Biodiversity

DefinitionThe 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