Transcript Biodiversity

Biodiversity
Definition
The number and variety of life forms including species
found within a specific region as well as all the number
and variety of ecosystems within and beyond that
region
How to Measure Biodiversity
• Canopy Fogging: low dose of pesticide
sprayed at the tree top and the insects that
fall are collected on a large screen, helps with
learning about cycles of insects
• Quadrat sampling: a pre-made square of
stakes and string 1m2 to 20m2. Different
species and their numbers are counted within
the quadrat. Counting is repeated many
times in different places throughout the
habitat to get an accurate representation
Measuring Biodiversity
• Transect sampling: using a transect line,
unrolled into a habitat and marked at certain
intervals where counting is done in the habitat
• Netting: nets captured birds and bats and
fish. Once captured organism is identified
tagging may occur, genetic analysis and
measuring can be done before the organism
is released.
Biodiversity Hotspots
• A place where there is an exceptionally large
number of species in a relatively small area.
• In Canada: Carolinian Canada and the
Leitrim Wetlands (both in Ontario)
• In tropics: East Africa, Lake Malawi 1000 fish
compared to 150 in lake Erie
• Biodiversity index: number of species
total number of organisms
Communities
• All the populations of the different species
that interact in a specific area or ecosystem
• Dominant Species: so abundant, biggest
biomass of any community member
– In terrestrial ecosystems dominant species are
always primary producers
– Removal of a dominant species can result in lower
biodiversity
• Keystone Species: a species that greatly
affects population numbers and the health of
an ecosystem. Generally not abundant and
can be plants and animals. E.x. Sea otters
Sea otters keystone species
•
Ecosystem Engineers
• Species that cause dramatic changes to the
landscape and create ecosystems. E.g.
Beavers with their dams creating calm beaver
pond ecosystems which many organisms
favour over rushing water from a river.
• Succession: series of changes in a
ecosystem that occur over time, following a
disturbance. Each stage is ideal for a
different species until you get to the most
diverse
Succession diagram
Aquatic succession: ponds