to Galapagos Islands which are at risk of overfishing, tourism?

improve surveillance of its marine reserve to reduce illegal fishing and overfishing

use an improved model of ecotourism to more sustainably manage tourism in area

measures put in place to protect Snowdonia National Park?

removing invasive species such as Himalayan balsam, maintaining footpaths to prevent further damage

permission is also needed to build anything new there

problems with Lake District

popular place for visitors, generated income for area

however, placing strain on ecosystems through land development, path erosion and lake pollution

solution: maintains paths to prevent erosion

permission neede to build anything there

What is a niche?

specific role of a species in an ecosystem

What is true about a niche?

Multiple species cannot overlap in a niche and every species has evolved to occupy one niche

why cant multiple species have the same niche?

species with identical niches also have identical needs, which means they would compete for precisely the same resources.

How does outcompeting affect population size?

Out-competing is a biotic factor.

When two species compete for the same resource, one species can out-compete the other.

A species is out-competed when one species is more well-adapted to the environment than the other.

This species is better at gaining resources and reproducing.

Out-competing allows one species to increase in population size and causes the other species to decrease in population size

What is primary succession?

Primary succession takes place on newly exposed or newly formed land.

What is secondary succession?

Secondary succession takes place where part of an ecosystem is disturbed and remnants of the previous community remain.

Explain how you might estimate the size of a crocodile population in a lake

mention assumptions made

Use a mark, release, recapture experiment.

First, capture a sample of crocodiles in a set amount of time or a set area.

Mark the captured animals and then release them back into the lake.

Leave enough time for the crocodiles to randomly distribute throughout the lake. Then recapture a sample in the same time or area

Calculate population by doing Population = (Total number in initial capture x Total number in second capture) ÷ Number of marked individuals in second sample)

Assumptions: marking crocodiles does not affect their survival e.g. paint is not toxic

there is no migration of crocodiles

that the crocodiles randomly distributed after first release

Wht

What is the Holocene extinction?

sixth mass extinction currently being observed on earth right now

the current rate of species loss is estimated to be between 100 and 1000 times greater than the natural background rate

potential causes of Holocene mass extinction (Hint: how humans pose risk to biodiversity)

• Population growth

  • rapid population growth increases the demand for space, food, natural resources.
    

• Resource exploitation

  • Exploiting natural resources damaging local ecosystems and the world as a whole.

  • Deforestation in regions like the Amazon rainforest has a huge impact on biodiversity.

  • Carbon dioxide released from fossil fuel exploitation is resulting in global warming which causes polar ice to melt and sea temperatures to rise. A recent study estimates that 50% of the Great Barrier Reef has been bleached to death since 2016 mostly due to small sea temperature rises.