Content uploaded by Artur Obidziński
Author content
All content in this area was uploaded by Artur Obidziński on Apr 01, 2014
Content may be subject to copyright.
Content uploaded by Artur Obidziński
Author content
All content in this area was uploaded by Artur Obidziński on Apr 01, 2014
Content may be subject to copyright.
Artur OBIDZIŃSKI1*, Anna ORCZEWSKA2, Piotr CIELOSZCZYK1
1 Warsaw University of Life Sciences, Department of Forest Botany,
Nowoursynowska 159, 02-776 Warszawa, Poland,
*e-mail: artur_obidzinski@sggw.pl (corresponding author)
2 University of Silesia, Faculty of Biology and Environmental Protection, Department of Ecology,
Bankowa 9, 40-007 Katowice, Poland
THE IMPACT OF BEAVERS’ (CASTOR FIBER L.) LODGES ON
VASCULAR PLANT SPECIES DIVERSITY IN FOREST LANDSCAPE
POLISH JOURNAL OF ECOLOGY
(Pol. J. Ecol.)
59 1 63–73 2011
Regular research paper
ABSTRACT: Beavers lodges represent spe-
cific, zoogenic habitats. Their flora show some
distinctive features differentiating them from the
species composition of the areas surrounding the
lodges. Studies were conducted in the Romincka
Forest, in north-eastern Poland. Although lodges
and their surroundings did not differ in the total
number of vascular plants recorded in their area,
the 40 beavers lodges studied had a significantly
higher mean species richness, however half of
the total species cover compared with the lodges’
surroundings. Species from the Lamiaceae, Po-
lygonaceae and Asteraceae families were more
often present in lodges rather than in their sur-
roundings. Within the lodges there were more
species tolerating disturbance (r strategy), more
hemicryptophytes and therophytes, more species
associated with eutrophic habitats and of neutral
soil reaction. Aside from this, species from the Al-
netea glutinosae, Bidentetea tripartiti, Scheutze-
rio-Caricetea, Artemisietea vulgaris, and Stellari-
etea mediae classes had a bigger share compared
to lodges’ surroundings. Finally, there were also
more euhemerobic species recorded in that habi-
tat. By contrast, the communities which surround
the lodges had a higher representation of stress-
tolerant species (s strategy), typical for mesotro-
phic habitats with acidic soils and more mesohe-
merobous and urbanophobous species. The above
mentioned tendencies allowed to conclude that
beavers’ lodges contribute to the increase in the
diversity of habitats and subsequently may be re-
garded as an important factor influencing flora
and vegetation biodiversity.
KEY WORDS: beaver lodges, animal pres-
sure, floral transformations, NE Poland
1. INTRODUCTION
The influence of engineer organisms on
conditions of vegetation development have
been given much of attention for over a de-
cade. Engineer organisms are considered to
be ones that make certain environmental
resources available to other species through
transformation of some qualities of eco-
systems (Jones et al. 1994). Ever since this
concept was proposed, a number of stud-
ies were carried out (e.g. Wilby et al. 2001,
Guiterrez et al. 2003, Machicote et al.
2004, Moore 2006). At first, it was consid-
ered, that the engineer species influence spe-
cies diversity only on a large scale (Jones et
al. 1997). Later, their impact was recognized
as independent of the scale (Croo k s 2002).
However this hypothesis needs a further con-
firmation (Pr i ngl e 2008). As well, in spite
of critical opinions about engineer species,
they seem to enjoy ever bigger recognition
as a factor of shaping ecosystems (e.g. Wilby
2002, Jone s et al. 1997, Gi l ad et al. 2004,
Artur Obidziński et al.
Crain and B e rt n e ss 2006, Wr ig h t and
Jones 2006).
Beavers (Castor fiber L. 1758 and
C. canadensis Kuhl. 1820) are one of the best
known engineer animal species (Wr i g ht et al.
2002, Ros e l l et al. 2005). Creation of ponds
(Johnston and Na i man 1990a, Sch l o ss e r
1995), alteration of rivers’ course and water
chemistry (Naim a n et al. 1994, Gu rn e l l
1998, K l otz 1998), change of hydrological
conditions on adjacent areas (Woo and Wad -
dington 1990, Gurnell 1998), as well as
transformations of neighbouring canopies
(Johnston i Na i man 1990b, Nolet et al.
1994), are the most important effects of beavers’
activity. The above mentioned changes in the
environment enable development of new plant
communities (Barnes and Dibble 1988, Ray
et al. 2001, Bonn e r et al. 2009) and settling of
new species of fauna (Grover and B a ld a s -
sarre 1995, Snod g r ass and M e f fe 1998,
Harthun 1999, C ol l en and G ibson 2001,
Dalbeck et al. 2007). All these activities lead
to an increase in species diversity at the level of
ecosystems as well as landscape. The level of in-
crease of the diversity depends on the variety of
environmental conditions before inhabitation
by beavers and on the intensity of beavers’ ac-
tivity (Na i m an et al. 1988, R o se l l et al. 2005).
Beavers’ activity can be responsible for as much
as 25% of species diversity in the habitats trans-
formed by them (Wright et al. 2002).
In reference to this, lodges seem to be the
least recognized habitat created by beaver,
which are also inhabited by various animal
and plant species (Fr anc e 1997). Lodges
are dome-shaped constructions built from
branches, grass, slime and mud. They provide
winter and breeding period shelters for bea-
vers in places where low banks make it im-
possible to dig dens. They consist of a nesting
chamber situated over the water surface and
of one or a number of tunnels. They usually
reach the height of 1 to 3.5 m and diameter of
2 to 20 m. The walls of the lodge are 0.5 to 1
m thick (Żu r o w s k i 1992). Accumulation of
organic matter on the surface of the lodge en-
ables its overgrowing by plants. Thus, lodges
constitute a specific habitat with an increase
of trophic conditions and constantly dis-
turbed initial soil substratum. In relation to
that, the aim of the research was to investigate
if the flora of the lodges was distinct from the
surrounding habitats. In the case of a confir-
mation of this distinction, a second aim was
to determine its character, especially in terms
of synanthropisation. Thus these stated goals
were followed by a hypothesis that the flora
of the lodges demonstrated a higher species
richness and diversity as well as a higher par-
ticipation of species tolerating disturbances
and preferring eutrophic and synanthropic
habitats, in comparison with control plots.
Fig. 1. Location of the study sites in Romnicka Forest (NE Poland).
64
Vascular plant species diversity on beavers’ lodges
2. STUDY AREA
The research was carried out in the
Romincka Forest in NE Poland, close to the
border with the Russian Federation (54°17’25”
– 54°21’30”N and 22°17’30”–22°44’40”E), on
an area of ca 180 km
2
(Fig. 1). The Romincka
Forest is situated in the macroregion of the
Lithuanian Lakeside, within the range of the
Eastbaltic Lakeside, that belongs to the prov-
ince of Eastbaltic Belarussian Lowlands (Kon-
dracki 1994). The relief created by morraine
and kame hills of the Baltic glaciation, reaches
143–278 m a.s.l. Boulder clays, more rarely
loamy sands and sands that created brown soils
and small plots of podzol soils are dominant in
the area. Broadleaved and mixed forests pre-
vail on brown soils, while coniferous forests on
podzol soils. Numerous peat bogs have been
created in lower parts of the terrain. Spruce
dominating the canopies of the Romincka
Forest for the most part was planted. The for-
est has a well developed hydrologic net that is
favourable for beaver’s settling. The climate
of the Romincka Forest bears continental fea-
tures. The mean temperature of February over
years has been –5.6°C, of July 17.3°C and of
the whole year 6.1°C. The snow cover remains
approximately 101 days. Mean sum of yearly
precipitation is 576 mm (Kondracki 1994).
3. MATERIAL AND METHODS
Field investigations were carried out in
July of 2005–2006. The studies of 40 beaver
lodges, included the estimation of their loca-
tion, size, type and the amount of material
which they were composed of, and the per-
centage cover of herb layer species develop-
ing on their surface. Forty reference plots,
each equal in surface to its matching lodge,
with no evidence of beaver activity, were set
up within a distance of 25 meters from the
lodges. The data on the species composition
of vascular plants were collected from the
lodges and their surrounding, reference plots.
The nomenclature of vascular plants followed
that one given by Mi re k et al. (2002).
Species richness (number of species),
Shannon diversity index, and species evenness
for the reference plots and for the lodges were
calculated, using MVSP 3.1 package. Besides,
the floristic similarity index of lodges’ and
their surroundings’ flora, based on the species
frequency was calculated according to the fol-
lowing formula (Krebs 1996, page 406).
Similarity index = 2z (x+y)–1
where: x – number of species in the first
community, y – number of species in the sec-
ond community, z – number of species com-
mon to both communities
Furthermore, these two habitats were
compared according to the number of species
representing different Raunkiaer’s life forms
(Zarz y c k i et al. 2002), Grime’s life strategies
(Grime et al. 1996), phytosociological (syn-
taxonomic) behaviour (Matus z k ie w icz
2006), systematic status (Mirek et al. 2002)
and hemeroby index (Frank et al. 2002).
Then, mean values of the above mentioned
ecological attributes of species for both habi-
tats were compared with the Mann-Whitney
U-test (Statistica 8.0 package). The ecologi-
cal requirements of species present on lodges
and in their surroundings were defined using
ecological indicator values (moisture – F, soil
reaction – R, nitrogen content – N, and light
conditions – L) after Ellenb e rg et al. (1992).
In order to identify the main directions
of plot and species variation detrended cor-
respondence analysis DCA, in its standard
form was used (Canoco 4.5). Then, Spear-
man’s rank correlation coefficients were cal-
culated between the sample scores of the first
Table 1. General characteristics of the beavers’ lodges in Romincka Forest (N = 40).
Parameter Mean (±SD)
Diameter (m) 5.90 (±2.20)
Height (m) 1.61 (±0.61)
Main component:
wood (%) 51.25 (±18.51)
humus (%) 28.50 (±17.71)
soil (%) 20.25 (±18.74)
Area covered by vascular plants (%) 40.25 (±22.98)
65
Artur Obidziński et al.
two DCA axes and the environmental data
for each plot on the number of species rep-
resenting different, above mentioned traits
(Statistica 8.0).
4. RESULTS
Among the forty lodges present in the area
studied, 21 were totally surrounded by sedges
communities, whereas another 19 from their
inland side were also adjacent to forests. An
average diameter of lodges reached almost 6
meters, and their height exceeded 1.5 meters.
Twig s an d br an ch es o f tr ee s an d bu sh es w ere
the main material the lodges were composed
of. Such composition covered more than a
half of the lodges surface. Almost 30% of
the area of lodges consisted of the decayed
wood, and the remaining part was composed
of soil and mud that had been transported
and stored there by beavers. An average area
covered by plants reached more than 40% of
lodges, with the extreme values ranging from
10 to 90% (Table 1).
The total cover of vegetation which had
developed on lodges reached only half of
which was recorded in their surroundings.
However, both habitats had a comparable
mean and total number of vascular plant
species. The overall number of species pres-
ent on lodges reached 201 herbs, whereas in
the plots from surrounding areas 216 species
were recorded. As well, higher species diver-
sity and evenness were observed on lodges
than within their surrounding communities
(Table 2).
The list of species most frequently pres-
ent on lodges included: Urtica dioica L., Scu-
tellaria galericulata L, Lycopus europaeus L.,
Lysimachia vulgaris L., and Solanum dulca-
mara L., whereas Juncus effusus L., Alisma
plantago-aquatica L., Aegopodium podagraria
L., Quercus robur L., and Equisetum sylvati-
cum L. were the most often occurring in the
reference plots. An average frequency of spe-
cies mainly associated with lodges was twice
as high as that one of the species most often
occurring in their surroundings. The herbs
which either occurred exclusively on lodg-
es or in their surroundings belonged to the
group of sporadic species. Mean phytocoeno-
ses similarity index between lodges and their
surroundings equals 0.39 (± SD=0.15).
Both habitats were dominated with spe-
cies typical for grassy, aquatic, and forest
communities, reaching together 75% of the
total number of species. However, compared
to reference plots, among the flora of lodges,
a higher mean number of aquatic species
and species reflecting human impact (synan-
thropic species), were observed. Such tenden-
cies were reflected in the higher number of
species from the Alnetea glutinosae, Bidente-
tea tripartiti, Scheutzerio-Caricetea, Artemis-
ietea vulgaris, and Stellarietea mediae classes
on lodges (Table 3).
Among the Raunkiaer’s life forms,
hemicryptophytes, reaching more than a half
of all species, predominated, regardless of the
habitat studied. Additionally, an increased
proportion of phanerophytes and geophytes
were observed. The lodges were character-
ized by a significantly higher mean number of
hemicryptophytes and therophytes (Table 3).
In both habitats, species tolerating high level of
competition (c strategy) and with the mixed,
cs and csr strategies, had the highest share.
Lodges were characterized by a significantly
higher number of species tolerating distur-
bance (r and cr strategies), assisted by a lower
number of stress-tolerant species (s strategy)
than found in surroundings (Table 3).
When the level of synanthropization
of both habitats was analyzed, we observed
the dominance of non-synanthropic species
among their flora. The difference between the
Table 2. Mean values of the variables studied for lodges and their surroundings (N = 40) and the sig-
nificance level of differences between these values according to Mann-Whitney U-test ** – P ≤ 0.01;
**** – P≤ 0.0001; n.s. – not significant
Variable Lodges Surrounding P
Total cover of species (%) 40.25 85.28 ****
Number of species 23.70 21.03 n.s.
Shannon diversity index 2.54 2.18 **
Evenness 0.82 0.73 **
66
Vascular plant species diversity on beavers’ lodges
Table 3. Ecological character of flora on lodges and their surroundings (N = 40) and the significance
level of differences between mean values according to Mann-Whitney U-test; * – P ≤ 0.05, ** – P ≤ 0.01,
*** – P ≤ 0.001, **** – P ≤ 0.0001, n.s. – not significant. For explanation of life strategies see the text.
Variable
Lodges Surroundings
PNumber of species Number of species
Tota l Me a n Total M e an
Species characteristic to the syntaxonomic groups representing communities
Grassy 46 5.30 46 5.36 ns
Aquatic 40 5.63 45 3.90 *
Forest 39 5.03 48 5.05 n.s.
Synanthropic 29 3.93 26 2.33 ***
Most frequently represented classes
Molinio-Arrhenatheretea 41 4.93 39 4.68 n.s.
Querco-Fagetea 25 2.20 32 2.70 n.s.
Phragmitetea 24 3.88 27 3.00 n.s.
Artemisietea vulgaris 19 3.03 17 1.75 **
Alnetea glutinosae 10 2.50 9 1.73 *
Bidentetea tripartiti 8 1.18 7 0.48 **
Stellarietea mediae 8 0.78 7 0.45 *
Life forms
Hemicryptophytes 108 13.25 112 11.05 *
Therophytes 19 2.68 16 1.28 ***
Megaphanerophytes 14 1.38 15 2.03 n.s.
Nanophanerophytes 11 1.98 12 1.45 n.s.
Geophytes 13 1.00 16 1.50 n.s.
Hydrophytes 8 0.73 14 0.90 n.s.
Chamaephytes 7 0.63 8 0.73 n.s.
Life strategies
c 73 8.20 76 8.73 n.s.
cs 49 6.60 59 5.95 n.s.
csr 53 5.60 55 4.53 n.s.
cr 19 2.38 17 1.18 **
r 3 0.33 3 0.10 **
rs 3 0.55 3 0.35 n.s.
s 2 0.05 3 0.20 *
Categories of synantropization
natyphytes 117 13.13 137 13.03 n.s.
apophytes 81 10.33 75 7.85 *
antropophytes 4 0.25 4 0.15 n.s.
Most frequently represented families
Poaceae 26 2.95 29 3.00 n.s.
Asteraceae 20 2.13 26 1.75 n.s.
Lamiaceae 12 2.48 7 0.98 ****
Cyperaceae 12 0.73 17 1.43 **
Polygonaceae 12 1.38 9 0.60 ***
67
Artur Obidziński et al.
lodges and their reference plots was seen in
the significantly higher number of the native,
synanthropic species (apophytes) on lodges
than in the other habitat (Table 3).
Species from the Poaceae and Asteraceae
families were the most frequently recorded,
both on lodges and in their surroundings. As
well, a high, although not significant share of
species from the Rosaceae, Caryophyllaceae,
and Fabaceae families, was observed. Dis-
tinctively more species from the Lamiaceae
and Polygonaceae families were recorded on
lodges, whereas in their surroundings there
was a high number of the Cyperaceae family
represented (Table 3).
When ecological requirements of species
present on lodges and in their surroundings
were compared, a slightly higher share of
light-demanding species on lodges (L ≥ 7),
assisted with the lower of shade-tolerant ones
(L d 3) and of the average demands for light
(L d 6) were recorded. The flora of lodges
showed a higher share of herbs preferring wet
habitats (F ≥ 7), whereas among the species
of reference plots those associated with moist
sites (4 d F d 6) predominated. On lodges
there were more species of eutrophic sites
(N ≥ 7), whereas in their surroundings those
preferring oligo- and mesotrophic habitats
were better represented (N d 6). Species pres-
ent on lodges and in their surroundings did
not differ in their preference for soil reaction
(Fig. 2).
More euhemerobic species were recorded
among the flora of lodges, whereas among
the species of the lodges’s surroundings, more
oligo- and mezohemerobic species were pres-
ent (Fig. 3).
Although the ordination scatter plot in
the DCA of sites, did distinguish separate
patches of plots originating from lodges and
their surroundings, it also showed some
distinctive tendencies in their arrangement
within the graph. Lodges’ plots concentrated
in the center of the graph, whereas reference
sites were located on their peripheries. This
pattern was seen well especially along the x
axis (eigenvalue = 0.473). The reference plots
originating from the sedges communities
were located on the left side and the refer-
ence plots of forested character on the right
Fig. 3. The level of synanthropization of the flora
of lodges and their surroundings expressed as
hemeroby: 1 – ahemerobic, 2 –oligohemerobic, 3 –
mezohemerobic, 4 – euhemerobic, 5 – polyhemer-
obic 6 – metahemerobic; (after Fr an k et al. 2002).
Fig. 2. Ecological requirements of species present on lodges and their surroundings, according to indi-
cator values 1–9 of Ellenberg (1992), dd – data deficient.
68
Vascular plant species diversity on beavers’ lodges
Table 4. Spearman’s rank correlation coefficients (SRCC) between the sample scores on the first two
DCA axes and the environmental variables (number of species representing given categories). Only
statistically significant correlations are presented; * – P ≤ 0.05, ** – P ≤ 0.01, *** – P ≤ 0.001, **** – P ≤
0.0001, ***** – P ≤ 0.00001.
Axis 1 SRCC P
Querco-Fagetea class 0.51 *****
Vaccinio-Piceetea class 0.43 ****
megaphanerophytes 0.45 ****
geophytes 0.35 **
natyphytes 0.26 *
Rosaceae family 0.22 *
Scheuzerio-Caricetea class –0.26 *
Potametea class –0.34 **
Alnetea glutinosae class –0.37 ***
Phragmitetea class –0.51 *****
hydrophtes –0.40 ***
Axis 2 SRCC P
Trifolio-Geranietea class 0.40 ***
Molinio-Arrhenatheretea class 0.35 **
Agropyretea class 0.34 **
Artemisietea class 0.24 *
Epilobietea class 0.24 *
hemicryptophytes 0.42 ***
geophytes 0.41 ***
apophytes 0.53 ****
competitors 0.55 *****
Poaceae family 0.46 ****
Asteraceae family 0.43 ****
Phragmitetea class –0.28 *
Scheuzerio-Caricetea class –0.29 **
hydrophytes –0.29 **
Fig. 4. The DCA scatter plot illustrating the distribution of plots of lodges and their surroundings.
69
Artur Obidziński et al.
part. Also observed was similar pattern of the
plots from lodges, with those surrounded by
sedges communities situated on the left and
those adjoining forest communities on the
right side of the graph. The distribution of
plots according to y axis (eigenvalue = 0.332)
is not so distinctive (Fig. 4).
The ordination of species revealed some
interesting tendencies, which were found to
be in accordance with the distribution pattern
of plots. Thus, species characteristic for the
aquatic communities were mainly grouped
on the left side of the diagram, whereas forest
species were concentrated on the right side.
Species characteristic for grassy communities
were grouped more at the top part of the dia-
gram and for synanthropic communities in
the middle (Fig. 5).
The DCA sample scores along the first
axis were positively correlated with the num-
ber of forest species (excluding those charac-
teristic for wet alderwood community), and
negatively with the number of species charac-
teristic for aquatic communities. Thus such a
result reflects a decreasing moisture gradient.
DCA sample scores along the first axis were
also positively correlated with the number of
geophytes, megaphanerophytes and with spe-
cies of a mixed G/H life form, and negatively
with the number of hydrophytes and Hy/H
life forms (Table 4).
DCA sample scores for the second axis
were positively correlated with the number of
species characteristic for the grassy commu-
nities, communities of open habitats within
forests, and with the synanthropic species,
but negatively with the sedges communities.
Thus, the second axis can be interpreted as a
one representing the increasing light gradi-
ent. Positive correlation of the DCA sample
scores for the second axis with the number of
geophytes, hemicryptophytes, and competi-
tive species (c strategy) was also observed,
and negative with the number of hydrophytes
(Table 4).
5. DISCUSSION
Literature about lodges has so far con-
cerned their spatial distribution, structure
and conditions inside (Dieter and McCab e
1989, Żu rowsk i 1992, D y c k and MacAr-
thur 1993). Flora overgrowing lodges has
not been presented in literature yet.
The results obtained indicate a higher
diversity and floristic distinctness of beaver
lodges than in the surrounding communities
both, in the case of sedge communities and
forest. These differences are mainly expressed
in a more frequent presence of ruderal and
segetal species and therophytes that toler-
ate disturbances on lodges. The species from
Fig. 5. The DCA scatter plot illustrating the distribution pattern of plant species representing different
ecological groups.
70
Vascular plant species diversity on beavers’ lodges
those groups demonstrate higher light, tro-
phic and humidity demands. Such character
of the flora of lodges may be a result of the
peculiarity of the habitat created by beaver.
It can be assumed that accumulation of soil,
slime and plant material leads to a rise in tro-
phic conditions of these specific habitats. Re-
moval of trees in the surrounding area results
in an increase in insolation which accelerates
mineralization and therefore leads to the fur-
ther growth of trophic conditions. Constant
repairing of lodges by beavers results in dam-
ages to plants. Such activities are harmful to
the growth of perennials whereas tolerated by
annual plants.
Beaver dams are relatively similar habitats
to lodges. Fairly similar species composition
is recorded on dams although they contain
more swamp and meadow species and less
synanthropic species (Medwe c ka-Kornaś
and Ha w ro 1993, Zwoli c k i and Nowa-
kowski 2005). This difference may result
from the fact that dams hardly rise over the
surface of the water of the ponds while lodges
are raised even to the height of 1 to 3 meters.
Certain similarities are observed between
the specific flora of lodges and other places
shaped by animals, e.g. burrows of fossorial
rodents (E ng li sh and Bo w er s 1994), badger
setts (Obidz i ńs ki and G ło gows k i 2005,
Obidziński and K i ełt y k 2006), bison wal-
lows (Copped g e and S h o w 2000), and wild
boar rooting (Fali ńs k i et al. 1996). Similar-
ily, participation of therophytes and species
tolerant to disturbances is higher in the above
mentioned places than in their surroundings.
Besides, in the case of burrows, species of eu-
trophic habitats are more frequently repre-
sented than in the surroundings.
Thus, lodges definitely match the other
engineer activities of beavers. They constitute
a peculiar habitat occupied by plant species
not present or rare in the environment before
lodges were created. Species diversity and the
mosaic character of the flora of the habitat
created by beaver increase due to the cre-
ation of lodges. Invertebrate fauna (France
1997) and small rodents (Ul e v ic i u s and
Janu la i t i s 2007) demonstrate a similar re-
action. This phenomenon parallels with other
activity of beaver that contributes to the in-
crease in biodiversity through creation of
wetlands and removal of trees (Na i man et
al. 1988, Wrig h t et al. 2002, Ro s s el l et al.
2005).
It is worth mentioning that a higher oc-
currence of synanthropic and eutrophic spe-
cies on lodges indicates changes described as
anthropogenic. However it cannot be seen
as the influence of any human activity in
this case. Therefore, consideration should be
made whether transformations of flora and
vegetation of this type should be called “zoo-
genic”, similarly to the case of badger setts
and fox dens (Obid z i ński and Głogow s k i
2005, Obi d z ińs k i and K i e łty k 2006).
Therefore the category of “synanthropic spe-
cies” should be redefined and applied to the
more limited group of taxa.
The results obtained encourage further
analyses whose goal will be to measure the
changes in the mosaic character of the envi-
ronment, expressed by the peculiarity of the
flora of lodges, as well as to determine the sta-
bility and reversibility of these changes. It also
seems important to recognize impact of the
lodges size, distance from land, period of us-
age, and types of neighboring plant communi-
ties on the level of their floristic distinctness.
6. CONCLUSIONS
1. The flora of beaver lodges shows a greater
species diversity and clear distinctness
from their surroundings. It is connected
with a higher participation of disturbance
resistant therophytes and synanthropic
plants.
2. Beaver, as an engineer species, creates
conditions not only favourable for devel-
opment of aquatic and swamp plant spe-
cies but for synanthropic herbs as well.
3. Floristic composition on lodges is similar
in its character to the one of habitats cre-
ated by animals activity.
4. It is probable that based on further re-
search on this problem, it will be possible
to distinguish among synanthropic plants,
a separate category of species linked with
animal activity.
ACKNOWLEDGEMENTS: Authors would
like to express their gratitude to the Administra-
tion of Gołdap State Forests District for providing
an access to data on the location of beaver lodges
in the Romincka Forest.
71
Artur Obidziński et al.
7. REFERENCES
Barnes W.J. , Di bble E. 1988 – The effects of
beaver in riverbank forest succession – Can. J.
Bot. 66: 40–44.
Bonner J.L., Anderson J.T., Rentch J.S.,
Grafton W.N. 2009 – Vegetative composi-
tion and community structure associated with
beaver ponds in Canaan Valley, West Virginia,
USA – Wet. Ecol. Manage. 17: 543–554.
Collen P., Gibson R.G. 2001 – The general
ecology of beavers (Castor spp.), as related to
their influence on stream ecosystems and ripar-
ian habitats, and the subsequent effects on fish
– a review – Rev. Fish. Biol. Fisher. 10: 439–461.
Coppedge B.R., Show J.H. 2000 – Ameri-
can bison Bison bison wallowing behavior and
wallow formation on tall grass prairie – Acta
Theriol. 45: 103–110.
Crain C.M., Bertness M.D. 2006 – Ecosys-
tem engineering across environmental gradi-
ents: implications for conservation and man-
agement – BioScience, 56: 211–218.
Crooks J.A. 2002 – Characterizing ecosystem-
level consequences of biological invasions:
the role of ecosystem engineers – Oikos, 97:
153–166.
Dalbeck L, Lüscher B., Ohlhoff D. 2007
– Beaver ponds as habitat of amphibian com-
munities in a central European highland –
Amphibia-Reptilia, 284: 493–501.
Dieter C.D., McCabe T.R. 1989 – Factors
influencing beaver lodge-site selection on a
prairie river – Am. Midl. Nat. 122: 408–411.
Dyck A.P., MacArthur R.A. 1993 – Seasonal
variation in the microclimate and gas compo-
sition of beaver lodges in a boreal environ-
ment – J. Mammal. 74: 180–188.
Ellenberg H . , Weber H.E., D ül l R ., Wir t h
V. , We r ne r W., P au l i ss en D. 1992 – Zei-
gewerte von Pflanzen in Mitteleuropa. 2. Ver-
besserte und erweiterte Auflage – Scripta Geo-
bot. 18: 1–258.
English E.L., Bowers M.A. 1994 – Vegeta-
tional gradients and proximity to woodchuck
(Marmota monax) burrows in an old field – J.
Mamlam. 75: 775–780.
Faliński J.B., Głowacki Z., Załuski T.
1996 – The colonisation of wild boar rooting
sites and game wallows by green plants. (In:
Cryptogamous plants in the forest communi-
ties of Bialowieża National Park. Phytocoeno-
sis 8 (N.S), Eds: J.B Falinski., W. Mulenko) –
Archivum Geobotanicum, 6: 145–146.
France R.L. 1997 – The importance of beaver
lodges in structuring littoral communities
in boreal headwater lakes – Can. J. Zool. 75:
1009–1013.
Frank S., Kühn I., Durka W. 2002 – Bioflor
– Eine Datenbank mit biologisch-ökologi-
schen Merkmalen zur flora von Deutschland.
Bundesamt für Naturschutz. Bonn.
Gilad E., von Hardenberg J., P rovenzale
A., Shachak M., Meron E. 2004 – Eco-
system engineers: from pattern formation to
habitat creation – Phys. Rev. Lett. 93: 1–4.
Grime J.P., Hodgson J.G., Hunt R. 1996
– Comparative plant ecology. A functional ap-
proach to common British species – Unwin
Hynan, London, Boston, Sydney, Wellington.
Grover A.M., Baldassarre G.A. 1995 – Bird
species richness within beaver ponds in south-
central New York – Wetlands, 15: 108–118.
Gurnell A.M. 1998 – The hydrogemorphologi-
cal effects of beaver dam-building activity –
Prog. Phys. Geog. 22: 167–189.
Gutierrez J.L., Jones C.G., Strayer D.L.,
Iribarne O.O. 2003 – Molluscs as ecosys-
tem engineers: the role of shell production in
aquatic habitats – Oikos, 101: 79–90.
Har th u n M. 1999 – The influence of the Euro-
pean beaver (Castor fiber) on the biodiversity
(Odonata, Mollusca, Trichoptera, Ephemerop-
tera, Diptera) of Brooks in Hesse (Germany)
– Limnologica, 29: 449–464.
Johnston C.A., Naiman R.J.1990a – Aquatic
patch creation in relation to beaver population
trends – Ecology, 71: 1617–1621.
Johnston C.A., Naiman R.J. 1990b – Browse
selection by beaver: effects on riparian forest
compositon – Can. J. For. Res. 20: 1036–1043.
Jon es C.G., Lawton J.H., S h a c h a k M.
1997 – Positive and negative effects of organ-
isms as physical ecosystem engineers – Ecol-
ogy, 78: 1946–1957.
Jon es C.G., Lawton J.H., S h a c h a k M.
1994 – Organisms as ecosystem engineers –
Oikos, 69: 373–386.
Klotz R.L. 1998 – Influence of beaver ponds on
the phosphorus concentration of stream water
– Can. J. Fish. Aquat. Sci. 55: 1228–1235.
Kondracki J. 1994 – Geografia Polski. Mezore-
giony Physico-geograficzne [Geography of
Poland. Physico-geographical mezoregions] –
PWN, Warszawa (in Polish).
Krebs C.J. 1996 – Ekologia. Eksperymentalna
analiza rozmieszczenia i liczebności [Ecology.
Experimental analysis of distribution and
abundance] – PWN, Warszawa.
Machicote M., Bran ch L.C., Vi l l a r re a l D.
2004 – Burrowing owls and burrowing mam-
mals: are ecosystem engineers interchangeable
as facilitators?– Oikos, 106: 527–535.
Matuszkiewicz W. 2006 – Przewodnik do
oznaczania zbiorowisk roślinnych Polski [A
guide for the identification of Polish plant
72
Vascular plant species diversity on beavers’ lodges
Received after revision October 2010
communities] – PWN – Polish Scientific Pub-
lishers, Warszawa.
Medwecka-Kornaś A., Hawro R. 1993 –
Vegetation of beaver dams in the Ojców Na-
tional Park (southern Poland) – Phytocenolo-
gia, 23: 611–618.
Mirek Z., Pi ęko ś-Mirkowa H., Zając A.,
Zając M. 2002 – Flowering plants and pteri-
dophytes of Poland. A checklist – W. Szafer In-
stitute of Botany, Polish Academy of Sciences,
Kraków.
Moore J.W. 2006 – Animal ecosystem engineers
in streams – BioScience, 56: 237–246
Na im an R . J., Pinay G., Jo h n s on C.A.,
Pastor J. 1994 – Beaver-induced influences
on the long-term biogeochemical characteris-
tics of boreal forests drainage networks – Ecol-
ogy, 75: 905–921.
Na im an R.J., Jo h n s t on C.A., Kelley J. C .
1988 – Alteration of North American streams
by beaver – BioScience, 38: 753–762.
Nolet B.A., Hoekstra A., Ottenheim
M.M. 1994 – Selective foraging on woody
species by the beaver Castor fiber, and its im-
pact on a riparian willow forest – Biol. Con-
serv. 70: 117–128 .
Obidziński A., Głogowski R. 2005 –
Changes of forest flora composition in vicinity
of dens of red fox and setts of Euroasian bad-
ger – Pol. J. Ecol. 53: 197–213.
Obidziński A., Kiełtyk P. 2006 – Changes
in ground vegetation around badger setts and
red fox dens in the Białowieża Forest, Poland –
Pol. Bot. Stud. 22: 407–416.
Pringle R.M. 2008 – Elephants as agents of
habitat creation for small vertebrates at the
patch scale – Ecology, 89: 26–33.
Ray A.M., Rebertus A.J., Ray H.L. 2001
– Macrophyte succession in Minnesota beaver
ponds – Can. J. Bot. 79: 487–499.
Rosell F., Bozsér O., Collen P., Parker
H. 2005 – Ecological impact of beavers Cas-
tor fiber and Castor canadensis and their abil-
ity to modify ecosystems – Mammal Rev. 35:
248–276.
Schlosser I . J. 1995 – Dispersal, boundary pro-
cesses and trophic level interactions in streams
adjacent to beaver ponds – Ecology, 76: 908–
925.
Snodgrass J.W., Meffe G.K. 1998 – Influ-
ence of beavers on stream fish assemblages:
effects of pond age and watershed position –
Ecology, 79: 928–942.
Ulevičius A., Janulaitis M. 2007 – Abun-
dance and species diversity of small mammals
on beaver lodges – Ekologija, 53: 16–21.
Wilby A. 2002 – Ecosystem engineering: a trivi-
alized concept – Trends. Ecol. Evol. 17: 307.
Wilby A., Shachak M., Boeken B. 2001
– Integration of ecosystem engineering and
trophic effects of herbivores – Oikos, 92:
436–444.
Woo M.K., Waddington J.M. 1990 – Effects
of beaver dams on subarctic wetland hydrol-
ogy – Arctic, 43: 223–230.
Wrigh t J.P., Jones C. G. 2006 – The concept
of organisms as ecosystem engineers ten years
on: progress, limitations, and challenges – Bio-
Science, 56: 203–209.
Wright J.P., Jones C.G., Flecker A.S. 2002
– An ecosystem engineer, the beaver, increases
species richness at the landscape scale – Oeco-
logia, 132: 96–101.
Zarzycki K., Trzcińska-Tacik H.,
Różański W., Szeląg Z., Wołek J., Ko-
rzeniak U. 2002 –Ecological indicator val-
ues of vascular plants of Poland – W. Szafer In-
stitute of Botany, Polish Academy of Sciences,
Kraków.
Zwolicki A., Nowakowski S. 2005 – Tamy
bobrze jako nowe i specyficzne siedlisko
roślin naczyniowych [Beaver dams as, new
and specific habitat for vascular plants]. (In:
Streszczenia referatów i plakatów 53 Zjazdu
Polskiego Towarzystwa Botanicznego [Ab-
stracts of conference papers of 53rd Congress of
Polish Botanical Society], Ed. E. Jendrzejczak)
– Toruń-Bydgoszcz, 6–11 September 2004.
Żurow sk i W. 1992 – Building activity of bea-
vers – Acta Theriol. 37: 403–411.
73
