The slides contain a summary on my research on the ''abundances and distribution of the five most preferred food species for the mountain gorilla of the Virungas''. The presentation was delivered at the University of Twente, the Faculty of Geo-Information Science and Earth Observation (ITC). It is part of a continuous follow up on the student's research - required for the successful completion of a Master of Science at ITC, NL

1. MODELLING THE ABUNDANCE AND
SPATIAL DISTRIBUTION OF MOUNTAIN
GORILLA FORAGE SPECIES IN
RWANDA
PRESENTED BY: PROVIDENCE AKAYEZU
NATURAL RESOURCES MANAGEMENT
MSC THESIS MID-TERM PRESENTATION
SUPERVISORS:
DR.I.C. VAN DUREN
DR.IR.T.A GROEN
18 NOVEMBER 2015

2.  Critically endangered mammal species
 Inhabit high altitude tropical rainforest
 Recently increased in number
 Feeding behaviour
 Main threats
INTRODUCTION
MOUNTAIN GORILLA: GORILLA BERINGEI BERINGEI

3. VEGETATION STRUCTURE ON
BISOKE VOLCANO

4. Research gaps on:
 Their abundance in each vegetation
type
 How strong is the correlation between forest
structure characteristics and their abundance
 Testing the accuracy of remote sensing
variables to predict their occurrence
 Mapping the distribution of those five plant species
RESEARCH PROBLEM
FIVE MOSTLY PREFERRED FOOD SPECIES

5.  How do gorilla forage species abundance vary within different vegetation
types?
RESEARCH OBJECTIVES, QUESTIONS & METHODS
DETERMINING THE GORILLA FOOD SPECIES ABUNDANCE
WITHIN DIFFERENT VEGETATION TYPES
DIC
Landsat-8
2015
Gorilla food
abundance
Vegetation
classes
ANOVA-test
F value, p
value
(table)

6.  What is the relationship between vegetation types and Landsat derived
vegetation indices?
ASSESSING THE RELATIONSHIP BETWEEN VEGETATION
TYPES AND REMOTE SENSING DERIVED VARIABLES
Classified
image
(vectorized)
Field
visited
locations
Landsat-8
Band reflectance
extraction
Calculate VIs
MLR
Vegetation
map

7.  How much variation is explained by the model of canopy cover and
Landsat-8 band reflectance values?
 How strong is the relationship between individual gorilla forage species
and canopy cover, stem density, tree height and dbh?
DETERMINING THE RELATIONSHIP BETWEEN GORILLA FOOD
SPECIES AND FOREST STRUCTURE CHARACTERISTICS
Band
refl.
value
Canopy
cover
Canopy
cover map
MLR
Gorilla food
species
abundance
dbh
ht
std
cc
MLR
Regression
equation,
R-sq

8.  What is the error in modelling and mapping the gorilla forage species
presence?
MODELLING THE DISTRIBUTION OF EACH OF THE FIVE GORILLA
FORAGE SPECIES
Gorilla food
species
occurrences
Predictors
ccano
py
canopy
vegetation
std
dbh
BRT
LAP
RUB
PLI
CRN
GAL
LAP
Five SD maps

9. Systematic sampling:
 At each 300 m trail distance and 100 m trail
buffer
 In total 95 (Dataset 1) samples have been
taken, and distributed inequitably in each
vegetation type
DATA COLLECTION
PLOT LOCATION
SELECTION
Study
area

10. DATA COLLECTION
SAMPLING DESIGN: CIRCULAR PLOTS (12.62 M RADIUS)
Trees: 500 sq.m plot size,
radius=12.62 m
Shrubs: 5 sq.m plot size,
radius=1.26 m
Herbs: 1sq.m plot size,
radius=0.56 m

11. DATA COLLECTED
LOCATION, CANOPY COVER, VEGETATION ABUNDANCE, STEM
DENSITY, TREE HEIGHT & DBH

12. Characteristics Dataset 1 Dataset 2
Sampling strategy Systematic sampling Random stratified sampling
Measuring gorilla food
species
Braun-Blanquet approach • Count the number of
stems
• Harvest leaves and
stems
• Measure stem
length/diameter and leaf
length
• Weigh and sun-dry them
Area covered Samples taken at the east,
centre and west of the park
Only the Karisoke
(Karisimbi~~ Bisoke
volcanoes)
Variables recorded Altitude, vegetation types,
Tree height, canopy cover,
stem density, dbh, x and y
Vegetation types, altitude,
Gorilla food densities, x and
y
DATA EXPLORATION
COMPARING DATASET 1 AND DATASET 2

13. Characteristics Dataset 1 Dataset 2
Number of plots 95 958
Vegetation samples in:
HAG-HYR 8 517
HERB 13 58
NEO 7 0
MF 18 24
ALP 5 62
SUBA 4 80
BAMB 14 33
SAV 11 0
MIMU 9 0
BR 6 164
MED 0 20
DATA EXPLORATION
COMPARING THE TWO DATASETS

14. DATA EXPLORATION
MAPPING ALL SAMPLE PLOTS LOCATIONS

15.  Check for spatial autocorrelation
 Useful variables from Karisoke:
 Gorilla food species locations and biomass (can be used for SDM)
 Vegetation types associated with each gorilla food species
 Stem densities for Hagenia abyssinica and Hypericum revolutum (can be
used for correlating gorilla food species and forest structure
characteristics)
 Complete the Thesis chapters
NEXT STEPS
HOW TO COMBINE THE TWO DATASETS?