European Beaver (Castor
(Castor fiber L.)
L.):: Objectives and
Challenges for Future Potential Projects
on Control of the Local Populations
Populations
Olgirda Belova
Institute of Forestry LRCAF
Liepu st. 1 Girionys LT-53101, Kaunas district, Lithuania,
e-mail: [email protected]; http://www.balticforestry.mi.lt
Beaver Castor fiber L. is an indispensable part of forest biota.
It is unchallenged that through dam building and feeding activities
this keystone species affects the forest and water bodies significantly.
significantly
Mass-media announced that
“…Beavers
Beavers (…)
( ) actively convert holdings of Lithuanian landowners and
foresters into the trackless areas floating fields and forests, damaging drainage
facilities and roads while their restoration will be concern of the owners
themselves. Holders off the huntingg grounds
g
ought
g to defend
f
landowners against
g
the strenuous workers. However, hunters take their time to do it because beaver
fur is not marketable (Tavorienė 2005). ..
Thus, the problem of the decrease in beaver number comes evident.
It seems that overflow draining in the beaver sites or lodge
destroying would be enough for animal retreat whereas they
move to the neighbouring sites and continued their usual
activities…
Beaver becomes a real rod in the private and state forests.
H
However,
th are favourable
there
f
bl conditions
diti
for
f the
th increase
i
in beaver number till we have abandoned lands and
drainage channels.
Although many people consider beavers as conspicuous disturbers,
from the beaver viewpoint,
p
the main disturbers are people themselves …
In Lithuania,
Beaver is not protected or rare species,
and their natural regulation is unreal today.
Beaver embraces the dual state as a keystone and conflict species.
This complex status requires to find the solution
on purpose to protect forests and preserve species in the same time
explaining to society their not only negative
but also positive features and activities
First of all, animal activity should be considered depending on the local
environmental factors (abiotic,
(abiotic biotic and human).
human)
Climatic conditions ?
Relations with other game species?
Foraging and damdam-building conditions?
Ratio of forested and open areas?
Drainage system conditions?
The structure of channel banks suitable for burrowing?
Forest edge effect?
F
Forest
t characteristics?
characteristics
h
t i ti ?
Forest management activities?
Possible changes in animal behaviour?
= there is a number of questions that are needed to be solved considering
benefits and disadvantages of beaver activities
= It stipulates the need to know beaver distribution and habitat
preferences that emerged
p
g from
the Delineation of territory for beaver.
Assessment of the beaver social formations ?
It is important to know the social structure of the local beaver population and the
main limiting abiotic factors striving to envisage possible impact on forests and
open lands.
l d
The changes in the population density affect the social structure (increase in the
mortality of juveniles, changes in the family composition and the escalation of the
relations between families).
As beavers are animals who are unable to recover the increased mortality, it is
necessary to consider the current climate anomalies
that are not frequent but in the local populations , the negative results occurred
eventually.
y
Beaver activities stimulate the concentration of predators,
predators herbivores and wild
boar in the territory of beaver sites including increase in the wolf and fox number.
Th analysis
The
l i off beaver
b
intra-population
i
l i structure
helps us to follow and foresee changes in the local population including
their distribution
The increase in the number of single animals and pairs
is the indicator of p
potential formation of the new sites and families.
The increase in family number indicates favourable living conditions
given the average three
three-year
year term of the generation.
generation
The number of young beavers
is a significant factor of the population distribution on the certain
territory.
territory
They are the most vulnerable while they find the favourable territory.
Th census off beaver
The
b
sites
it should
h ld be
b done
d
making
ki the
th roundd off the
th
hydrographical network including drainage channels and other
water bodies in the forest and outer wood.
= It will be possible on the ground of approval of the census methods
and their implementation
Striving to implement an integrated wildlife damage management strategy to
protect
p
otect forestry,
o est y, agriculture
ag cu tu e aandd other
ot e va
valuable
uab e resources
esou ces from
o da
damage
age by
beaver , the different actions should be included as technical assistance and
direct control via physical exclusion, habitat management by water level
manipulation and population management .
manipulation,
All available tools would be given careful
consideration when beaver control projects
will be planned .
The actions and their effects would be
confined
fi d to sitesite
i -specific
ifi beaverbeaver
b
-damage
d
areas.
The adverse impacts of beaver management activities on the human environment
would not be significant
significant.
Positive benefits, however, would accrue.
The action’s possible effects on human welfare and safety should be minimal.
Control methods should not compromise the safety of either the public or
individuals conducting beaver damage management.
P
Protection
i off roads,
d dams
d
on man
man--made
d impoundments,
i
d
levees,
l
andd ditches
di h andd
drainages should also enhance the protection of human welfare and safety.
Lands , wild and scenic areas, ecologically unique areas, historical sites, and other
unique physical features of the existing environment
should not be adversely
y affected.
The number of animals affected by the potential
actions is small in comparison to the total population.
Effects on wildlife and fish and their habitat
should be minimal.
There should be no significant cumulative effects resulting from the possible
projects and other actions implemented or planned.
planned
Beaver management activities should be have no negative impacts on cultural
or historical resources
All mentioned actions would be available
preparing
p
p
g the Beaver Control Regulations
g
including education of the public
and participating landholders and foresters about the best
strategies for managing beaver damage,
damage
conducting workshops and programmes on beaver damage
management and beaver ecology for civic and professional
organizations schools,
organizations,
schools landholder groups and others.
others
Financing?
= the parties concerned focusing interest not only at the national but also at
the
h European
E
level
l l
In conclusion, some essential noticed should be considered in the future projects
implementing actions for Beaver population control:
Animal resources have to be used on the ground of their annual count,
count beaver
site protection against the unfounded destroying and measures for the
improvement
p ove e t of
o feeding
eed g co
conditions.
d t o s.
The animal count should be based on the direct observations, trapping, or by
animal feeding.
The nonnon-selective catching,
catching, as the beaver age is not considered, will decrease
the number of adults and will affect the age structure and density of the local
pop lation .
population
The annual use of 15-20 % is recommended for the local population control .
The
h norm off 15%
1 % will
ill stabilize
bili the
h local
l l population
l i
while the use of 20% (including 50% of the young animals) is need in the
case of the increase in the animal number and their damage.
In the favourable habitats, the number of uncontrolled and unused population
exceeds
d th
the habitat
h bit t carrying
i capacity,
it andd the
th fear
f off the
th invasive
i
i andd
bacterial diseases increases.
The share more then 20% is not recommended as it will reduce the local
population considering their comparatively slow rotation (as 3 years).
The most suitable time is December–March for hunting, and October-March for
trapping
Beaver should be trapped on the all territory in sites of the most damage selecting
the young animals,
animals remaining the breeders and considering that only one pair will
breed.
If only one breeder will be trapped, the beaver site will remain as the
reproduction renews just in the next breeding period after the new
i t d / t
intruder/mature
young animals
i l will
ill take
t k the
th place
l
off trapped
t
d beaver.
b
When
Wh
several animals from the family will be trapped , the trapping should be
finished after the breeder will be caught .
The help came at a most seasonable time ….
Thank for your attention