Biodiversity 1 Flashcards
How do we understand where and how to act, as well as evaluating if we are achieving our goals?
We need to understand biodiversity patterns and how they change
How many species are there?
We don’t know
Estimated 3-30 million on land and 1-10 million in the sea.
Approximately 2.2 million species have been described
Terry Erwin’s fogging in 1971
Terry Erwin fogged 19 trees of Luehea seemanii which produced 1200 species of beetles
163 were estimated (guessed) to be specific to that tree species (>10%)
His logic:
- assume 40% of arthropods are beetles
+ 30% of fauna is in the litter layer
x 50,000 tropical woody tree species with the same number of species = 25 million species
+ 5 million non specific species
= 30 million
- Lots of problems with these estimates
What factors determine global patterns?
Climate
- temp, precipitation, seasonality, extreme microclimates
Geology/topography
- mountains, oceans, size, altitudinal and depth gradients
Landscape
- Resources, habitat heterogeneity, isolation
History
- Evolutionary, speciation/extinction, dispersal/colonization
Biotic factors
- Interactions, traits, resources
People
Conservation priorities - how should we prioritize?
Conservation status - rare and threatened species
Irreplaceability - e.g., endemic species
Complementarity - polar bears don’t eat penguins
Urgency - are there threats facing the areas/species?
Opportunity - where do we get most for our money
Global biodiversity hotspots - the idea
- High percentage of plant life found nowhere else on the earth. “in other words, it is threatened and irreplaceable”
- Must have 30% or less of its original natural vegetation. “in other words, it is urgent”
Summary
We are far from having certain knowledge about numbers of species or their patterns
Driving forces in the distribution –> high biodiversity in the tropics, in mountains, along the coast, in old ecosystems and close to people
These patterns and trends are critical for priority setting and assessing interventions
