lecture 5 - habitat degradation

Question 1

define habitat degradation

Answer 1

• When habitat is left relatively intact, but is damaged by human activities in other ways.
  
  • Decline in habitats, not complete destruction
  • Inability for habitat to support life / biodiversity

Question 2

pesticide pollution impact?

Answer 2

Biomagnification: pesticides become concentrated as they move up the food chain
• Run off, indirect
• Ex - eating a high fish diet = more magnified in humans than fish

Question 3

ddt in humans?

Answer 3

• ex. DDT safe in small amounts for humans
○ Animals at bottom of food chain exposed = spread throughout food chain up towards humans
Lengthy breakdown time

Question 4

how is water polluted

Answer 4

• Pesticide use
• Microbeads (plastic) build up in ocean
Floating of microbeads = consumed by organisms = large impact on global ecosystem (ie filter feeding organisms)

Question 5

air pollution impacts and causes?

Answer 5

• Acid rain from release of sulfur oxide and nitrogen oxide
  
  • Ph 4-4.5 (1000x more than 7/neutral)
  • Chimneys 300 m up- release smoke/gas at higher levels to avoid pollution at ground level -disperse throughout world
  • Tragedy of commons - atmosphere

Question 6

what happens to fish at phs 4, 5, 6?

Answer 6

○ All fish die at 4.2 pH
○ At pH 6 - reproductive issues
○ Eggs unable to produce at pH 5

Question 7

how can we measure pollution in the arctic?

Answer 7

○ Can measure pollution based on atmospheric gas levels and pollution in snow

• 
• Ex. Passive pollution in arctic - lead buildup in greenland despite no production - from global distribution also can measure CO2 and emmissions directly

Question 8

what is climate change? greehouse effect?

Answer 8

• Changes in climate characteristics bc of an increase in temps as a result of an increase in greenhouse gases
•
• Greenhouse effect: gases trapped between atmopshere and earth (methane, co2, water)
○ Ex. Ice core data

Question 9

ice core data use?

Answer 9

○ Drill out data and study what water content and air looked like in the past (arctic, greenland)
§ Measure amount of co2 by separating isotopes using a magnet and determine where co2 came from based on isotopic analysis

Question 10

how have humans impacted the carbon cycle? suess effect?

Answer 10

• More co2 as time goes on bc anthropoegenic
• Less co2 when covid restrictions - evidence
• Suess effect - isotopic analysis of carbon -14C in atmosphere - decrease with the burning of fossil fuels depleted in 14C
○ Burning fossil fuels vs not burning
○ Changes natural production of CO2

Question 11

is climate change uniform? how does it vary?

Answer 11

• Not uniform - cooler vs warmer areas
• Northern latitudes getting warmer compared to southern areas - black dirt vs white surfaces (ie snow)
○ Albedo
○ Positive feedback loop: once snow melts, warm up occurs event faster

Question 12

list of impacts of global warming

Answer 12

• Some effects of global warming:
○ Increased temp and incidence of heat waves
○ Melting glaciers and polar ice
○ Rising sea levels
○ Earlier spring activity - ie flowers bloom earlier, requires pollinators present
○ Shift in species ranges
○ Pop. Declines
○ Briefer periods of precip
○ Lower water levels - ex. NS river
§ Saskatchewan glacier melting and source running lower (fresh water)
○ Coral bleaching - loss of symbiosis
§
○ Ice melting
§ Shipping lares as ice melts - risks exposure to oil spills and other disruption leading to habitat loss

Question 13

range shift impact and ex?

Answer 13

○ Range shift - Mountainous species tend to move upward as temp increases (temp drops as u increase altitude)
§ Ex. Picas- older pops in warmer rangers while newer pops show expansion into colder regions

Question 14

what is a fundamental niche

Answer 14

defined as the set of conditions within which a species can live in the absence of competitors
Fundamental niche - effect of environmental conditions

Question 15

niches and zones?

Answer 15

zone of intolerance - species absent, unavailable niche
zone of physiological stress - marginal niche, species infreq., lower limit of tolerence
optimal range - preferred niche, sp. abundant
upper limit: zone of physiological stress and intolerance, marginal + unavailable niche

Question 16

tolerance limits?

Answer 16

• Each environmental factor (temperature, nutrient supply, etc.) has both minimum and maximum levels beyond which a species cannot survive or is unable to reproduce.

Question 17

realized niche?

Answer 17

• Realized niche = result of species interactions + environment tolerance

Question 18

how does GIC work - geographic information system

Answer 18

• niche modeling
Uses data layers ( often independently collected) to combine = get a complete pic of the area
• Ex. Street data + building data + vegetation data = integrated data
• Uses niche modeling to determine ideal habitat of species

Question 19

examples of over exploitation?

Answer 19

• Threat to biodiversity
  
  • Overfishing - 1/3 of catch thrown back dead into ocean
  • Fishing is cost effective at providing resources to people - tragedy of the commons
  • Elephant tusk exchange on black market
  • Penguin harvesting - no resource of survival reasoning behind this
  • Cactus plant exploitation in deserts
  • Amphibians and reptiles as household pets

Question 20

ant eating pangolin ex?

Answer 20

moost illegally trafficed animal

Question 21

what are invasive species?

Answer 21

• species that cause harm in regions where they have been introduced by humans and did not
naturally occur.

Question 22

costs of invasion?

Answer 22

•an "invisible tax"
 Global: > $1.4 trillion/yr 
• Canada 
• Ten aquatic species > $187 
million/yr 
• Estimate "invisible tax" for 
only sixteen species > $20 
billion 
• US: 
• $120 billion/yr for all exotic 
animals alone 
• $3 billion/yr for weed control; 
crop loss > $25 billion in 
California alone

Question 23

examples of invasive sp.

Answer 23

• Alberta’s regulated weeds
○ Prairie grasses - often considered invasive sp. Bc of how easy it spreads and takes over other grass sp.
• Zebra mussels
○ Dead mussel shells covering beaches
○ Change aquatic ecosystem by filter feeding out so much plankton that other sp. Cannot survive
○ Easily transportanble as they stick to surfaces easily ie boats
○ Ballast water - used to keep boat low in shallow water by filling boat w water = resulting in spreading non-native sp. When dumped

Question 24

invasion process steps?

Answer 24

transport: • Non natives begin as individuals in native
range transported to new area
establishment: • Established self-sustaining population in
new range
Spread: • May grow in abundance & expand range

impact: Typically only after increase in abundance &
spread does impact occur
• Rule of tens - 1 in ten survive each step

Question 25

ex of invasive sp. excluding other sp?

Answer 25

flowering tree invasive to UK beats out all other mosses, grasses, and forbs

Question 26

brown tree snake ex?

Answer 26

Native to Papua New Guinea 
Probably introduced to Guam after WWII 
in cargo. 
A generalist predator that climbs well, 
but not particularly fast reproducer. 
Maximum densities of up to 5000/sq. km 
observed. 
Few native predators on Guam and has 
resulted in the extinction of most native 
birds and lizards. 10-12 native forest 
birds species decimated in forests.

Question 27

worm ex of invasion?

Answer 27

• In NA there are no native earthworms ( ecosystem engineers)
  
  • Reintroduced by glaciers from europe
  • Once established, they are moved/dumped everywhere by fishers and farmers

Question 28

why is disease a concern for invasive sp? example?

Answer 28

• Concern based on an ability of species to pass diseases onto other species
  
  • Bat ex
  • Isolated in caves typically
  • Effected by fungus based disease - up to 90% of populations of bats introduced by human interaction

Question 29

what is the tragedy of commons?

Answer 29

tragedy of commons - when a resource is shared/a public good, people do not have interest to preserve it whereas when its someones own property, they tend to protect it - passing it to the commons = less incentive to care for it by the individual

Question 30

what is the suess effect in detail?

Answer 30

The Suess effect is dilution of the atmospheric concentrations of heavy isotopes of carbon (13C and 14C) by the admixture of large amounts of fossil-fuel derived CO2, which is depleted in 13CO2 and does not contain any 14CO2.