Hunt et al. 106737520 Page 1
Applied Vegetation Science
APPENDIX TO:
A new practical tool for deriving a functional signature for herbaceous vegetation
Hunt, R., Hodgson, J.G., Thompson, K., Bungener, P.,
Dunnett, N.P. & Askew A.P.
Additional methodological details
Part 1. Calculating the C-S-R signature
The conversion of floristic data into a C-S-R signature is a multi-stage process which is
carried out automatically by the first, or ‘calculator’, part of our spreadsheet tool (main
paper, Fig. 2).
(i) The user pastes-into a labelled, two-dimensional field a data matrix containing
quantitative records from one vegetation sample. The format follows the usual
conventions, having one named species per row together with a value of percent
abundance (any consistent measure may be used). There are as many rows as
there are species, up to a maximum of 100. In each use of the tool the original
data represent one ‘snapshot’ of a vegetation, arranged into one combination of
location, treatment type and/or time of recording. The data can be averaged across
replicate samples, if any, or these can be treated separately.
(ii) From internally-stored tables, covering approximately 1000 European species, the
tool looks-up the C-S-R identity (functional type) of each of the species presented.
If no match is found for a species that fact is flagged. The user then faces three
options: (a) to estimate the unknown type from first principles by means of the
simple literary and laboratory procedure described by Hodgson et al. (1999), (b)
to substitute for the name of the species that of a presumptive C-S-R type chosen
from Part 1 of the tool (worksheet ‘Standard coordinates’), (c) to group the taxon,
and any others like it, under the single eliminator ‘unknown’.
(iii) Within each of the (maximum nineteen) C-S-R functional types present as known,
estimated or presumed components of the vegetation, the tool sums all the
individual species abundances into a percent abundance of the whole type. The
sample thus becomes redescribed, not in terms of the relative abundance of its
plant species, but in terms of the relative abundance of its functional types. Put
formally, the percent abundance P of functional type type i is calculated as
n
Pi =
 Pj
j=1
where the Pj are the percent abundances of the n species that are present both
within the sample and within the type.
(iv) For each type represented, the tool next imports the numerical, three-part, C,S,R
coordinate from a copy of the standard list shown in Part 1 of the tool (worksheet
‘Standard coordinates’). The tool then chooses each of the three parts (ordinates)
of the C,S,R coordinate in turn and multiplies it by the percent abundance of the
type within the sample. Each of these three products is then summed across all
types present and a net value is calculated. This provides a single, weighted value
for each of the three ordinates, a ‘C-S-R signature’ for the whole community
Hunt et al. 106737520 Page 2
which specifies its mean position in C-S-R space. Thus, in the general case
(assuming no unknown species), for types i = 1 to 19 where Pi is again the percent
abundance of type i and LDi is the standard ordinate of type i in dimension D, then
for D = C, S, R in turn the weighted average for each ordinate is calculated as:
19

Pi LDi
i=1
D = ———— ·
100
(v)
The tool plots this net position onto a triangular representation of C-S-R space
(main paper, Fig. 1b). For reference, the tool also reports which of the nineteen
standard C-S-R positions lies closest to the calculated signature. Finally, a variety
of indices of diversity (Ludwig & Reynolds 1988) are reported, and this is done
on the basis of both species and types.
Part 2. Comparing C-S-R signatures
The second, or ‘comparator’, part of the spreadsheet tool accepts the text identifiers of
up to 25 different communities together with their C-S-R signatures. The positions of
any or all of these signatures can then be chosen for simultaneous display on a single
triangular diagram covering all of C-S-R space. Between each of up to three pairs of
signatures the tool also reports the direction and magnitude of any differences between
the C, S and R components of the signatures and calculates the net Cartesian distance
between whole signatures (main paper, Fig. 3). A ‘zoom’ facility in a separate graphic
allows signatures data to be displayed at larger scale within subsets of C-S-R space, if
required
Additional details of an example already in the published paper
The native species in the Sheffield study were Allium oleraceum, Aquilegia
vulgaris, Astragalus glycyphyllos, Campanula glomerata, Cirsium acaule, C.
heterophyllum, Dianthus deltoides, Genista anglica, Geranium sanguineum, Parnassia
palustris, Polemonium caeruleum, Rubus chamaemorus, Serratula tinctoria, Silaum
silaus, Thlaspi caerulescens, Trollius europaeus, Ulex minor, Viola lutea and the alien
species were Armoracia rusticana, Chenopodium bonus-henricus, Foeniculum vulgare,
Fallopia japonica, Fragaria  ananassa, Galega officinalis, Lepidium draba,
Leucanthemum  superbum, Lupinus  regalis, Medicago sativa, Mentha  villosa,
Mentha spicata, Petasites fragrans, Puccinellia distans, Rumex pseudoalpinus,
Solidago canadensis, S. gigantea, Veronica filiformis.
The full results of the analysis of the Sheffield data appear in Appendix Table 1.
In this Table, the equitability index represents the relative evenness of distance between
individual abundances when these are arranged in order of abundance; the ShannonWiener index represents a composite of equitability and richness; the Simpson index
measures degree of dominance; the ‘Number’ is a simple index of species- or typerichness.
Hunt et al. 106737520 Page 3
Appendix Table 1. C-S-R coordinates and indices of diversity for the Sheffield vegetation samples.
Alien
Alien
lowland
upland
unmanaged managed
Alien
Native
upland
lowland
unmanaged managed
Native
Native
lowland
upland
unmanaged managed
Native
upland
unmanaged
8
117
10
90
69
59
0.518
0.508
ns
0.409
0.413
ns
0.544
0.566
ns
0.303
0.311
ns
0.375
0.413
<0.01
0.261
0.266
ns
0.292
0.309
ns
1970s
1997
P
0.131
0.143
ns
0.159
0.191
ns
0.136
0.141
ns
0.483
0.403
ns
0.404
0.377
<0.1
0.583
0.566
ns
0.506
0.475
<0.05
R-coordinate
1970s
1997
P
0.351
0.349
ns
0.433
0.396
ns
0.320
0.293
<0.05
0.214
0.287
<0.1
0.221
0.210
ns
0.156
0.168
ns
0.202
0.215
ns
Net Cartesian
distance
Between
dates
0.013
0.040
0.029
0.089
0.039
0.017
0.031
Equitability
(species)
1970s
1997
P
0.752
0.757
ns
0.820
0.808
ns
0.753
0.748
ns
0.816
0.837
ns
0.796
0.787
ns
0.832
0.825
ns
0.817
0.826
ns
Equitability
(types)
1970s
1997
P
0.720
0.733
ns
0.721
0.754
ns
0.729
0.718
ns
0.711
0.778
<0.05
0.751
0.741
ns
0.731
0.705
ns
0.722
0.738
ns
Shannon-Wiener
(species)
1970s
1997
P
1.718
1.697
ns
2.095
2.189
ns
1.664
1.614
ns
2.501
2.630
ns
2.078
1.898
<0.01
2.189
2.203
ns
2.262
2.263
ns
Shannon-Wiener
(types)
1970s
1997
P
1.256
1.262
ns
1.302
1.436
ns
1.233
1.211
ns
1.606
1.692
ns
1.513
1.395
<0.01
1.252
1.242
ns
1.471
1.510
ns
Simpson
(species)
1970s
1997
P
0.282
0.290
ns
0.172
0.145
ns
0.299
0.314
ns
0.142
0.119
ns
0.198
0.232
<0.05
0.175
0.174
ns
0.162
0.160
ns
Simpson
(types)
1970s
1997
P
0.383
0.384
ns
0.340
0.298
ns
0.399
0.409
ns
0.290
0.256
ns
0.306
0.340
<0.05
0.382
0.404
ns
0.316
0.308
ns
Number
(species)
1970s
1997
P
10.729
10.771
ns
14.250
15.375
ns
9.991
9.675
ns
23.700
24.700
ns
15.156
12.533
<0.001
17.203
17.435
ns
16.407
16.593
ns
Number
(types)
1970s
1997
P
6.018
6.066
ns
6.500
6.875
ns
5.730
5.744
ns
9.600
9.000
ns
8.011
7.067
<0.01
6.912
7.043
ns
7.915
8.000
ns
Habitat
Date
Records
Both dates 166
C-coordinate
1970s
1997
P
S-coordinate
Hunt et al. 106737520 Page 4
Additional worked examples not included in the published paper
Buxton: Treatment effects in a stable community
Near Buxton (Derbyshire, northern England) is a steep, north-west-facing slope
over Carboniferous limestone that is in use for climate-change impacts studies (Grime
et al. 2000). The site receives an annual rainfall in excess of 1300 mm, with little
seasonality, and has a mean annual temperature of 8 ºC. The soils are locally variable,
both in surface pH and depth. The flora comprises Festuca ovina-Helictotrichon
pratense grassland and is dominated by S-types, including a substantial sedge
component. Annuals and monocarps are very rare under the continuous vegetation
cover, which reflects the long previous history of light grazing by cattle and sheep.
Various experimental climate treatments are now maintained at the site, all within 3msquare plots that are replicated five times.
Among the regimes imposed is one that maintains both elevated winter
temperature and summer droughting. From November to April inclusive, computercontrolled heating cables raise soil surface temperatures to 3°C above ambient;
throughout July and August, rainfall receipt is inhibited by automatically-operated,
translucent rainshelters that deploy during every rainfall event. At the end of the
growing season all plots are cut to 5cm. A point-quadrat analysis of the vegetation is
done annually in late June/early July, at the time of maximum plant growth and
immediately before the imposition of drought (thus the data collected in any one year do
not reflect the immediate effects of that year’s droughting).
Results for the period 1994 to 2001, converted to C-S-R signatures, are shown in
Appendix Figure 1. The control plots maintained a relatively stable composition over
this period. Though year-to-year variations were present, little general trend with time
was discernible in the C-, S- or R-components of the community. In contrast, the warm
winter/dry summer treatment produced dramatic effects, particularly in the earlier years,
with the net signature heading quickly towards the S-corner of C-S-R space (Appendix
Fig. 1a). As a result, both the C- and the R-components within the vegetation were
progressively reduced (Appendix Figs. 1b,d) and the S-component rose to a new and
relatively stable plateau (Appendix Fig. 1c). It is likely that the winter warming
promoted the C-component annually at the expense of the R- (Dunnett et al. 1998), but
the accentuated summer drought then depleted the C-component, allowing the Scomponent to achieve a gradual increase.
Despite having almost unchanging C-S-R signatures, the control plots
(Appendix Figs. 2a-c, closed symbols) nevertheless exhibited subtle changes over the
years in the indices of diversity for both species and types (the scaling of values varies
between these two because there are more species than types). Both species richness and
species equitability increased in the controls (and also, therefore, the Shannon-Wiener
index). Consequently, there was a slight decline in the degree of dominance within the
vegetation (Simpson). The effect of the warm winter/dry summer treatment was to
arrest, or even reverse, the trends seen in both species and types in the control plots:
equitability declined (and the Shannon-Wiener index with it), and the dominance index
(Simpson) increased.
In respect of numbers present (Appendix Fig. 2d), the divergence between
control and treated plots is less marked in the case of functional types than it is in the
case of species. However, the control plots shows a very slow upwards drift with time
in both. The net effect of treatment is to arrest the increase in number of species while
Hunt et al. 106737520 Page 5
continuing the slow increase in number of types. Species being lost from the system are
slowly replaced by other, fewer species of different types; this is sufficient to bring
about the movement seen in the C-S-R signature (Appendix Fig. 1a).
This example shows how the C-S-R signature, together with the indices of
diversity, can reveal and summarize by means of direction and velocity of change the
effects of a treatment imposed upon a natural vegetation. The subtle interplay between
the three components of the signature and the indices of diversity also suggests
mechanisms that can explain the treatment’s impacts.
Fribourg: Treatment effects in a changing community
Near Fribourg (western Switzerland) is an area of semi-natural grassland
(Arrhenaterion elatioris alliance) which, though formerly sheep-grazed, has been
enclosed since 1998 and used to expose intact, permanent vegetation to open-air
fumigation by ozone. The experiment contains six circular plots of 7 m diameter. Three
of these are control plots and three are exposed to ozone (Volk et al., 2003). Among the
many measurements, destructive sampling of random 0.25 m2 sub-plots has been used
to estimate the mean abundance of individual species in the spring of each year.
The C-S-R signatures reveal that the control community was not in a stable
condition between 1999 and 2000, though it equilibrated more between 2000 and 2002.
Despite considerable year-to-year variations (Appendix Fig. 3), opposing trends were
discernible in the C- and the S-components of the control plots. There was a net drift in
the controls towards the S-corner of C-S-R space, doubtless representing a continued
adjustment to the recent cessation of sheep grazing. Annual cutting, which was the
replacement regime, was clearly more deleterious towards the C- and R-components of
the vegetation than was the grazing. This permitted a corresponding a rise in the Scomponent. The treatment with ozone appeared to accelerate all of these drifts, being
differentially severe on CR-types and their near neighbours. Species with strong C- or
R-type features all possess short-lived, fast-decomposing, palatable leaves of high
specific leaf area (Grime et al. 1997, Diaz et al., submitted), a configuration which is
especially sensitive to both physical and physiological damage by ozone (McKee 1994,
BIOSTRESS 2003).
This example demonstrates that despite the short time-period and the initially
unstable nature of the control comparison, the C-S-R signature is able to indicate at least
approximately the direction and magnitude of possible treatment effects within the
community. Statistical analysis is barely feasible under these circumstances, of course,
but the signature still provides an early indication of the emergence of signal from
noise.
Appendix References
BIOSTRESS 2003. Biodiversity in herbaceous semi-natural ecosystems under stress by global
change components. EC FP5 project, reported at http://www.uni-hohenheim.de/biostress/.
Díaz, S., Hodgson, J.G., Thompson, K., Cabido, M., Cornelissen, J.H.C., Jalili, A., MontserratMartí, G., Grime, J.P., Zarrinkamar, F., Asri, Y., Band, S.R., Basconcelo, S., Castro-Díez,
P., Funes, G., Hamzehee, B., Khoshnevi, M., Pérez-Harguindeguy, N., Pérez-Rontomé,
M.C., Shirvany, F.A., Vendramini, F., Yazdani, S., Abbas-Azimi, R., Bogaard, A.,
Boustani, S., Charles, M., Dehghan, M., de Torres-Espuny, L., Falczuk, V., GuerreroCampo, J., Hynd, A., Jones, G., Kowsary, E., Kazemi-Saeed, F., Maestro-Martínez, M.,
Romo-Díez, A., Shaw, S., Siavash, B., Villar-Salvador, P. & Zak, M.R. 2004. The plant
Hunt et al. 106737520 Page 6
traits that drive ecosystems: evidence from three continents. Journal of Vegetation Science
115: 295-304.
Dunnett, N.P., Willis, A.J., Hunt, R., & Grime, J.P. 1998. A 38-year study of relations between
weather and vegetation dynamics in road verges near Bibury, Gloucestershire. Journal of
Ecology 86: 610-623.
Grime, J.P., Brown, V.K., Thompson, K., Masters, G.J., Hillier, S.H., Clarke, I.P., Askew, A.P.,
Corker, D. & Kielty, J.P. 2000. The response of two contrasting limestone grasslands to
simulated climate change. Science 289: 762-765.
Grime, J.P., Thompson, K., Hunt, R., Hodgson, J.G., Cornelissen, J.H.C., Rorison, I.H., Hendry,
G.A.F., Ashenden, T.W., Askew, A.P., Band, S.R., Booth, R.E., Bossard, C.C., Campbell,
B.D., Cooper, J.E.L., Davison, A.W., Gupta, P.L., Hall, W., Hand, D.W., Hannah, M.A.,
Hillier, S.H., Hodkinson, D.J., Jalili, A., Liu, Z., Mackey, J.M.L., Matthews,N., Mowforth,
M.A., Neal, A.M., Reader, R.J., Reiling, K., Ross-Fraser, A.M., Spencer, R.E., Sutton, F.,
Tasker, D.E., Thorpe, P.C. & Whitehouse, J. 1997. Integrated screening validates primary
axes of specialisation in plants. Oikos 79: 259-281.
Hodgson, J.G., Wilson, P.J., Hunt, R., Grime, J.P. & Thompson, K. 1999. Allocating C-S-R
plant functional types: a soft approach to a hard problem. Oikos 85: 282-294.
Ludwig, J.A. & Reynolds, J.F. 1988. Statistical ecology: a primer in methods and computing.
John Wiley & Sons, Chichester.
McKee, D.I. 1994. Tropospheric ozone. Lewis Publications, Boca Raton.
Volk, M., Geissmann, M., Blatter, A., Contat, F. & Fuhrer, J. 2003. Design and performance of
a free-air exposure system to study long-term effects of ozone on grasslands. Atmospheric
Environment 37: 1341-1350.
0.20
(a) C-S-R space
(b) C-coordinate
0.15
2
1994
R = 0.57
0.10
0.05
2
R = 0.83
0.00
1992
0.95
1996
1998
2000
2002
0.20
(c) S-coordinate
0.90
1994
(d) R-coordinate
2
R = 0.77
0.15
2
R = 0.36
0.85
0.10
0.80
0.05
0.75
1992 1994 1996 1998 2000 2002
2
R = 0.67
2
R = 0.33
0.00
1992 1994 1996 1998 2000 2002
Appendix Fig. 1. Vegetation at the Buxton site, 1994-2001. (a) Trajectories of C-S-R
signatures with time through a subset of C-S-R space of side 0.12 units (cf. main paper,
Figure 1b); the signatures are shown within a field bounded by the limits C = 0.05 to
0.17, S = 0.78 to 0.90 and R = 0.05 to 0.17. (b-d) Changes with time in the individual C,
S and R coordinates, with quadratic trendlines and R-squared values. Throughout, the
circles represent control plots and the squares represent treated plots (warm winters and
dry summers).
Hunt et al. 106737520 Page 7
1.0
4
(b) Shannon-Wiener
(a) Equitability
0.8
3
0.6
2
0.4
1
0.2
0
1992 1994 1996 1998 2000 2002
0.8
1992 1994 1996 1998 2000 2002
40
(c) Simpson
(d) Number
0.6
30
0.4
20
0.2
10
0.0
0
1992 1994 1996 1998 2000 2002
1992 1994 1996 1998 2000 2002
Appendix Fig. 2. Indices of diversity at the Buxton site, 1994-2001, with linear
trendlines. Closed symbols represent species, and open symbols functional types; circles
and dashed lines represent control plots, and squares and solid lines represent treated
plots (having warm winters and dry summers). From top to bottom of each diagram the
four R-squared values are: (a) 0.33, 0.30, 0.00, 0.28; (b) 0.63, 0.33, 0.42, 0.12; (c) 0.34,
0.25, 0.50, 0.46; (d) 0.66, 0.19, 0.34, 0.15.
0.42
(a) C-S-R space
(b) C-coordinate
2
0.40
1999
R = 0.79
2
0.38
R = 0.36
0.36
0.34
1998 1999 2000 2001 2002 2003
0.32
0.38
(c) S-coordinate
0.30
2
R = 0.75
0.36
2
0.28
2
R = 0.57
0.34
0.26
0.32
0.24
0.30
1998 1999 2000 2001 2002 2003
R = 0.004
2
R = 0.66
(d) R-coordinate
1998 1999 2000 2001 2002 2003
Appendix Fig. 3. Vegetation at the Fribourg site, 1999-2002. (a) Trajectories with time
through a subset of C-S-R space of side 0.10 units (see main paper, Figure 1b); the C-SR signatures of the whole vegetation are shown within a field bounded by the limits C =
0.35 to 0.45, S = 0.23 to 0.33 and R = 0.31 to 0.41. (b-d) Changes with time in the
individual C, S and R coordinates, with linear trendlines. Circles and dashed lines
represent control plots, squares and solid lines represent treated plots (with ozone
fumigation).