210 diversity index

17
How to describe a Community structure keystone species succession composi0on diversity

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how to calculate diversity index for ecology

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How to describe a

Community)structure

keystone)species

succession

composi0on

diversity

Species)diversity

more food resources

more)habitats

more)resilience

greater)diversity)=)greater)stability

Species)diversity

Species)richness

rela0ve)abundance

Total)number)of)different)species

propor0on)each)species)represents

Variety)of)organisms)that)make)up)the)community

Two)communi0es)can)have)the)same)species)richness)but)a)different)rela0ve)abundance

Basic)Methodology)Transect)SamplingLine)Intercept)Transect)Sampling:

•))Measure)length)of)“contact”)by)the)feature)of)interest)(intercept).

•))Compare)with)total)length)of)transect.

•))Results)are)usually)rela0ve)values)–)expressed)as)percentages.))e.)g.)%)shrub)cover

•))Transects)are)usually)straight)lines,)but)may)be)curved)or)circular.

Data)collec0on

Data)collec0on

Species)diversity:)SIMPSONS)INDEX

Mathema0cal)indices

2)random)samples)contain)same)taxon

diversity

Simpson)index

Low)#)=)0)=)all)taxa)equally)present

High)#)=)1)=)one)taxon)dominant

There%are%several%quan-ta-ve%species%diversity%indices.%The%one%most%commonly%used%is%the%Shannon)index:

pi = proportion of individuals in the ith species

s = number of species in the community

Community)Structure

Mathema0cal)indices

diversity)can)be)measured)muchlike)the)informa0on)contained)in)a)code)

informa0on)index

Shannon’s)index

the)longer)and)more)complex)the)code,)the)greater)the)diversity).

Affected)by)evenness

More)sp)+)more)even)=)greater)Shannon)index

Step)1:

)Add)all))of)the)observed)numbers)together)to)get)

total

Shannon’s)index)Calcula0on

Step)2:

For)each)species)divide)observed)numbers)by)total)

So)17)/20)=)0.85

This)is)our)propor0on)value)pi

Step)3:

Take)the)natural)log)of)pi

Natural)log)of)0.85)=)d0.163

Step)4:

d0.163)mul0ply)by)pi

0.163)x)0.8)=)d0.139)

Step)5:

Add)all)these)together)and)change)the)signStep)6:

Repeat)steps)1)through)5)for)each)ecosystem

Step)7:

Compare)ecosystems

what)does)that)mean?

High)values)of)H)represent)more)diverse)communi0es

If)the)species)are)evenly)distributed)then)the)H)value)would)be)high

Values)of)the)Shannon's)diversity)index)for)real)communi0es)typically)fall)

between)1.5)and)3.5.

Pop)1 Pop)2

≨Pop)1 Pop)2

))))Are)Species)Common)or)Rare?

Highest)to)lowest

Step)1:

)Add)all))of)the)observed)numbers)together)to)get)

total

Step)2:

For)each)species)divide)observed)numbers)by)total)

So)76)/256)=)29.7

This)is)our)rela0ve)abundance

))))Are)Species)Common)or)Rare?

Rankdabundance)diagram

slower)slope)=))higher)evenness

longer)length)of)curve)=)higher)species)richness

Formal)Report

Ques0on:)is)there)a)difference)between)2)forest)remnants)on)UFV)campus

handout)on)drive

1)per)group)of)2

Addi0onal)Guidelines

Results)–)as)long)as)one)can)understand)and)follow)the)presenta0on)of)the)data)the)length)can)vary

do)we)need)to)rewrite)methods?

Abstract))d)200)words)or)less

Visuals)need)to)be)clean)and)clear

Formal)Reportd)data

Hypothesis:)is)there)a)difference)between)2)forest)remnants)on)UFV)campus

Invertebrate)both

Transects)both

Soils)both

Predic0on:)Higher)biodiversity)of)plants)and)invertebrates)will)be)observed)in)areas)with)greater)soil)nitrogen)and)phosphorus)levels.

Data)Analysis

Transects

Soils

Compare)species)richness,)frequency,)abundance,)etc.)from)table)in)lab)handout)compare)ShannondWeiner)Diversity)Index

Compare)species)richness,)abundance,)etc.)compare)ShannondWeiner)Diversity)Index

Compare)texture,)color)and)chemistry

Invertebrate

Forest)Transect)Data)AnalysisTake%your%vegeta-on%map%data%and%fill%in%table:

1%vegeta-on%maps%for%your%forest%(20%transect%points%of%1%m2%plots%per%50%m%transect%line)

Tables%from%5%other%lab%groups%will%be%posted%onDline

12

Species #)of)Individuals)per)50)m)transect)(ni)

Frequency Density)(d))per)20)m2

Rela0ve)Density

Rela0ve)Abundance)(%)of)total)individuals)

Rela0ve)Cover)–)omit)cover)all)together??

Red%Alder

Forest)Calcula0on)Examples

Frequency%=%#%of%plots%containing%species%A%%%%x%%100

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%total%#%of%plots%

(15%plots%with%red%alder%/%20%plots)%*%100%=%75

Species #)of)Individuals)per)50)m)transect)(ni)

Frequency Density)(d))per)20)m2

Rela0ve)Density

Rela0ve)Abundance)(%)of)total)individuals)

Rela0ve)Cover)–)omit)cover)all)together??

Red%Alder 15/20*100=75%%

Forest)Calcula0on)Examples

%%%%%%%%%Density%=%sum%of%species%A%

%%%%%%%%%%%%%%%%%%%%%%%%%%Area%(m2)

for%example:%%15%red%alders%/%20%m2%=%0.75%red%alder%per%m2

Species #)of)Individuals)per)50)m)transect)(ni)

Frequency Density)(d))per)20)m2

Rela0ve)Density

Rela0ve)Abundance)(%)of)total)individuals)

Rela0ve)Cover)–)omit)cover)all)together??

Red%Alder 75%% 0.75

Forest)Calcula0on)Examples

Rela-ve%Density%=%%%%%%%species%A%density%%%%%%%%%%%%x%100

% % %%%%%%%%%%%%sum%of%all%species%densi-es

Red%Alder:%%0.75%/%sum%of%density%column%for%en-re%50%m%transect

Species #)of)Individuals)per)50)m)transect)(ni)

Frequency Density)(d))per)20)m2

Rela0ve)Density

Rela0ve)Abundance)(%)of)total)individuals)

Rela0ve)Cover)–)omit)cover)all)together??

Red%Alder 75%% 0.75

Rela-ve%Abundance%=%#%of%individuals%of%species%A%%%%%%%x%100

% % %%%%%%%%%%%%%sum%of%individuals%of%all%species

Red%Alder:%%[(20%red%alders%recorded%during%the%en-re%50%m%transect%line)%/%(sum%of%‘#%of%individuals%per%50%m%transect’%column)]%*%100

Simple'way'of'examining'the'most'abundant'to'least'abundant'species….can'be'used'to'es9mate'dominant'species

Species #)of)Individuals)per)50)m)transect)(ni)

Frequency Density)(d))per)20)m2

Rela0ve)Density

Rela0ve)Abundance)(%)of)total)individuals)

Rela0ve)Cover)–)omit)cover)all)together??

Red%Alder 20 75%% 0.75