M3L3 - Aquatic Environments & Invasive Species

Question 1

Tipping point

Answer 1

• A level of change in system properties beyond which a system reorganises, often in a non-linear manner, and does not return to the initial state even if the drivers of the change are abated
• Once crossed often have severe impacts on humans
• e.g. Coral reef die off

Question 2

Broad climate change predictions on aquatic systems

Answer 2

• Global increases in temperatures (air and water)
• Decreased winter periods
• More variability in weather
• Increased fire occurrence

Question 3

Warming water

Answer 3

• Affects feeding, growth & reproduction of aquatic species
• Can intensify low oxygen zones in lake bottoms
• Reduces habitat suitability for cool and coldwater fishes

Question 4

Shifting streamflow

Answer 4

• alters species abundance and composition
• Threatens mussel habitat
• Mismatches the timing of biological events like emergence & migration

Question 5

Drying wetlands

Answer 5

• Reduces habitat quality & connectivity
• Shifts vegetation to dry-land types
• Reduces breeding success for frogs and salamanders

Question 6

Endotherms

Answer 6

• Animals that are able to regulate their body temperature internally
• Higher metabolic rate (using more energy) to maintain body temperature

Question 7

Ectotherms

Answer 7

• Rely on external heat sources to maintain their body temp
• More susceptible to changes in water temperature. Slow down when cold.

Question 8

Are most aquatic animals endotherms or ectotherms

Answer 8

Ectotherms

Question 9

Invasive species

Answer 9

• Changes in environmental conditions can favour or promote certain invasive species
• Movement of species aided by climate change
• Once they take hold can become hard to get rid of
• Often have limited or no natural predators

Question 10

Effects of climate change on invasive species

Answer 10

• More frequent extreme weather events: stress native species and create opportunities for invasive movement
• Melting sea ice opens new pathways for spread
• Changing climate can affect species life cycles
• Increased Co2 leads to higher uptake in plants, increasing herbicide resistance

Question 11

Sleeper species

Answer 11

Non native species that are limited in their invasion by certain environmental conditions

Question 12

Example of sleeper species

Answer 12

• Mountain Pine BEetle
• Extended periods of cold weather kills off
  beetles
• Limits their range
• Warmer weather enhances survival and
  increases range