Phylogenetics and conservation Flashcards
what is phylogenetic diversity
having lots of species
and/or
having evolutionary distinct species (spread out through tree, lots of independent evolutionary history)
advantages of PD as a metric
no need to worry about species definitions - as are using a phylogeny
just need DNA samples to construct
removes need to measure trait data
functional diversity
are all species worth conserving
metric based on variation in “functional traits”
challenge of finctional diversity
quantifying it is hard
different traits and finctions are different in different contexts
these traits also will change in future
need to measure trait data
proxy for FD?
Phylogenetic diversity
FD and PD are correlated
werer both similarly able to predict ecosystem function (biomass used as measure of this)
Phylogenetic gambit?
maximising PD we conserve should lead to conservation of more PD - better than just picking species at random
doesnt perfectly proxy to FD but does a better job than random selection
why conserve evolutionary history?
Longer phylogenetic branch length may correspond with unusual distinctive taxa
aye-aye, hoatzin
maintianing PD might facilitate adaptation to future conditions (more varied traits conserved - more options for adapting to environmen changes)
metric of Evolutionary distinctiveness
for each branch
ED score=
branch length/no. of extant species it leads to
for each species:
sum all of the ED scores for all branches root to tip
less extant species on branch - more likely that that branch is lost when species go extinct
Globally endangered metrics?
0- least concerned
1 - No threat
2 - Vulnerable
3 - Endangered
4 - Critically endangered
EDGE score
combination of Evolutionary Diversity
and Globally endangered metrics
EDGE=
ln(1+ED[myr]) + GE*ln(2)
for high edge score
need to be very endangered and on long branch by self
future: few long branches?
want to prioritise preservation of very long independent branches (e.g. Hoatzin)
-which can act as insurance policy for climate/environmental change by maximising total diversity
-HOWEVER - gene pools for these pops are small - hard for them to adapt quick
are they just in process of dying out?
future: many twigs:
prioritising conserving groups that have radiated fast very recently
(twiggy)
pro - may divesify rapidly in future
con - preserving many similar morphologies
just because they diversified rapidly recently - can’t know if they will in future - hard to know what will rapidly radiate when
comb vs brush shape phylogeny
save 12 species at random from each
which will save more evo history
conserve more when random from balanced phylogenies that are comb shaped opposed to brush shaped
comb shaped species share much less evo history
saving at random saves more
using phylgenetic data to gain more insight into extinction?
lose more monotypic genera (1 species) than polytipic genera from extinction
lose fewer genera if extinction risk is randomly distributed
conclusions:
-with current threats - looks like will lose more genera than random BAD
-extinction risk is clustered - may be due to conserved traits that predispose to certain extinction conditions
correlates with extinction risk
use independent contrast of phylogenies correlating traits to IUCN extinction risk
in mammals - body size
others:
-weaning age
-gestation length
-population density
-geographic range size (smaller - higher extinction risk)
-external threat index
-human population density
interaction between all these variables and body size (>3kg)
