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Global and Continental Factors
Size of An Area
Biodiversity increases as this increases because large
continuous places with less boundaries encourage migration
AND support wider range of species
History and Age
Biodiversity is greatest in the oldest and least disturbed
ecosystems
Isolation
Altitudinal Range
This (on remote islands for example) can reduce the number
of species, but also encourages endemism – a species being
exclusive to a place and specialising as a result.
Going from valley floors to high mountains means that a
variety of climatic zones are crossed, so therefore a
higher biodiversity could be expected due to the range of
the environments. The same would apply to ocean depth ;
going from shallow reefs to deep ocean trenches increases
the range of species found.
Regional Factors
Productivity
Habitat Architecture
Habitat Heterogeneity
High temperature and humidity levels, coupled with good
nutrient supplies and sunshine hours and a lack of
seasonal variation, means that photosynthesis in plants
and therefore Primary Productivity (PP) is high. This
means consumers at higher trophic levels will have more
energy available to them. Coral Reefs and Rainforests are
good examples of these. Cold and dry places have limited
Biodiversity.
In ecosystems with high Primary Productivity (PP) a
complex food web will form due to all the ecological
niches available to species – for example the many
different layers of trees and shrubs in the rainforest
means the structure of the ecosystem allows species to
live and specialise in very localised areas of the forest.
A varied physical environment will have a greater
biodiversity as it provides a greater range of habitats
for species – for example an environment that consists of
mixed woodland (coniferous and deciduous trees) will be
able to support a wider variety of species that a woodland
made up of only coniferous tree species.
Local Factors
Succession
Biodiversity increases as species establish themselves and
in doing so the species interact and alter the environment
Interaction between
species
This can lead to competition which can lead to the
extinction of a certain species, especially where an
alien/exotic species is introduced.
Disturbance
Environmental disasters like fires, flooding and storms
can reduce biodiversity.
Dispersal and
Colonisation
The speed at which a species releases its seeds or
colonises a new area can be a factor– high rates of speed
and/or efficiency can enhance biodiversity.
Habitat Destruction
Often the factor attributed most to humans - this can also
include degradation of a habitat as well as total loss.
Effective Conservation
and Restoration
This has become a more prominent factor over the last 50
years with the establishment of designations to protect
and enhance wildlife around the world.