Dynamics of Helichrysum arenarium (L.) Moench populations growing in fallow field on barren soil

Anna Katarzyna Sawilska

University of Technology and Life Sciences, Faculty of AgricultureDepartment of Botany and Ecology

Prof. S. Kaliskiego 7, building 3.1, 85–789 Bydgoszcz, Polande-mail: sawilska@utp.edu.pl

Abstract. The aim of the study was to determine the influence of habitat factors on growth and development dynamics of Helichrysum arenarium individuals growing in extreme and unstable ecosystems. The impact of phytocoenosis type and weather conditions on the population density, biomass, potential fertility, dry mass and the number of shoots per specimen were analyzed in detail. The study was conducted on two Sandy Everlasting populations growing on fallows and representing different succession stages. Measurements and phenological observations were carried out during growing seasons from 2003 to 2005 in four permanent plots, two for each population. The populations remained under a strong influence of habitat factors, which was evidenced by their different phytosociological position. Growth and development processes in these populations were modified by weather conditions. The potential fertility of specimens was significantly correlated with the precipitation amount. Biomass and its seasonal distribution within the populations depended on weather conditions and the number of species building the phytocoenoses. Key words: plant biomass, phenology, phytocoenosis, population density, weather conditions.

1. Introduction

Helichrysum arenarium (L.) Moench is a rhizome pe-rennial of the sunflower family. It has erect branching stems up to 30 cm tall, gray woolly leaves, flowerheads arranged in dense umbelliform panicles. Involucres are yellow or orange. Flowering time: July–October. Sandy Everlasting grows in sunny places on sandy soils, in abandoned fields, along waysides, and in dry forests and thickets (Rutkowski 2004). The species occurs in both natural and anthropo-genic communities. Studies on its populations can give a valuable insight into dynamic of extreme and unstable ecosystems.

The species is partially protected in Poland. The plant is a source of valuable herbal material

(Ożarowski 1983). Inflorescence of Sandy Everlasting (In-florescentia Helichrysi = Flos Stoechados citrini) collected

at the beginning of the blooming process contains, along with other compounds, a wide spectrum of flavonoids (Czinner et al. 1999; FP 2002). Herbal compositions com-prising Inflorescentia Helichrysi are used for treatment of digestive system diseases (Buchwald 1992; Gawron- -Gzella et al. 2003). Sandy Everlasting is also an ornamen-tal plant supplying material for dry bouquets.

Within past few years in the area of Kuyavian-Pomer-anian Voivodship and many others regions of Poland the cultivation of barren, sandy soils was stopped for economic reasons. As a result of vegetation succession, Helichrysum arenarium has started to grow in these areas. However, the advancing succession changes the floristic composition of phytocoenoses and leads to retreat of this species (Sawilska 2004; Sawilska & Dąbrowska 2006). In the past there were some attempts at growing H. arenarium in plantations, but many plants died in the second year of cultivation. Getting

Ecological Questions 9/2008: 93–101 doi: 10.2478/v10090-009-002 -4 x

94 Anna Katarzyna Sawilska

a better understanding of H. arenarium populations dynam-ics, especially the process of generative shoots forming and its correlation with habitat factors, is a prerequisite for suc-cessful growing of this species.

The aim of the study was to determine the influence of chosen habitat factors on growth and development dynam-ics of Helichrysum arenarium individuals. The impact of phytocoenosis type and weather conditions on the popula-tion density, biomass, potential fertility, dry mass and the number of shoots per specimen were analyzed in detail.

2. Material and methods

Two sandy everlasting populations representing differ-ent succession stages were analyzed. One of the objects un-der study, referred to as the first population, grew in a fal-low field in Fordon (outskirts of Bydgoszcz). Two sample plots of size 1 m2, numbered 1a and 1b, were randomly placed within the area occupied by the population. The sec-ond population, with randomly located sample plots 2a and 2b, occurred in village of Łosiny near Chojnice within Bory Tucholskie forest complex. The syntaxonomic position of all vegetation patches under study was determined based on their floristic composition, according to the phytoso-ciological system proposed by Matuszkiewicz (2005). Soil type was identified using the granulation system (Trzciński 1989).

Measurements and phenological observations were car-ried out in four study periods during the years 2003–2005, from appearance of seedlings and vegetative propagules in spring to shoot decay in autumn. The Sandy Everlast-ing vigorous germination phase was observed in April and May. This study period was referred to as IV/V. Shoots were being developed and buds formed during June and July (stage VI/VII). The blooming process peaked in July and August (stage VII/VIII). Towards the end of Septem-ber, most shoots were producing achenes and started to dry out. In this period (stage IX/X) rhizomes were developing leaf rosettes as new vegetative propagules.

Shoot density was determined for each sample plot. During the growing season, 30 specimens (i.e., clumps well separated from each other) at subsequent development stages were collected in the vicinity of each sample plot. The number of shoots per specimen, and the fresh and air-dry mass were determined according to commonly used methods (Falińska 2002; Sawilska 2002). The potential fer-tility, i.e. the generative reproduction effort defined as the ratio between the inflorescence mass and the whole plant mass (Wilkoń-Michalska 1976), was also established. The biomass was defined as the ratio of fresh shoot mass to area (Falińska 2002).

Statistical analysis of the influence of habitat factors on Sandy Everlasting population dynamics was performed

using EXCEL and STATISTICA PL software. Correlation coefficients were computed to assess the relationships be-tween variables.

Results

Helichrysum arenarium (L.) Moench is a species characteristic of the order Corynephoretalia canescentis R. Tx. 1937. The first two stands represent the association Diantho-Armerietum elongatae Krausch 1959. In total, in sample plots 1a and 1b in Fordon 28 species were found: Helichrysum arenarium (L.) Moench, Festuca ovina L., Hi-eracium pilosella L., Galium verum L., Trifolium arvense L., Armeria maritima (Miller) Willd, Cerastium arvense L., Corynephorus canescens (L.) P. B., Chondrilla juncea L., Artemisia campestris L., Rumex acetosella L., Elymus repens (L.) Gould, Poa angustifolia L., Holosteum umbel-latum L., Petrorhagia prolifera (L.) P. W. Ball et Heyw., Veronica verna L., Erophila verna (L.) Chevall., Spergula arvensis L., Jasione montana L., Crepis tectorum L., Ero-dium cicutarium (L.) L`Hér., Vicia hirsuta (L.) S. F. Gray, Vicia villosa Roth, Viola arvensis Murray, Taraxacum offi-cinale Coll., Myosotis stricta Link, Conyza canadensis (L.) Cronq. and Senecio erucifolius L.

The second population grows in the association Spergu-lo vernalis-Corynephoretum (R. Tx. 1928) Libb. 1933. In sample plots 2a and 2b established in the village of Łosiny only 15 taxa were recorded: Helichrysum arenarium (L.) Moench, Corynephorus canescens (L.) P. B., Veronica dil-lenii Crantz, Spergula morisonii Bor., Cerastium semide-candrum L., Jasione montana L., Scleranthus perennis L., Erophila verna (L.) Chevall., Potentilla argentea L., Co-nyza canadensis (L.) Cronq., Crepis tectorum L., Allium oleraceum L., Viola arvensis Murray, Chenopodium album L., Pinus sylvestris L. (seedlings).

Phytosociological affiliation of the community with the first Sandy Everlasting population indicates that it repre-sents a later succession stage; in turn, the second popula-tion grows in a community at an earlier succession stage. Both populations occupy sunny, sandy soil habitats (the soil is either clayey or friable sandy). The light intensity depends on the succession stage. Phytosociological struc-ture of the communities changes during the succession: the relative participation of Sandy Everlasting decreases while that of other perennials becomes higher.

Temperature conditions among the locations analyzed were similar during the study period (tab. 1). Monthly av-erage air temperature in May, June and July in 2003 and 2005 was higher by ca. 1–3oC than recorded in 2004. In turn, April 2003 was slightly cooler than April of 2004 and 2005. Clear differences in the precipitation amount were observed for both the populations analyzed and the study years compared (tab. 1). Most differences were found in

95Dynamics of Helichrysum arenarium (L.) Moench populations growing in fallow field on barren soil

the year 2004. Precipitation amount recorded for the first population in the years 2003–2005 was lower from that for the second population by 29.7%, 11.8% and 26.1%, respec-tively. Precipitation amount observed in the first population in the years 2003 and 2005 was lower from that observed in 2004 by 47.7% and o29.7%, respectively. The differenc-es for the second population were less prominent: 34.3% and 16.1%, respectively. Note that the precipitation sum in 2005 from June to October was below normal (tab. 1).

Weather conditions in 2004 promoted vigorous growth and development of Sandy Everlasting shoots (tab. 1). The relatively low precipitation amount in spring 2003 re-sulted in a smaller number of seedlings and leaf rosettes in the populations studied. In the next years with a larger winter and spring precipitation amount, a higher number of vegetative propagules where found in April and May. The number of leaf rosettes found in the first population at the turn of April and May 2004 was higher than that in the same period in 2003 and 2005 by 22.4% and 15.2%, re-spectively. For the second population, the differences were even higher and amounted to 72.8% and 38.5%, respec-tively. Because of ground frosts in May 2004 the death rate of leaf rosettes in the second population was higher (tab. 1). From the beginning of June to mid August generative shoots prevailed (tab. 1). In 2003 new shoots appeared in both populations in blooming time, probably due to storms in June and heavy rains in July that year. In May and Au-gust 2004-2005 the average number of shoots per specimen kept decreasing, and new leaf rosettes started to show up only towards the end of September.

The mean number of shoots per specimen in the first pop-ulation in the years 2003 and 2004 was similar, but in 2005 it was lower by 13.8% and 14.7%, respectively (tab. 1). In the first population, the highest ratio of generative shots to the to-tal number of shoots was reported for the intensive blooming period (VII/VIII) in the second study year. At the same time, an intensive encroachment of other perennials into the com-munity and retreat of the studied species was observed.

In 2004 and 2005, the number of shoots per specimen and the relative number of individuals with generative shoots in the second population were considerably higher than in the first one (tab. 1). In the study period VII/VIII, the number of inflorescence shoots in the second popula-tion reported for three subsequent years was higher than in the first one by 7.8%, 16.6% and 20.9%, respectively. The blooming process in the first population occurred later than in the second one.

The air-dry mass of the specimens was changing with time. The effects of water deficiency in the years 2003 and 2005 can clearly be seen (tab. 1). The air-dry mass of the specimens recorded for the second population in the inten-sive blooming period (VII/VIII) was similar in the years 2003 and 2005. The value of this feature determined for the first population in the same period was lower in 2005 than

in 2003 by 40.9%. The highest values of the air-dry mass for the second population in the study periods VII/VIII and IX/X were recorded in 2004 (increase by 40.8 and 44.8%, respectively, in comparison with the previous year).

Moisture deficiency and high air temperature in 2003 and 2005 resulted in a relatively low inflorescence mass per specimen compared to that in 2004 (tab. 1), and, in consequence, in low herbal yield. At the turn of July and August 2003, the mean air-dry mass of inflorescence per specimen from the first population was higher than that for the second population (0.26 vs. 0.17 g). In the next two years the results were the opposite: the mass was higher for inflorescences from the second population (0.5 and 0.27 g) compared with that for the first one (0.35 and 0.12 g).

The potential fertility for both populations in each study period is also compiled in table 1. In 2003–2004, values of this feature in the study period VII/VIII for the first popu-lation were quite similar to one another and higher than in 2005. In 2004 a significant increase in potential fertil-ity was observed for the second population; a similar value was recorded in 2005. The highest values of the potential fertility were obtained for both populations in 2005 at the turn of summer and autumn (IX/X).

The shoot density determined for the first population in all study periods was lower than in the second one (fig. 1). The highest figures were always obtained for the sample plot 2b. The highest number of leaf rosettes per area was observed in both populations in spring (IV/V). Then some propagules withered; later some others kept withering, but in good weather conditions new rosettes appeared. From the end of May until the end of June some shoots elongated and formed apical buds (VI/VIII). Floral capitulae were ap-pearing in the turn of July and August (VII/VIII). Bloom-ing lasted till autumn. After intensive blooming period new leaf rosettes started to grow from the rhizomes (IX/X).

In the first population the seasonal variability of bio-mass was clearly manifested (fig. 2). In 2003 the highest biomass value for the sample plot 1a was recorded in the blooming period (VII/VII). In the next year the figure was the highest in the period VI/VII, and in 2005 the highest biomass level was attained in the last period (IX/X). The sample plot 1b had the highest biomass yield in 2003 and 2005 in the period IX/X, and in July/August 2004. The bio-mass value was slowly decreasing over the study years in both sample plots.

In the second population, the highest biomass values during the study years were obtained in the period VII/VIII (fig. 2). The biomass yield in 2004 was the highest.

Statistical analysis revealed significant correlations be-tween the mass of generative parts, potential fertility, and the precipitation amount. Other correlations were found be-tween biomass, density and the number of species growing in communities with Sandy Everlasting. These and other interesting correlations are compiled in table 2.

Tabl

e 1.

Wea

ther

con

ditio

ns a

nd t

he d

ynam

ics

of S

andy

Eve

rlast

ing

shoo

t nu

mbe

r, dr

y m

ass

and

pote

ntia

l fe

rtilit

y in

the

sub

sequ

ent

mon

ths

of 2

003–

2005

(da

ta

from

met

eoro

logi

cal s

tatio

ns in

Byd

gosz

cz a

nd C

hojn

ice)

Pr

ecip

itatio

n su

m

[mm

]Te

mpe

ratu

re su

m [o C

]N

umbe

r of s

hoot

s per

spec

imen

Dry

mas

s

to

tal

gene

rativ

e sh

oots

[%]

tota

l [g]

inflo

resc

ence

s[%

]Ye

ar20

0320

0420

0520

0320

0420

0520

0320

0420

0520

0320

0420

0520

0320

0420

0520

0320

0420

05Ye

arM

onth

sB

ydgo

szcz

Firs

t pop

ulat

ion

Mon

ths

I–II

I37

117.

189

.3–1

87–8

5.9

–84.

1

IV–V

36.6

86.5

117.

464

7.4

572.

360

0.2

5.30

6.83

5.79

00

00.

720.

570.

320

00

IV/V

VI–

VII

136.

693

.364

.111

2394

9.4

1048

3.98

4.79

4.08

63.6

54.1

69.4

1.44

1.74

0.97

4.9

5.2

8.2

VI/V

IIV

III

17.7

138.

716

.357

0.4

554.

950

5.3

3.56

3.48

3.54

62.9

69.5

47.7

1.32

1.77

0.78

19.7

19.8

15.4

VII

/VII

IIX

–X50

.710

3.8

23.5

553.

765

3.8

740.

73.

444.

254.

7455

.860

.540

.11.

171.

740.

917

.91.

732

.2IX

/XTo

tal

278.

653

9.4

310.

627

0826

4528

114.

074.

844.

6360

.861

.452

.41.

161.

460.

7414

.28.

918

.6M

ean

C

hojn

ice

Seco

nd p

opul

atio

n

I–II

I76

.113

7.1

121.

9–1

42–7

1.6

-53.

7

IV–V

68.9

114.

911

1.2

619.

857

4.8

596.

93.

7013

.68.

370

00

0.38

0.79

0.38

00

0IV

/VV

I–V

II15

6.8

125.

911

710

7492

510

183.

065.

034.

9760

.166

.872

.40.

481.

861.

174.

29.

148.

5V

I/VII

VII

I29

.312

8.8

58.1

539.

456

1.1

496

3.37

3.71

4.61

68.2

83.3

60.3

1.25

2.11

1.19

13.6

23.7

22.7

VII

/VII

IIX

–X54

.310

4.6

63.4

556.

966

5.9

735.

13.

695.

64.

6945

.352

.346

.31.

061.

920.

7219

.821

.929

.2IX

/XTo

tal

385.

461

1.3

471.

626

4826

5527

923.

466.

995.

6657

.967

.559

.70.

791.

670.

8712

.518

.320

.1M

ean

Tabl

e 2.

Cor

rela

tion

coef

ficie

nts

betw

een

prec

ipita

tion

amou

nt, t

empe

ratu

re, t

he n

umbe

r of s

peci

es g

row

ing

in c

omm

uniti

es w

ith H

. are

nariu

m a

nd s

elec

ted

feat

ures

of i

ndiv

idua

ls

and

popu

latio

ns o

f San

dy E

verla

stin

g.

Year

Feat

ure

Number of shoots per specimen

Number of generative shoots per specimen

Mean number of shoots per specimen

Mass of vegetative parts

Mass of generative parts

Mean total mass

Potential fertility

Density

Biomass

2003

Prec

ipita

tion

–0.2

464

0.19

17–0

.264

9–0

.142

0–0

.537

8–0

.260

9–0

.473

1–0

.178

9–0

.466

1Te

mpe

ratu

re–0

.213

60.

2623

–0.0

873

0.06

60–0

.523

0–0

.084

7–0

.502

8–0

.321

9–0

.441

9N

umbe

r of s

peci

es0.

1400

0.11

730.

4852

0.54

040.

1755

0.49

440.

0756

–0.5

579

–0.4

413

2004

Prec

ipita

tion

–0.2

663

0.41

47–0

.187

20.

4081

0.52

170.

4829

0.60

120.

0005

0.48

73Te

mpe

ratu

re–0

.302

20.

4604

–0.2

166

0.55

07–0

.251

70.

3251

–0.1

890

–0.1

169

0.01

47N

umbe

r of s

peci

es–0

.206

1–0

.179

0–0

.349

3–0

.162

7–0

.244

0–0

.204

8–0

.370

0–0

.769

9–0

.617

0

2005

Prec

ipita

tion

0.51

86–0

.257

20.

6639

–0.1

266

–0.6

842

–0.3

415

–0.7

354

0.53

080.

0965

Tem

pera

ture

–0.4

078

0.57

48–0

.193

00.

5229

–0.1

086

0.39

47–0

.092

2–0

.152

0–0

.041

2N

umbe

r of s

peci

es–0

.124

6–0

.218

7–0

.407

2–0

.198

7–0

.106

8–0

.201

2–0

.047

1–0

.798

4–0

.818

8

Cor

rela

tions

in b

old

are

stat

istic

ally

sign

ifica

nt a

t 95%

con

fiden

ce in

terv

als

N=8

98 Anna Katarzyna Sawilska

4. Discussion

The number of inflorescences and flowers is associated with the general plant habit (Czarnecka 1995). The number and mass of Sandy Everlasting inflorescences depend on

the number of shoots per plant (tab. 1). Growth and de-velopment of specimens are modified by habitat factors. The studies conducted showed that H. arenarium grow-ing in communities at an earlier succession stage exhibited a higher potential fertility (tab. 1). The number of dicoty-

Fig. 1.

0

200

400

600

800

1000

1200

1400

1600

IV/V VI/VII VII/VIII IX/X

2003study period

shoo

ts p

er m

2

sample plot 1asample plot 1bsample plot 2asample plot 2b

0

200

400

600

800

1000

1200

1400

1600

IV/V VI/VII VII/VIII IX/X

2004study period

shoo

ts p

er m

2

0

200400

600800

1000

12001400

1600

IV/V VI/VII VII/VIII IX/X

2005

study period

shoo

ts p

er m

2

Fig. 1.

0

200

400

600

800

1000

1200

1400

1600

IV/V VI/VII VII/VIII IX/X

2003study period

shoo

ts p

er m

2

sample plot 1asample plot 1bsample plot 2asample plot 2b

0

200

400

600

800

1000

1200

1400

1600

IV/V VI/VII VII/VIII IX/X

2004study period

shoo

ts p

er m

2

0

200400

600800

1000

12001400

1600

IV/V VI/VII VII/VIII IX/X

2005

study period

shoo

ts p

er m

2

Figure 1. Shoot density dynamics in Sandy Everlasting populations during growing seasons 2003–2005

Fig. 2.

104,32 236,36 189,74 132,4656,8134,64 136,88

64,9856,54

395,2634,12

241,4167,64

482,12

1050,72

414,07

0

200

400

600

800

1000

1200

1400

1600

1800

2000

IV/V VI/VII VII/VIII IX/X

2004study period

biom

ass

[g/m

2 ]

31,46 41,48 37,0581,618,63 33,75 35,42

100,33

53,28

157,92220,22

135,66

136,98

152,54

187,22 108,78

0

50

100

150

200

250

300

350

400

450

500

IV/V VI/VII VII/VIII IX/X

2005study period

biom

ass

[g/m

2 ]

183,06 211,05 312,8103,7

167,31 144,4158,53

172,48

215,52 159,1

535,72

271,92

272,8391,78

588,72

237,17

0

200

400

600

800

1000

1200

1400

1600

IV/V VI/VII VII/VIII IX/X

2003study period

biom

ass

[g/m

2 ]

sample plot 2bsample plot 2asample plot 1bsample plot 1a

Figure 2. Biomass dynamics in Sandy Everlasting populations during growing seasons 2003–2005

100 Anna Katarzyna Sawilska

ledon perennials and grasses in phytocoenoses increases as the succession progresses. As the competition for light, water and mineral salts intensifies, the stress increases. Sandy Everlasting, as any other species, can tolerate only a certain range of habitat conditions. Beyond the tolerance limit the species cannot win the interspecific competition (Falińska 2004; Sawilska, Dąbrowska 2006). Shadow from the neighboring plants seems to be a major stress factor. The precipitation amount is also essential for the blooming process, as the species grows on sandy soils with low hu-mus content and therefore low capability to retain water.

Weather conditions varied greatly among the study years (tab. 1). Very dry and warm spring of 2003 did not favor the development of leaf rosettes of Sandy Everlast-ing, which resulted in a smaller number of shoots at further development stages and lowered the mass of inflorescences (tab. 1). In 2004 more precipitation was recorded, and more leaf rosettes appeared in spring, especially in the second population, but many of them withered because of ground frosts in May that year. Spring 2005 was relatively warm and moist, but there was not enough precipitation in the next months. In June and July that year the second popu-lation received more moisture which resulted in a higher number and larger mass of shoots. Weather conditions in the second study year were most favorable for growth and development of Sandy Everlasting, which was reflected in the ratio between inforescence mass and whole plant mass, as well as the quantity of biomass produced in the blooming period (tab. 1). The figures for the second popu-lation were higher than for the first one. Potential fertil-ity determined for the first population remained stable in subsequent years, despite of variable weather conditions, whereas shoot density and biomass decreased. This may be explained by increasing competition from neighboring spe-cies (such as Festuca ovina, Hieracium pilosella, Galium vernum, Artemisia campestris, Chondrilla juncea, Elymus repens, Jasione montana, Rumex acetosella), and resulting light deficiency.

No significant correlation between neither shoot num-ber per specimen in subsequent development stages nor the potential fertility and the density was found (tab. 1, fig. 1). The mortality of seedlings and vegetative propagules is well accounted for by weather conditions and influence of other species in the community. Taxa that subsequently en-ter the community hinder the growth and development of H. arenarium. Disturbances in growth caused by temporary water deficiency and high air temperature (tab. 1), espe-cially in the 2005 growing season, resulted in withering of adult individuals of Sandy Everlasting and promoted inva-sion of other species, like Erodium cicutarium in the first population, or Conyza canadensis in the second one.

Comparison of shoot density (fig. 1) and biomass (fig. 2) dynamics with the patterns by Grime (1974, 1979) shows that Sandy Everlasting is able to modify its life strategy:

from S, through S-R to C-S-R. Therefore, H. arenarium is a stress (S) and disturbance (R) tolerant species, but it is sensitive to competition (C), especially for light (Sawil-ska 2004).

The species grows and develops simultaneously: veg-etative propagules are formed and rhizomes expand during the whole growing season (though with different intensi-ty). Resource allocation to the vegetative and generative growth occurs at an early development stage. Sandy Ev-erlasting blooms from June through October, weather per-mitting, which reflects adaptation to variable environment conditions.

Conclusions

The conducted study revealed that:observed populations remain under a strong influence 1) of environment factors which is evidenced by differ-ent phytosociological position of the communities ana-lyzed;growth and development processes in 2) H. arenarium populations are modified by weather conditions; the potential fertility is correlated significantly with the precipitation amount;the amount of biomass and its seasonal distribution de-3) pends on weather conditions and the number of plant species coexisting in the analyzed phytocoenoses.

References

Buchwald W., 1992, Kocanki piaskowe ginącym gatunkiem [Sandy Everlasting as a vanishing species], Wiadomości Zielarskie 34 (5): 5–6.

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