ch 23 : global conservation of biodiversity Flashcards
ecological hotspots
endemic species
where are endemic species most common?
what are the two values of biodiversity
intrinsic value and instrumental value
a focus on the inherent value of a species, not tied to any economic benefit
intrinsic value of biodiversity
a focus on the economic value a species can provide (e.g., the value of lumber and crops)
instrumental value of biodiversity
what would be the purpose of intrinsic value of biodiversity?
people who place intrinsic value on biodiversity feel religious, moral, or ethical obligations to preserve the world’s species
what is the difficulty with intrinsic value of biodiversity?
it is difficult to prioritize conservation efforts based on intrinsic values
what is the difficulty with instrumental value of biodiversity?
many species remain undiscovered so the value of species and ecosystems can be difficult to estimate
what are the benefits of diversity?
benefits of diversity are estimated at $319 billion per year in the United States, and globally at $3 trillion to $54 trillion per year
benefits of biodiversity that humans use, including lumber, fur, meat, crops, water, and fiber
provisioning services
benefits of biodiversity that include climate regulation, flood control, and water pollution
regulating services
benefits of biodiversity that provide aesthetic, spiritual, or recreational value (e.g., hiking, camping)
cultural services
benefits of biodiversity that allow ecosystems to exist (e.g., primary production, soil formation, and nutrient cycling)
supporting services
over the past 500 million years, how many mass extinction events has the world experienced?
5
events in which at least 75% of the existing species go extinct within a 2-million-year period.
mass extinction events
what are some facts about species
- 1.3 million species have received Latin names; 15,000 new species are described each year.
- estimates for the total number of species range from 3 to 100 million; most scientists agree that there are about 10 million species.
first mass extinction
most species lived in the oceans; an ice age caused sea levels to drop and ocean chemistry to change
second mass extinction
much of the ocean lacked oxygen; reasons for this phenomenon are unclear
third mass extinction
causes are uncertain; 96% of all species went extinct
fourth mass extinction
hypotheses for this extinction include volcanic activity, asteroid collisions, and climate change
fifth mass extinction
volcanic eruptions generated cold weather, followed by an asteroid impact in the Yucatan Peninsula
what made earth much less hospitable to dinosaurs and many other groups?
dust from the asteroid impact blocked the sun’s rays
what are some notes about a sixth mass extinction?
- only a small percentage of all species that ever lived on Earth are present today.
- over the past 3.5 billion years, it is estimated that 4 billion species have existed on Earth; 99% of these species are now extinct.
- scientists have hypothesized increases in human population during the past 10,000 years has initiated a sixth mass extinction event.
- comparison of mammalian extinction rates over the past 500 years with historic rates suggests a higher current rate of extinction.
- the United Nations Convention on Biological Diversity estimates that the extinction rate over the past 50 years is 1,000 times historic rates.
- ****if this rate continues for hundreds of years, it could qualify as a mass extinction event.
how far back can we see human impacts on diversity?
starting with the arrival of humans 10,000 years ago
what does the risk of a sixth mass extinction depend on?
how many species go extinct during the next few centuries
the animal was known to exist in the year 1500, but no individuals remain alive today
extinct
the only individuals remaining are in captivity
extinct in the wild
species at high risk of extinction; endangered species
threatened
species likely to become threatened in the future
near-threatened
species with abundant populations
least-concern
currently, our best data to assess the decline in biodiversity are which groups of species?
conifers, birds, mammals, amphibians, and fish
patterns of declines in these groups may be representative of what?
many other groups for which data are poor
fewer than 10% of all flowering plant species, reptiles, and insects have been assessed; 46% to 74% of assessed species are ________
threatened
what are declines in genetic diversity caused by?
-declining population sizes
- inbreeding depression
- the bottleneck effect
what is the effect of declines?
they reduce the probability that a population is able to survive changing conditions (i.e. climate, emerging infectious diseases)
why do humans need genetic diversity?
- all animals that humans consume or use for labor include just seven mammal species and four bird species.
- likewise, humans consume only about 150 species of plants; just 12 species make up the vast majority of people’s diets (e.g., wheat, rice, and corn).
why is livestock genetic diversity important to know about?
- humans have bred livestock species for a wide variety of different traits (e.g., size, strength, quality of meat).
- many livestock varieties have not been maintained; modern livestock operations favor relatively few breeds.
- ten percent of all domestic bird breeds have gone extinct and another 21% are at risk.
- reduced livestock genetic diversity provides less diversity to us if we need to breed new varieties that can live in novel environments
why is plant genetic diversity important to know about?
- modern varieties of cultivated plants (e.g., corn) look very different from their ancestors.
- humans bred varieties that grew well under local environmental conditions
what did modern farming practices (e.g., irrigation) reduce?
harshness of growing conditions and favored only top-producing varieties
what happens when there is reduced crop genetic diversity?
there is a reduction of options to respond to environmental conditions and challenges
what was built to protect seed diversity from natural disasters?
the Svalbard Global Seed Vault in the Artic region north of Norway
what has been the largest cause of declining biodiversity?
the destruction and degradation of habitat
habitat loss leads to what?
fragmentation and smaller populations that are likely to go extinct
fragmented areas have more ______ _____ that can alter abiotic conditions of the interior habitat and favor edge species
edge habitat
describe overharvesting
human tech has allowed us to harvest species at a more rapid rate and drive some species to extinction
is extinction by hunting and fishing a recent phenomenon?
no
what fishing techniques have increased the number of fish and shellfish caught
- long fishing lines
- large nets
- trawlers
what has overfishing led to?
an increase in the number of collapsed fisheries
fishing areas that no longer have populations that can be fished
collapsed fisheries
how often do collapsed fisheries occur?
in more than 25% of species assessed of the coast of the northeastern US
has the government done anything to regulate harvesting?
yes; regulations must balance the benefit of conserving species with the economic benefits to humans though
introductions of species can be both ________ and __________
intentional and accidental
what are some facts about introduced species?
- only about 5% of introduced species become established in a new region, but those that do have a variety of effects.
- some species provide important benefits (e.g., the common honeybee); others can have negative effects on native species.
the number of introduced species has _________ over time
increased
the process by which unique species compositions originally found in different regions slowly become more similar due to the movement of people, cargo, and species
biotic homogenization
the process by which the concentration of a contaminant increases as it moves up the food chain
biomagnification
global climate change
- humans have increased concentrations of greenhouse gases in the atmosphere
- increased greenhouse gases have led to a 0.8°C increase in the average temperature of the Earth; some areas (e.g., Alaska) have experienced increases as high as 4°C
- warming has had a number of
effects, such as a reduction in ice mass in Antarctica. - ice melting has led to a 0.2 m
sea level increase in 140 years; in the past 20 years, sea level has risen ~3 mm per year.
what has warming led to?
shifts in the timing of many ecological events (i.e. breeding, pollination) and shifts in the range of many species
what is the difficulty with global climate change?
predicting it; the outcome will partly depend on how much CO2 is added to the atmosphere
how do we slow declines in biodiversity
we must stabilize the size of the human population and reduce human-caused sources of mortality
why is habitat protection important?
habitats much be large enough to support a minimum viable population and to prevent local catastrophes from threatening an entire species
the smallest population size of a species that can persist in the face of environmental variation
minimum viable population (MVP)
the habitat needs of a population change with ___________
seasons
what needs to be set aside for species that migrate?
large tracts of land need to be set aside, managed, and protected
today, 57% of the world countries have protected at least ___________ of their land.
one-tenth
what is the NPS largest restoration project to date?
elwha river dam removal
what does reducing the harvest of a declining species do?
increases its abundance, although some species can take a tong time to recover
some species have declined so low in abundance that what?
they require human intervention to save them from extinction
- reintroductions are costly, but efforts to save one species can have positive effects on many other species
what is our hope for our future?
- sustain ecosystem services
- maintain biodiversity
- minimize human impacts
- sustainable alternative practices
what are some ways to minimize human impacts aka ecological footprints?
- conservation
- legislation (clean air/water acts, endangered species act)
- global cooperation — treaties (kyoto)
