Journal of Biogeography
SUPPORTING INFORMATION
Scale-dependent species–area and species–isolation relationships: a review and a test study from a fragmented semi-arid agroecosystem
Itamar Giladi, Felix May, Michael Ristow, Florian Jeltsch and Yaron Ziv
Appendix S2 Summary of the literature review of studies that tested the relationship between species density and fragment (patch)
area (D-SAR), and species density and fragment isolation (D-SIR). When studies included tests of the relationship between fragmentlevel species richness (SR) and fragment area (SAR) or isolation (SIR) these results were also noted.
For each study we noted the vegetation type, the pattern(s) that were tested by this study, the grain size at which species
density was measured and the findings (i.e. whether a pattern was found significant or not). Also included are the methods for
measuring/estimating fragment area and fragment isolation (or, connectivity, as an inverse measure of isolation).
Some studies used Hanski’s connectivity index (CI) (Hanski, 1996), other distance to nearest neighbor (ENN) and others proximity
index (as explained in the main text). CI was calculated for each target fragment as follows:
n
CI   exp(   d j  A j ) ,
j i
where dj and Aj are the distance to and area of neighbouring fragment j, respectively.
α and β are parameters representing dispersal capabilities of the studied organisms and the weight of area effect, respectively. These
are often taken from the literature or set to equal 1.
The results of each study (finding) for each respective pattern are marked as either non-significant (n.s.), # – significant when
data are stratified by plant species characteristics, $ – significant when data are stratified by habitat or landscape characteristics, H* –
significant only when historical landscape configuration is used for area and/or isolation calculations and simply * – significant pattern
when data are used without any stratification.
The functional form used to model (D)-SAR or (D)-SIR in each of the studies we included here is given in brackets using the
following key: [C] – categorical, [L] – linear, [P] – power and [S] – semilog. In some cases the description was not sufficiently
detailed to allow us to judge which functional form has been used. In a few studies, different functional forms were applied to the
same data for different purposes. In any case we encourage the interested reader to refer to the original publications.
1
Study
Vegetation
type
Longleaf pine
woodland
Pattern
Grain size of
Species density
1 m2, 100 m2
and 1000 m2
Findings
Area
Connectivity
Comments
n.s.
n.s.
Current
fragment
area, [L]
Species composition
(but not richness)
was affected by
historical
connectivity.
SAR
DSAR
SIR
DSIR
4 x 2 m2
*
#
#
#
Categorical:
large vs.
small, [C]
Total area of
forest (56 years
prior the study)
within 150 m of
sampling plot,
[L]
a) CI, r = 2km,
α = 0.5 (0.3, 1),
β = 0.5
b) % habitat
within 2 km
radius
c) Nearest
neighbor, [L]
Brueckmann
et al. 2010
Grassland
Cagnolo et al.
2006
Cagnolo et al.
2009
Woodland
DSAR
DSIR
2 x 500 m2
*
n.s.
Simple area,
[P]
Cook et al.
2002
Old-field
DSAR
DSIR
1m2
n.s.
#
Cousins 2006
Grassland
DSAR
4 m2
$
Area of
experimental
isolated
patches, [L]
Simple area,
Brudvig &
Damschen
DSAR
DSIR
2011
2
* DSIR was tested
using three different
connectivity indices;
DSAR, SIR and
DSIR were
significant when
only specialist
species were
considered
Distance to
Species density was
nearest larger
accumulated from
patch, [P]
two 500 m2 plots
separated by
distance that was
correlated with patch
size.
Slope of DSAR
steeper for rare vs.
common species
Categorical: near Significant only after
or far from a
matrix species were
‘mainland’
excluded from the
forest, [L]
analysis
CI, r = 700 m,
Area was found to
DSIR
*
[S]
α = 1, β = 1, [S]
% continuously
managed habitat
in the landscape,
[?]
NA
Cousins 2009
Grassland
DSAR
DSIR
1 m2
n.s.
*
Simple area,
[?]
Cousins &
Aggemyr
2008
Grassland grazed exfields
DSAR
SAR
0.25 m2 plots in
center of field
and at transects
from edge
inside
n.s.
n.s.
Area of exfield, [P]
Cousins &
Vanhoenacker
2011
Grasslands
SIR
(17 rectified
plots (each
0.25 m2)
0.25 m2
H*
NA
% grassland area
in the landscape
(historical or
current) , [L]
Simple area,
[P]
CI, r = 1 km,
α = 1, β = 1, [P]
DSIR
Cousins et al.
2007
Grasslands
SAR
DSAR
SIR
DSIR
1 m2
1 m2
*
* (current
and 50
years ago)
n.s.
n.s.
n.s.
3
be significant in
modern, but not in
traditional
landscapes
DSIR was nonsignificant when
analysis was
restricted to
grassland
specialists
SAR was significant
for continuously
grazed, but not for
abandoned
grasslands.
Helm et al.
2006
calcareous
grasslands
DSAR
DSIR
2827 m2
2827 m2
H*
H*
Simple area,
[S]
HernandezStefanoni
2005
tropical subdeciduous
forest
DSAR
DSIR
100 m2 (used 25 n.s.
m2 for sampling *
shrubs)
Simple area,
[?]
Holt and
Robinson (as
cited by Holt
1992)
Kelly et al.
1989
Experimental
grassland
SAR
DSAR
*
n.s.
Experiment
al patch
area, [P]
NA
1m2
Forest and
scrub
SAR
DSAR
DSIR
100 m2
100 m2
*
$
n.s.
Island area,
[S]
Distance to
mainland or
nearest large
patch, [S]
Kiviniemi &
Eriksson 2002
Kochy &
Rydin 1997
Seminatural
grasslands
Grassland
(low-medium
tree cover)
DSAR
0.04 m2, 0.25
m2, 4 m2, 28 m2
n.s. at all
scales
*
n.s.
n.s.
n.s.
*
*
Simple area,
[P]
Simple area,
[S]
NA
Island area,
[S]
NA
*
n.s.
n.s.
n.s.
Simple area,
[L(P)]
CI, r = 8 km,
α = 1, β = 1
(ENN was also
calculated, but
was highly
Kohn &
Walsh 1994
Heather moor
(dicotyledons
only)
Krauss et al.
2004
Calcareous
grassland
SAR
DSAR
SIR
DSIR
SAR
DSAR
SAR
DSAR
SIR
DSIR
16 m2 plots
16 m2 plots
0.25 m2
25 m2 plots
25 m2 plots
4
CI, r = study
extent, α = 0.34,
β = 1, [S]
PI, r = 300m,
ENN, [?]
Distance to
mainland/large
island, [S]
Species density is
based on raw data
and extrapolation
using krigging
SAR was tested in a
precious study
(Quinn, Wilson and
Mark 1987).
DSAR was
significant in 1 out
of 5 habitat types
Scale-dependent
SAR was tested at
two scales: whole
patch and meadow
scale.
higher % of the
variance explained
when habitat is
stratified
No differences
between specialists
and generalists
Lawesson et
al. 1998
Beech forest
SAR
DSAR
calculated
*
n.s.
Simple area,
[P]
Lindborg &
Eriksson 2004
Grassland
SAR
DSAR
SIR
DSIR
Cumulative
1 m2
Cumulative
1 m2
n.s.
n.s.
H*
H*
Area of
current site,
[L]
Lobel et al.
2006
Dry
grasslands
DSAR
DSIR
4 m2
4 m2
*
*
Simple area
of
grassland,
[Other Poisson]
5
correlated with CI
and was not used)
, [L(P)]
N/A
Species density was
calculated from
(within-fragment?)
SAR. It is not clear
how exactly species
density was
determined.
CI, r = 1 or 2 km,
Species richness
α = 1, β = 1, [L]
was estimated
from species
accumulation over
10 1 m2 plots.
The effect of
historical CI on
SIR and DPIR
varies interactively
with time and
neighborhood size
(r in the CI
calculation)
% of other dry
When bryophytes,
grassland patches lichens and vascular
within a certain
plants were analyzed
radius from a
separately, DSAR
target patch
was significant for
(r = 0.1, 0.25,
bryophytes and
0.5,1, 2.5 km).
lichens and DSIR
Also explored
was significant for
ENN and CI, but lichens only.
these were not
Öster et al.
2007
Grasslands
SAR
DSAR*
DSAR*
Pärtel et al.
2007a
Grassland
Petit et al.
2004
Herbaceous
forest plants
Pueyo et al.
2008
Grassland
Reitalu et al.
2012
Rey Benayas
et al. 1999
DSAR
SIR
DSIR
SIR
DSIR
*
*
Simple area,
[L(P)]
*
1 m2
n.s.
n.s.
n.s.
n.s.
*H
DSAR
DSIR
4 m2
4 m2
$
$
DSIR
500 m transect
n.s.
SAR
DSAR
SIR
DSIR
wetland
Whole island
Cumulative,
10 m2
Cumulative,
0.5 m2
1 m2
DSAR
Simple area,
[Other Poisson]
[S]
0.25 m2
*
n.s.
H*
#
100-m2 plots
n.s.
Simple area,
[S]
0.25 m2
used in the
analysis, [Other Poisson]
CI, r = 1 or 2 km,
α = 1, β = 1,
[L(P)]
6
CI, r = study
extent, α = 0.34,
β = 1, [L]
a) Area within
500m;
b) Length of
hedgerows / lines
of trees recorded
in a 1 km2, [Other
- Poisson]
Categorical
(Continuous vs.
fragmented), [C]
% grassland
within 300 m
radius: Measured
for current and
historical
landscapes, [S]
SAR, cumulative
SAR (measured in
two scales) and
DSAR.
Results did not
change when
stratified for
specialists only
SIR was based on
grasslands species
only
Study restricted to
Ancient woodland
Indicator species.
DSAR and DSIR
significant in
lowlands but not in
uplands.
DSIR was
significant for
specialists with
current landscape
and for generalist
with historical
landscape
RodríguezLoinaz et al.
2012
Mixed oak
forest
Sfenthourakis
& Panitsa
2012
Stiles &
Scheiner 2010
Mediterranean SAR
shrubland
DSAR
Tangney et al.
1990
Westman
1983
Sonoran
desert
Beech forest
(analysis
restricted to
bryophytes)
DSAR
DSIR
SAR
DSAR
SIR
5 2x1 subplots
within 25x25m
plots
#
#
Simple area,
[C]
ENN, [L]
Whole island
100 m2
*
n.s.
Simple area,
[P]
N/A
*
n.s
n.s.
Simple area,
[S]
I 
DSAR
DSIR
Quadrate
(100 m2) and
transect (5
quadrates)
4 m2 ,100 m2
4 m2 ,100 m2
SAR
DSAR
DSIR
625 m2
625 m2
Significant for forest
specialists. Analysis
was conducted
separately for
different life forms.
n
log( A j )
j i
d ij2
,
[S]
*
*
Simple area,
[S]
Distance to
mainland or to a
larger island, [L]
*
n.s.
n.s.
[L]
[L]
7
Significance and %
variance explained
by DSAR varies
with microhabitat
and grain size.
A significant
positive SAR was
reported in previous
studies conducted in
the same system
REFERENCES
Brudvig, L.A. & Damschen, E.I. (2011) Land-use history, historical connectivity, and land management interact to determine longleaf
pine woodland understory richness and composition. Ecography, 34, 257-266.
Cagnolo, L., Cabido, M. & Valladares, G. (2006) Plant species richness in the Chaco Serrano Woodland from central Argentina:
Ecological traits and habitat fragmentation effects. Biological Conservation, 132, 510-519.
Cagnolo, L., Valladares, G., Salvo, A., Cabido, M. & Zak, M. (2009) Habitat fragmentation and species loss across three interacting
trophic levels: effects of life-history and food-web traits. Conservation Biology, 23, 1167-1175.
Cook, W.M., Lane, K.T., Foster, B.L. & Holt, R.D. (2002) Island theory, matrix effects and species richness patterns in habitat
fragments. Ecology Letters, 5, 619-623.
Cousins, S.A.O. (2006) Plant species richness in midfield islets and road verges – The effect of landscape fragmentation. Biological
Conservation, 127, 500-509.
Cousins, S.A.O. & Aggemyr, E. (2008) The influence of field shape, area and surrounding landscape an plant species richness in
grazed ex-fields. Biological Conservation, 141, 126-135.
Cousins, S.A.O., Ohlson, H. & Eriksson, O. (2007) Effects of historical and present fragmentation on plant species diversity in seminatural grasslands in Swedish rural landscapes. Landscape Ecology, 22, 723-730.
Cousins, S.A.O. & Vanhoenacker, D. (2011) Detection of extinction debt depends on scale and specialisation. Biological
Conservation, 144, 782-787.
Hanski, I. (1996) Metapopulation ecology. Population dynamics in ecological space and time (ed. by O.E.J. Rhodes, R.K. Chesser and
M.H. Smith), pp. 13-43. University of Chicago Press Chicago.
Helm, A., Hanski, I. & Pärtel, M. (2006) Slow response of plant species richness to habitat loss and fragmentation. Ecology Letters, 9,
72-77.
Hernandez-Stefanoni, J.L. (2005) Relationships between landscape patterns and species richness of trees, shrubs and vines in a
tropical forest. Plant Ecology, 179, 53–65.
Kelly, B.J., Wilson, J.B. & Mark, A.F. (1989) Causes of the species–area relation: a study of islands in Lake Manapouri, New
Zealand. Journal of Ecology, 77, 1021-1028.
Kiviniemi, K. & Eriksson, E. (2002) Size-related deterioration of semi-natural grassland fragments in Sweden. Diversity and
Distribution, 8, 21-29.
Kochy, M. & Rydin, H. (1997) Biogeography of vascular plants on habitat islands, peninsulas and mainlands in an east-central
Swedish agricultural landscape. Nordic Journal of Botany, 17, 215-223.
Kohn, D.D. & Walsh, D.M. (1994) Plant species richness – the effect of island size and habitat diversity. Journal of Ecology, 82, 367377.
8
Krauss, J., Klein, A.M., Steffan-Dewenter, I. & Tscharntke, T. (2004) Effects of habitat area, isolation, and landscape diversity on
plant species richness of calcareous grasslands. Biodiversity and Conservation, 13, 1427-1439.
Lawesson, J.E., de Blust, G., Grashof, C., Firbank, L., Honnay, O., Hermy, M., Hobitz, P. & Jensen, L.M. (1998) Species diversity
and area-relationships in Danish beech forests. Forest Ecology and Management, 106, 235-245.
Lindborg, R. & Eriksson, O. (2004) Historical landscape connectivity affects present plant species diversity. Ecology, 85, 1840-1845.
Lobel, S., Dengler, J. & Hobohm, C. (2006) Species richness of vascular plants, bryophytes and lichens in dry grasslands: the effects
of environment, landscape structure and competition. Folia Geobotanica, 41, 377-393.
Öster, M., Cousins, S.A.O. & Eriksson, O. (2007) Size and heterogeneity rather than landscape context determine plant species
richness in semi-natural grasslands. Journal of Vegetation Science, 18, 859-868.
Petit, S., Griffiths, L., Smart, S.S., Smith, G.M., Stuart, R.C. & Wright, S.M. (2004) Effects of area and isolation of woodland patches
on herbaceous plant species richness across Great Britain. Landscape Ecology, 19, 463-471.
Rey Benayas, J.M., Colomer, M.G.S. & Levassor, C. (1999) Effects of area, environmental status and environmental variation on
species richness per unit area in Mediterranean wetlands. Journal of Vegetation Science, 10, 275-280.
Rodríguez-Loinaz, G., Amazega, I. & Onaindia, M. (2012) Does forest fragmentation affect the same way all growth forms? Journal
of Environmental Management, 94, 125-131.
Sfenthourakis, S. & Panitsa, M. (2012) From plots to islands: species diversity at different scales. Journal of Biogeography, 39, 750–
759.
Stiles, A. & Scheiner, S.M. (2010) A multi-scale analysis of fragmentation effects on remnant plant species richness in Phoenix,
Arizona. Journal of Biogeography, 37, 1721-1729.
Tangney, R.S., Wilson, J.B. & Mark, A.F. (1990) Bryophyte island biogeography: a study in Lake Manapouri, New Zealand. Oikos,
59, 21-26.
Westman, W.E. (1983) Island biogeography: studies on the xeric shrublands of the inner Channel Islands, California. Journal of
Biogeography, 10, 97-118.
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