L20 - Biodiversity

Question 1

How many species have been identified currently?

Answer 1

• 1.75 M identified
• 8.7 M estimated
• Estimates have ranged 3M-100M

Question 2

What are drivers of species extinction?

Answer 2

• Habitat loss
  
  • Population size related to the probability of local extirpation
• Overexploitation
  
  • With a growing population, have arguably overexploited a lot of these resources
• Pollution
  
  • Eutrophication leads to algal blooms and then dead zones & fish kills
• Climate change
  
  • Species’ homes being destructed faster than they can adjust
  • Species moving to areas they are not well adapted to (Polar bears moving south)
• Invasive species
  
  • New predators can wipe out entire populations

Question 3

Biodiversity loss:

Answer 3

• ~900 species have gone extinct in the last 500 years
• ~ 400/50 000 vertebrate since 1900
• 10 000- 100 000 species lost per year?
• 1M species at risk (IPBES 2019)
• Potentially orders of magnitude beyond background rate
• Potentially changes in abundance before extinction

Question 4

Why should we care about biodiversity loss?

Answer 4

• The way our planet works relies on biodiversity
• Ecosystem services provided by biodiversity
  
  • Direct: resources (e.g., food)
  • Indirect: environmental modification
  • Lifestyle: recreation
• Ethics: Intrinsic value of biodiversity (beyond their services provided to humans)
• Culture
• Livelihood: many countries are economically dependent on these different species
• Medicinal discoveries from plants

Question 5

Medicinal properties of plants?

Answer 5

• Drug vincritine to treat leukemia
  from rare Rosy Periwinkle
• Taxol for ovarian cancer from
• Pacific Yew tree

Question 6

Food resources?

Answer 6

• Wheat
• Soy
• Cattle

Question 7

Culture?

Answer 7

• Hunting & fishing
• Beaver, salmon - species significant to a nation/culture

Question 8

Indirect services

Answer 8

• Climate control
• Physical stability (coral reefs)
• Recreation

Question 9

Economic valuations?

Answer 9

• Use value: direct use value
  
  • Consumptive use value: provisioning services
  • Non-consumptive use value: cultural services
• Indirect use value:
  
  • Regulating services, supporting services
• Non-use value:
  
  • Existence value
  • Option value
  • Bequest value
    
    • Provision, cultural, regulating, supporting services…

Question 10

Examples of ecosystem services?

Answer 10

• Provision of food, fuel and fibre
• Provision of shelter and building materials
• Purification of air and water
• Detoxification and decomposition of wastes
• Stabilization and moderation of the Earth’s climate
• Moderation of floods, droughts, temperature extremes and the forces of wind
• Generation and renewal of soil fertility, including nutrient cycling
• Pollination of plants, including many crops
• Control of pests and diseases
• Maintenance of genetic resources as key inputs to crop varieties and livestock
  breeds, medicines, and other products
• Cultural and aesthetic benefits
• Ability to adapt to change

Question 11

What species (types) play a role?

Answer 11

• Predominantly plants !!!!
• Some species of animals
• Specific types of organisms and species that provide these ecosystem services, not just “biodiversity” at large

Question 12

What is the niche complementarity hypothesis?

Answer 12

Differences between species in their functional traits (feeding habits, spatial distribution, and reproductive strategies) will enhance ecosystem functioning by allowing greater complementarity in resource use between species (avoiding direct competition with each other)

Question 13

Which ecosystem is “better”? More stable? For which should we spend resources to conserve?

Answer 13

• 50s & 60s: the one with more interactions
  
  • The more pathways there are, the less severe the failure of any one pathway.
• 70s & 80s: more complex systems (higher biodiversity) are the least stable
  
  • more pathways/opportunities of failure
• Current: depends on the types of interactions

Question 14

Species environment interactions: redundancy & stability

Answer 14

• Improved stability with increasing diversity:
• Portfolio effect/Statistical Averaging
  
  • Sum of many random fluctuations will average out to produce a more stable ensemble

Question 15

What is the spatial insurance hypothesis?

Answer 15

Local diversity may be maintained by immigration from the region, which provides the source of variation (species or genetic diversity) that can buffer ecosystem processes against environmental variation.

Question 16

Can diversity affect stability?

Answer 16

Yes.

Question 17

Policies: what are we doing about it?

Answer 17

• Canadian Biodiversity Strategy
  
  • Canada’s national strategy
• Endangered Species Act (USA)
  
  • Protection of individual species and their critical habitat
• Species At Risk Act (SARA)
  
  • Protection of individual species
• Environment Canada Protected Areas Network
  
  • Over 90 million ha in land protected (National Wildlife Areas, Migratory
  • Bird Sanctuaries, Marine Wildlife Areas, International, other)
• Canadian Wildlife Act
  
  • Habitat Conservation Program & others
• AAFC: Agriculture and Agri-Food Canada
  
  • Programs to protect biodiversity, genetic resources, sustainable land use
• Canada National Marine Conservation Areas Act
  
  • Parks Canada
• Others … (Intergovernmental Platform for Biodiversity & Ecosystem Services (IPBES)