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Conservation Biology > Habitat Loss > Flashcards

Habitat Loss Flashcards

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1
Q

What are the seven major threats to biodiversity?

A
  1. Habitat destruction
  2. Habitat fragmentation
  3. Habitat degradation (incl pollution)
  4. Global Climate change
  5. Overexploitation
  6. Spread of invasive exotics
  7. Spread of pathogens
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2
Q

Habitat loss comprises of what ?

A
  1. Habitat destruction
  2. Habitat fragmentation
  3. Habitat degradation
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3
Q

Define sustainable

A
  • something that can continue indefinitely

* most human activities are NOT

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4
Q

What is population momentum?

A

Population momentum is defined as the ratio of the size of the population at that new equilibrium level to the size of the initial population.[1] Population momentum usually occurs in populations that are growing.

  • If limit birth rate to equal death rate, does not immediately translate into changes to population growth rate (this is why we are still growing so fast as a global pop).
  • it takes years before this turns into a stable age structure bc this will not occur until todays babies are reproductive members of pop
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5
Q

What type of characteristics might contribute to a population exhibiting population momentum?

A
  • generation time
  • # offspring
  • # offspring mortality
  • life span (short lived cannot show much momentum )
  • population momentum does not mean specifically positive or negative it could be either
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6
Q

Define habitat loss

A
  • habitat fragmentation and damage associated with pollution, as well as wholesale loss of habitat (habitat destruction
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7
Q

What is the main cause of current biodiversity loss?

A
  • habitat loss
    L> ex: in Canada we have the largest intact ancient forest…much of it is currently being managed for logging
    L> most of the USA is secondary growth
    L> Canada has the fastest disappearing rainforest
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8
Q

What is the ecosystem value of tropical rain forests?

A
  • most diverse terrestrial biome
  • goods and services
  • role in watershed management , moderate regional climate, carbon sink
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9
Q

What are the risks to tropical rainforests?

A
  • shifting cultivation
    L> aka slash and burn, swidden agricultural
    L> type of subsistence farming in which trees are cut down and burned away to clear land…farming occurs for a few years and then it is abandoned due to low soil fertility, soil erosion . Farmers move to a new patch
  • commercial interests / large scale land owners
    L> large scale cattle ranches, cultivation of commercially valuable crops
    L> logging to sell lumbar -> removal of nutrients from ecosystem, increased incidence of large scale fires (dead limbs, trees left behind)
  • increased infrastructure / roads to support commercial interests
  • worse for biodiversity : occurs on larger scale, fragments remaining habitat
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10
Q

Describe the coltan mining example for habitat loss.

A
  • coltan is a mineral used in all technology (prevents overheating /fires)
  • it is completely recyclable
  • mining for it pollute nearby land (toxic contaminant), exploits local workers (esp child labour), dangerous working conditions
  • 77% decline in Gorilla subspecies over 20 years -> decline linked to illegal mining
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11
Q

How are tropical seasonal forests threatened?

A
  • suitable for agriculture more so than rainforests (less water -> less leaching of nutrients -> richer soil)
  • shifting cultivation , 5x as many people
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12
Q

How are temperate grasslands threatened?

A
  • very fertile, nutrient rich soils, v good for agriculture
  • NA and Euro grasslands are almost completely destroyed by humans
    only ~40% grasslands protected worldwide
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13
Q

How are wetlands threatened?

A
  • critical habitat for various sp of fish, inverts and birds
  • services include: flood control, drinking water, power production
  • often filled/drained for development, altered for dams/water courses, subject to pollution
  • ~98% of streams in USA are degraded , only 0.02% of rivers in Japan is considered wild
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14
Q

How are mangroves threatened?

A
  • some tropical coastal zones dom by salt tolerant evergreen trees/shrubs, habitat for many animals, including unique ones (ex manatee)
  • services include: roots of plants trap sediments and build up shore lines, , protest inland habitat form storm surges and tsunamis
  • 50% lost by 2009
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15
Q

How are coral reefs threatened ?

A
  • 1/3 of fish species inhabit them
  • 20% of them destroyed mainly via pollution (nutrient pollution, sedimentation, costal dev, destructive fishing) and exacerbated by climate change
  • coral reject zooxanthella when they are stressed from heat, zoo cannot survive without coral..BLEACHED(occurs via warming of ocean temps..if temp doesn’t lower, coral dies)
  • 3 global bleaching events happening
    ex: staghorn coral wiped out via water temp and disease..replaced by another coral…El nino event hoped the replacement coral out
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16
Q

What does ocean acidification do to marine life?

A

lessens the ability of sp to create bicarbonate shells

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17
Q

Whats weird about deep sea coral?

A
  • down have a mutualism with zoo
  • how do they get nutrients?
  • these coral are still very species rich as well
  • at risk of trawling
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18
Q

What is desertification?

A
  • conversion foe ecosystems in seasonally dry climates into man made deserts via human activities
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19
Q

What habitats are at risk of desertification?

A
  • grasslands
  • shrublands
  • deciduous forests
  • temperate shrublands
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20
Q

What risks are associated with desertification?What is the outcome over time?

A
  • Risks: repeated agricultural use (soil erosion and mineral leaching), overgrazing by domestic livestock, woody plants harvested for fuel
  • Outcome: increases fire incidence, loss of species (not replaced by desert biome, so becomes empty wastelands without flora or fauna)
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21
Q

What is habitat fragmentation?

A
  • process by which a large, continuous area of habitat is reduced in an area and divide into multiple fragments
  • remaining fragments often isolated from each other by a highly modified or deranged landscape
22
Q

Habitat fragmentation:

- what are edge effects?

A
  • habitat fragmentait increases the amount of edge habitat and edges experience altered states of conditions (diff microclimates )
    L>ex: interior of a forest is surrounded by trees so it is quite cool; edge of a forest , the soil is only shaded part of the time, so warmer soils, diff wind conditions
23
Q

Habitat fragmentation:

- How do fragments differ from original habitat?

A
  1. fragments have greater edge per habitat (compared to OG area)
  2. Fragments are closer to edge habitat
  3. Formerly continuous habitat supported larger populations than fragments can support (pop subdivide into smaller ones)
24
Q

What are the main impacts of habitat fragmentation?

A
  1. Population effects
  2. Edge effects
    3.
25
Q

Impact of Habitat fragmentation:

- Describe the population effects.

A
  • fragments can create barriers to dispersal, restricted where organisms can travel, can prevent patches from being recolonized after local extinction events
  • if access to art of range is restricted, could prevent species from accessing key resources (including finding mates) -> can lead to pop declines
  • parts of population in diff fragments could become isolated from one another -> meta pop structure or even completely isolated populations (decrease in pop size) ?
26
Q

Impact of Habitat fragmentation:
1. Population effects
L> describe the metapopulation concept

A
  • metapopulaiton = set of local subpopulations that persist in balance between random local extinctions and establishment of new local populations
  • immigration and immigration between subpopulations are rare
  • intervening habitat (called habitat matrix) is a barrier to dispersal
  • basically the idea that occasional movement between patches facilitates recolonization after stochastic events
27
Q

Impact of Habitat fragmentation:
1. Population effects
L> metapopulations: Source vs Sink.

A
  • sources: high reproductive success in good patches
  • Sinks: low reproductive success in poor patches
  • individuals move from source to sink in density dependent manner. Emigrants outnumber immigrant sin source, opposite is true in sinks
28
Q

What is the relationship between meta populations and habitat loss via characteristics about the patches ?

A
  • habitat fragmentation can create metapopulation structure. As patches shrink/become more isolated, harder to recolonize after local extinctions. If extinction rate > colonization rate, metapopulation will collapse (total extinction).
  • Isolation by distance : patches that are further apart are more isolated, reducing colonization rate
  • reduce effect reduced when patches are further apart.
  • effect of patch size: smaller patches are harder to find and also support less individuals (more likely to be empty at any given point in time
29
Q

Impact of Habitat fragmentation:

- Describe the three main impacts of habitat fragmentation on edge effects.

A
  • Main impacts:
    1. edge habitat can have a different microclimate than intact interior regions of habitat.
    2. Increased risk of exotic and native pests /predators invading habitat from disturbed habitat edges
    3. Potential for disease transmission between wild animals and domesticated animals via habitat edges
30
Q

Impact of Habitat fragmentation:
- Describe the interior vs edge habitat characteristics of a mature forest. What happens when fragmentaiton increases edge habitat (edge effects happen)?

A

Ex: Mature forests
L> leaf layer absorbs/reflects sunlight, preventing it from reaching ground = soil temps cool, moist, shaded.
L> vegetation reduces air movement, trapping heat at night = less daily temp canes at ground level
L> Forest edges receive direct sunlight and are subject to increased wind movement = soils warmer in day, cooler at night, and more arid overall
L> Edges support different plant sp (vines and pioneer sp) than forest interior
L> If mature forest is broken into smaller habitat fragments, this will increase amount of edge relative to rest of habitat = tree deaths/ change in community composition

**basically see increase in edge habitat and species but a decrease in interior habitat and species

31
Q

Define habitat degradation

A
  • decline in the quality of a habitat that makes it less suitable or less available for species that rely on it (can occur without obvious change in community structure)
32
Q

What are the two types of habitat degradation?

A
  1. Physical degradation

2. Chemical degradation

33
Q

What are examples of physical habitat degradation ?

A
  • soil loss, sedimentation depositions, desertification due to agricultural practices, water usage for corp irrigation, hydropower
34
Q

What are examples of chemical habitat degradation?

A
  • pesticide usage, other chemical pollutants, N inputs due to fertilization or untreated sewage (algal blooms, make and ocean eutrophication), greenhouse gasses through fossil fuel consumption
35
Q

Define biomagnification / bioamplification / biological magnification

A
  • when substance increases in concentration as it moves up a food chain
36
Q

What are causes of bioamplification?

A
  • inability of organisms to break it down (store in fat etc instead)
  • food chain energetics
  • water soluble chemicals have a low rate of degradation or excretion
37
Q

Describe the impact of chemical degradation via DDT and other organochlorine pesticides.

A
  • use of these pesticides are linked to declines in raptors, predator fish, dolphins, other predator sea mammals
  • declines in beneficial insects, endangered insects also reported
  • target insects showed increased resistance, reducing effectiveness of insecticide over time
  • high concentrations found in polar bear tissues (effects of DDT spread far beyond area where it was used)
38
Q

Describe how other insecticides, herbicides, fungicides are linked to declines in honeybees, bumblebees, other wild bee pollinators?

A
  • esp fungicides
  • honey bees have a mutualism with fungi to preserve pollen in the bee hive, fungi eat the pollen and bee larvae eat the fungi so if bringing this pest control into hives will cut out its food supply
39
Q

Explain raptor decline via chemical degradation by DDT usage.

A
  • After 1940s rapid decline until almost completely extirpated in 1970s, listed as endangered in USA
  • high pesticide DDT concentration in raptor tissues, and nest failure
  • increased levels of DDT led to fragile eggs (females would break eggs while attempting to incubate them via low reproductive success)
  • DDT usage has been banned in most industrialized countries. Conservation efforts aimed at captive breeding programs (using puppets to mimic parent feeding). Once hand raised birds old enough, released into wild. Partial recovery now.
40
Q

Explain colony collapse disorder

A
  • is the phenomenon that occurs when the majority of worker bees in a colony disappear and leave behind a queen, plenty of food and a few nurse bees to care for the remaining immature bees.
  • fungicide is one reason for this
  • leaves one queen left
  • 50% wild bee sp have gone extinct too, not just domestic honey bees
41
Q

Explain how water pollution occurs, and its impact on the rest of the environment.

A
  • nutrient pollution, pesticides, herbicides, oil products, heavy metals, detergents, toxic chemicals, industrial waste products that end up in water directly killing organisms
  • pollutants can also diffuse over wide areas and make environment inhospitable to species through effects like biomagnification
42
Q

What is eutrophication?

A

excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen
** nitrogen and phosphorus pollution from anthropogenic sources = algal blooms = increased decomposition and decrease oxygen = dead zones
L> lakes and oceans have N and P deficiency so when they increase, primary productivity increases, algal blooms happen

43
Q

What is an inverted energy pyramid?Related it to eutrophication.

A
  • when biomass is highest on the lowest end of the energy pyramid..like algal
    L> when eutrophication happens, there is so many algal that the food chain goes from most algal being eaten to now algal going through their life cycle and dying..sinking to the bottom. Decomposers are happy but oxygen decreases in area, resulting a dead zone
44
Q

What is a dead zone?

A
  • an area of an ocean (or lake) that has too little oxygen to support marine life because it is hypoxic. Dead zones are increasing in shallow coastal and estuarine areas as a result of human activities
45
Q

What is biomanipulation?

A
  • deliberately altering an ecosystem by adding or removing species
46
Q

What are the two ways biomanipulation can be used to remediate eutrophication?

A
  1. Bottom up regulation
    L> focuses on controlling nutrient inputs through managing terrestrial ecosystems -> often involves setting up buffer zones along rivers/restoring wetlands near lakes/ oceans to prevent nutrients from making it into aquatic systems (costly, or sometimes not possible to do)
  2. Top down regulation
    L> uses food web dynamics to control phytoplankton
    L> only solution when cannot control nutrient inputs , generally cheaper option (eg stocking fish)
    *stocking brings fisherman, so you can get funding via licenses
47
Q

What is the cheapest option for remediation of eutrophication in lakes?

A
  • top down regulation
  • if you can increase the number of zooplankton that consume phytoplankton, this a control algal blooms without costly terrestrial management
  • zooplankton are eaten by zooplanktonivorious fishes, so can increase zooplankton by decreasing fishes that eat them
  • zooplanktonivorous fishes are eaten by piscivorous fishes, so if increase higher level consumers, can lead to trophic cascade that can control algae numbers
  • for this type of regulation, controlling the top trophic level impacts all trophic levels below it (trophic cascade)
48
Q

What management technique can be used for marine dead zones (eutrophication in oceans)?

A
  • cannot use top down regulation bc it isn’t feasible (sp can just leave area)
  • bottom up is the only option
  • this can be done via wetland construction/restoration -> filter nutrient pollution out of water before it reaches the ocean
    L> added benefits -> wetlands offer flood protection / storm surge protection for inland habitats (esp important in face of climate change)
49
Q

What are two forms of air pollution discussed in class?

A
  • Acid rain

- Photochemcial smog

50
Q

What is acid rain?

A
  • smelting operations / coal plants -> nitrogen and sulfur released to atmosphere = combine with water vapour to form nitric and sulphuric acids
  • decreases pH in rainwater, soil moisture, water bodies
  • effects: weakens/kills trees, kills aquatic organisms, decreases reproductive success for fish and amphibians, inhibits soil decomposition, lowers speed of nitrogen cycle = decrease of primary productivity
51
Q

What is photochemical smog?

A
  • hydrocarbons and n-oxides (produced by industrial activities) react to sunlight by producing ozone and other secondary compounds
  • effects: ozone at ground level -> damages plant tissues, reducing productivity; harmful when inhaled = can kill animals (including people); airborne nitrogen compounds deposited in rain/dust = can lead to nitrogen pollution combining with acid rain to decrease density of mutualistic soil fungi (decreasing tree health indirectly)
52
Q

How was acid rain and ozone depletion solved?

A
  • USA Clean Air Act and Canada’s version
  • required all cars to have catalytic converters and phase out elated gasoline, also included industrial smokestack requirements to control for sulphur emissions
  • there has been a decrease in pH precipitation in USA

**The cheeto Trump plans for rollbacks…eek

Conservation Biology (13 decks)

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