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Attractive, climate-adapted and sustainable? Public perception of non-native planting in the designed urban landscape

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Throughout Europe climate change has rendered many plant species used in contemporary urban planting design less fit for use in public greenspaces. A growing evidence base exists for the ecological value of introducing non-native species, yet urban policy and practice guidance continues to portray non-native species negatively, focusing on their assumed invasiveness. In this context there is a lack of research focusing on the cultural relevance of non-native species in the urban landscape. To address this gap we surveyed 1411 members of the UK public who walked through designed and semi-natural planting of three levels of visual nativeness: “strongly native”; “intermediate” and “strongly non-native”, whilst completing a site-based questionnaire. Semi-structured, in-depth interviews were then carried out with 34 questionnaire participants. A majority (57.6%) of our respondents would be happy to see more non-native planting in UK public spaces, rising to 75.3% if it were better adapted to a changing climate than existing vegetation. Respondents recognised the three broad levels of nativeness, yet this was not a factor driving perceptions of the attractiveness of the planting. In addition to climate change, we identified four key factors driving acceptance and rejection of non-native planting: aesthetics; locational context; historic factors and inevitability; and perceptions of invasiveness and incompatability with native wildlife. Our research indicates that in the context of a changing climate, focus should be placed on the potentially positive role of non-invasive, climate-adapted, aesthetically pleasing species within urban planting schemes as these could be well-received by the public.
Content may be subject to copyright.
Landscape
and
Urban
Planning
164
(2017)
49–63
Contents lists available at ScienceDirect
Landscape
and
Urban
Planning
journal homepage: www.elsevier.com/locate/landurbplan
Research
Paper
Attractive,
climate-adapted
and
sustainable?
Public
perception
of
non-native
planting
in
the
designed
urban
landscape
Helen
Hoyle,
James
Hitchmough,
Anna
Jorgensen
Department
of
Landscape,
University
of
Sheffield,
United
Kingdom
h
i
g
h
l
i
g
h
t
s
75.3%
participants
positive
about
climate-adapted
non-native
planting.
Climate
change
identified
as
major
driver
of
acceptance
of
non-native
plants.
Acceptance
also
related
to
aesthetics,
context,
perceived
invasiveness.
Perceived
attractiveness
not
related
to
perceived
nativeness.
Contradictions
in
perception
of
non-native
plants
identified.
a
r
t
i
c
l
e
i
n
f
o
Article
history:
Received
15
November
2016
Received
in
revised
form
22
March
2017
Accepted
23
March
2017
Keywords:
Climate
change
Urban
planting
design
Cultural
relevance
Non-native
Species
Aesthetic
Public
perception
a
b
s
t
r
a
c
t
Throughout
Europe
climate
change
has
rendered
many
plant
species
used
in
contemporary
urban
plant-
ing
design
less
fit
for
use
in
public
greenspaces.
A
growing
evidence
base
exists
for
the
ecological
value
of
introducing
non-native
species,
yet
urban
policy
and
practice
guidance
continues
to
portray
non-native
species
negatively,
focusing
on
their
assumed
invasiveness.
In
this
context
there
is
a
lack
of
research
focusing
on
the
cultural
relevance
of
non-native
species
in
the
urban
landscape.
To
address
this
gap
we
surveyed
1411
members
of
the
UK
public
who
walked
through
designed
and
semi-natural
planting
of
three
levels
of
visual
nativeness:
“strongly
native”;
“intermediate”
and
“strongly
non-native”,
whilst
com-
pleting
a
site-based
questionnaire.
Semi-structured,
in-depth
interviews
were
then
carried
out
with
34
questionnaire
participants.
A
majority
(57.6%)
of
our
respondents
would
be
happy
to
see
more
non-native
planting
in
UK
public
spaces,
rising
to
75.3%
if
it
were
better
adapted
to
a
changing
climate
than
existing
vegetation.
Respondents
recognised
the
three
broad
levels
of
nativeness,
yet
this
was
not
a
factor
driving
perceptions
of
the
attractiveness
of
the
planting.
In
addition
to
climate
change,
we
identified
four
key
factors
driving
acceptance
and
rejection
of
non-native
planting:
aesthetics;
locational
context;
historic
fac-
tors
and
inevitability;
and
perceptions
of
invasiveness
and
incompatability
with
native
wildlife.
Our
research
indicates
that
in
the
context
of
a
changing
climate,
focus
should
be
placed
on
the
potentially
positive
role
of
non-invasive,
climate-adapted,
aesthetically
pleasing
species
within
urban
planting
schemes
as
these
could
be
well-received
by
the
public.
©
2017
The
Authors.
Published
by
Elsevier
B.V.
This
is
an
open
access
article
under
the
CC
BY-NC-ND
license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
1.
Introduction
In
much
of
contemporary
urban
policy
and
practice
non-native
plant
species
are
presented
as
being
of
little
value
at
best
or
harmful
at
worst.
These
positions
feed
an
overriding
presumption
within
many
planners,
landscape
architects,
local
authority
officers
and
Corresponding
author
at:
Centre
for
Sustainable
Planning
and
Environments,
University
of
the
West
of
England,
Frenchay
Campus,
BS16
IQY
Bristol.
E-mail
addresses:
helenehoyle1@gmail.com
(H.
Hoyle),
j.d.hitchmough@sheffield.ac.uk
(J.
Hitchmough),
A.jorgensen@sheffield.ac.uk
(A.
Jorgensen).
conservation
practitioners
that
the
sustainable
urban
green
infras-
tructure
of
the
twenty
first
century
should
consist
exclusively
of
native
planting
(Davis
et
al.,
2011;
Hitchmough,
2011).
Pol-
icy
guidance
such
as
BREEAM
UK
New
Construction
non-domestic
buildings
technical
manual
(2014)
reinforces
this
stance,
advocat-
ing
the
exclusive
use
of
native
plant
species
in
order
to
‘minimise
impact
on
existing
site
ecology’.
At
the
local
level
in
the
UK,
bio-
diversity
action
plans
highlight
‘reducing
the
impact
of
non-native
species’.
The
main
argument
used
in
defence
of
this
position
is
the
assumed
invasiveness
of
all
non-native
exotic
plant
species
(Pollan,
1994)
yet
many
of
the
claims
which
drive
this
perception
of
the
aggressive
invasive
alien
are
not
backed
by
data
(Davis
et
al.,
2011).
http://dx.doi.org/10.1016/j.landurbplan.2017.03.009
0169-2046/©
2017
The
Authors.
Published
by
Elsevier
B.V.
This
is
an
open
access
article
under
the
CC
BY-NC-ND
license
(http://creativecommons.org/licenses/by-nc-nd/4.
0/).
50
H.
Hoyle
et
al.
/
Landscape
and
Urban
Planning
164
(2017)
49–63
Scientific,
and
ultimately
much
wider
public
concerns
about
non-native
plants
can
be
traced
back
to
Elton’s
(1958)
The
Ecology
of
Invasions
of
Animals
and
Plants
that
led
to
the
discipline
of
Invasion
Ecology,
yet
recent
findings
indicate
that
agriculture
is
profoundly
more
harmful
to
biodiversity
than
even
the
most
aggressive,
inva-
sive
non-native
plant
species
(Burns
et
al.,
2016).
A
clear
body
of
evidence
now
exists
that
invasiveness
is
not
a
fundamental
property
of
non-native
plant
species
but
rather
a
characteristic
of
both
native
and
non-native
species
possessing
certain
ecological
traits
(Didham,
Tylianakis,
Hutchinson,
Ewers,
&
Gemmell,
2005;
Gurevitch
&
Padilla,
2004;
Sagoff,
2005;
Thomas
&
Palmer,
2015;
Thompsonet
al.,
2003)
and
a
growing
minority
within
ecology
now
see
hostility
towards
non-natives
as
a
diversion
from
the
real
issue
of
maintaining
diversity
in
ecosystems,
a
role
towards
which
non-
native
species
can
make
a
positive
contribution
(Davis
et
al.,
2011).
Gleditsch
and
Carlo
(2010),
Owen
(1991)
and
Smith
et
al.
(2006)
have
shown
that
non-native
plant
species
are
equally
valuable
as
food
sources
for
many
native
animals
and
more
so
in
some
cases
than
native
species.
Non-
native
plants
can
also
provide
specific
benefits
to
native
invertebrates
such
as
the
extension
of
pollen
and
nectar
availability
beyond
the
flowering
season
of
native
plant
species
(Salisburyet
al.,
2015).
Another
important
factor
in
hostility
to
non-natives
is
the
idea
that
they
do
not
belong:
that
they
are
brought
here
by
people,
are
not
fit
for
the
environment
and
hence
lie
outside
what
is
“natural”.
This
idea
is
rooted
in
the
notion
that
the
past
was
like
the
present,
which
is
clearly
not
the
case.
Within
our
own
time
climate
change
has
already
had
a
profound
impact
on
the
distribution
of
plant
and
animal
species
throughout
the
world,
with
species
migrating
polewards
or
to
higher
elevations
as
temperatures
rise
(Hickling,
Roy,
Hill,
Fox,
&
Thomas,
2006;
Parmesan,
2006;
Parmesan
&
Yohe,
2003)
fashioning
new
ecosystems.
It
is
unrealistic
and
impractical
to
attempt
the
restoration
of
habitats
to
‘some
“rightful”
historic
state’
(Davis
et
al.,
2011)
consisting
exclusively
of
currently
native
species,
because
climate
change
will
render
some
of
these
(such
as
Betula
pendula
in
Southern
England)
increasingly
poorly
fitted
Within
designed
urban
landscapes
there
is
a
need
to
incorporate
new
species
with
potential
utility
in
terms
of
‘fitness’
to
a
warming
climate,
but
this
raises
questions
of
what
is
culturally
acceptable
(Hitchmough,
2011).
Biological
concerns
about
the
invasiveness
of
non-native
plants
and
their
incompatibility
with
native
wildlife
seem
to
have
mor-
phed
in
some
cases
into
the
belief
that
these
plants
are
less
attractive
or
culturally
relevant
to
people
than
native
plants
(Hitchmough,
2011).
Indeed,
attitudes
to
non-native
plants
are
heavily
constructed
within
cultures
(Coates,
2006;
Head
&
Muir,
2006;
Kurz
&
Baudains,
2012;
Zagorski,
Kirkpatrick,
&
Stratford,
2004)
and
have
fluctuated
widely
in
Britain
and
many
other
coun-
tries
over
past
centuries
(Chew,
2009;
Starfinger,
Kowarik,
Rode,
&
Schepker,
2003).
In
parts
of
the
world
most
recently
colonised
by
Europeans
such
as
Australia
and
New
Zealand
native
plants
were
initially
viewed
negatively
as
‘common’
and
‘aggressive’
for
the
first
half
of
the
20th
century,
while
northern
hemisphere
plants
from
North
America,
Europe
and
Asia
were
valued
as
rare
and
out-of-the-ordinary
(Aitken,
2016).
Towards
the
end
of
the
20th
century
native
plants
became
fashionable,
in
parallel
with
Australia
and
New
Zealand’s
growing
identity
as
Australasian-Pacific
nations
(Jay,
2004).
In
these
parts
of
the
world,
where
cultural
and
institu-
tional
disdain
for
non-natives
is
particularly
high
and
attitudes
to
natives
are
politically
contested
due
to
these
historic
factors,
non-
native
plants
remain
popular
with
many
gardeners
who
are
free
to
choose
what
they
plant,
(Kendal,
Williams,
&
Williams,
2012;
Zagorski
et
al.,
2004).
Landscape
preference
studies
in
Australia
and
New
Zealand
(Head
&
Muir,
2006;
Jay
&
Stolte,
2011;
Kendal
et
al.,
2012;
Kurz
&
Baudains,
2012;
Zagorski
et
al.,
2004)
have
considered
‘nativeness’
as
a
specific
plant
or
garden
trait.
Kendal
et
al.
(2012),
found
clear
patterns
of
preference
for
both
visual
plant
traits
such
as
leaf
colour
and
flower
size,
and
‘nativeness’.
The
response
to
native
plants
was
polarised,
however,
with
some
people
reacting
very
pos-
itively
to
them,
and
others
strongly
disliking
them.
In
Australasia,
plants
imported
and
popular
during
the
colonial
past
typically
had
larger
flowers
and
more
luxuriant
leaves
than
many
highly
xeric
native
species,
suggesting
that
preference
was
as
much
to
do
with
morphology
and
fashion
as
nostalgia
for
the
country
of
origin.
Evo-
lutionary
habitat
theories
of
landscape
preference
predict
a
lower
preference
for
native
Australian
plants,
as
their
frequently
nar-
row
leaves
indicate
a
poor-quality
habitat
(Williams
&
Cary,
2002).
Social
and
cultural
values
may,
however,
override
this
evolutionary
response,
with
evidence
that
higher
levels
of
educational
attain-
ment
may
promote
greater
acceptance
of
the
aesthetics
of
native
plants
due
to
enhanced
environmental
knowledge
(Kendal
et
al.,
2012).
These
findings
are
broadly
consistent
with
those
from
earlier
studies
(Head
&
Muir,
2006;
Zagorski
et
al.,
2004).
In
contrast,
other
studies
conducted
in
the
USA
(Nassauer,
Wang,
&
Dayrell,
2009)
and
in
Western
Australia
(Kurz
&
Baudains,
2012)
concluded
that
attitudes
to
native
plants
were
largely
related
to
gardening
norms
in
the
neighbourhood.
Preference
for
native
and
non-native
plants
is
likely
to
be
most
polarised
where
native
and
non-native
species
look
very
different,
as
in,
for
example
the
Southern
Hemisphere.
In
Europe,
historically,
non-native
plants
were
positively
per-
ceived
as
novel
and
interesting
(Shephard
&
Musgrave,
2014;
Wulf,
2008)
and
widely
used
in
landscapes
and
parks
since
the
Renais-
sance
(Steele,
1793)
and
in
many
cases
long
before
this.
Here
attitudes
to
non-natives
appear
to
be
less
polarised
(Fischer
et
al.,
2011)
perhaps
because
it
is
more
obvious
to
all
that
most
land-
scapes
are
heavily
culturally
transformed
(Hitchmough,
2011)
and
that
non-native
plants
are
important
in
these
transformations.
To
date
however
there
appear
to
be
few
studies
that
have
examined
how
important
notions
of
nativeness
in
landscape
planting
are
to
European
citizens.
An
issue
central
to
this
is
the
capacity
of
lay
peo-
ple
to
distinguish
between
native
and
non-native
plants
in
practice
in
the
landscape.
Alien
plants
have
been
important
in
European
culture
for
so
long,
that
public
understanding
of
what
is
native
and
non-native
have
often
become
very
confused
(Davis
et
al.,
2011).
If
this
is
the
case
then
“nativeness”
is
little
more
than
an
abstract
idea.
Findings
from
an
extensive
(n
=
2378)
European
study
(Fischer
et
al.,
2011)
suggest
that
“nativeness”
is
not
an
identifiable
vis-
ible
characteristic
for
the
general
public,
who
are
most
likely
to
make
judgements
based
on
perceived
attractiveness
of
species
to
themselves.
Within
this
line
of
reasoning
Rodriguez
et
al.
(2004)
have
argued
that
plant
attractiveness
to
the
public
should
be
a
cri-
terion
used
in
biodiversity
management.
Hitchmough
(2011)
has
suggested
that
landscape
professionals
and
householders
with
pri-
vate
gardens
in
Britain
and
many
other
parts
of
the
world
chose
plants
because
they
found
them
attractive
or
useful,
rather
than
because
they
were
native
or
non-native.
This
view
is
supported
by
research
conducted
in
61
domestic
gardens
in
Sheffield,
(Smith,
Gaston,
Warren,
&
Thompson,
2006)
which
indicated
that
30%
of
garden
plants
were
natives
(mostly
unchosen
garden
and
lawn
weeds)
and
70%
non-natives
(mostly
chosen),
mainly
from
Europe
and
Asia,
suggesting
an
acceptance
of
and
perhaps
preference
for
the
use
of
non-native
plant
species
in
these
contexts
amongst
the
UK
population.
This
raises
fundamental
questions
about
why,
out-
side
of
landscapes
whose
primary
role
is
biodiversity
conservation,
non-invasive,
but
well-fitted
non-native
species
should
be
posited
as
inappropriate
within
urban
landscapes.
The
study
discussed
in
this
paper
focuses
on
public
reaction
to
actual
woodland,
shrub
and
herbaceous
planting
in
designed
urban
landscapes
composed
of
native
and
non-native
plant
species,
in
an
attempt
to
unpick
these
complex
ideas.
The
environment
is
experienced
rather
than
simply
looked
at
(Ittleson,
1973)
so
in
order
to
inform
sustainable
and
culturally
relevant
landscape
H.
Hoyle
et
al.
/
Landscape
and
Urban
Planning
164
(2017)
49–63
51
design
our
study
was
conceived
at
the
scale
of
assemblages
of
plants,
rather
than
that
of
individual
plant
species.
A
method
was
devised
whereby
participants
walked
through
areas
of
planting
as
an
immersive
experience.
Planting
was
characterised
as
possessing
one
of
three
species
characters:
strongly
non-native,
intermediate
or
strongly
native.
This
gradient
of
character
was
derived
from
the
spe-
cific
morphology
or
visual
traits
of
the
species
present
within
the
planting
in
terms
of
their
similarity
to
common
native
species.
The
structure
of
the
planting
or
way
in
which
the
individual
plants
were
assembled
was
also
considered,
although
this
is
the
focus
of
another
publication.
For
the
purpose
of
the
research
we
hypothesised
that
species-plantings
that
resemble
native
UK
species
and
vegetation
are
seen
as
more
familiar
to
UK
citizens.
We
then
proceeded
to
ask:
1)
How
accepting
are
people
of
non-native
planting
in
the
designed
urban
landscape?
2)
Can
people
distinguish
between
native
and
non-native
planting
in
these
settings?
3)
What
are
the
key
factors
that
drive
acceptance
and
rejection
of
native
and
non-native
planting
in
these
settings?
4)
Do
these
perceptions
change
when
seen
against
a
background
of
climate
change?
2.
Methods
Our
study
involved
a
well-established
(e.g.
Jorgensen,
Hitchmough,
&
Dunnett,
2007)
two-stage
mixed
methods
approach.
A
large
sample
of
1411
site
users
were
guided
to
walk
through
woodland,
shrub
and
herbaceous
planting
of
strongly
non-native,
intermediate
or
strongly
native
species
char-
acter
at
31
sites
throughout
England
(Fig.
1)
whilst
participating
in
a
questionnaire
survey.
Semi-structured,
in-depth
interviews
were
then
carried
out
with
34
of
these
original
questionnaire
participants.
2.1.
Selection
of
case
study
sites
Specific
case
study
sites
(Figs.
2–4)
were
selected
to
represent
the
three
species
characters:
strongly
non-native,
intermediate
and
strongly
native.
In
the
UK
strongly
native
vegetation
is
exemplified
by
deciduous
woodland,
shrubby
woodland
edge
and
herbaceous
communities
of
tall
grasses
and
forbs,
all
composed
of
native
species.
For
example,
in
the
case
of
woodland,
broadleaved
decidu-
ous
trees
represent
a
‘strongly
native’
species
character,
whereas
broadleaved
evergreen
species
such
as
Eucalyptus
and
Cordyline
australis
are
‘strongly
non-native’
in
species
character
(Fig.
2).
In
the
case
of
woodland
(Fig.
2)
and
herbaceous
(Fig.
4)
planting
all
three
characters
were
represented.
In
the
case
of
shrub
planting
(Fig.
3)
two
were
represented,
with
the
‘intermediate’
character
omitted.
Nine
sites
were
in
public
parks
or
gardens:
The
Botanical
Gar-
dens
and
Bole
Hills,
Sheffield
(2),
Fairlands
Valley
Park,
Stevenage
(5),
Princess
Gardens
and
Kings
Gardens,
Torquay
(2)
and
twenty-
two
were
in
large
semi-public
gardens:
Beth
Chatto’s
Garden,
Colchester,
Essex
(3),
RHS
Wisley,
Surrey
(9),
Savill
and
Valley
Gardens,
Crown
Estate,
Surrey
(3),
Harold
Hilliers
Garden
and
arboretum,
Hampshire
(3),
and
Abbotsbury
Subtropical
Gardens,
Dorset
(4).
Sites
were
selected
to
capture
the
broad
range
of
species
character
ranging
from
the
strongly
native
(more
common
in
public
park
settings),
to
strongly
non-native
(more
common
in
institu-
tional
gardens).
2.2.
On-site
questionnaires
2.2.1.
Questionnaire
design
and
procedure
The
questionnaire
largely
took
the
form
of
attitudinal
and
belief
statements,
using
a
five
point
Likert
scale
from
+2
(agree
strongly)
to
2
(disagree
strongly),
following
established
methodology
(e.g.
Ives
&
Kendal,
2013),
(Table
1).
Three
questions
involved
partic-
ipants
answering
within
the
categories:
‘many’,
‘some’
‘few’
or
‘none’.
Statements
referring
to
participants’
aesthetic
reactions
to
the
planting
and
the
degree
to
which
they
found
it
restorative
to
walk
through
were
used
to
identify
the
key
factors
driving
the
acceptance
and
rejection
of
non-native
species.
Perception
of
famil-
iarity
with
the
planting
was
assessed
to
gauge
whether
people
did
in
fact
find
planting
in
the
category
‘strongly
native’
the
most
familiar.
The
questionnaire
also
captured
participants’
beliefs
about
non-native
species
and
climate
change.
A
section
focusing
on
the
respondents’
demographic
characteristics
was
included.
After
ethical
clearance,
the
questionnaire
was
piloted
in
April
and
May
2012
in
woodland
areas
at
RHS
Wisley,
Surrey
and
at
Fairlands
Valley
Park
Stevenage.
Walks
(approximately
30
m)
were
established
through
sections
of
planting
at
the
case
study
sites
(Figs.
2–4).
Site
users
were
invited
to
walk
through
the
plant-
ing
whilst
completing
the
self-guided
questionnaire.
All
site-users
walking
through
or
adjacent
to
the
marked
section
of
planting
were
approached
as
potential
participants.
Participants
were
allowed
the
opportunity
to
walk
independently
and
to
engage
fully
with
the
planting.
All
walks
were
carried
out
in
relatively
compara-
ble
weather;
dry
days
with
low
wind
speeds.
The
limitations
of
this
method
are
that
specific
light
or
weather
conditions,
or
the
exact
configuration
of
plants
cannot
be
controlled
as
in
pho-
tographs,
(Purcell
&
Lamb,
1998;
Purcell,
Peron,
&
Berto,
2001),
digital
manipulation
of
photographs
(Jorgensen,
Hitchmough,
&
Calvert,
2002;
Todorova,
Asakawa,
&
Aikoh,
2004),
or
videos
(Van
den
Berg,
Jorgensen,
&
Wilson,
2014),
yet
we
concluded
that
for
the
purposes
of
this
study
the
three-dimensional
multi-experiential
benefits
of
the
immersive
approach
outweighed
these
disadvan-
tages.
The
approach
has
been
used
previously
(Martens,
Gutscher,
&
Bauer,
2011;
Qiu,
Lindberg,
&
Nielsen,
2013).
All
(n
=
1411)
on-site
walks
and
questionnaires
were
completed
during
spring,
summer
and
autumn
2012
and
2013.
This
comprised
595
questionnaires
at
13
different
woodland
sites,
348
at
8
different
shrub
sites
and
486
at
10
different
herbaceous
sites.
2.2.2.
Data
analysis
All
questionnaire
data
were
analysed
using
SPSS
version
20.
In
order
to
address
research
questions
(2)
Can
people
distinguish
between
native
and
non-native
planting
in
these
settings?
and
(3)
What
are
the
key
factors
that
drive
acceptance
and
rejection
of
native
and
non-native
planting
in
these
settings?,
Principal
Components
Analysis
(PCA)
with
a
varimax
rotation
was
applied
to
questionnaire
items
relating
to
these
questions
(Table
1).
The
PCA
identified
items
which
varied
in
a
consistent
pattern
and
loaded
onto
single
components,
each
measuring
a
specific
dimension
of
participants’
perceptions
(Table
4).
ANOVA
techniques
were
used
to
explore
these
components’
relationship
to
species
character.
Firstly,
one-way
ANOVA
was
conducted
with
the
emergent
perceptional
principal
components
as
dependent
and
species
character,
other
planting
varibles
(planting
structure
and
%
flower
cover
and
veg-
etation
community)
and
demographic
variables
as
independent,
to
identify
all
significant
variables.
Multi-factor
ANOVA
was
then
conducted
with
the
emergent
components
as
dependent
and
all
planting
and
demographic
variables
identified
as
significant
in
the
first
analysis
as
independent.
This
ascertained
the
residual
inde-
pendent
main
effect
of
species
character,
adjusting
for
demographic
variables
and
other
planting
variables.
Post
hoc
multiple
compar-
isons
using
the
Sidak
correction
(Table
5)
distinguished
significant
differences
between
groups
or
categories.
Pearson
correlations
were
then
carried
out
between
perceived
attractiveness,
and
four
separate
indicators
of
plant
or
invertebrate
biodiversity
(Table
6)
to
establish
if
the
perception
of
specifically
‘native’
biodiversity
had
a
role
in
influencing
people’s
perceptions
of
attractiveness.
The
measure
of
perceived
attractiveness
was
that
52
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/
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164
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49–63
Fig.
1.
The
geographical
distribution
of
case
study
sites,
England
UK.
Fig.
2.
Images
of
the
woodland
sites
used
in
the
study,
showing
the
gradient
of
species
character
from
strongly
native
to
strongly
non-native.
H.
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et
al.
/
Landscape
and
Urban
Planning
164
(2017)
49–63
53
Fig.
3.
Images
of
the
shrub
sites
used
in
the
study,
showing
the
two
levels
of
species
character:
strongly
native
and
strongly
non-native.
Fig.
4.
Images
of
the
herbaceous
sites
used
in
the
study,
showing
the
gradient
of
species
character
from
strongly
native
to
strongly
non-native.
derived
from
responses
to
the
attitudinal
statement,
‘the
planting
on
this
walk
is
attractive’.
The
two
variables
used
to
measure
per-
ceived
native
plant
and
invertebrate
diversity
were
those
related
to
the
questions
‘How
many
native
UK
plant
species
do
you
think
there
are
in
this
planting?’
(Perceived
number
of
native
UK
plant
species),
and
‘How
many
species
of
native
UK
insects
(flies,
but-
terflies,
bees)
do
you
think
this
planting
will
support?’
(Perceived
number
of
native
UK
insects).
The
two
variables
used
to
measure
perceptions
of
overall
plant
diversity
and
invertebrate
abundance
corresponded
to
the
question
‘How
many
different
plant
species
in
total
do
you
think
there
are
here?’
(Perceived
number
of
differ-
ent
plant
species)
and
the
statement
‘The
planting
along
this
walk
appears
good
for
butterflies,
bees
and
other
insects’.
(Perceived
suitability
of
planting
for
insects).
54
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/
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164
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49–63
Table
1
Research
questions
and
corresponding
questionnaire
attitudinal
and
belief
statements
and
questions.
Items
in
bold
were
included
in
the
Principal
Components
Analysis
(PCA).
Question
number
Research
Question
Attitudinal
statements/questions
1
How
accepting
are
people
of
non-native
planting
in
the
designed
urban
landscape?
Planting
in
parks
and
gardens
should
be
restricted
to
native
species
Native
plants
support
more
native
butterflies,
bees
and
other
insects
than
non-
native
plants
I
would
be
happy
to
see
more
non-native
species
like
those
below
(Fig.
5)
growing
in
UK
parks
and
gardens
2
Can
people
distinguish
between
native
and
non-native
planting
in
these
settings?
How
many
different
plant
species
in
total
do
you
think
there
are
here?
How
many
native
UK
plant
species
do
you
think
there
are
in
this
planting?
How
many
species
of
native
UK
insects
do
you
think
this
planting
will
support?
The
planting
along
this
walk
appears
familiar
3
What
are
the
key
factors
that
drive
acceptance
and
rejection
of
native
and
non-native
planting
in
these
settings?
The
planting
along
this
walk
is
attractive
The
planting
along
this
walk
is
interesting
The
planting
on
this
walk
is
colourful
The
combination
of
colours
is
attractive
in
this
planting
The
planting
along
this
walk
is
good
for
butterflies,
bees
and
other
insects
The
planting
on
this
walk
looks
tidy
The
planting
on
this
walk
looks
designed
The
planting
on
this
walk
looks
cared
for
This
walk
reveals
a
special
unique
place
I
feel
relaxed
on
this
walk
I
feel
comfortable
along
this
walk
This
walk
allows
me
to
escape
from
more
mundane
routines
and
work
4
Do
these
perceptions
change
when
set
against
a
background
of
climate
change?
I
believe
global
climate
change
is
happening
I
believe
that
global
climate
change
will
have
serious
consequences
I
think
global
warming
will
change
the
plant
species
most
suited
to
grow
in
UK
parks
and
gardens
over
the
next
50
years
I
would
accept
non-native
species
like
those
(Fig.
5)
in
UK
parks
and
gardens
if
they
were
better
suited
to
the
climate
than
present
day
species
2.3.
Semi-structured
interviews
2.3.1.
Interview
design
and
procedure
Semi-structured
interviews
were
conducted
with
a
self-
selecting
subset
of
the
original
questionnaire
participants
who
provided
their
contact
details
at
the
end
of
the
questionnaire.
The
original
intention
was
to
conduct
one
interview
per
‘walk
site’
(31
in
total),
but
this
proved
impossible,
as
did
sampling
across
the
age
range
whilst
still
achieving
a
gender
balance.
Questionnaire
par-
ticipants’
contact
details
were
obtained
for
all
31
sites,
yet
many
were
unavailable
for
interview
on
the
appointed
dates.
Interviews
were
conducted
to
explore
the
key
factors
driving
acceptance
and
rejection
of
non-native
species
in
the
designed
landscape,
against
a
background
of
climate
change.
Themes
addressed
were
attractive-
ness,
restorative
effect
and
relaxation,
native
invertebrate
diversity,
tidiness,
climate
change
and
attitudes
to
the
use
of
non-native
plant-
ing.
These
were
defined
by
the
original
research
questions
and
were
confirmed
as
meaningful
by
the
exploratory
principal
com-
ponents
analysis
(PCA)
of
the
questionnaire
data
(Tables
4
&
5).
Interviews
were
semi-structured
and
flexible
(after
Bryman,
2012)
allowing
participants
to
diverge
from
the
themes
identified
by
the
interviewer.
An
interview
‘guide’
was
used
(after
Bryman,
2012)
allowing
the
interviewer
flexibility
in
the
ordering
and
exact
wording
of
questions.
Participants
were
presented
with
a
range
of
8
photographs
of
planting
of
varying
species
character
of
the
same
vegetation
community
as
they
had
originally
walked
through
during
the
questionnaire
phase,
i.e.,
either
woodland,
shrub
or
herbaceous
(Figs.
2–4),
to
act
as
a
cue
to
discussions,
as
well
as
a
photograph
of
Abbotsbury
Garden
“Mediterranean
Bank”
(Fig.
4)
during
discussion
of
non-native
planting.
Following
ethical
clear-
ance
and
participant
consent,
34
interviews
representing
walks
at
24
sites
(9
woodland,
8
shrub
and
17
herbaceous
interviewees)
were
conducted
from
20th
March
to
31st
July
2014.
With
the
excep-
tion
of
three
pilot
interviews
(included
in
the
data
set)
which
took
place
in
the
University,
all
interviews
were
conducted
at
the
origi-
nal
walk
sites.
It
was
thought
that
this
would
help
interviewees
to
recall
and
remember
their
original
walk
through
the
planting.
All
interviews
were
audio-recorded
and
later
transcribed
in
full.
2.3.2.
Data
analysis
Interview
data
were
analysed
via
qualitative
content
analysis
(after
Saldana,
2013)
using
the
interview
themes
above
as
ini-
tial
deductive
coding
categories
(after
Mayring,
2014).
Emergent
themes
were
also
coded
and
extracts
taking
a
particular
standpoint
were
grouped
together
using
an
indexing
system
to
categorise
data
(after
MacQueen,
McLellan,
Kay,
&
Milstein,
1998).
3.
Results
and
discussion
3.1.
Participants’
socio-demographic
characteristics
There
were
more
female
than
male
questionnaire
participants
(n
=
1411).
They
were
drawn
from
the
older
age
groups
(Table
2).
Most
were
White
British/Irish
from
a
wide
range
of
educational
backgrounds.
A
sub-sample
of
this
larger
group,
the
much
smaller
interviewee
sample
(n
=
34),
was
similar
in
profile
(Table
3)
yet
contained
a
higher
percentage
of
participants
from
landscape
or
environmental
professions.
The
strongly
biocentric
(nature-
centred,
after
Ives
&
Kendal,
2014)
focus
of
the
interviewee
sample
is
evident
(Table
4).
Participants
all
showed
some
interest
in
the
environment,
landscape
or
horticulture.
3.2.
Questionnaire
participants’
perceptions
of
the
planting:
The
role
of
species
character
Five
components
were
extracted
from
the
PCA
of
questionnaire
items
relating
to
research
questions
2
and
3
(determined
by
par-
allel
analysis,
(Watkins,
2005)),
together
accounting
for
65.33%
variability
in
our
participants’
responses
(Table
4).
These
were
interpretable
as:
Colour,
attractiveness,
interest
and
invertebrate
presence
(30.56%
variance);
Restorative
effect,
(12.36%
variance);
Neatness,
(9.75%
variance);
Native
plant
and
invertebrate
biodi-
H.
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et
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/
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Urban
Planning
164
(2017)
49–63
55
Table
2
Questionnaire
participants’
(n
=
1411)
demographic
profile
(valid%).
Gender
(Overall
missing
values
=
29
respondents)
Woodland
walks
Shrub
walks
Herbaceous
Walks
Overall
M
232
(39.9%)
114
(33.4%)
178
(37.4%)
524
(37.5%)
F
349
(60.1%)
227
(66.6%)
298
(62.6%)
874
(62.5%)
Age
(Overall
missing
values
=
34
respondents)
Woodland
walks
Shrub
walks
Herbaceous
Walks
Overall
18–24
38
(6.5%)
19
(5.6%)
33
(6.9%)
90
(6.5%)
25–34 35
(6.0%) 28
(8.3%) 43
(9.1%) 106
(7.6%)
35–44 54
(9.3%) 29
(8.6%)
53
(11.2%)
136
(9.8%)
45–54
95
(16.4%)
48
(14.2%)
95
(20.0%)
238
(17.1%)
55–64
172
(29.6%)
82
(24.3%)
114
(24.0%)
368
(26.4%)
65+
187
(32.2%)
131
(38.9%)
137
(28.8%)
455
(32.7%)
Ethnicity
(Overall
missing
values
=
187
respondents)
Woodland
walks
Shrub
walks
Herbaceous
Walks
Overall
White
British/Irish
413
(90.8%)
285
(88.0%)
405
(87.9%)
1103
(89%)
White
(other)
30
(6.6%)
25
(7.7%)
35
(7.6%)
90
(7.3%)
Mixed
white/black
Caribbean
2
(0.4%)
1
(0.3%)
1
(0.2%)
4
(0.3%)
Mixed
white/black
African
0
0
0
0
Mixed
white/Asian
1
(0.2%)
0
4
(0.9%)
5
(0.4%)
Mixed
other 1
(0.2%) 3
(0.9%) 1
(0.2%)
5
(0.4%)
Asian
Indian
0
5
(1.5%)
5
(1.1%)
10
(0.8%)
Asian
Pakistani
0
1
(0.3%)
0
1
(0.1%)
Asian
Chinese
4
(0.9%)
0
4
(0.9%)
8
(0.6%)
Asian
other
3
(0.7%)
0
5
(1.1%)
8
(0.6%)
Black
African 0
1
(0.3%) 0
1
(0.1%)
Black
Caribbean
0
1
(0.3%)
0
1
(0.1%)
Black
other 1
(0.2%)
2
(0.6%)
0
3
(0.2%)
Arab
0
0
1
(0.2%)
1
(0.1%)
Educational
Qualifications
(Overall
missing
values
=
123
respondents)
Woodland
walks
Shrub
walks
Herbaceous
Walks
Overall
None
87
(16.3%)
39
(12.3%)
66
(14.6%)
192
(14.7%)
GCSE/O’
level
(or
equiv)
183
(34.3%)
76
(23.9%)
115
(25.4%)
374
(28.7%)
A
level
(or
equiv)
86
(16.1%)
61
(19.2%)
83
(18.3%)
230
(17.6%)
Degree
127
(23.8%)
104
(32.7%)
128
(28.3%)
359
(27.5%)
Masters’
degree
36
(6.8%)
28
(8.8%)
49
(10.8%)
113
(8.7%)
Doctorate
14
(2.6%)
10
(3.1%)
12
(2.6%)
36
(2.8%)
Landscape
professional?
(Overall
missing
values
=
482
respondents)
Woodland
walks Shrub
walks Herbaceous
Walks Overall
Yes
11
(3%)
10
(3.9%)
11
(3.4%)
32
(3.4%)
No
353
(97%)
246
(96.1%)
314
(96.6%)
913
(96.6%)
versity,
(6.39%
variance)
and
Unfamiliarity
and
complexity,
(6.27%
variance).
The
individual
attitudinal
statements
loading
onto
spe-
cific
components
are
shown
(Table
4).
The
multi-factor
ANOVA
identified
that
species
character
had
a
significant
main
effect
on
all
four
factors
referring
to
partici-
pants’
aesthetic
perceptions
of
the
planting:
Colour,
attractiveness,
interest
and
invertebrate
presence,
(2.8%
variance
explained,
F
=
16.70,
P
<
0.001),
Neatness,
(1.3%
variance
explained,
F
=
4.19,
P
<
0.05),
Native
plant
and
invertebrate
biodiversity,
(4.0%
variance
explained,
F
=
22.40,
P
<
0.001),
and
Unfamiliarity
and
complexity,
(2.0%
variance
explained,
F
=
10.35,
P
<
0.001),
but
not
on
their
per-
ceptions
of
the
Restorative
effect
of
walking
through
the
planting
(Table
5).
These
effects
were
the
residual
individual
main
effects
once
the
statistical
effect
of
%
Flower
cover
had
been
removed.
3.3.
How
accepting
are
people
of
non-native
species
in
the
designed
urban
landscape?
The
majority
(57.6%,
804/1397)
of
our
questionnaire
partici-
pants
either
agreed
strongly
(20.2%),
or
agreed
(37.4%)
that
they
Fig.
5.
‘Non-native’
planting
with
visual
‘cues’
such
as
spiky
xeric
leaves
as
shown
in
the
questionnaire.
would
be
happy
to
see
more
non-native
plant
species
(as
Fig.
5)
in
56
H.
Hoyle
et
al.
/
Landscape
and
Urban
Planning
164
(2017)
49–63
Table
3
Interviewees’
(n
=
34)
demographic
profile.
Gender
Woodland
walks
(n
=
9)
Shrub
walks
(n
=
8)
Herbaceous
Walks
(n
=
17)
Overall
(n
=
34)
M
5
(56%)
4
(50%)
5
(29%)
14
(41%)
F
4
(44%)
4
(50%)
12
(71%)
20
(59%)
Age
Woodland
walks
(n
=
9)
Shrub
walks
(n
=
8)
Herbaceous
Walks
(n
=
17)
Overall
(n
=
34)
25–34
0
1
(12.5%)
2
(12%)
3
(9%)
35–44 1
(11%) 0
2
(12%) 3
(9%)
45–54 3
(33%) 2
(25%)
2
(12%)
7
(21%)
55–64
5
(56%)
2
(25%)
4
(23%)
11
(32%)
65+
0
3
(37.5%)
7
(41%)
10
(29%)
Ethnicity
Woodland
walks
(n
=
9) Shrub
walks
(n
=
8) Herbaceous
Walks
(n
=
17)
Overall
(n
=
34)
White
<