Threats To Biodiversity Flashcards
What are the main threats to biodiversity?
Over exploitation
Habitat loss and fragmentation
Introduced, naturalised and invasive species
Climate change
Bottleneck effect
Describe over exploitation
The consumption of resources at a rate faster than they can be replaced
Describe the bottleneck effect
Where a significant percentage of the population is killed or prevented from reproducing
Population may now not be able to adapt environmental changes or pressures
Reproduction between Genetically similar surviving members Will be equivalent to inbreeding causing further loss of variability and reproductive success
What can cause habitat fragmentation?
Geological processes: that slowly alter the layout of the physical environment
Human activity: rapid
Describe habitat fragments
They have a smaller total surface area than the original habitat
They have a lower species richness than a large area of the same habitat
Describe edge to interior ratio in habitat fragmentation
Fragmentation leads to an increase in the ratio of edge to interior, favouring species that are adapted to living on the edge
Habitat fragments suffer from degradation at the edges
It’s species me then invade the habitat interior at the expense of species already there
What are habitat corridors?
Pathways of natural habitat linking otherwise disconnected fragments
They allow recolonisation, meeting, feeding, territorial behaviour
Solve the problem of isolation but not of loss of interior and act as are safe passage for species between neighbouring habitats however could allow the spread of disease
What are introduced (non-native) species
Species that people have moved either intentionally or accidentally to new geographical locations
What are naturalised species?
Introduced species that have become established within wild communities
What are invasive species?
Groups of naturalised species that have spread rapidly and eliminated native species
Why are non-native species successful ?
Lack predators
Lack parasites and pathogens
Like competitors that would normally limit the population
Can pray on native species
Out compete native species for resources
What is climate change?
A natural part of the history of the planet
What is the greenhouse effect?
Heat Energy from the Sun strikes the Earth and is reflected from its surface
Carbon dioxide and methane in the atmosphere trap some of this heat energy
What is anthropogenic climate change?
The increasing human population has led to increased demand for food and resources causing:
Deforestation: trees that would be removing carbon dioxide from the atmosphere
Burning fossil fuels: adds carbon dioxide to atmosphere
Effects of climate change on biodiversity
Change in distribution and abundance of species
Change in timing of seasonal events e.g. migration
Changes in composition of plant and animal communities
Habitat loss
Increase in sea temperatures
Overall a loss of biodiversity
