Challenges to biodiversity Flashcards
What is an invasive species?
Species introduced into areas outside their native range that can use harm in the new area
Invasive species may outcompete native species for resources or habitat, altering community structure and potentially leading to extinctions
Where were Kudzu introduced to and where are they from?
Introduced to USA from Asia in late 1800s as ornamental plant
What is the problem with Kudzu as an invasive species?
Plant grows very rapidly and enshrouds ground, shrubs, trees and even houses and old cars in suffocating girdle of vines
Where were prickly pears imported to and why?
Imported to Australia in 19th century to use as natural agricultural fence and establish cochineal dye industry
Why was prickly pear an issue?
Widespread invasive species that rendered 40,000 km^2 of farmland unproductive
What was the successful biological control used to deal with prickly pear?
Moth from South America
The larvae eat prickly pear
They almost wiped out the population
How can introduced species impact a habitat?
Grazing, browsing and rooting by introduced mammals
Introduced plants overgrowing and shading out native plants
Plants modifying natural fire regime
Using vast amounts of water
Nitrogen fixing, fertilising the soil
Give some examples of competition of invasive species and native species.
American grey squirrel caused drastic decline in population of native red squirrel in UK
House gecko caused line of native lizard populations on Pacific islands by outcompeting for insect prey
What is the negative affect of hybridisation from invasive species?
Embryos often end up aborted but females are removed for a year from the breeding population Dangerous for already fragile populations
Name the characteristics of invasive species.
Fast growth Rapid reproduction High dispersal ability Phenotypic plasticity Tolerance of a wide range of environmental conditions Ability to live off wide range of food types Associations with humans Prior successful invasion history
Why is invasive Rhododendron having a negative impact?
Blocks light
Carries diseases fatal to native trees
Why were mink introduced to the UK and what negative impact have they had?
Introduced for fur farming
Native water vole experienced most rapid and serious decline of any Britisj wild mammal in the 20th century due to mink
What is the negative affect of single crayfish being introduced to the UK?
Driven native white-clawed crayfish towards extinction due to competition and transmission of crayfish plague
Burrows into riverbanks leading to erosion and increased flood risk
What is the negative impact of Muntjac deer being introduced to the UK?
Serious impacts on woodlands by clearing shrubs and preventing tree regeneration
What is the negative impact of introduced of Himalayan balsam?
Crowds out native plants including tansy
What is the problem with Japanese Knotweed in the UK?
Forms dense stands that are really hard to control
All across Great Britain
Can reduce capacity of channels in flood defences
Damages concrete foundations, buildings, flood defences, roads, paving, etc
What was the turning point for urbanisation where more than 50% of the world population lived in cities?
2007
What is urbanisation?
Population shift from rural to urban areas
Process by which towns and cities are formed
What are urban heat islands?
Formed when industrial and urban areas produce and retain heat
In cities, with less vegetation and exposed soil, sun’s energy is absorbed by buildings and asphalt, leading to higher surface temperatures
How much hotter is a city normally compared to the surrounding landscapes?
1 to 3 degrees celsius
Why does urbanisation cause ecological degradation?
Creates highly fragmented, heterogenous and altered environments
It is often associated with declines in animal and plant richness, abundance and diversity
What is built habitat?
Buildings and sealed surfaces, such as roads
What is managed vegetation?
Residential, commercial, and other regularly maintained green spaces
What is ruderal vegetation?
Empty lots, abandoned farmland, and other green space that is cleared but not managed
What is natural ruderal vegetation?
Remaining islands of original vegetation (usually subject to substantial non-native plant invasion)
What is eutrophication?
When rain occurs in large cities, it filters pollutants such as carbon dioxide onto the ground below
Chemicals washed directly into rivers, streams and oceans, causing a decline in water quality and damaging marine ecosystems
What does it mean if a species is an urban avoider?
Very sensitive to human habitat disturbances
large mammals, old forest birds, late successional plants
What does it mean if a species is an urban adapter?
Frequently found in suburban matrix areas
Cultivated plants, weedy species, edge species animals, omnivore birds
What does it mean if a species is an urban exploiter?
Excel in urban areas, even dependent on human resources
Grasses
Birds and mammals that inhabit and exploit human dwellings
What is light pollution?
Presence of anthropogenic light in the night environment
Why is light pollution bad?
Compromises health, disrupts ecosystem and spoils aesthetic environments
Circadian rhythm affected
Light favours predators
Interferes with spatial orientation
How can light pollution be minimised?
Unnecessary lights extinguished
Spectrum chosen to minimise imputes (not UV or blue)
Only as bright as needed and only used when/ where needed
Is urban health on average better or worse?
On average health levels are better
What are some health issues associated with urban areas?
Urban areas like slums disproportionately suffer from disease, injury and premature death
Children at more risk of being overweight
BMI and cholesterol levels are higher
Chronic diseases
What is tillage?
Agricultural preparation of soil by mechanical agitation
What does primary tillage do?
Loosens the soil and mixes in fertiliser and/ or plant material, resulting in soil with rough texture
What is an example of a primary tillage method?
Ploughing
What does secondary tillage do?
Produces finer soil and sometimes shapes the rows, preparing the seed bed
What are the positives of tillage?
Loosens and aerates
Mixes harvest residue, organic matter and nutrients
Mechanically destroys weeds
Dries the soil before seeding
Helps exposed soil crumble over winter through frosting and defrosting
What are the negatives of tillage?
Soil loses nutrients and water storage ability Lessens cohesiveness of the soil inducing erosion Reduces organic matter in the soil Reduces microbes, worms, etc Compaction of soil Eutrophication Attracts slugs Crop diseases in surface residues
What is agricultural drainage?
System by which water drained on or in the soil
What is intercropping?
Growing two or more crops in proximity
What are the benefits of intercropping?
Encourages biodiversity
Resource partitioning
Mutualism
Pest management
What is resource partitioning?
Planting a deep-rooted crop with a shallow-rooted crop, or planting a tall crop with a shorter crop that requires partial shade
What is mutualism?
Plants interact in a way increases one or both of the plant’s fitness
What is mixed intercropping?
Crops are totally mixed in the available space
What is row intercropping?
Crops arranged in alternate rows
What is temporal intercropping?
Practice of sowing a fast-growing crop with a slow-growing crop
What is relay intercropping?
Second crop sown during the growth, near the onset of reproductive development, of first crop
What is trap cropping?
Plating crop nearby that is more attractive to pests than the production crop
What is repellant intercrop?
Repellant crop masking the smell of the production crop
What is push-pull cropping?
Mixture of trap cropping and repellant intercropping
What is agricultural rotation?
Practice of growing a series of dissimilar or different types of crops in the same area in sequenced seasons
Prevents soil of farms not being used for only one set of nutrients
Reduces soil erosion and increases soil fertility
What is grazing?
Method of feeding in which a herbivore feeds on plants such as grasses, or other multicellular organisms like algae
Conversion by domestic livestock of grass and other forage into meat, milk and other products
What are the two types of defences plants have against grazers?
Constitutive defences
Induced defences
What are constitutive defences?
Always present in the plant
What are induced defences?
Produced or mobilised to the site where a plant is injured
Benefit is only produced when needed, so potentially less costly
Examples of plant defences against grazers.
Chemical defences
Anti-herbivory compounds
Mechanical defences
Mimicry and camouflage
What is the negative impact of fertiliser use?
Reduces species asynchrony, leading to less production over time
Eutrophication
Soil acidification and toxicity
Methane emissions- climate change
How many people rely on fish for animal protein?
4.3 billion
Why does aquaculture need to diversify and step up the domestication of aquatic species?
To meet global food security demands in a sustainable way
Less food, less space and less water
Plus dealing with warmer temperatures
How much do fisheries in Wales contribute to rural and coastal economies?
More than £30 million per year
What are the main challenges faced by intensive aquaculture?
To reduce its ecological footprint
To reduce the risk of disease
To prevent the introduction of invasive species
Why are fish parasites so common?
Fish are abundant and diverse
Co-evolution
Human interference: breaking down barriers and translocation
Aquaculture: high host density and stress
How can we prevent fish parasites spreading?
Maintain optimal environment for host, not parasite
Sterilise water, nets and equipment
Control of intermediate/ reservoir hosts
Ensure optimal nutrition
Minimise stress
Know fish behaviour
What are some threats to fish biodiversity and aquaculture?
Overfishing Habitat destruction Introduced species/ farm escapees Pollution Global climate change Parasites
