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)