Transcript The Short-Term Effects of Hurricane Richard on the Diet, Behaviour

The Short-Term Effects of Hurricane
Richard on the Diet, Behaviour, and
Sub-Grouping Patterns of Spider
Monkeys (Ateles geoffroyi) at Runaway
Creek Nature Reserve, Belize
Jane Champion1, Kayla Hartwell1, Mary Pavelka1,
and Hugh Notman1 & 2
1University
of Calgary and 2Athabasca University, Alberta, Canada
Hurricane Richard
• October 25, 2010
• Category 2 hurricane
• Winds up to 155 kph
• Runaway Creek
Nature Reserve
directly in path
Belize Weather Center
• $80 million (US)
damage
Runaway Creek Nature Reserve
Belize Protected Areas
RCNR
Hurricane Richard damage at RCNR
Damage assessment:
– 42.8% major damage
– 27.6% minor damage
– 29.6% no observable damage
Hurricane Iris
• Monkey River, Belize
• October 8, 2001
• Category 4 hurricane
• Top winds 230 kph
www.NOAA.com
Hurricane Iris
• 100% forest defoliation
• No fruit available for 18 months
• Diet switched to total folivory
• Increase in time spent inactive
• Decrease in social behaviour
Results
120
7
100
6
Group Size
80
5
4
60
Pop Density
3
40
2
Frugivory
20
1
0
0
Season
Number of individuals
Dramatic reduction in population density, group size, and
fruit availability/consumption
Objective of this Presentation
Document short-term effects of Hurricane
Richard on Runaway Creek Nature Reserve
spider monkey population, diet, activity,
and subgroup size and stability.
Predictions
1. Population losses
2. A change in diet, which will reflect changes in food
availability
– Lower fruit consumption
– Increase consumption of leaves and fallback foods
3. A change in activity budgets
– More time dedicated to traveling
– Less time spent in social activities
4. Reduced sub-group size
Methods
• 10 minute focal samples on adults and subadults
• Instantaneous subgroup scans every 30 minutes
• Subgroup composition changes recorded via ad libitum
sampling
• 4 months pre- and 3 months post-hurricane data used
– 35 field days during each period (70 days total)
Results: Population Changes
Group composition as of January 2011
Male
Female
Adult
Subadult Juvenile
5
2
5
13
2
6
Total individuals: 37
Infant
3
1
• All individuals accounted for in 3 months posthurricane
• 3 births between December 2010 and January 2011
Results: Diet
Mean proportion of feeding activity
0.6
*
Pre-hurricane
0.5
Post-hurricane
*
0.4
*
0.3
0.2
*
0.1
0
Flowers
•
•
•
•
Ripe Fruit
Unripe Fruit
Leaves
Taken from all instantaneous subgroup scan samples
Paired t-tests
Less ripe fruit (p<0.001)
More flowers (p=0.015), leaves (p<0.001), and unripe fruit (p<0.001)
Results: Activity
Mean proportion of activities
*
*
• Taken from all instantaneous subgroup scan samples
• Paired t-tests
• More time feeding (p=0.001), and in social activities (p=0.023)
Mean number of individuals per subgroup per day
Results: Subgroup Size
4.5
4
3.5
*
Pre-Hurricane
Post-Hurricane
3
2.5
2
1.5
1
0.5
0
• Taken from all focal and scan samples
• Paired t-tests
• Average subgroup per day decreased (p=0.026)
Mean frequency of fissions/fusions per
observation hours
Results: Subgroup Stability
*
*
• Collected ad libitum during subgroup follows
• Paired t-tests
• Both fissions (p=0.005) and fusions (p=0.014) per hour decreased
Summary of short term-effects of
the hurricane
1.
2.
3.
4.
No population losses
Evidence of dietary flexibility
Minor changes to activity budget
Evidence of grouping flexibility toward
smaller, more stable subgroups
Implications and directions for
research
• Spider monkeys more resilient to major
habitat disturbance than expected, at least in
the short-term.
• Support some of the findings reported for
Hurricanes Emily and Wilma (Rebecchini et al)
• Future research is required to examine forest
regeneration in more detail and the long-term
effects of these changes to spider monkeys
and other primate species
Acknowledgements
• Project supervisors: Mary Pavelka and Hugh
Notman
• Co-author: Kayla Hartwell
• Field support: Stevan Reneau and Gilroy Welch
• Statistical support: Dr. Tak Fung
• Natural Sciences and Engineering Research
Council of Canada, National Geographic Society,
The University of Calgary