Biodiversity Flashcards
Sampling
Used to estimate the number of organisms in a given area (abundance)
- can also measure a particular characteristic e.g. average height of a crop
Types of sampling
- Random
- non random- opportunistic, systematic, stratified
Opportunistic
Uses organisms that are conveniently available
Stratified
Populations divided into strata (subgroups) and then randomly sampled e.g. male and female
Systematic
Carried out using a line or belt transect. Samples taken systematically (following a set pattern)
Reliability
Samples can never be entirely representative of abundance of organisms
You can reduce the likelihood of these 2 issues:
1. Sampling bias- use random sampling
2. Chance- use larger sample size (repeat it more times)
Ethical considerations when sampling animals
- always handle animals carefully and for a short a time as possible
- animals must always be released as soon as they have been identified, counted and measured
Animal sampling techniques
Pooter- catching small insects
Sweep net- catching insects in long grass
Kick sampling- study organisms in a river
Tree beating- catch invertebrates living in trees or bushes
Pitfall traps- catch small crawling invertebrates
Sampling plants- transects
Belt transect
- best
- provides more information on abundance
Point quadrants
- each species that the pins touch are counted
Frame quadrants
Used to calculate:
- density: exact number of organisms
- frequency: number of squares containing organisms are counted. Useful for plants such as moss or grass. E.g. 60/100 squares contain moss, frequency = 60%
- percentage cover: estimation by the eye of the % of the quadrat covered by an organism
Species richness
The number of species per sample
- more species present, the richer the sample is
- takes no account of the number of individuals of each species present
- e.g. 1 daisy has as much influence on the richness of an area as 1000 buttercups, both still have a richness of 1
Species evenness
Relative abundance of different species making up the richness of an area
Example
Sample 1 Sample 2
Daisy: 300 20
Dandelion: 335 49
Buttercup: 365 931
Total: 1000 1000
- Sample 1 and sample 2 are taken from two different fields
- total number of individuals and species richness are the same but 1 has more evenness
Measuring biodiversity
A community dominated by 1 or 2 species is less diverse than one in which several different species have a similar abundance
- as species richness and evenness increase, so does biodiversity
Simpson’s index
Polymorphism
Genetic polymorphism occurs when there are 2 or more alleles present at a single loci
- polymorphic loci have multiple alleles
- most common allele must have frequency if less than 95-99%
- if more than this, alleles are extremely rare
- monomorphic is a locus that doesn’t have multiple alleles/one allele
Proportion of polymorphic gene loci
number of polymorphic gene loci
Total number of loci
- gives P
Limitations of P
- the proportion of polymorphic genetic loci (P) does not illustrate the allele richness of a breed or species
Polymorphic gene
A gene with more than one allele
Factors affection biodiversity (8)
- climate change
- predators
- water and food availability
- extinction
- invasive species
- deforestation
- poaching
- human: population growth, agriculture
Deforestation
- directly reduces tree numbers
- reduces species richness/evenness by felling only certain types of trees
- destroys habitats- reduces animals species present
- forces animals to migrate
- contributes to global warming - less CO2 sequestered
Agriculture
Monoculture
- removal of biodiverse land to grow only one type of crop
- fewer animal species supported
Chemicals
- pesticides and herbicides
Removal of hedgerows
- reduces plants species present
- destroys habitats of many birds, mammals and invertebrates
Climate change IPCC findings
- sea levels risen
- average arctic temperature increased at twice the average global rate from last 100yrs
- snow cover declined in both hemispheres
- upwards trend in participation
Global warming
Refers only to the earths rising surface temperature
Climate change
Includes warming and the side effects of warming
How does climate change affect biodiversity
Melting polar ice caps
- extinction of plant and animal species
- habitat shifts (animals forced to migrate are new competition for animals)
Rising sea levels
- flooding
- saltwater entering freshwater habitats
Higher temperatures + less rainfall
- some plant species unable to survive
- xerophytes become more dominant
Costa Rica
- biodiversity hotspot
- covers 0.03% global landmass
- contains 5% of earths biodiversity, making it most biodiverse country on the planet
Arguments for maintaining biodiversity
- Aesthetic
- Economic
- Ecological
Maintaining biodiversity: aesthetic
- attracts millions of tourists each year
- landscape provides inspiration for people
- relaxation- mental health
Maintaining biodiversity: economic
- prevents soil depletion
- prevents soil erosion
- genetic variation- crops less susceptible to disease
- promotes tourism
- protecting undiscovered species- medicinal uses
Maintaining biodiversity: ecological
- protects keystone species- must be protected to protect entire ecosystems
- interdependence of species- plants rely on pollinators
Keystone species
A species which has a disproportionately large effect in their environment, relative to their abundance
Keystone species examples
Eurasian beaver- dam building creates and maintains wetlands, which provides critical habitats and supports biodiversity in freshwater ecosystems (prevents flooding)
Starfish- predation on mussels and sea urchins prevents them from dominating intertidal zones, maintaining species diversity in marine systems
Grey wolf- predation on large herbivores like elk and deer prevents plants from being eaten too much
How are species classified in a conservation context
- Lower risk
- Threatened
- Extinct
Conservation
Preservation and management of the environment and natural resources
- in situ- within the natural habitat
- ex situ- outside if the natural habitat
In situ
Wildlife reserves
Wildlife reserves are protected areas which must be actively managed:
Active Management
- control poaching
- culling or removal of invasive species- the selective killing of members of an animal population in order to reduce the overall population size
- reintroduction of species
- feeding of animals
- halting succession- ways that succession can be deliberately prevented e.g. introducing grazing animals to prevent growth of shrubs
- restricting human access
- controlled grazing- management of forage with grazing animals. It limits access to grazing
In situ: marine conservation zones
- protection for marine zones which would otherwise be devastated by overfishing
- aim is not to prevent fishing in the entire area, but create areas of refuge so that populations can build up
- requires large areas of sea- target species move or breed in different areas
Ex situ
Botanic gardens
- plant species are grown through management
- nutrients are supplied, watering, pest removal
seed banks
Captive breeding programmes
Purpose
Programmes can breed individuals of a species so their offspring can be released into the wild
Challenges
- small species populations can reduces genetic diversity
- certain animal species won’t breed in captivity
- not all zoos can provide adequate habitats for animals with specific needs
- expensive
Why organisms may not be related
- genetic mutation
- too adapted to life at zoo
- not adapted to wild environment- learned behaviour
- habitat destruction
- susceptible to disease
Countryside Stewardship Scheme (CSS)
- provided funding to farmers and private landowners in England who used environmental management strategies to protect and increase the natural biodiversity on their land
scheme was replaced by the Environmental Stewardship Scheme
What do farmers and private landowners have to do to qualify for CSS
- provide and protect valuable wildlife habitats e.g. ponds, hedgerows, buffer zones around farms
- ensure their land is managed well, maintaining traditional character
- protect any natural resources or historic features present on their land
- conserve any traditional crops or livestock present on their land
- provide visitor opportunities so people can learn about the countryside and how important it is in sustaining biodiversity
International Union for the Conservation of Nature (IUCN)
• the IUCN is described as the “global authority on the status of the natural world and the measures needed to safeguard it”
• The main role is assessing the conservation status of animal and plant species around the world
Animals that are on the IUCN Red Lost of Threatened Species can be seen online as this list is made public
Convention of Biological Diversity (CBD)
The convention has 3 main goals:
- conservation of biological diversity by use of a variety of different conservation methods
- the sustainable use of biological resources
- the fair and equitable sharing of benefits arising from genetic resources
Convention on International Trade in Endangered Species (CITES)
- global agreement signed by over 150 countries
- it’s aim is to control the trade of endangered species and their associated products
E.g. elephants and ivory tusks
CITES categories of endangered and vulnerable species:
1: species that are endangered and face the greatest risk of extinction e.g. red panda
2: species that are not currently endangered or facing extinction but will be unless trade is closely controlled e.g. Venus fly trap
3: species included at request of the country that is regulating trade of species and trying to prevent its over exploitation e.g. two toed sloth
