lecture 5 - habitat degradation Flashcards
define habitat degradation
- 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
pesticide pollution impact?
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
ddt in humans?
• 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
how is water polluted
• Pesticide use
• Microbeads (plastic) build up in ocean
Floating of microbeads = consumed by organisms = large impact on global ecosystem (ie filter feeding organisms)
air pollution impacts and causes?
- 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
what happens to fish at phs 4, 5, 6?
○ All fish die at 4.2 pH
○ At pH 6 - reproductive issues
○ Eggs unable to produce at pH 5
how can we measure pollution in the arctic?
○ 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
what is climate change? greehouse effect?
• 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
ice core data use?
○ 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
how have humans impacted the carbon cycle? suess effect?
• 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
is climate change uniform? how does it vary?
• 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
list of impacts of global warming
• 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
range shift impact and ex?
○ 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
what is a fundamental niche
defined as the set of conditions within which a species can live in the absence of competitors
Fundamental niche - effect of environmental conditions
niches and zones?
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
tolerance limits?
• Each environmental factor (temperature, nutrient supply, etc.) has both minimum and maximum levels beyond which a species cannot survive or is unable to reproduce.
realized niche?
• Realized niche = result of species interactions + environment tolerance
how does GIC work - geographic information system
• 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
examples of over exploitation?
- 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
ant eating pangolin ex?
moost illegally trafficed animal
what are invasive species?
• species that cause harm in regions where they have been introduced by humans and did not
naturally occur.
costs of invasion?
•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
examples of invasive sp.
• 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
invasion process steps?
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
ex of invasive sp. excluding other sp?
flowering tree invasive to UK beats out all other mosses, grasses, and forbs
brown tree snake ex?
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.
worm ex of invasion?
- 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
why is disease a concern for invasive sp? example?
- 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
what is the tragedy of commons?
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
what is the suess effect in detail?
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.
