Conservation Ecology: Human Impacts Flashcards
what % is the human population growing per yr?
1.1% (135 million births and 55 million deaths)
major impacts to earths ecosystems resulting from human population growth
habitat loss
what is the most invasive form of habitat loss?
deforestation
which country has the largest density of people per sqr/km
india
which country has the smallest density of people per sqr/km
usa
where has the highest growth rate?
africa, india
when did human population start to ramp up in a hx context?
industrial revolution
_____ and _____ lead to the current huge human popularion
large families, low mortality
methods of deforestation
clear cutting, variable retention, and selective cutting
selective cuttign
removal of single trees by helicoper
- leaves small gaps in the canopy in which seedling develop
- most similar to natural disturbance
- cost prohibitive in most areas
variable retention
leave representative old growth in each cut block (10-30%) retention, low profit margin due to high costs of road contruction
clear cutting
remove all trees in patches up to 2000ha (80yr rotation) - most invasive, most widespread around the globe, greatest profit margin
human population increases by ____ million per year
80
soil and lemur population
- in madagascar forests were comprised for profit
- lateritic soil (leached of silica after deforestation)
- concentration of iron, maganese, aluminum, nickle
- leaked into the ocean and killed coral reefs
- lemurs still exist but will go extinct
amazon deforestation
- deforestation for cattle export
- burned/slashed agriculture
- largest cattle farm in the world, sent cattle to 170 countries (3x export in past 3 years)
what country has the highest rate of deforestation per year?
brazil
- protest by indigenous
- little response by the educated class
Brazil implemented new laws to combat deforestation; however, locals complain that these laws are______and allow those responsible for the main environmental impacts to go ______
ineffective, unpunished
brazils new laws about deforestation
- remission of penalties in landowners who illegally remove native vegetation
- reduce the areas classified as “requiring restoration”
- injustice in the population
- means that insect collectors are charged with high fines but landowners receive no
-punishment for illegal reforestation
what did the ecuadorian government annouce?
- recent signings of 2 new oil concession in yasuni national park
- piplines, wells, drilling platforms, etc
what ecosystem has the greatest biomass/ha?
coastal temperate rainforests
what is remaining of BC’s coastal temperate rainforest?
1/4
on haida gwaii, 70% of the forest is…
gone
loss of forests due to
logging
gribbrell island
- government clearcut river
- was main source of salmon for bears
- 80% reduction of their major protein source for bears
haida gwaii logging
- 70% of best forest gone
- spokes person said there is more oldgrowth forest now than 100 years ago (which is FALSE)
- 1967 = first clear cutting, all large trees are now gone expect in protected areas
about ___ of the worlds temperate rainforests have been cut
1/2, 55%
how much of washingtons,oregons, and cali’s ancient rainforests is gone?
95%
grasslands and savannas have the biggest ___
herds
grasslands/savannas are mostly used by humans for ___ and ____
crop land, pasture land
increased loss of grasslands/savannas is a direct result of ___
human population growth - need to feed all these people
where are the only natural grasslands left?
albera and saskatchewan
edge effect leads to
reduced fragment size
what does reduced fragment size lead to?
reduced size of populations and reduced number of species
creation of forest edges has global impact on forest vertebrates: what did they do?
assembled global database on species response to fragmentation
creation of forest edges has global impact on forest vertebrates: what % of abundances of species are affected?
85%, positively or negatively by forest edges
creation of forest edges has global impact on forest vertebrates: which species were most likely to be listed as threatened?
species that live in the centre of the forest (forest core), reached peak abundances at sites further than 200-400m from forest edge
creation of forest edges has global impact on forest vertebrates: what experienced larger reduction in suitable habitat?
smaller bodied amphibians, larger reptiles, and medium sized nonvolant mammals compared to other forest core species
ecological impacts of global warming on terrestrial ecosystems
a) Northerly range expansion of southern species
b) Reduction or loss of Arctic species, seasonal migrants
c) Loss of tundra, permafrost, sea ice
d) Sea level rise and flooding of coastal zones
e) Increased major weather events (eg, hurricanes, aridity, fires)
f) Loss of species with restricted distributions
g) Increased human mortality during elevated summer temperatures
h) Ecological shifts to early seral stage communities
i) Exacerbates the effects of habitat loss
biodiversity, origination and extinction in the fossil record: what did they do?
analyzed fossil record for the last 520myr against estimates of low latitude sea surface temp for the same period
biodiversity, origination and extinction in the fossil record: what did they find?
global biodiversity is related to temp and has been relatively low during ‘greenhouse’ phases, while during the same phases extinction and origination rates of lineages have been high
biodiversity, origination and extinction in the fossil record: what do the results indicate?
clear evidence that global climate may explain substantial variation in the fossil record in simple and consistent manner
what are the atmospheric contaminants pertaining to global warming?
- carbon dioxide
- black carbon
- methane
- nitrogen trifluoride
- chlorofluorocarbons
- sulphur dioxide
explain the greenhouse effect
Co2 lets sunlight through but retains the heat generated by the sun
what does adding co2 to the air do to the greenhouse effect?
increases it
what does removal of co2 from the air by ______ and _____ do?
photosynthesizing plants and algae, decreases the greenhouse effect
is the atmospheric carbon dioxide graph about global warming?
no, graphs depicting atmospheric carbon dioxide are about co2 not global warming
atmospheric co2 can be measured by
antarctic ice cores
what is the evidence that co2 rise is due to the burning of fossil fuels?
co2 from fossil fuels is made from different radioisotope than typical co2
atmospheric co2 concentrations historically range from _______, recently they have risen to _____
190ppm to a max of 380ppm, risen to 414 ppm (as of oct 2022)
when looking at co2ppmv and years, they also looked at ____. what was the pattern?
temperature. as co2 goes up, so does temperature
fossil fuels were formed about ____ from the forests and swamps of the ____
300 million years ago, paleozoic
atmospheric co2 three isotopes:
C12(99%), C13(~1%), C14 (0.0000000001%-radiocarbon)
living plants absorb co2 with…
C12, C13 & C14
what do dead plants absorb?
nothing, no absorption
C14 is ____, ___% decays to ___ every _____.
unstable, 50%, N14, 5730yrs (half-life)
most C14 in plants disappears in…
1 million years
co2 from fossil fuels lacks…
C14
burning fossil fuels relases ____ without ___
co2, c14
what does measuring atmospheric levels of C14 provide info on?
fossil fuel consumption
highest co2 concentrations are in…
europe and eastern USA
black carbon
particles of soot from incomplete combustion
- subparticles that float up into the atmosphere
what is black carbon from?
campfires, burning of anything
black carbon is responsible for…
50 percent of the total temperature increases in the Arctic from 1890 to 2007.
black carbon is produced by ____ (naturally) and _____ (human created_
forest fires, industry
global and regional climate changes due to black carbon: black carbon in soot is the _____
dominant absorber of visible solar radiation in the atmosphere
global and regional climate changes due to black carbon: most are concentrated in the ___
tropics where solar irradiance is highest
global and regional climate changes due to black carbon: black carbon is transported…
over long distances
global and regional climate changes due to black carbon: emissions of black carbon are
the second strongest contribution to current global warming
global and regional climate changes due to black carbon: combo of what things makes black carbon strong contribution to global warming?
high adsorption, regional distribution aligned with solar irradiance, capacity to form atmospheric brown clouds with other aerosols
global and regional climate changes due to black carbon: in the _____ region, solar heating from black carbon at high levels….
himalayan, may be just as important as co2 in the melting of snowpacks and glaciers
global and regional climate changes due to black carbon: interception of solar radiation by ____ leads to
atmospheric brown clouds, dimming at the earths surface
sources of methane
30% natural sources, 70% anthropogenic (mainly agriculture and fossil fuels)
what is the distribution of methane in a global conext?
not much in the southern hemisphere, primarily in the northern hemisphere
atmospheric ch4 concentration typically cycles between ____ but in 2023 was ____
325 ppbv to 700, 1917 ppbv
how do we analyze methane?
ice cores
one molecule of methane has…
~80 times the
effect on global warming as one molecule of carbon dioxide
NF₃ (nitrogen trifluoride)
industrial gas used in semiconductor manufacture (which are now being mass produced now)
NF₃ relative efficiency and global warming potential relative to a molecule of CO₂…
17,200 times worse than co2
nitrogen trifluoride in the global atmosphere: what were they looking at?
trends of NF3 as a greenhouse gas
nitrogen trifluoride in the global atmosphere: NF3 concentration has risen, what does this correspond to?
about 620 metric tons of current NF3 emisions globally per yr, or about 16% of global NF3 production estimate of 4000 metric tons
ozone is a natural atmospheric gas formed in the _____ at 20km elevation
stratosphere
atmospheric ____ absorbes 99% of UV-C and 50% of UV-B
o3 (ozone)
order of most to least powerful UV lights
UVC (<290nm), UVB (290-320nm), UVA (320-400nm)
what does o3 do?
absorbs UV radiation form the sun effectively
CFC
inert, non-reactive solvent, refrigerant, aerosol that rises high in the atmosphere
CFCs are only inert until the are struck with _____ _____, then they destroy ozone
UV radiation
there has been an increase in _____ _____ in whales as a result of the ozone hole
skin cancer
which pollutants increase smog but reduce global warming?
So2 - sulfure dioxide
which pollutants increase global warming?
CO₂, black carbon, CH₄, (methane) NF₃,(nitrous fluoride) NO,(Nirtous oxide) CFC (chlorofluorocarbons)
burning of fossil fuels rich in sulphur results in
increased acidity of precipitation
_____ counteracts global warming
SO2
SO₂, NOx + H₂O in the atmosphere =
H₂SO₄
HNO₃
HNO₃ is ___% of acid rain
H₂SO₄ is ___% of acid rain
25
75
pH of natural rain = ~___
pH of acid rain = ___-___
5.8
3.2-5.0
acid rain damages _____ and ____ in eastern US, _____ in China
forests
crops
agriculture
acid rain results in
-major loss of forests and death of aquatic ecosystems in lakes of northern hemisphere
acid rain kills ____ in lakes
primary production
environment: the case for clean air: dirty air can ____ lifespan
decrease
WHO has set the healthery level of air quality at ___ micrograms
25
nuclear power plant pros:
high efficiency
require little fuel
few greenhouse gases
nuclear power plant cons:
high environmental and human damage with failure
cost of _____ for a nuclear power station: $10 B
cost of _____ for a nuclear power station: $190 B
construction, clean-up
in the human population, Chernobyl lead to increased _____ and _____
cancer, birth defects
what do nuclear power plants use for fuel?
uranium or plutonium
what cancers have increased due to radiation exposure
200% increase in breast cancer, 10% increase incidence of cancer and leukemia, 2400% increase of thyroid cancer
environmental impacts of chernobyl
- 99% of the Belarius is contaminated to degrees above internationally accepted levels
- 2,000 towns and villages were evacuated
- more than 400,000 thousand have been relocated and 70,000 ppl are still waiting to evacuate
- 30-70 squred km will nver be able to be liveable again
- half life of 24,400 years
how many people died from radiation exposure in chernobyl
1 million but another study says that there is no scientific evidence of any significant radiation-health effects to most ppl
aquatic pollutants
- ocean warming
- ocean acidifcation
- oil spills
- industrial chemicals and biocides
- plastics
“effect of ocean acidification on iron availability to marine phytoplankton”
the bioavailability of _____ may decline because of ocean acidification. the ongoing acidification of seawater is likely due increase the _____ stress of phytoplankton populations in some areas of the ocean
iron
Number of major oilspills have been ______ most years over the last 3 decades
decreasing
exxon valdez was a result of _____ _____
human error
what did Hazelwood do?
- drunk and drove a boat into rocks
- 250, 000 barrels of oil discharged (10 million gallons)
- polluted 2100 km of coastline
- killed 250, 000 seabirds, 2800 sea otters, 300 harbour seals, 250 bald eagles, 22 whales
what molecule experiences biomagnification
DDT
DDT bioaccumulates up trophic levels, causing and 80% mortality of bird eggs and chicks because it disrupts proper _____ ______
shell formation
“silent spring” lead to a ban on _____
DDT
when was there a ban of DDT in US and a world ban of DDT?
- ban in US: 1972
- world ban 2002
- some countries still use DDT to kill mosquitoes because malaria is such an issue
polychlorinated biphenyl study
Fish travelling to Alaska are carrying PCB with them
- may be harmful for the regions top carnivores
- [PCB] 7x higher here
- comparable to lake superior (highly populated)
St. Lawrence Beluga Whales that washed up dead on shores had high levels of ______ (disease)
intestinal cancer
St. Lawrence Beluga Whales that washed up dead on were highly contaminated with ______ (chemical)
PAH (polycyclic aromatic hydrocarbons - a chemical found in all fossil fuels, cooked meats)
what animal is the most contaminated from polychlorinated biphenyl?
- orcas
- PCB mediated effects on reproduction and immune function threated long-term viability of >50% of killer whale populations (in high industrial populations and feeding at high trophic levels)
Ivory gull populations
mercury pollution has risen nearly 50-fold in the feathers over the past 130 years
what are some major insecticides?
organophosphates (parathion, malathion)
what do insecticides inhibit?
cholinesterase (required for nervous system) - lethal
Use of broad acting insecticides in the 1960’s and 1970s were followed by
widespread
collapse of both high and low trophic levels bird species
Research began towards identifying non-destructive biocides which led to…
the discovery of neonicotinoids, a natural insecticide related to nicotine, a common anti-browsing compound produced by plants.
neonicotinoids bind to
nicotinic acetylcholine receptors in the nervous system of animals
neonicotinoids
-extremely toxic to insects,
-particularly toxic to sucking insects such as aphids etc
- used as a natural pesticide to stop the collapse of bird species
neonicotinoids became widely used from 1990’s around the world as a coating to seeds of food crops
and for spraying on growing food crops
- greatly reduced insect damage after coating or spraying
- -in 2014, all corn planted in US is coated in neonicotinoids
neonicotinoids: by early 2000…
first suggestion of negative impact on bees, other insects and their
predators (bats and birds)
neonicotinoids: in 2006
major loss of bee populations which are the major natural pollinator of
plants including agricultural crops
what did neonicotinoids lead to
-led to widespread colony collapse disorder (CCD)
neonicitinoids north american songbirds
- use of neonicotinoids = decrease in insect population
- depleting birds food supply; dec in bird pop
- more prevalent in NE of NA
- more prevalent in birds that migrate short distances
plastic and marine birds
- plastic smells good to these birds because when plastic is exposed to seawater it releases DMS
- birds prey releases DMS and birds smell this out
how does plastic kill animals that consume it?
animals starve to death (they can’t digest it)
major threats to the integrity of earth’s ecosystems
habitat loss/modification
overhunting/overfishing
introduction of exotic (non-native) species
most important fish in north atlantic
atlantic cod
- this fish is depleting and catch per unit effort is rising
difference in table fish in 1900 and 2000
in 2000 the ocean basically empty compared to 1900, fishery science began in 1930
difference between legal trade in 1990-1994 and 2012
- # ’s of legal trade increased (except parrots)
- live primates went from 35,000 to 70,000 - 15,000,000 furs/y and 350,000,000 coral fish/y
monkeys in research Grimm
- Grimm says that monkeys used in the laboratory may become extinct with the partnerships between sanctuaries and research centres
- but we need conservation of this species and many others
how many elephants are poached each year
35,000-50,000
which country has the highest % of elephant poaching?
china - 36%
how has the rhino poaching numbers changed from 2007 to 2013
2007: 13/y
2013: 1004/y
what was the revenue for legal trading in wildlife for 2000 and 2020?
2000: $10 billion/y revenue
2017: $150 billion/y revenue
which countries are the major exporters?
Argentina, Australia, Bolivia, Brazil, Canada, China,
Columbia, Congo, Honduras, India, Indonesia, Nepal,
Philippines, South Korea, Taiwan, Thailand, US
which countries are the major importers (most to least)
european Union, UK, US, United Arab Emirates,
Canada, China, HongKong, Japan, Korea, Singapore,
Taiwan, Yemen
challenges for the great whales: some populations estimated to have been reduced by…
99% of their pristine abundance
challenges for the great whales: the removal of whales by _____ has…
whaling, impacted ecosystems in which they played major role as consumers and enhanced primary productivty
Japan: 2004 commercial hunt (food delicacy, tradition)
444 Striped dolphins
197 bottlenose dolphins
102 Pantropical spotted dolphins
293 Risso’s dolphins
117pilot whales
12 false killer whales
* Additional 200 captured alive/y ($250,000 per dolphin)
how many legal seals killed/y and what is the revenue
100,000 - 400,000 legal seals killed/y ($30 million revenue)
what is the large contraction in grizzly bear’s historical range vs current range due to?
largely due to hunting
what happened in BC in 2017 with regards to grizzly bears?
total ban on legal grizzly bear hunting
what are the current rates of black bear hunting in BC?
-conservation officers kill 500-1000/y
-10,000 Black bears/y killed legally (recreational), 6000 bear killed illegally (gall bladders)
why would black bears be killed illegally for their gall bladders?
is said to have a great export market…
what does recreational hunting breach?
the criminal code against animal cruelty, which is regarding causing unnecessary suffering to animals
BC government killed ___ of wolf population in BC interior
80%
why is the BC government killing wolves?
to protect caribou, wolves eat them.
what is the BC government now using against wildlife?
assault style rifles :(
europeans colonized…
africa, north america, south america, australia, new zealand and decimated indigenous peoples and natural ecosystems
what was introduced during human colonization?
non-native species - mainly pigs and goats, were introduced for human consumption
what were the effects of introducing non-native species during colonization?
- major habitat alteration and decline of native species
what other animal was brought due to their association with humans and what did this lead to?
rats, led to large decline of native birds (many of which were flightless bcuz were on islands - hawaii, new zealand, bc, etc) from rat predation
____ were introduced to control rats but they also consume ___. what did this lead to?
mongoose, birds and bird eggs. led to significant predation on native bird species
domestic cats were brought with humans to control _____ but had ____ impacts on ____
rats and mice, devastating, on native ecosystems primarily small native mammals and songbirds
introduced cats eating a continental fauna: what #/% of natives species are killed by cats?
1,114 million, 40% of native species
impact of free-ranging domestic cats on wildlife US: free ranging cats kill…
1.4-3.7 billion birds and 6.9-20.7 billion mammals annually
impact of free-ranging domestic cats on wildlife US: free ranging cats are likely..
the single greatest source of anthropogenic mortality for US birds and mammals
what are the top 3 threats to birds?
cats, windows, vehicles
on average, a species persists for about ___
a million years in the fossil records before disappearing
characteristics of natural extinction of a species is that it is replaced. why?
it gets usually outcompeted by a different species
when something goes extinct, there is no overall _____ in the community
trophic change
with extinction there is occasionally _____
complete change over
…eg. extinction of the large dinosaurs and replacement by
mammals
australian disappearances: how many mammals have disappeared?
34 mammals, highest levels of extinction
australian disappearances: what was one suggestion for these extinctions?
small population sizes and therefore lack of genetic diversity
australian disappearances: what did they find?
high genetic diversity indicating that the populations were large
australian disappearances: what did they conclude extinction was from?
european colonization, went extinct not from small numbers but from colonization
what are some examples of recorded extinctions, 1600s to present?
stellers seacow, great auk, passenger pigeon, eskimo curlew, dodo, carolina parakeet, hawaiian endemic plants
of the 91 hawaiian honey creeper species how many extinct and how many endangered
51 species extinct, 40 endangered
what was the driving force for the decline in honeycreepers?
increased temp that allowed spread of avian malaria -> honeycreepers we see today live at high elevation where there are no mosquitos
if there is an island 25km squared and 1 km squared what is the extinction rate in 100 years
1 km squared: 50% extinction rate in 100 years
25 km squared: 10% extinction rate in 100 years
_____ species are at risk of extinction
one in four
