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Social structure and habitat preferences of moose population in Biebrza National Park. Włodzimierz Jędrzejewski Bogumiła Jędrzejewska Tomasz Borowik Kris Hundertmark Marcin Górny. Mammal Research Institute, Polish Academy of Sciences, Białowieża - PowerPoint PPT Presentation
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Social structure and habitat preferences of moose population in Biebrza National Park
Mammal Research Institute, Polish Academy of Sciences, BiałowieżaProject: Biodiversity protection of Red Bog (Czerwone Bagno) - relic of raised bogs in Central Europe
Włodzimierz JędrzejewskiBogumiła JędrzejewskaTomasz BorowikKris HundertmarkMarcin Górny
Biebrza National Park
Biebrza Moose Data
• Observations by park personnel– group size and composition– location– date
• 1998-2010 (most from Sept. 2006-February 2010)• 1534 observations• 2770 total moose• Classified as adult male, adult female, juvenile, or calf• 2041 adults of known sex
Sexual segregation• Sexes use different areas/habitats outside of the mating season
• Common in ungulates with body-size dimorphism
– Larger difference in body size is associated with more extreme sexual segregation
• Some hypotheses (among others)
– Predator avoidance by females and calves
• Females choose less risky environments whereas males choose riskier environments to gain back
condition after breeding season
– Food selection
• Females (smaller body size) seek out high-quality forage
• Males (larger body size) seek out more abundant but more fibrous forage due to their gut
morphology
– Activity budget
• Larger-bodied males spend more time ruminating and less time feeding than
smaller-bodied females and therefore can’t synchronize movements
Moose group dynamics• Group size: mean = 1.6 (SD 1.3), range = 1—20 • Adult males: 1—11• Adult females: 1—8 • 67% of all observations are singletons (cows with calves
included)
Group type for multi-adult groupsG = 1.76, p = 0.18
Month; LS Means
Vertical bars denote 0.95 confidence intervals
1 2 3 4 5 6 7 8 9 10 11 12
Month
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
Gro
up s
ize
F = 4.68, p < 0.0001
Open Closed
Season Mean SD Mean SD t P(1-tailed)
Spring 1.89 1.33 1.79 1.14 -0.69 0.25
Summer 1.42 1.20 1.45 1.09 0.18 0.43
Fall 1.68 1.83 1.47 1.07 -1.67 0.048
Winter 1.74 1.05 1.44 0.89 -2.55 0.0055
Group size by habitat closure by season (α’ = 0.0127)
Are the sexes distributed differently across the landscape?
• Create 2041 random points within the park
• Compare with 2041 observations of adults
• Tested moose locations vs. random locations– Dispersion significantly different (p < 0.0001)
• Tested males vs. females seasonally– Šidák correction for multiple comparisons: α’ =
0.0127– Winter (21 Oct.—30 Apr.) p < 0.0001 – Spring (1 May—30 June) p = 0.011– Summer (1 July—20 Sept.) p = 0.005– Rut (21 Sept.—20 Oct.) p = 0.35
Are the sexes distributed differently across the landscape?
Social segregation
• Measured by social segregation coefficient– Varies from 0 (complete aggregation) to 1
(complete segregation)
What habitat characteristics are driving the segregation of the sexes?
• Classify observations by habitat characteristics• Account for potential location error
Forest
Meadow
100 m
• Classify observations by habitat characteristics• Account for potential location error• Characterize random points in the same manner
to represent available habitat• Randomly assign a sex to each random point• Use stepwise logistic regression to identify
factors influencing space use
What habitat characteristics are driving the segregation of the sexes?
Possible predictors
Landscape metrics• Distance to road• Distance to village• Distance to arable land• Distance to railway• Distance to forest edge• Distance to marsh/water
• Year• Season
Habitat metrics• Deciduous forest
• Coniferous forest
• Other forest
• Marsh
• Meadow
• Arable land/orchard
• Wetland (yes/no)
• Edge (yes/no)
Temporal metrics
How do moose respond to those factors?
Selection coefficients
• = (use – availability)/(use + availability)• – 1 (complete avoidance) to +1 (complete preference)
*
*
*
*
Habitat selection
* Males ≠ females
*
* *
*
*
**
*Males ≠ females
Importance of marsh to calving• 16 May-15 June• 90% of all female locations in marsh• 50% of all male locations in marsh (40% in
deciduous forest)Use
Selection during calving
What patterns are there in space use that could lead to segregation?
– Use variables identified by logistic regression– Test sex × location (random vs. observed)– Test sex × season × location
observed random
deciduousconiferous
F F MM
"Season2"*Location*Sex; LS Means
Wilks lambda=.99120, F(21, 11659.)=1.7117, p=.02232
Effective hypothesis decomposition
Vertical bars denote 0.95 confidence intervals
Location: Observed
Season2:Winter
CalvingSummer
Breed1600
1800
2000
2200
2400
2600
2800
3000
3200
3400
3600
dis
t ro
ad
Location: Random
Season2:Winter
CalvingSummer
Breed
F M
observed random
Dis
tan
ce
to
ro
ad
FM
wintercalving
summerbreeding
wintercalving
summerbreeding
"Season2"*Location*Sex; LS Means
Wilks lambda=.99120, F(21, 11659.)=1.7117, p=.02232
Effective hypothesis decomposition
Vertical bars denote 0.95 confidence intervals
Location: Observed
Season2:Winter
CalvingSummer
Breed-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
con
ifero
us
fore
st
Location: Random
Season2:Winter
CalvingSummer
Breed
F M
observed random
co
nif
ero
us
fore
st
wintercalving
summerbreeding
wintercalving
summerbreeding
FM
"Season2"*Location*Sex; LS Means
Wilks lambda=.99120, F(21, 11659.)=1.7117, p=.02232
Effective hypothesis decomposition
Vertical bars denote 0.95 confidence intervals
Location: Observed
Season2:Winter
CalvingSummer
Breed-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
de
cid
uo
us
fore
st
Location: Random
Season2:Winter
CalvingSummer
Breed
F M
observed random
de
cid
uo
us
fo
res
t
wintercalving
summerbreeding
wintercalving
summerbreeding
FM
wintercalving
summerbreeding
wintercalving
summerbreeding M
F
Dis
tan
ce
to
fo
rest
ed
ge
observed random
Conclusions
• Group size in Biebrza moose is small• Group size in open habitats is greater than in closed habitats,
particularly in winter• Mixed-sex groups are not common, males and females are equally
solitary• Moose in Biebrza segregate outside of the breeding season on a
very fine scale• In general, open habitats were avoided and forested habitats were
selected• Males have a higher preference for deciduous forest in winter and
summer and are farther from roads• Females have a higher preference for coniferous forest in winter
and are closer to roads• Females use coniferous forest more in winter than do males• Marsh habitat, although generally avoided, is very important during
the calving season
Thank you