Biodiversity & biodiversity loss

Question 1

Reasons for declines in biodiversity

Answer 1

• Overuse: Overgrazing, Overfishing, overhunting and collecting (direct decline and extinction).
• Habitat fragmentation and destruction: Urbanization, agriculture, forest logging (land use changes).
• Invasive species: Ecosystem changes, predation, competition.
• Pollution: Ecosystem changes, input of nitrogen, synthetic compounds, i.e. pesticides, plastics.
• Global warming and climate change: Range shifts, changes of environmental conditions within habitats.

Question 2

What are the consequences of biodiversity loss?

Answer 2

Consequences for humans and human wealth:
• Loss of ecosystem services, i.e. pollination of crop plants
• Ecosystems become less stable and less resistant against extreme climate conditions (drought, flood)
• Loss of sources for developing new drugs
Consequences for species and ecosystems:
• Reduced population sizes, reduced fitness Loss of seed dispersers and pollinators
• Ecosystems less resistant to disturbances (insect outbreaks, physical damages (floods, landslides…)
• Loss of ecological interactions between species

Question 3

Co-extinction

Answer 3

Specialist species are prone to extinction if their host species/pollinator/interaction partner becomes extinct.