Lecture 33 - Conservation Biology (part 1) Flashcards
Conservation biology
integrates ecology, physiology, molecular biology, genetics, and evolutionary biology to conserve biodiversity
What are the 3 ways we can classify biodiversity in?
- Genetic Diversity
- Species Diversity
- Ecosystem Biodiversity
Genetic diversity
comprises the genetic variation of individuals within populations as well as the genetic variation between populations
What is genetic diversity associated with?
adaptations to local conditions
Extinction may be a result of…
a loss of genetic variation
Genetic diversity is the source of what?
source of variations that enable populations to adapt to environmental changes
Species diversity is important in…
maintaining structure of communities & food webs
What does ecosystem diversity provide?
life-sustaining services such as nutrient cycling & waste decomposition
Species diversity
is the variety of species within an ecosystem or across the biosphere
What can species diversity use?
a variety of different indices and measure to describe species diversity
What does extinction cause?
species diversity to be reduced
Extirpation
Species extinction that happens AT a LOCAL scale
Global extinction
is the loss of a species from the ENTIRE biosphere
Mass extinction
is the loss of lots of species AT ONE TIME
What does The International Union For Conservation of Nature (IUCN) assess?
assesses the global conservation of species and maintains a Red List of species that are threatened to be lost
What is The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) & what do they provide?
- A panel of Canadian scientists tasked with assessing the status of species in Canada
- Provide recommendations to the federal government which species should receive protected status under SARA
What does the COSEWIC use?
uses quantitative criteria to assess a species’ status
• Declining abundance, limited distribution, small population sizes, etc
_____ of Canada’s mammals are considered endangered, threatened or of special concern
~1/3
Species At Risk Act (SARA) includes:
- Extinct
- Extirpated
- Endangered species
- Threatened species
- Special Concern
Extinct
species are already globally gone
Extirpated
species are locally gone
Endangered species
are at risk of imminent extirpation or extinction
Threatened species
is likely to become endangered or extinct if NOTHING is done to reverse the trajectory
Special Concern
species may risk becoming threatened
Ecosystem diversity
is the variety of the biosphere’s ecosystems
What can alter ecosystems?
Human activity
IUCN has developed a criteria to assess…
ecosystems and have produced a Red List for ecosystems threatened by human activity
What is the IUCN criteria to assess ecosystems & Red List for ecosystems threatened by human activity?
- Collapsed
- Critically endangered
- Endangered
- Vulnerable
Collapsed example
equivalent to species extinction
• Ex. Aral Sea in central Asia due to water extraction for irrigation fragmenting the sea into separate, super salty lakes
Critically endangered example
Ex. Raised bog ecosystems in Germany, only occupy 2% of original distribution
Endangered example
Ex. Caribbean coral reefs due to loss of herbivores keeping algae away from corals
What is the goal of ecosystem diversity?
is identify ecosystems that are at risk of losing biodiversity or ecological functions
Why should we care about biodiversity?
- Biodiversity makes us happy -> biophilia
- Concern for future generations
- Benefits of species and genetic diversity
- Loss of species means loss of genes
Biophilia
-> Biodiversity makes us happy
• Sense of connect to nature and all life
• Other species are entitled to life
• Ecosystem services -> ecosystems purify water and air, detoxify/decompose wastes, sustain life
Ecosystem services
ecosystems purify water and air, detoxify/decompose wastes, sustain life
Concern for future generations:
“We must consider our planet to be on loan from our children, rather than a gift from our ancestors” ~ G.H. Brundtland
Benefits of species and genetic diversity:
- Many threatened species can provide food, fibres, medicines, and other NATURAL RESOURCES
- If we lose plant biodiversity surrounding agriculture lands, we can reduce the diversity of pollinators that could help with FOOD PRODUCTION
- Many plant chemicals produced as anti herbivory/pathogen defense also have MEDICINAL USES
Many threatened species can provide…
- food
- fibres
- medicines, and other natural resources
If we lose plant biodiversity surrounding agriculture lands, we can…
reduce the diversity of pollinators that could help with food production
Many plant chemicals produced as anti-herbivory/pathogen defense also have…
medicinal uses
• Ex. Madagascar periwinkle (Catharanthus roseus) produce alkaloids with anti-cancer properties, successful in treating Hodgkin’s lymphoma and childhood leukemia
Loss of species means loss of genes:
Taq polymerase (enzyme needed in PCR and creating gene libraries) is isolated from extremotolerant Thermus aquaticus, isolated from Yellowstone hot springs
What are the threats to biodiversity?
- Habitat loss
- Fragmentation
- Introduced Species
- Overharvesting
Habitat loss
- Brought on by agriculture and urban development, industry (farming, forestry, mining, etc)
- Global climate change is also changing ecosystem dynamics
- When no alternative habitat is available for species, could lead to extinction
Fragmentation
breaking up large areas of continuous habitat
Habitat loss and fragmentation is huge…
- ~98% of tropical dry forests in Central America and Mexico are gone
- ~1% of Asian rainforests are destroyed each year
• ~97% or native prairie grasslands and 88% of mixed woodland ecosystems have been converted for human use in Canada
- Make up ~6% of Canada’s land, but contain over 50% of all species at risk
Populations in fragmented habitats are more likely to…
go extinct
Why are populations in fragmented habitats more likely to go extinct?
- Population sizes are smaller
* Abiotic environment, food sources and predation risk has been ALTERED
Aquatic systems are hugely affected by…
habitat loss
How are aquatic systems hugely affected by habitat loss?
- Declines in coral reefs (provide habitat for ~1/3 of marine fish species)
- Freshwater habitat is lost due to dams, reservoirs, channel modifications (or diversions), or via inputs of rugs, chemicals, etc from human consumption and waste
Introduced Species
- Non-native or exotic species not normally found in that habitat
- Free from predators, parasites, and pathogens that limit their population size, invasive species can grow exponentially in a new area
Introduced species can be brought in via many means and cause…
huge disruptions
• Accidentally brought in by humans via boats, transport of fruits/veggies,
trains, etc
Introduced species can…
• Can prey on native species or outcompete them
- Ex. Brown tree snake accidently brough to Vietnam by military which resulted in
the loss of 12 species of birds and 6 species of lizards from the native habitat
• Can damage aquatic ecosystems
- Sea lampreys in the Great Lakes brough in from constructed canals which
devastated trout populations
- Zebra mussels in Manitoba waterways displace native freshwater species and
also clog water intake structures
Overharvesting
human harvesting of wild organisms at rates exceeding natural population rebound
Overharvesting disproportionally affects…
species with restricted habitats (ie small islands), large organisms with slow reproductive rates (ie elephants and rhinos)
Overharvesting devastated…
local fish populations (ie East Coast cod populations, which killed the Newfoundland fishing industry shows little improvement despite strict commercial fishing regulations)
How do we conserve biodiversity at the species and population levels?
- Small-population approach
* Declining population approach
Small-population Approach
- Small populations are vulnerable to genetic drift and inbreeding
- Can cause populations to go down an extinction vortex
Genetic drift
chance events that decrease genetic variation in a population
Extinction vortex
Moving towards an smaller and smaller population until extinction is reached
The Greater Prairie chicken case study:
• At the time of European colonisation of North America, the prairie
chicken (Tympanuchus cupido) inhabited tall-grass prairie from Alberta
to Texas
• Loss of prairie due to agriculture led to its extirpation from Canada and
habitat fragmentation in the US.
• Conservationists reintroduced prairie chickens from larger populations
back into Illinois populations and the populations rebounded back
Minimum viable population (MVP)
is the population size that a species can maintain is population numbers
• Takes into many factors that an affect growth rate
Effective population size
is the portion of the population that is able to breed (ie the breeding population)
Ne = 4NfNm/Nf + Nm
What is a key component of MVP?
Effective population size
Nf and Nm
are the number of females and males respectively
Ne
is the effect population size
If every individual breeds and we have equal females and males…
Ne = actual population size
If we don’t have every male and female breeding…
Ne will go down compared to the actual population size
What is the goal of conservation?
is to keep Ne higher than MVP
Grizzly Bear case study:
- Grizzle bear populations declined in Yellowstone after park dumps were closed
- Dr. Shaffer used models using year-to-year birth and death rates to estimate MVP
- Predicted that a population of 70-90 individuals had 95% chance to survive up to 100 years whereas a population of 100 individuals would have 95% chance for surviving 200 years
Declining population approach
Focuses on threatened or endangered populations that are showing a downward trend, even if population is above MVP
Small population approach emphasises…
population smallness, not necessarily decline
Declining population approach emphasises…
environmental factors for decline, not necessarily small populations
Steps for Intervention for the declining population approach (case-by-case basis):
- Confirm using population data that the species was more widely abundant or distributed in the past
- Study the natural history of the species and related species to determine its environmental needs
- Develop hypotheses for all possible causes of decline, including human activities and natural events and list predictions for each hypothesis
- Test the most likely hypothesis first (some may be correlated)
- Apply results of diagnosis to manage threatened species and monitor recovery
Most COSEWIC studies use this approach:
- Rufa red knot (Calidris canutus rufus) populations declined over the past decade and is listed as endangered by COSEWIC
- Red knots dying or failing to reproduce while nesting in Canadian arctic
- Mortality rates increased on southern feeding grounds
- Habitat loss
Habitat loss example
Stopover habitat in Delaware was declining due to reduction in horseshow crab populations resulting in population decline
