4. How do we measure species diversity Flashcards
what is species diveristy
it is how many different types of species are in a unit
what is alpha diversity
number of species in a unit being studied
what is gamma diversity
number of species in the system being studied
what is beta diversity
differences in species composition among units
what is multiplicative beta diversity
dimensionless number that implies number oof full changes in species composition among sample
what does multiplicative beta diversity show us
the proportion by which the speccies richness of a region exceeds the average richness of a single locality within the region
how to calculate multiplicative beta diversity
number of different species/ across the number of sites
then use gamma diversity to divide the above thing
what is additive beta diversity
shows difference in species composition among units
how do you calculate additive beta diversity
number of different species/ across the number of sites
then use gamma diversity to minus the above thing
what can beta diversity show us
diversity at different scales, spatial scale that is contributing to most species diversity
additive beta diversity how does it work
number of species that are added due to regions, fields and sites having different species compositioons
what do spatial scales tell us about diversity
recommend at which a certain group of taxa needs to be conserved
- if you see regions and fields have a higher proportion on the spatial scales, then you can implement conservation tactics on fields and regional services more
what is the challenge of counting species
The number of species you count is probably sensitive to sample size and the number of individuals
what does species richness not account for
relative abundance of different species
what does more effort/ sample size mean
more species, but there is a threshold
how does species accumulation work
discrete variable
as you sample more, it levels off
what does rarefaction curve give us information on
expected realtionship between effort (number of individuals) and number of species found, so useful for comparing biodiversity
is old growth more species rich than disturbed
no
does diversity change a lot if you use interpolated rarefaction curve
no
at what level of biodiversity would it be more effective to use rarefaction curves
at higher biodiversity
what is the CHAO1 estimator equation
d + n^2 /2n
d= number of species in sample
n1= number of species observed once only
n2= number of species observed just twice
what does CHAO1 tell us
estimates species richness
more species rich
means theres more species divided amongst a community, the relative abundance is more balanced across
whats the best way to compare communities, what index
simpsons diversity index
is simpson diversity index consistent
yes, no matter how many individuals are collected
what is the equation for simpsons’s diversity index (D)
add up the proportion of individuals of I species and square each of them first
and then 1-D
What is 1-D in simpsoons diveristy index
probability that two individuals picked at random are different species
turn number to %
what does shannon index (H) tell us
higher H means largeer amount of uncertainty
tells us how difficult it is to predict the species of randomly sampled individuals
what is the equatioon for shannon index (H)
add all the p together
multiply ln to pi
turn it negative
how does Shannon index increase
when there’s more individuals, it increases,
usually between 1.5-3.5
what is evenness
whether the species is evenly abundant , spread across
what is Simpson’s evenness equation
Dmax= 1/S
Evenness : 1-D/1-Dmax
S is the number of species sampled
what is shannon evenness equation
Hmax= lnS
J= H/Hmax
we know most about which types of species
vertebrates, but they are small proportion of species diversity
most per cent of known species worldwide are what?
invertebrates
least studies done on them though
which areas have high and low rates of monitoring biodiversity
high rates
- europe and north america
- forests
- Africa
least rates: where deforestation occurs
how can we monitor biodiversity
through citizen science reports
sampling porgrammes`
sampling programmes (extent, effort, grain levels)
big extent
medium effort
low grain
citizen science extent, effort, grain levels)
huge extent
low effort
low grain
what is extennt
area
what is grain
spatial frequency of sampling
local monitoring is good for ?
hypothesis testing, not really for impact assessment
what is effort
number of abiotic and biotic things measured
in a cube, where would monitoring programmes be at
in the center
what’s in coarse grained sampling
low density of sampling sites shows broad trend in organism abundance
one round peak
what’s in fine grained sampling
high density of sampling sites shows that there are local differences in factors influencing an organisms abundance
bumpy peaks
wetlands drive this
what is the national ecological observatory network (NEON)
US site that monitors variables of spatially stratification domains with environmental conditions
what is Alberta Biodiversity Monitoring institute (ABMI)
extensive monitoring
done every 5 years
what has ABMI evaluation showed
generally positive
some say ABMI should relate that to policy making, but that is not their primary goal
concerns to ABMI approach
poor temporal resolution because any given year site is very sparse in space
doesn’t disclose exact locations to reduces data sharing to outside people
grid can miss rare environment that are important to maintaining biodiversity
sampling effort isn’t stratified based on organisms or habitats of interest
what is BACI
before after control impact
to monitor effects of distinct environmental impacts of disturbances
impacted sites have less of variables than controls only after the impact
how to do extensive monitoring well
keep modifying research designs
ask new questions
don’t just monitor
use new technology
