Fitness declines toward range limits and local adaptation to climate affect dispersal evolution during climate-induced range shifts
Date
2016-06-14
Authors
Hargreaves, A.L.
Bailey, S.F.
Laird, Robert A.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Dispersal
ability
will
largely
determine
whether
species
track
their
climatic
niches
during
climate
change,
a
process
especially
important
for
populations
at
contracting
(low-latitude/low-elevation)
range
limits
that
otherwise
risk
extinction.
We
investigate
whether
dispersal
evolution
at
contracting
range
limits
is
facilitated
by
two
processes
that
potentially
enable
edge
populations
to
experience
and
adjust
to
the
effects
of
climate
deterioration
before
they
cause
extinction:
a)
climate-‐induced
fitness
declines
toward
range
limits,
and
b)
local
adaptation
to
a
shifting
climate
gradient.
We
simulate
a
species
distributed
continuously
along
a
temperature
gradient
using
a
spatially
explicit,
individual-‐
based
model.
We
compare
range-‐wide
dispersal
evolution
during
climate
stability
vs.
directional
climate
change,
with
uniform
fitness
vs.
fitness
that
declines
toward
range
limits
(RLs),
and
for
a
single
climate
genotype
vs.
multiple
genotypes
locally
adapted
to
temperature.
Dispersal
decreased
toward
stable
RLs
when
range-‐wide
fitness
was
uniform,
but
increased
when
fitness
declined
toward
RLs,
due
to
highly
dispersive
genotypes
maintaining
sink
populations
at
RLs,
increased
kin
selection
in
smaller
populations,
and
an
emergent
fitness
asymmetry
that
favoured
dispersal
in
low-‐quality
habitat.
However,
this
initial
dispersal
advantage
at
low-‐fitness
RLs
did
not
facilitate
climate
tracking,
as
it
was
outweighed
by
an
increased
probability
of
extinction.
Locally-‐adapted
genotypes
benefited
from
staying
close
to
their
climate
optima;
this
selected
against
dispersal
under
stable
climates
but
for
increased
dispersal
throughout
shifting
ranges,
compared
to
cases
without
local
adaptation.
Dispersal
increased
at
expanding
RLs
in
most
scenarios,
but
only
increased
at
the
range
centre
and
contracting
RLs
given
local
adaptation
to
climate.
Description
Sherpa Romeo yellow journal (pre-print only, accepted for publication)
Keywords
Dispersal evolution , Range shift , Climate change , Local adaptation , Individual based simulation model , Range contraction , Fitness gradient , Sink populations