results for the study - elephants...
TRANSCRIPT
Results for the study on “Elephant Dynamics” in Jejane
Marie Treuillier
From the 9-06-14 to the 13-08-14
I- Some details on the Sightings in that period........................................................................................... 3
1- The organisation, days of research in the Bush .................................................................................. 3
2- The proportion of identification .......................................................................................................... 4
II- Composition of the elephants population............................................................................................... 5
1- Proportion of Bulls and Cows .............................................................................................................. 5
2- The age of elephants ........................................................................................................................... 6
3- The groups’ structure .......................................................................................................................... 7
III- The estimation of the number of elephants around the reserve Jejane .......................................... 10
1- The number of sightings for each elephant seen (from the 9-06-14 to the 13-08-14) ..................... 10
2- The cumulative number of new-sightings and re-sightings .............................................................. 10
IV- The Elephant movements in Jejane ................................................................................................... 13
1- General movements around waterholes .......................................................................................... 13
2- The movements motivated or not by the other elephants ............................................................... 15
V- Tameness Indexes – level of stress of elephants .................................................................................. 16
Figure 1: Number of sightings per week, compared to the number of half-days spent in the Bush .................. 3
Figure 2: The elephants identified compared to all the elephants seen from the 9-06-14 to the 13-08-14 ...... 4
Figure 3: The proportion of identification success of elephants ......................................................................... 4
Figure 4: The proportion of Bulls and Cows identified in Jejane from the 09-06-2014 to the 13-08-2014 ........ 5
Figure 5: The proportion of Bulls and Cows identified in Jejane from the 15-04-2014 to the 08-06-2014 ........ 5
Figure 6: The proportion of Bulls and Cows identified in Jejane from the 12-02-2013 to the 23-05-2013, and
from the 15-04-2014 to the 13-08-2014 ............................................................................................................. 6
Figure 7: Number of identified elephants for each age class (in Bulls groups and Breeding Herds) .................. 6
Figure 8: The proportion of the different Classes of ages among the Bulls (in Bull groups only) ....................... 7
Figure 9: The different kinds of groups seen from the 9-06-14 to the 13-08-14 ................................................ 7
Figure 10: The composition of the groups of Bulls seen from the 9-06-14 to the 13-08-14 .............................. 8
Figure 11: The composition of the groups of Bulls seen from the 9-06-14 to the 13-08-14, in which all the
elephants have been identified, and with a "Total Count" or a "Best Guest" .................................................... 9
Figure 12: The composition of the groups of Bulls seen from the 9-06-14 to the 13-08-14, in which all the
elephants have been identified, and with a "Total Count” ................................................................................. 9
Figure 13: The total number of identified elephants seen in Jejane since the beginning of the research ....... 10
Figure 14: The number of times each elephant was seen ................................................................................ 10
Figure 15: Cumulative numbers of new-sightings and re-sightings of Bulls (or cumulative population growth)
from the 09-06-14 to the 13-08-14 ................................................................................................................... 10
Figure 16: Cumulative numbers of new-sightings and re-sightings of Bulls (or cumulative population growth)
from the 15-04-14 to the 13-08-14 ................................................................................................................... 11
Figure 17: Cumulative numbers of new-sightings and re-sightings of Bulls (or cumulative population growth)
from the 12-02-2013 to the 23-05-2013, and from the 15-04-2014 to the 13-08-2014 .................................. 12
Figure 18: The places of sightings (Bull and Breeding Herds) from the 9-06-14 to the 13-08-14 ..................... 13
Figure 19: the specific movements of Bull [6], who were seen 10 times in the 10 weeks of research ............ 14
Figure 20: the different groups of elephants in which [6] was seen from the 9-06-14 to the 13-08-14 .......... 15
Figure 21: Tameness Idexes of the identified elephants from the 9-06-14 to the 13-08-14 ............................ 16
Figure 22: the different Tameness Index remarked in each group (bulls and breeding herds), and the place
where they were seen ....................................................................................................................................... 16
I- Some details on the Sightings in that period
1- The organisation, days of research in the Bush
From the 09-06-14 to 13-08-14 (10 weeks): 53 half-days in the Bush in total (looking for elephants thanks to
game drives, bushwalks or standing in a hide), 22 different sightings, and a mean of 2,7 sightings per week.
Remark: when we see the same group in one day, it’s considered as only one sighting
Figure 1: Number of sightings per week, compared to the number of half-days spent in the Bush
We went out to look for elephants quite a lot of half-days per week, but without always getting
sightings, even if there are often foot prints on the roads: so we need to go out as often as possible!
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Research weeks
Number of sightings per week, compared to the number of half-days spent in the Bush
number of half-days in the Bush per week
number of half-days with sightings per week
2- The proportion of identification
Figure 2: The elephants identified compared to all the elephants seen from the 9-06-14 to the 13-08-14
Bulls Cows Total of elephants
Total number of elephants
seen during the 10 weeks
of research
82 19 99
number of elephants seen
and with enough pictures
to be identified
59 5 64
% of identification 72% 26% 65%
Figure 3: The proportion of identification success of elephants
Remark: 6 counts were qualified of “Total counts” (27%) and 16 were qualified of “Best Guests” (73%)
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Research weeks
The elephants identified compared to all the elepahants seen from the 9-06-14 to the 13-08-14
Total of elephants seen per week
Total of elephants with enough pictures to be identified per week
II- Composition of the elephants population 1- Proportion of Bulls and Cows
In the following results, only elephants we could identify are taken in account.
Results of Marie’s study (from the 09-06-2014 to the 13-08-2014 – 10 weeks)
Figure 4: The proportion of Bulls and Cows identified in Jejane from the 09-06-2014 to the 13-08-2014
Comparison with the results of Bo’s study (from the 15-04-2014 to the 08-06-2014 – 10 weeks)
Figure 5: The proportion of Bulls and Cows identified in Jejane from the 15-04-2014 to the 08-06-2014
Bulls 25
Cows 5
The proportion of Bulls and Cows identified in Jejane from the 09-06-
2014 to the 13-08-2014
Bulls 47
Cows 6
The proportion of Bulls and Cows identified in Jejane from the 15-04-2014 to
the 08-06-2014
Comparison to the results of all the studies (Annick, Bo and Marie) done in Jejane up to now (from the 12-
02-2013 to the 23-05-2013, and from the 15-04-2014 to the 13-08-2014 – 39 weeks)
Figure 6: The proportion of Bulls and Cows identified in Jejane from the 12-02-2013 to the 23-05-2013, and from the 15-04-2014 to the 13-08-2014
More Bulls were identified up to now in Jejane. It may be because it is a “new” area of moving for elephants
because of the recent opening of the fences toward the others reserves and the Kruger Park, and the
breeding herds need to be sure it is a safe place before to go there. They firstly need to see Bulls going and
coming back safely.
But we can see that in 2013, Annick really more breeding herd than in 2014. Maybe it is because at first, the
curiosity and attraction for the vegetation still so developed were stronger than the rest. Elephants were
coming in waves in the new area with a lot of vegetation, including Cows.
2- The age of elephants
In the following results, only elephants we could identify are taken in account.
Figure 7: Number of identified elephants for each age class (in Bulls groups and Breeding Herds)
Bulls 131 72%
Cows 50
28%
The proportion of Bulls and Cows identified in Jejane from the 12-02-2013 to the 23-05-2013, and from the 15-04-
2014 to the 13-08-2014
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< 5 years
5-10 years
10-15 years
15-20 years
20-25 years
>25 years
Number of identified elephants for each age class (in Bulls groups and Breeding Herds)
Bulls Cows
Figure 8: The proportion of the different Classes of ages among the Bulls (in Bull groups only)
Actually, we saw only quite young Bulls, because they are the more curious, the ones who don’t have a real
territory yet, who want to explore new areas such as Jejane.
3- The groups’ structure
The General structures
Figure 9: The different kinds of groups seen from the 9-06-14 to the 13-08-14
As we have already seen before, we saw only two Breeding herds, and then only Bulls, most of the time in
Groups.
We can also note that none of the Bulls were actually in musth for this period.
Size of the Bulls groups: from 2 to 13, with a mean of 5 per group
Size of the tow Breeding Herds: 10 and 7
<10 years 0
10-15 years 2
15-20 years
9
20-25 years
9
>25 years 0
The proportion of the different Classes of ages among the Bulls (in Bull groups only)
Lone Bull
2
Bulls Group 18
Breeding Herds 2
The different kinds of groups seen from the 9-06-14 to the 13-08-14
The composition of the groups of Bulls according to the different classes of age
In the following results, only elephants we could identify are taken in account.
Figure 10: The composition of the groups of Bulls seen from the 9-06-14 to the 13-08-14
On that last graph, took in account all the groups of Bulls but the problem is that we didn’t identified all the
elephants of each group, so we can’t have a so good idea of the proportion of each age class in each group.
That is why now in the following graph we just have the groups in which all the elephants were identified.
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The groups of Bulls
The composition of the groups of Bulls seen from the 9-06-14 to the 13-08-14
10-15 years 15-20 years 20-25 years
Figure 11: The composition of the groups of Bulls seen from the 9-06-14 to the 13-08-14, in which all the elephants have been identified, and with a "Total Count" or a "Best Guest"
The last graph is quite interesting but to be more accurate we need to consider only the groups in
which all the elephants were identified but then keeping only the groups we could make a “Total Count”,
that is why we now have the following graph.
Figure 12: The composition of the groups of Bulls seen from the 9-06-14 to the 13-08-14, in which all the elephants have been identified, and with a "Total Count”
So we don’t have that much data but we can say that in each groups, we have elephants of the two age
classes, the youngest ones supposing to follow and learn with the oldest maybe.
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The groups of Bulls in which all the elephants were identified, and with a "Total Count" or a "Best Count"
The composition of the groups of Bulls seen from the 9-06-14 to the 13-08-14, in which all the elephants have been identified, and with a "Total Count" or a "Best Guest"
15-20 years 20-25 years
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The groups of Bulls in which all the elephants were identified, and with a "Total Count"
The composition of the groups of Bulls seen from the 9-06-14 to the 13-08-14, in which all the elephants
have been identified, and with a "Total Count"
15-20 years 20-25 years
III- The estimation of the number of elephants around the reserve Jejane
The total number of identified elephants seen in Jejane since the beginning of the research From the 12-02-2013 to the 23-05-2013, and from the 15-04-2014 to the 13-08-2014
Bulls Cows Total
131 50 181 Figure 13: The total number of identified elephants seen in Jejane since the beginning of the research
1- The number of sightings for each elephant seen (from the 9-06-14 to the 13-
08-14)
Figure 14: The number of times each elephant was seen
2- The cumulative number of new-sightings and re-sightings
Results of Marie’s study: from the 09-06-14 to the 13-08-14 – a 10 weeks period June-August
Figure 15: Cumulative numbers of new-sightings and re-sightings of Bulls (or cumulative population growth) from the 09-06-14 to the 13-08-14
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Number of elephants concerned
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The number of times each elephant was seen
R² = 0,9514
R² = 0,8006
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Research weeks, looking for elephants
Cumulative numbers of new-sightings and re-sightings of Bulls (or cumulative population growth) from the 09-06-14 to the 13-08-14
Cumulative number of new sightings
Cumulative number of re-sightings
Log. (Cumulative number of new sightings)
Log. (Cumulative number of re-sightings)
During this period, we could identify 25 Bulls around the reserve, and we had quite a lot of re-
sightings, especially at the end. At the 8th week, we get more re-sightings than new-sightings. Also, we can
see that the polynomial line used as a model for the Cumulative number of new-sightings line is quite
accurate, and that accuracy is confirmed by the coefficient of accuracy R²=0,9514 (when R²>0,9 we can
consider that the model is quite accurate). So it means that for that closed period of 10 weeks, even if it’s a
short one, we can say that there are around 25 Bulls around the reserve, what isn’t that important then
(without forgetting the limits of the study: we couldn’t see and identify all the elephants there were in
reality).
The cumulative population growth using Bo and Marie’s results from the 15-04-2014 to the 08-06-2014 – a
19 weeks period April-August
Figure 16: Cumulative numbers of new-sightings and re-sightings of Bulls (or cumulative population growth) from the 15-04-14 to the 13-08-14
Here we can see that the graph isn’t made the same way because we take in account the number of
elephants already identified by Annick in 2013 before this 2nde period of research of 2014. So the new-
sightings are actually elephants that were not already identified before by Annick, and in the contrary, if an
elephant already identified by Annick in 2013 is seen again in 2014, it is considered as a re-sighting.
The graph here can’t really be commented like the first one because it also depends on the research
of 2013, but we can say that the new sightings are becoming quite stable.
R² = 0,9045
R² = 0,6782
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Research weeks, looking for elephants
Cumulative numbers of new-sightings and re-sightings of Bulls (or cumulative population growth) from the 15-04-14 to the 13-08-14
Cumulative number of new sightings, taking in account theelephants already identified in 2013
Cumulative number of re-sightings since Annick work, takingin account the elephants already identified in 2013
The cumulative population growth using Annick, Bo and Marie’s results from the 12-02-2013 to the 23-05-
2013, and from the 15-04-2014 to the 13-08-2014 – a 39 weeks period on February 2013-August 2014
Figure 17: Cumulative numbers of new-sightings and re-sightings of Bulls (or cumulative population growth) from the 12-02-2013 to the 23-05-2013, and from the 15-04-2014 to the 13-08-2014
Here all the results are on the same graph. We can have an idea of the evolution of the general
population of Bulls who came around Jejane from February 2013 to August 2014. But it is difficult to
comment because of the break of 47 weeks without research and elephant identifications. But apparently,
we will need a few years without break and with a method as much identic as possible for all the students to
get scientific results and to determine quite exactly the number of elephants coming to this region.
But as we said before, it is difficult to know the real number of elephants having an impact on
vegetation because they are never here together at the same time. As we said before with the first graph of
cumulative sightings we can consider there were “only” 25 Bulls in the reserve on a period of 10 weeks. And
the most part of elephants were seen only once in two years in the reserve, and it isn’t especially
representative because we are in a context of opening of the fences. That also explains why in 2013 a lot of
elephants (Bulls and Cows) were identified and then were not seen anymore. After having open the
landscape and exploring the new area, elephants don’t especially come back, or not before a long time.
R² = 0,8322
R² = 0,7112
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Research weeks
Cumulative numbers of new-sightings and re-sightings of Bulls (or cumulative population growth) from the 12-02-2013 to the 23-05-2013, and from the 15-
04-2014 to the 13-08-2014
Cumulative number of new-sightings
Cumulative number of re-sightings
Log. (Cumulative number of new-sightings)
Log. (Cumulative number of re-sightings)
IV- The Elephant movements in Jejane
1- General movements around waterholes
Figure 18: The places of sightings (Bull and Breeding Herds) from the 9-06-14 to the 13-08-14
We can see that we didn’t see that much elephants in the north, because of the thickness of the vegetation,
but also probably because there is no waterhole in the northern region. Then, we didn’t see so much
elephants swimming in waterholes because it is winter, even if they were clearly going from a water point to
another, most of the time they were walking fast toward water, drank, and then came back, without eating
so much around.
In addition, on this map we have the impression that elephants are seen more and more close to Bushcamp
from June to August. Maybe it is because they explore deeper and deeper the reserve for the ones who
maybe don’t know the area yet, but it is also possible that as the water is scarcer and dirtier in the reserve,
they are looking more for clear and fresh water of Bushcamp.
Figure 19: the specific movements of Bull [6], who were seen 10 times in the 10 weeks of research
This elephant seems to have stayed in Jejane the whole period, walking around the reserve from
waterholes to waterholes.
2- The movements motivated or not by the other elephants
Figure 20: the different groups of elephants in which [6] was seen from the 9-06-14 to the 13-08-14
Here we can see that [6] was seen in groups of different sizes, with different other elephants but
quite a lot of time with the same, thinking also to the fact that all the elephants of the group can’t always be
identified. Maybe the elephants know each other as one big group and the group doesn’t remain totally
form all the time. The distances between the members of one group can be quite long.
I could also see elephant [63] was seen with elephant [6] during this period (June to August 2014),
but they were also seen together in 2013 (during Annick’s study). So sometimes, the Bulls can stay with the
same ones for a long period. But I didn’t find that kind of result for the few other elephants I saw in common
with Annick so maybe it isn’t that often.
Finally, I also saw that elephant [66] were seen in 2013 by Annick in a mixt group, whereas I saw him
this year in 2014 in a Group of Bulls.
(tell me Glen if you are interested to get some tables that I made about the elephants seen with some of
them who was concerned by a lot a re-sightings since Annick study, because what I wrote just before are just
my few conclusions, observations that I made on those tables)
V- Tameness Indexes – level of stress of elephants
Figure 21: Tameness Idexes of the identified elephants from the 9-06-14 to the 13-08-14
The elephants don’t seem to be that stressed, and aggressive. But we can try to understand why
some of them had a Tameness Index of +3.
Figure 22: the different Tameness Index remarked in each group (bulls and breeding herds), and the place where they were seen
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Tameness Idexes of the identified elephants
Number of Bulls concerned
Nomber of Cows Concerned
We can’t really see a correlation between the area of the sightings and the Tameness Index.
So it must be other causes of an aggressive reaction, let’s study the different situations (we noted a
tameness index of +3 in 5 groups):
- Firstly it must be a factor on “individual elephant», because Subira [63] was seen twice, and we
remarked a tameness index of +3 (aggressive reaction toward the car) at each time!
- Then we noted another Tameness of +3 in the case of a Large Cow, because of the presence of
Calves to protect in the breeding herd. In addition, the other elephants of the breeding herds had
most of the time a tameness index of +2 and sometimes temporal secretion, which are a sign of
stress because of the presence of calves
- We also have the case of young bull with an aggressive reaction because we were standing. So
maybe with more studies we could prove that they are more stressed with people standing than
with the car
- We finally have the case of a group of young Bulls with only one older one with an aggressive
reaction. Maybe he wanted to show his superiority among the group.
So there can be some explanations of an aggressive reaction and stress, but not especially an influence
of the area, in the case of Jejane.