Hallgren, E., Palmer, M.W. & Milberg, P. (1999). Data diving with cross validation: an investigation of broad scale gradients in Swedish weed communities. 87, 1037-1051. Archive material.

Hallgren, E., Palmer, M.W. & Milberg, P. (1999). Data diving with cross validation: an investigation of broad scale gradients in Swedish weed communities. 87, 1037-1051. Archive material. Hallgren, E., Palmer, M.W. & Milberg, P. (1999). Data diving with cross validation: an investigation of broad scale gradients in Swedish weed communities. 87, 1037-1051.

Appendix 1 Summary of the environmental variables in the data set (n = 2000)

Variable	n	%

Nominal variables
Sowing season
Autumn-sown plots	1044	52.2
Spring-sown plots	956	47.8
Geographic regions: Swedish counties
A: Skane, Hallands lan	542	27.1
B: Blekinge, Gotland, Kalmar lan	308	15.4
C: Jonkopings, Kronobergs lan	63	3.2
D: Vastra Gotalands lan	319	16.0
E: Ostergotlands lan	127	6.4
F: Uppsala, Stockholms, Sodermanlands, Vastmanlands, Orebro lan	512	25.6
G: Kopparbergs, Gavleborgs, Varmlands lan	120	6.0
H: Jamtlands, Vasternorrlands, Vasterbottens, Norrbottens lan	9	0.4
Soil types
1: sandy soil	324	16.2
2: fine sand soil	387	19.4
3: silty soil	90	4.5
4: loamy soil	414	20.7
5: silty clay loam	443	22.2
6: heavy to very heavy clay soil	291	14.6
7: organogenic soil	79	4.0
Crops
Winter wheat	541	27.0
Winter barley	10	0.5
Rye	221	11.0
Winter rape	225	11.2
Winter turnip rape	47	2.4
Spring wheat	145	7.2
Spring barley	313	15.6
Oats	205	10.2
Spring rape	153	7.6
Spring turnip rape	140	7.0

Interval-scale variables
Years
1970	18	0.9
1971	29	1.5
1972	55	2.8
1973	48	2.4
1974	61	3.1
1975	65	3.3
1976	68	3.4
1977	80	4.0
1978	77	3.9
1979	87	4.4
1980	119	6.0
1981	123	6.2
1982	111	5.6
1983	103	5.2
1984	92	4.6
1985	114	5.7
1986	138	6.9
1987	139	7.0
1988	156	7.8
1989	106	5.3
1990	64	3.2
1991	59	3.0
1992	44	2.2
1993	26	1.3
1994	18	0.9
Organic content (%)
1: <2	35	1.8
2: 2-3	349	17.5
3: 3-6	1205	60.2
4: 6-12	303	15.2
5: 12-20	39	2.0
6: 20-40	14	0.7
7: >40	55	2.8

Continuous variables
Nitrogen (N/ha)
Maximum	261
Average	106
Minimum	0
Crop yield (kg/ha)
Maximum	10520
Average	3928
Minimum	180

Appendix 2 Weed species (short name used in ordination Figures) recorded in the 2000 trials. Nomenclature according to Tutin et al. (1964-1980); life-history classification according to Fogelfors (1977), Håkansson (1995) and personal field experience. Autumn/spring scores (not given for species with frequency <1%) are from a CCA with ‘season of sowing’ as environmental variable

		Dicot (D) Monocot (M)		Annual (A) Summer A (SA) Winter A (WA) Summer/winter A (SWA) Perennial (P)		Frequency (%)	Autumn (-) to Spring (+) score
Stellaria media (Stell)		D		SWA		44.9	-0.26
Viola arvensis (Viola)		D		SWA		31.3	-0.25
Matricaria perforata (Matri)		D		SWA		29.7	-0.66
Chenopodium album/suecicum (Cheno)		D		SA		26.1	1.03
Galeopsis speciosa/bifida/tetrahit (Galeo)		D		SA		21.1	0.73
Myosotis arvensis (Myoso)		D		WA		18.2	-0.45
Lamium spp.¹ (Lamiu)		D		SWA		14.7	-0.04
Galium aparine/spurium (Galiu)		D		SWA		13.7	-0.41
Bilderdykia convolvulus (Bilde)		D		SA		12.6	0.52
Veronica spp.² (Veron)		D		SWA		10.8	-0.75
Capsella bursa-pastoris (Capse)		D		SWA		9.7	-0.60
Fumaria officinalis (Fumar)		D		SA		7.3	0.98
Polygonum lapathifolium/persicaria (Po lap)		D		SA		7.2	1.08
Polygonum aviculare (Po avi)		D		SA		7.0	-0.07
Thlapsi arvense (Thlas)		D		SWA		4.9	0.53
Spergula arvensis (Sperg)		D		SA		3.9	1.07
Lapsana communis (Lapsa)		D		WA		3.8	0.81
Sinapis arvensis (Sinap)		D		SA		3.2	1.01
Erysimum cherianthoides (Erysi)		D		SA		3.1	1.03
Cirsium arvense (Cirse)		D		P		3.0	0.81
Equisetum arvense (Equis)				P		2.8	0.31
Papaver rhoeas/dubium/argemone (Papav)		D		WA		1.8	-0.88
Elymus repens (Elymu)		M		P		1.7	0.52
Poa annua (Poa)		M		SWA		1.6	-0.33
Sonchus arvensis (So arv)		D		P		1.5	1.08
Apera spica-venti (Apera)		M		WA		1.4	-0.86
Centaurea cyanus (Centa)		D		SWA		1.5	-0.88
Chamomilla recutita (Chamo)		D		SWA		1.4	-0.32
Consolida regalis		D		WA		1.0
Sonchus asper/oleraceus (So asp)		D		SA		1.0
Buglossoides arvensis		D		WA		0.7
Brassica rapa ssp. sylvestris		D		A		0.6
Geranium spp.³/Erodium cicutarium		D		A		0.6
Sinapis alba		D		A		0.4
Convolvulus arvensis		D		P		0.4
Hieracium sp.		D		P		0.4
Taraxacum officinale		D		P		0.3
Arenaria serpyllifolia		D		SWA		0.3
Vicia hirsuta		D		SWA		0.3
Myosurus minimus		D		A		0.2
Barbarea vulgaris		D		P		0.2
Galium mollugo		D		P		0.2
Cerastium fontanum		D		P		0.2
Ranunculus repens/arvensis		D		P/A		0.2
Stachys palustris		D		P		0.2
Arabidopsis thaliana/Cardaminopsis arenosa		D		A/A-P		0.1
Erophila verna		D		A		0.1
Euphorbia helioscopia		D		SA		0.1
Odontites verna		D		A		0.1
Raphanus raphanistrum		D		A		0.1
Anagallis arvensis		D		A		0.1
Anchusa arvensis		D		SA		0.1
Anthemis arvensis		D		A		0.1
Atriplex patula		D		A		0.1
Bidens tripartita		D		A		0.1
Filaginella uliginosa		D		SA		0.1
Silene noctiflora		D		A		0.1
Valerianella locusta		D		A		0.1
Viola tricolor		D		A		0.1
Achillea ptarmica		D		P		0.1
Plantago major		D		P		0.1
Silene alba		D		P		0.1
Stellaria graminea		D		P		0.1

Crop species occurring as weeds
Rape and turnip rape	D		A		4.5
Cereal crop	M		A		0.8
Clover	D		P		0.1
Timothy	M		P		0.1
Poa pratensis	M		P		0.1

^{1L. purpureum, hybridum, amplexicaule, mollucelifolium

^{2Six species of Veronica occur on arable land in Sweden:
agrestis and arvensis dominate while hederifolia and persica are
fairly widespread
^{3G. dissectum, pusillum}}}