Conservation Bio Exam 2

Is extinction natural?

Yes

What is natural and unnatural about extinction?

Speciation can be caused by natural disasters; the RATE of extinction due to humans is too rapid

how many mass extinction events have there been?

5

when did dinosaurs go extinct?

End of Cretaceous era

we are currently entering the __th mass extinction

6

extinction rate

the number of extinctions per year per species

unit for extinction rate

MSY (per million species-years)

how can you interpret 1E/MSY “one extinction per million species-years”?

if we had a million species, we should expect one extinction per year

if we had 10,000 species, we should expect __ extinction(s) per 100 years

1

based on the fossil record, what is the background rate?

1-2 E/MSY

number of extinctions is __% higher than predicted

53%

how many vertebrate extinctions were expected since 1900?

9

modern extinction rates for vertebrates is __-__ times higher than the background rate

24-100

defaunation

general decline in abundance of survivors

causes of population decline and extinction

1. changing climate

1. land use change

2. overexploitation

3. invasive species

4. infectious disease

Arrhenius, 1896

asked “why is the temperature of the Earth so suitable for humans and animals?”

Greenhouse Gases (GHGs)

CO2, CH4, N2O, CFCs

Greenhouse gas effect

a natural process that enables life on Earth to fluorish; GHGs trap heat

why is the world warming?

human activity is causing elevated concentrations of GHGs in the atmosphere

how much warmer are the land and sea compared to pre-industrial era?

~0.9C / 1/6F

which years were the hottest years recorded?

2016 and 2020

lag effect

even if emissions/GHG concentrations were to cease to increase immediately, some warming will happen; lag between emission level and trapping of heat

effects of global warming on the physical environment

-melting ice

-sea level rise

-extreme drought and rainfall

-more powerful storms

-ocean acidification

-positive feedback loops

sea ice

frozen ocean water

sea ice covers ~___ of the Earth

25 million km²

what is happening to sea ice as climate changes?

declining in extent and volume

glaciers

perennial ice originating on land

glaciers cover ~__ of the Earth

706,000 km²

what is happening to glaciers as climate warms?

retreating around the world; could disappear in some mountain ranges this century

major continental ice sheets

Antarctica and Greenland

Antarctica covers ~___ of the Earth

14.2 million km²

Greenland covers ~___ of the Earth

2.2 million km²

what is happening to continental ice sheets as climate warms?

reduction in mass of major basins

how much has sea level risen since 1880?

21-24 cm / 8-9 inches

why has sea level risen?

melting glaciers and ice sheets, thermal expansion from warming water

what is an endangered historic place due to sea level rise?

The Tidal Basin, D.C.

sea level is projected to rise at least __ over the next 100 years

1m

__% of the U.S. population lives within 50 miles of the coast

52

annual average precipitation has generally increased in the ___ and decreased in the ___

East; West

how much will precipitation increase on the wettest day of the year?

5-15%

negative effects of long dry spells

hardened soil reduces ability to absorb water, leading to damaging flash flooding; major implications for biodiversity, food production, infrastructure

T or F: warmer atmospheres increase energy for storms

TRUE

largest and strongest hurricanes recorded in history (cat. 5)

Hurricanes Irma and Maria (2017)

what is ocean acidification?

CO2 → carbonic acid

T or F: increased CO2 absorption makes oceans more acidic

TRUE

how many pH units has the ocean increased by since pre-industrial?

0.1

how much more acid is in the oceans?

30%

the runaway greenhouse effect is an example of

positive feedback loops

positive feedback loops

when the product of a reaction increases the effect of the reaction

examples of runaway greenhouse effects

albedo effect, melting permafrost, wildfires

albedo effect on ice

melting ice, more dark space/less ice reflection, sea absorbs more radiation, more ice melts

melting permafrost

permafrost melts, releases stored carbon, increased GHGs, more permafrost melts

wildfires positive feedback loop

snow melts earlier leading to longer summers and dryer environments, fires release carbon, increase GHGs, more warming

what geographical areas are most vulnerable to the physical effect of changing climate?

-peninsulas (sea-level rise)

-vast areas that are dry

-developed countries that increase CO2 emissions

-Arctic/Antarctic (ice melting → habitat loss)

-coastal areas

-low-lying areas

-drought/flood prone areas

how can organisms respond to climate change?

change physiology, phenology, distribution; or adapt in situ

oceans have warmed more than __

1 degree C

how are species distributions changing (marine)?

moving poleward

how are species distributions changing (terrestrial)

moving poleward and up in altitude/upward range movement across taxonomic groups

examples of species moving up mountains

birds, invertebrates, reptiles, amphibians

examples of physiological effects

acidification changes calcification rate and compromises growth and skeletal strength in marine species

what are the shells and skeletons of marine species made of?

calcium carbonate

T or F: if the oceans get too acidic, calcium carbonate shells and skeletons may just dissolve

TRUE

ecototherms

metabolic rates are dictated by ambient temperatures

oxygen limitation hypothesis

higher temps increase oxygen demand and heart rate, but reduce blood oxygen; anaerobic metabolism kicks in, leading to a build-up of waste products

phenology

timing of seasonal activities

T or F: small, insectivorous bird species are nesting and laying their eggs later

FALSE; earlier

T or F: many migratory birds are changing their migration times or ceasing to migrate

TRUE

T or F: many plant species are budding and flowering later in the spring

FALSE; earlier

behavioral adaptations in situ

change in timing of activity to mitigate rise in temperature (diurnal → nocturnal), or duration of activity to mitigate food availability (forage longer)

genetic changes to adapt in situ

reduced body size and/or resistance to anaerobic end products to mitigate metabolic effects from rising temperature

how might climate warming change species interactions?

-rising temps decouples mutualism between coral and algae, leading to coral bleaching

-mismatch cues

mismatched cues example

birds feed caterpillars to nestlings; but now caterpillar food supply buds too early, doesn’t match with time that nestlings hatch

which species are particularly vulnerable to extinctions?

species that occur at poles, species that occur at high altitudes, low-lying island species (endemic)

example of species that occur at poles

emperor penguins (severe range contractions and population declines)

example of species that occur at high altitudes

American pika extirpation from the ~12 populations in the rocky mountains

T or F: biological communities do not respond as a unit

TRUE; individual species respond at their own rate and in their own direction

T or F: surviving species will assemble into new ecosystem configurations

TRUE

example of effects on phenology (in-class discussion)

Snowshoe hare color molts - coat turns at a different time of the year, exposing them to predators

actions to mitigate changing climate

-new technologies to reduce emissions

-reforestation

-eat less meat

new tech to reduce emissions

less reliance on fossil fuels and investment in renewable energy

reforestation

~1 billion ha of land outside urban and agricultural areas could be converted to forest, storing 205 gigatons of carbon; ~25% of the CO2 currently in the atmosphere would be absorbed

eat less meat

reduce emissions from large scale agriculture

4 categories of strategies to mitigate ecological effects

1. land and water protection and management

2. direct species management

3. monitoring and planning

4. law and policy

land and water protection and management

-increase extent of protected areas

-protect and restore core habitat of threatened species

-suite of legal tools for this, utilized by governmental and non-governmental organizations

-smart reserve design to facilitate range shifts

-create new habitat

T or F: larger populations means more resilience

TRUE; more potential for adaptation to changes in climate

__ networks may fail to achieve original objectives in future ecosystems

static

smart reserves

create reserves with a natural elevational gradient (species can colonize uphill); protect movement corridors, stepping stones, and refugia (areas with minimal climate impacts)

example of creating new habitat

“bird islands” from dredged sediment offsets climate-driven habitat loss among the Atlantic Coast

direct species management

-focus resources on species that might become extinct

-translocate species at risk of extinction

-establish captive populations of species that would otherwise go extinct (zoos)

-reduce pressures on species from sources other than climate

translocation

assisted migration - move species to areas with suitable conditions under new projected climates

what is the challenge with assisted migration?

difficult to predict optimal locations for assisted dispersal; concern over potential for transplanted species to have negative consequences in their new range (invasion)

reduce pressures on species from sources other than climate

-reduce negative synergies with climate

-give species the max. flexibility to evolve responses to changing climates

(this may be the only practical large-scale adaptation policy for marine systems)

dynamic management

we need to apply novel and innovative ways to increase biodiversity to meet the unprecedented challenges posed by changing climate change

world leader of mammal extinctions

Australia

how many mammal extinctions have there been in Australia since settlement in 1788?

38 (1-2 extinctions per decade)

by how much has the critically endangered species number increased?

80%

by how much has the endangered species number increased?

50%

by how much has the vulnerable species number increased?

30%

what is the “critical weight range” in Australia?

35 g - 5.5 kg

where do species persist in Australia?

islands, intensively managed fenced areas