The
foxes
educed
seabi d
populatio s,
which
mea t
less
ut ie t- ich
gua o
eached
the
isla ds.
A ctic
foxes
i t oduced
to
mo e
tha
400
Alaska
isla ds
fo
fu
cha ged
fa
mo e
tha
the
local
wildlife.
Acco di g
to
a
study
published
i
jou al
Scie ce,
by
p eyi g
o
seabi ds,
they
dis upted
the
flow
of
ut ie ts
f om
the
ocea
to
la d
a d
helped
tu
some
of
the
Aleutia
Isla ds
f om
g assla ds
i to
ma itime
tu d a.The
foxes
we e
i t oduced
afte
the
ma itime
fu
t ade
collapsed
i
the
late
19th
a d
ea ly
20th
ce tu ies.
They
we e
b ought
to
the
isla ds
as
a
additio al
sou ce
of
fu .
But
while
foxes
sp ead
ac oss
ma y
isla ds,
some
emai ed
fox-f ee
because
i t oductio s
failed
o
we e
eve
attempted.The
study
compa ed
18
isla ds
i
the
Aleutia
a chipelago,
i e
with
foxes
a d
i e
without
them.
Resea che s
exami ed
seabi d
umbe s,
soil
ut ie ts
a d
pla t
commu ities
to
u de sta d
how
the
i t oductio
of
the
p edato s
had
affected
the
wide
ecosystem.
Seabi d
populatio
dis upted
The
biggest
cha ge
was
i
seabi d
umbe s.
B eedi g
seabi d
de sities
we e
almost
100
times
highe
o
fox-f ee
isla ds
tha
o
isla ds
with
foxes.
Resea che s
estimated
that
a ual
seabi d
gua o
i put
fell
f om
a
media
of
361.9
g ams
pe
squa e
met e
o
fox-f ee
isla ds
to
just
5.7
g ams
o
fox-i fested
isla ds.That
loss
had
a
majo
effect
o
soil
fe tility.
Seabi ds
b i g
ut ie ts
f om
the
ocea
to
la d
th ough
thei
gua o.
O
the
fox-f ee
isla ds,
total
soil
phospho us
was
mo e
tha
th ee
times
highe
tha
o
isla ds
with
foxes.
Seabi ds
gathe
a ou d
Aleutia
Isla ds
(Pictu e:
Natio al
Audubo
Society)
The
diffe e ce
could
also
be
see
i
the
vegetatio .
G ass
biomass
was
almost
th ee
times
highe
o
fox-f ee
isla ds,
while
sh ub
biomass
was
about
10
times
lowe .
The
it oge
co te t
of
g asses
a d
fo bs
was
also
highe
o
the
fox-f ee
isla ds.
These
isla ds
we e
la gely
domi ated
by
g asses
a d
othe
g ami oids,
while
fox-i fested
isla ds
had
a
mo e
eve
mix
of
g asses,
sh ubs
a d
fo bs.This
showed
that
the
foxes
we e
affecti g
pla ts
without
di ectly
feedi g
o
them.
Thei
impact
moved
th ough
the
ecosystem.
By
educi g
seabi ds,
they
educed
the
amou t
of
ma i e-de ived
ut ie ts
eachi g
the
soil.
The
poo e
soil
the
favou ed
pla ts
that
eeded
fewe
ut ie ts.
Testi g
ut ie t
li k
Scie tists
also
ca ied
out
a
fe tilisatio
expe ime t
o
a
la ge
fox-i fested
isla d.
They
wa ted
to
see
whethe
addi g
ut ie ts
could
p oduce
the
ki d
of
pla t
commu ity
fou d
o
fox-f ee
isla ds.Ove
th ee
yea s,
fe tilised
plots
eco ded
a
24-fold
i c ease
i
g ass
biomass
compa ed
with
co t ol
plots.
G ass
quickly
became
domi a t
i
the
fe tilised
a eas.
Its
sha e
of
total
pla t
biomass
ose
f om
about
22%
to
96%.
I
the
co t ol
plots,
g ass
levels
ba ely
cha ged.The
expe ime t
p ovided
st o g
evide ce
that
ut ie t
availability
was
d ivi g
the
diffe e ce
betwee
the
isla d
ecosystems.
The
esea che s
co cluded
that
the
ut ie ts
supplied
by
seabi d
gua o
we e
e ough
to
explai
the
co t asti g
pla t
commu ities.Measu eme ts
of
it oge
isotopes
p ovided
fu the
evide ce.
Soils,
pla ts
a d
seve al
te est ial
a imals
o
fox-f ee
isla ds
showed
st o ge
sig s
of
eceivi g
it oge
f om
ma i e
sou ces.
This
i dicated
that
the
seabi d
colo ies
we e
helpi g
move
ut ie ts
f om
the
ocea
i to
the
isla d
ecosystem.The
esea che s
co cluded
that
the
i t oductio
of
A ctic
foxes
t a sfo med
pa ts
of
the
Aleutia
a chipelago
f om
g assla ds
to
ma itime
tu d a.
The
foxes
educed
seabi d
populatio s,
which
mea t
less
ut ie t- ich
gua o
eached
the
isla ds.
This
educed
soil
fe tility
a d
eve tually
cha ged
the
pla t
commu ities,
with
g asses
givi g
way
to
mo e
sh ubs
a d
fo bs.The
impact
of
the
foxes
has
also
led
to
esto atio
effo ts
i
the
Aleutia
Isla d.
Acco di g
to
the
US
Fish
a d
Wildlife
Se vice,
A ctic
foxes
have
bee
emoved
f om
most
isla ds
withi
the
Alaska
Ma itime
Natio al
Wildlife
Refuge.