lab quiz 2 Flashcards
Mark and recapture strength
- provides info about birth, death, and movement rates
- provides info on absolute abundance
why do we care about population size
- if we want to know how the population is changing over time
- if we want to compare 2 populations
- if you want to look at interactions between species
what is the problem with grizzly bears
- gap in scientific understanding in grizzly bear ecology
- don’t know how to quantify them
- lack of ethics
Mark and recapture assumptions
- marking method must not affect the animals
- mark must last entire sampling period
- marked animals must disperse completely in the population
- likelihood of recapture is not influenced by age of the animal
- no immigration, no emigration (closed population)
- not births or deaths during the study
Peterson mark and recapture method
- mark and recapture once
Schanble mark and recapture method
- mark and recapture multiple times
how is the schnable method advantageous?
- easier to determine the violations (6 things)
Jolly Seabird mark and recapture method
- mark animals, release and recapture, the ones that weren’t marked you mark again
When would you use the Jolly Seabird method?
when you have an open population
What makes a population closed?
- Dispersal barriers
- Large surveyed area
- Low birth/death rate
- ONE OTHER THING? low immigration emigration?
what does a low confidence interval mean
precise estimate
when would you want to know the population size
- before undertaking a biological study
- designing conservation strategies
- setting management goals
what was the first ecological use of mark-and-recapture
to look at population estimates and mortality rates in fish
shortcomings of mark and recapture
- require considerable time and effort to get enough data
- each technique has a set of strict assumptions that should be met for the estimate to be reliable
what mark and recapture technique was used in the grizzly bear study?
Genetic analysis
- used hair samples to identify individual bears
what were the sampling methods on the grizzly bear study
- baited, barbed-wire hair traps
2. unbaited bear rub trees
how were grizzly bear population estimates corrected for lack of geographic closure
- by using a new method that utilizes information from radiocollared bears and the distribution of bears captured with DNA sampling
What method was used to estimate the distribution and abundance of showshoe hares?
- fecal-pellet plot counts
- mark and recapture estimates
How and what samples were gathered for population analysis
- took fecal pellet counts at annually cleared and uncleared plots
4 methods used for estimating snow leopard abundance
- prey biomass ratios
- capture/recapture density estimation
- photo-capture rate
- individual identification through genetic analysis
what are the long-term effects of flipper bands on king penguin populations
- 16% lower survival rate
- produced fewer chicks
- arrived later at the breeding grounds
- caused drag when the penguins swim
what is the main assumption of mark and recapture that is violated using flipper bands
- marking method does not affect the animal
explain how food availability had an effect on banded birds
- when resources were plentiful the researchers didn’t observe much of a difference between banded and unbanded
- studies that last under a year may not how banding has any effect
what is the major advantage that flipper bands have when compared to RFID chips
they are visible
what are RFID chips
- electronic chips that are inserted under the penguins skin
- emit radio waves that the researchers can use to track the penguins’ movements
major species in the great bear rainforest
- otters
- trees: spruce
- whales
- wolves
- sea lions
- eagles
- salmon
- spirit and black bears
where are the grizzleys and where are the black bears
grizzleys on the mainland and black bears on the island , some grizzleys have migrated to the islands now
How would competition influence food choice
- different food choices
- bears will eat the gonads of the salmon, wolves will eat the brains
- even tho they eat the same resource, can still reduce the competition
- wolves have been known to target bears but this is much more dangerous than eating salmon
advantageous of eating salmon
- good food source (protein)
- less handling time
diet of wolves from the mainland vs. diet of wolves from the island
Mainland: 25% marine, 75% terrestrial
Inner Island: 50% marine, 50% terrestrial
Outer Island: 75% marine, 25% terrestrial
different between Ho and Ha… location studies
Ho: diet is independent of location
Ha: diet is not independent of location
What does a large chi squared mean
- more significant
- smaller p-value
what are the main prey of grey wolves (Canis lupis)
Ungulates: the main prey of wolves - mule deer other prey: - river otter - black bear - beaver marine resources can be other prey - spawning salmonids and intertidal scavenging
why is knowledge of wolf feeding ecology critical
- for economics and conservation
what is dietary analysis used for
- understanding predator-prey relationships
- looking for the effect of ecological stressors such as habitat change
what is the most accurate determination of food habits? What is this methods downfall?
- direct observation of prey kills and scavenging sites
downfall: time and logistic constraints
what causes deer populations to be impacted
- loss of habitat due to logging
why are alternative prey species important
- if one species population is impacted (temporal fluctuations), can go for a different prey
when is a chi-squared test for independence applied
- and why is it used
- when you have 2 categorical variables from a single population
- simple random sampling is the sampling method
- used to determine if there is a significant association between the 2 variables
what is the chi-squared sample data displayed in and what is the expected frequency count for each cell
- contingency table
- expected frequency count for each cell is 5
What are the steps for a chi-squared test
1) state the hypothesis
2) formulate an analysis plan
3) analyze sample data
4) interpret results
What is the null and alternative hypothesis for chi-squared tests
Ho: variable A and variable B are independent
Ha: variable A and variable B are not independent
i.e. the alternative hypothesis suggests the variables are related but the relationship isn’t necessarily causal
What do you do when u formulate an analysis plan?
- choose significance level (between 0 and 1)
- test the method, chi-squared test for independence to determine whether there is a significant relationship between 2 categorical variables
analyze sample data
- degrees of freedom
- expected frequencies
- test statistic
- P-value
how to calculate degrees of freedom
DF = (r-1)(c-1) r = number of levels for one categorical value c = number of levels for the other categorical value
what are expected frequencies and how to calculate it
expected frequency counts are computed separately for each level of one categorical variable and at each level of the other categorical value
Erc = (nr x nc)/n
what is the test statistic and how do you calculate it
test statistic is a chi-squared random variable (X^2) defined by the following equation:
X^2 = sum [(Orc - Erc)^2 / Erc]
- Orc is the observed frequency count at level r of variable a and level c of variable b
- Erc is the expected frequency count at “”
what does the p-value in a chi-squared test represent??
- probability of observing a sample statistic as extreme as the test statistic
- need the degrees of freedom and to use the chi-square distribution calc
interpret the results
- compare the p-value to the significance level
- reject null hypothesis if the p-value is less than the significant level
if you were to explain why you use chi-squared analysis what would you say
If you use this approach on an exam, you may also want to mention why this approach is appropriate. Specifically, the approach is appropriate because the sampling method was simple random sampling, the variables under study were categorical, and the expected frequency count was at least 5 in each cell of the contingency table.
How and where was sample hair collected in this paper?
- Sampled hair from the mid-ventral region of 15 museum and taxidermist pelts and one field-collected sample of shed hair
- Limited samples to pelts from winter-killed wolves which ensured folly grown guard hairs
- Wolves were from a wide geographic range within BC
Why are museums important for future ecological work?
- Huge deposit of information for biodiversity
- Somewhere in the museum there is collections of different species with info where the species was caught, environmental conditions
- Years later experimenters can go back and do research
- There are researchers that are going back and using fur from pelts and discovering their diet
how are beetles a good method to ask questions about biodiversity ?
- hugely diverse (species-rich group)
- found everywhere
- have been used as indicators of habitat change
- easy to trap and identify
archipelago
a group of islands
what is central to the field of biogeography
the distribution of species
what did Robert MacArthur and E.O. Wilson do
combined some of the ideas that were observed for patterns of species diversity on islands
- lead to the formalization of “Theory of Island Biogeography (IBT)”
Island biota
island like habitats (secluded) include examples such as: mountain tops, forest fragments, and tree canopies
(beetles in forest patches)
what does the diversity of an island reflect (3)
- diversity of the mainland (source) area
- the size of the island
- the distance of the island from the source
what does fragmentation do
- limits genetic diversity
- caused native habitats to appear as habitat islands in a landscape matrix
biodiversity definition
- integration of biological variability across spatial scales and is composed of structural, compositional, and functional components and deals with ecological processes
diversity includes:
- diversity within a species
- diversity among species
- comparative diversity among ecosystems
ultimate goal in recording biological diversity
to build a factual foundation for answering basic questions about evolution and ecology
what is the global biodiversity crises accelerated by
- habitat loss
- extinction of species
factors that influence the collection of biodiversity data (5)
- temporal sequencing (life histories, succession)
- IBT principles (size of area that is sampled)
- type of sample design
- type of collecting method used
- environment sampled and taxa of interest
INCREASED SAMPLING EFFORT OF ANY OF THESE WILL ALMOST ALWAYS RESULT IN AN INCREASE OF SPECIES RECORDED
what are the 2 sampling strategies for biodiversity
- individual based
2. sample based
what are the 2 sampling methods represented by
- individual based
- represented by collector curves - sample based
- represented by the choice of sampling methods such as transects and quadrats along with the type of traps used (e.g. pitfall traps)
what does a species accumulation curve plot?
- the cumulative species richness (y-axis) against the cumulative number of samples (x-axis)
- does the curve reach an asymptote?? After how many beetles collected??
family richness
the tally of different beetle families that were collected from each forest site
family diversity
SIMPSONS INDEX (EVENNESS) - reflects the number of families present and the relative distribution of individuals within a community
Simpsons index
- as Ds increases, diversity decreases (dominance increases)
- take the reciprocal always!! makes more sense; low Ds when taking the reciprocal means a low diversity
Distinctiveness
looks at how different the communities are from one another
- jaccard coefficient of community (CCj)
CCj = c/S
c = number of species
S = total number of species present in the 2 communities
what preservative is typically used in a pitfall trap?
propylene glycol and 70% ethanol
what are guide vanes used for?
may help guide the organisms into the cup
how is rainwater kept out of the traps?
can be covered
Community ecology
addresses biodiversity of life on earth and factors that contribute to observed patterns of species richness and evenness
2 major forms of diversity indices
- simpson index
2. shannon weiner index
effects of fragmentation
- loss of habitat
- reduction of remnant patch size
- increasing isolation of remnant patches
- decree of contentedness and edge effects
what is an edge
the abrupt transition between forest and matrix habitats
- changes resident species habitat in terms of physical conditions
invertebrate responses to fragmentation
invertebrate abundance increases toward the forest edge
- due to the replacement of the natural forest community with invasive edge-adapted species
multitaxa approach
- using a diverse group of inverts
