Annual Report 2006 Table of contents Annual Report 1. Brown

Transcription

Dr. Ingrid Wiesel
P. O. Box 739, 204 Ring Street, Lüderitz, Namibia
Tel.: ++264 (0)63 202114
Fax: ++264 (0)63 202114
strandwolf@iway.na
www.strandwolf.org.za
Annual Report 2006
Table of contents
Annual Report
1. Brown Hyena Movement, Behaviour and Abundance, and Implications
for their Long-term Conservation within the Diamond Mining Area
2
2. Demography in inland areas of the Sperrgebiet
17
3. Environmental Information Centre
20
4. Collaborations
a) Namibian Biodiversity Programme
20
b) University of Central Florida
20
c) Queens University, Canada
20
d) Raleigh International
20
e) University of Pretoria
20
Planned projects
Brown hyena conservation along the Orange River
21
Human wildlife conflict with spotted hyenas around the Sperrgebiet boundary
23
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Annual Report - January 2007
Brown Hyena Movement, Behaviour and Abundance, and Implications
for their Long-term Conservation within the Diamond Mining Area in the
Southern Coastal Namib Desert
INTRODUCTION
The brown hyena is a species adapted to arid living conditions and their density
is high along the Sperrgebiet coastline where they feed on Cape fur seals pups
that are born on mainland colonies or scavenge seals and other marine carrion
along the beaches. The Sperrgebiet supports four mainland seal colonies. These
provide a permanent, concentrated food source and are essential for the
maintenance of a healthy and viable brown hyena population as other food items
are scarce. Brown hyenas are the apex predators along the coast and fill the
highest trophic level in the food chain, as other large predators are absent and as
they feed and prey on marine predatory mammals. This unique predator-prey
ecosystem is influenced by new and existing land development. Prospecting
along the coast has identified mining sites at 14 diamond bearing beach deposits
(pocket beaches). The exploitation of these mines was likely to have negative
impacts on predators, as it involved improvement of roads and the establishment
of housing facilities near the coast, where the predators forage. Furthermore the
animals were suffering a habitat loss and the population was likely to be affected
by direct (e.g. road kills) and indirect mortality (e.g. lower reproductive success).
Food availability often is a limiting factor to population growth and human activity
around the food source might have negative effects on brown hyena foraging
behaviour. The disturbance of food source and habitat therefore might have
cumulative effects. Information gathered in the course of this study influences
present decision-making with regard to the exploitation of existing and future
mines.
In this study we (a) surveyed home range size, habitat use and activity
patterns through GPS telemetry of coastal brown hyenas, (b) determined
changes in behaviour through the analysis of GPS data in the area most likely
affected by mining disturbance, and (c) gained spatial information (e.g. about
location of core areas). The goal was to provide information about brown
hyena behavioural ecology and the sensitive nature of their predator-prey
ecosystem to reduce long-term threats and impacts posed by land use.
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STUDY AREA
The study area lies in the central coastal part of the Sperrgebiet. The mining
deposits stretch from Chamais Bay in the south to Van Reenen Bay in the
north (Figure 1). Site 2 was mined from 2004. Construction at Site 11&12
(Bogenfels) commenced in October 2005 and first dredging is planned for
March 2007.
Figure 1: Study area and location of seal colonies and beach deposits.
MATERIAL AND METHODS
Brown Hyena Capture
Brown hyenas were immobilised under veterinary supervision to fit them with
GPS collars. One brown hyena was fitted with a GPS collar in the area around
the Baker’s Bay seal colony in March 2004 and three brown hyenas were fitted
with GPS collars in the area around the Van Reenen Bay seal colony between
June 2005 and April 2006. The recorded GPS positions were used to calculate
home range sizes, to evaluate habitat use and to determine activity.
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BBHb1m (Halenge) was collared for 11 months, VRB1m (Django) for 5 months,
VRBHb2m (Floggy) for 3 weeks (died of old age) and VRB3m (Ray) is collared
since April 2006.
Home Range Size and Activity Pattern
Home Range Size was estimated by using the Minimum Convex Polygon
(MCP) and Adaptive Kernel Volume (AKV) methods. GPS positions of
occasional excursions out of the home range area were regarded as outliers
and excluded from analysis.
The hourly straight distance between successive GPS positions was
calculated for each hyena to determine the distance travelled during different
times of the 24 hour period (activity pattern).
Habitat Use in the Mining Area
All recorded GPS positions were used to evaluate the importance of the coast
and the seal colonies with regard to brown hyena movement and activity.
Brown Hyena Abundance and Density
Brown hyena abundance was determined in two study areas around mainland
Cape fur seal colonies (Van Reenen Bay and Baker’s Bay). A photographic
identification of natural marks was used to identify individual brown hyenas. To
obtain a definite identification, photographs of both ears and forelegs, from the
front and the side, were taken. Abundance was estimated using sightings from
systematic monitoring of the seal colonies (high effort) and using only incidental
sightings (low effort). A modified version of the Peterson estimate was used to
calculate abundance. The abundance estimates for the two coastal areas and the
home range sizes of the corresponding GPS collared brown hyenas were used to
determine the density of coastal brown hyenas per 100 km2.
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RESULTS
Brown Hyena Capture
One brown hyena was fitted with a GPS collar in the Baker’s Bay study area
in March 2004.
BBHb9m (“Halenge”)
Capture site: Baker’s Bay seal colony
Date of capture: 2 March 2004
Recovery of GPS collar: 25 March 2005
Number of GPS positions: 2529
Sex: male
Age: Age Class IV (7 – 10 years)
Contition: excellent
Home Range size (MCP): 460 km2
Status: resident male
Three male brown hyenas were fitted with GPS collars in the Bogenfels study
area since June 2005 and the results are summarised below.
VRBHb1m (“Django”)
Capture site: Van Reenen Bay seal colony
Date of capture: 21 June 2005
Recovery of GPS collar (due to injury): 7 October 2005
Sex: male
Age: Class IV (10 years)
Condition: excellent
Home range size (AKV): 870 km²
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VRBHb2m (“Floggy”)
Capture site: Van Reenen Bay seal colony
Date of capture: 25 February 2006
Recovery of GPS collar (due to death of animal): 26 March 2006
Sex: male
Age: Class IV (12 – 14 years)
Condition: poor
Home range size (AKV): 1500 km²
Status: nomadic male
VRBHb3m (“Ray”)
Capture site: Van Reenen Bay south
Date of capture: 17 April 2006
Last data download: 13 January 2007
Sex: male
Age: Class IV (7 - 9 years)
Condition: excellent
Home range size (MCP): 310 km2
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Home Range Size
Home range sizes varied significantly throughout the year (Table 1). However,
the coastal area was more frequently used at all times than the inland areas of
the home ranges. Most activity took place around the seal colonies and along
beaches (Figure 2).
MCP
in km²
Adaptive Kernel Volume (AKV) in km²
Hyena ID
Floggy
Django
Halenge
Ray
Year
Month
2006
90%
80%
70%
60%
50%
40%
30%
20%
10%
20
1500
1000
630
400
270
170
110
50
2005
All
870
510
300
190
130
80
50
30
10
2005
June
800
580
440
340
260
170
120
70
30
2005
July
660
480
330
230
160
110
60
40
10
2005
August
730
460
330
220
150
110
70
50
10
2005
September
470
230
130
80
50
30
20
10
0
2005
October
80
60
40
30
20
20
10
10
0
2004
All
360
240
150
90
60
40
20
10
0
2004
March
340
190
100
70
60
40
30
10
0
2004
April
360
240
150
100
60
40
20
10
0
2004
May
310
180
110
70
30
20
10
10
0
2004
June
400
230
130
80
60
40
20
10
10
2004
July
440
320
230
160
110
70
40
30
10
2004
August
420
310
230
170
110
70
50
20
10
2004
September
420
300
220
150
100
70
40
20
10
2004
October
350
170
100
70
50
30
20
10
0
2004
November
230
120
80
60
40
20
10
10
0
2004
December
310
150
90
70
50
30
20
10
0
2005
January
400
230
140
90
60
30
20
10
0
2006
All
90
20
10
10
0
0
0
0
0
2006
April
70
10
10
0
0
0
0
0
0
2006
May
230
70
20
10
10
0
0
0
0
2006
June
110
20
10
10
10
0
0
0
0
2006
July
20
10
10
0
0
0
0
0
0
2006
August
50
10
0
0
0
0
0
0
0
2006
October
30
10
10
0
0
0
0
0
0
2006
November
80
20
10
10
10
0
0
0
0
2006
December
80
40
20
20
10
10
0
0
0
2007
January
100
40
30
20
10
10
10
0
0
Table 1: Home range sizes and changes in there.
Two brown hyenas had clearly defined home range boundaries without any
outlying positions and it was possible to calculate their MCP home range in
addition to the AKV estimate.
6
100%
460
310
267
Figure 2: AKV home range sizes (for legend see Figure 7 & 8) in winter, spring, summer and autumn.
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Figure 3: Django’s movement direction along the coast and in inland areas.
Movement within the home ranges varied. Hyenas moved from north to south
and vice versa in coastal areas and from east to west and vice versa in inland
areas of their home range (Figure 3).
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Activity Pattern
All brown hyenas were significantly more active at night. Django was mainly
active between 19:00 and 23:00 h, Floggy between 21:00 and 05:00 h, Halenge
between 21:00 and 05:00 h and Ray between 19:00 and 08:00 h (Figure 4).
Django
Floggy
4
Distance in km
Distance in km
4
3
2
1
0
0
1
2
3
4
5
6
7
8
1
0 1 2 3 4 5 6 7 8 9 11 13 15 17 18 19 20 21 22 23
Time of day
Time of day
Halenge
Ray
4
Distance in km
Distance in km
2
0
9 12 15 17 19 20 21 23
4
3
2
1
0
3
1
3
5
7
9
12
17
Time of day
19
21
23
3
2
1
0
0 1 2 3 4 5 6 7 8 9 11 13 15 17 18 19 20 21 22 23
Time of day
Figure 4: Activity pattern (distance walked in km per time of day) for four GPS
collared brown hyenas.
Differences in monthly activity could only be analysed for three hyenas. Django
spent more time active between June and August than between September and
October. Halenge spent more time active in July and August than in June and
Ray spent more time active between November and May than between June and
October (Figure 5).
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Django
Distance in km
4
3
2
1
O
ct
ob
er
be
r
Se
pt
e
m
ug
us
t
A
Ju
ly
Ju
ne
0
Month
Halenge
Ray
4
3
Distance in km
2
1
2
1
Month
A
ug
us
t
ct
ob
e
N
r
ov
em
be
D
r
ec
em
be
r
Ja
nu
ar
y
O
Ju
ly
Ju
ne
M
ay
ay
Ju
ne
Ju
ly
A
u
Se gu
s
pt
t
em
be
r
O
ct
ob
N
ov er
em
b
D
ec er
em
be
r
Ja
nu
ar
y
M
pr
il
0
A
M
ar
ch
0
3
A
pr
il
Distance in km
4
Month
Figure 5: Monthly activity pattern for three GPS collared brown hyenas.
Halenge was more active during the day in winter and autumn than in spring and
summer. Django also spent more time active during the day in winter than in
spring, but Ray did not show any differences in activity between seasons (Figure
6).
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Django
spring
3.5
3.0
3.0
2.5
2.0
1.5
1.0
0.5
2.5
2.0
1.5
1.0
3
2
1
0
1
2
3
4
5
6
7
8
0.0
9 12 15 17 19 20 21 23
0
1
2
3
4
5
6
7
8
0
9 12 15 17 19 20 21 23
Time of day
Time of Day
Halenge
winter
Halenge
spring
Halenge
summer
Halenge
autumn
5
4
4
4
4
2
1
3
5
7
9
1
0
12 17 19 21 23
1
3
5
7
9
2
1
0
12 17 19 21 23
1
3
5
7
9
3
2
1
0
12 17 19 21 23
1
3
5
7
9
12 17 19 21 23
Time of Day
Time of Day
Time of Day
Time of Day
Ray
winter
Ray
spring
Ray
summer
Ray
autumn
3
2
1
0 1 2 3 4 5 6 7 8 9 11 13 15 17 18 19 20 21 22 23
Time of day
4
Distance in km
4
Distance in km
4
0
2
3
3
2
1
0
0 1 2 3 4 5 6 7 8 9 11 13 15 17 18 19 20 21 22 23
Time of day
4
Distance in km
1
3
Distance in km
5
Distance in km
5
3
0 1 2 3 4 5 6 7 8 9 11 13 15 17 18 19 20 21 22 23
Time of day
5
0
Distance in km
4
0.5
Distance in km
Distance in km
0.0
Floggy
autumn
Distance in km
3.5
Distance in km
Distance in km
Django
winter
3
2
1
0
0 1 2 3 4 5 6 7 8 9 11 13 15 17 18 19 20 21 22 23
Time of day
3
2
1
0
0 1 2 3 4 5 6 7 8 9 11 13 15 17 18 19 20 21 22 23
Time of day
Figure 6: Seasonal activity changes of GPS collared brown hyenas.
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Habitat Use in the Mining Area
Halenge was fitted with a GPS collar at Baker’s Bay in March 2004. The collar
dropped off in March 2005 and 2529 data points were analysed to predict the
impacts of mining activity at the Bogenfels Sites 11&12.
The results and predictions were as follows (Figure 7):
1. Result: Foraging activity is greatest at beaches and around the Baker’s Bay
seal colony
⇒ 1. Prediction for Bogenfels: Foraging activity will concentrate at Bogenfels Site
11&12 and the Van Reenen Bay seal colony
2. Result: Activity is greatest at night and dusk and dawn
⇒
2.
Prediction
for
Bogenfels:
Human-brown
hyena
encounters
will
predominately happen between sunset and sunrise.
Two of the brown hyenas that were fitted with GPS collars were resident animals,
whereas the third hyena (Floggy) is a nomadic living male and therefore excluded
for this analysis. Our predictions regarding home range size and movement from
Halenge’s data were met as follows (Figure 8):
•
Bogenfels Site 11&12, which will be mined in future, forms the main
foraging ground for resident brown hyenas
•
The Van Reenen Bay seal colony to the north is the major food source for
resident and non-resident brown hyenas
Additionally it was discovered that the fresh water spring to the east of the mining
site is visited by resident and non-resident brown hyenas on a regular basis, and
access to fresh water therefore seems to be more important than previously
thought.
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Figure 7: Prediction of habitat use in proposed mining area.
Figure 8: Verification of habitat use in proposed mining area.
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Possible implications for the mining site were identified as follows:
1. Mining disturbance at Bogenfels beach will have an influence on brown
hyena foraging activity, but enough food can be found at the Van Reenen
Bay seal colony.
2. Brown hyenas are predominately active at night (see above) and cross the
future haul-out road in east to west and vice versa direction to reach other
parts of their home range and also the fresh water spring, therefore
mitigation measures to avoid road accidents are necessary.
3. Fresh water seems to be important and brown hyenas have to cross the
future haul-out road to reach the spring to the east of the mining site.
Other conservation considerations were that human presence in the area will
attract scavengers such as brown hyenas and jackals.
Django’s movement before the construction phase of the mine had begun
showed a homogenous use of the future mining area (Figure 9).
Figure 9: Brown hyena activity in proposed mining area before commencement of
construction phase.
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Figure 10: Brown hyena activity in proposed mining area after commencement of
construction phase.
In contrast, Ray’s movement after the commencement of the construction phase
and after the accommodation site at Bogenfels was upgraded shows
concentrated movement around the camp.
Brown Hyena Abundance and Density
Brown hyena density in the Bogenfels area ranged from 1.4 to 4.3 animals per
100 km2 depending on the home range estimate method used and the size of the
corresponding home range of the individual hyena (Table 2).
Hyena
ID
Halenge
Study
area
Baker's
Bay
Django
Bogenfels
Ray
Bogenfels
Abundance
estimate
period
Method
2002 - 2004
2001 - 2002
2003 - 2004
2001 - 2002
2003 - 2004
MCP
AKV
AKV
MCP
MCP
Home
range size Clan
in km²
size
460
870
870
310
310
Density/100
km²
12.0
13.5
12.0
13.5
12.0
2.6
1.5
1.4
4.3
3.9
Table 2: Abundance and density estimates in the study areas.
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The results suggest that brown hyena density is within the normal range and not
disproportionally high compared to estimates from other studies. Factors
influencing brown hyena abundance in coastal areas of the Sperrgebiet could be
intraspecific competition, existence of times of food shortage or maintenance of
large home range sizes due to habitat constraints (e. g. existence of denning
habitat). However most activites take place in coastal areas of the hyenas’ home
ranges and hence density differs spatially within the home ranges and is high
along the coast.
CLOSING REMARKS
This study will continue for at least another four years depending on the
development of mining plans. Brown hyenas will be fitted with GPS collars until
after the mining area’s rehabilitation phase is completed.
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Demography of brown hyenas in the larger Kaukasib and Klinghardt
Mountains area in the Sperrgebiet, Namibia
INTRODUCTION
Brown hyenas are a carnivore species, which has been intensively studied in
the Kalahari ecosystem during the 70ties. In contrast to these areas, Namib
brown hyenas are apex carnivores with hardly any competitive pressure from
other carnivores. Therefore this study tries to broaden the knowledge about
brown hyenas in an undisturbed, different and unique habitat.
The inland areas of the Sperrgebiet distinguish themselves from all our other
study sites, as there is no concentrated food source such as mainland Cape
fur seal colonies nearby and therefore brown hyena density is expected to be
lower, their home ranges are expected to be larger and they are expected to
use a wider variety of food items and to depend more on density and
movement of their prey species.
The only home range estimates available for the Namib Desert of 107 km²
and 220 km² were calculated in 1986 (Goss 1986) through radio tracking
brown hyenas. The BHRP has been radio tracking brown hyenas since 1998
with similar results. The limited network of roads, the strict ban of off-road
driving and the clustered resting behaviour of brown hyenas create a bias in
these fixes, which leads to an under-representation of home range sizes. GPS
telemetry provides a solution for these problems, as we have seen after the
retrieval of our first GPS collars in February 2004 (see Annual Report 2006).
This project is a joint venture of different partners and will contribute to the
overall Succulent Karoo Ecosystem Planning (SKEP) aims, but especially to
their high priority aim of creating a Land Use Plan for the entire SKEP region
in Namibia and to carry out baseline assessment and research concerning
mammals. Brown hyenas are one of the Succulent Karoo Biome’s (SKB)
flagship species. Their occurrence within this biome is of extreme importance
but so far not well understood and researched. The Critical Ecosystem
Partnership Fund (CEPF) and the Namibian Environment Fund (NEF) already
recognized the importance of this project and already secured or provided
funding for this long-term project.
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The Sperrgebiet has just recently been declared a National Park. Brown
hyenas as a flagship species can draw a lot of attention to this unique area
and ecosystem and therefore play an important role in the development and
use of this area.
In this study we (a) survey home range/territory size, habitat use and activity
patterns through GPS telemetry of brown hyenas, (b) determine their relative
density, (c) determine true density in some areas through camera trapping
and den observations, (d) determine feeding habits and diet composition
through faeces analysis and stable isotope analysis, and (e) gain spatial
information through GPS telemetry and mapping of the study areas. The goal
is to provide demographic information about brown hyenas in inland areas of
the Sperrgebiet and to provide information about brown hyena occurrence and
relative density for the biodiversity inventory mapping and sensitivity mapping
for the entire Sperrgebiet.
RESULTS
A male brown hyena (GHb1m) was captured in the Gabusib area (SE of the
Klinghardt Mountains) on 2 December 2006. He was fitted with a GPS collar
that was programmed to take 24 GPS locations per day. The first data
download was done in January 2007, but the data has not been analysed yet.
Some interesting behavioural differences between coastal and inland hyenas
became apparent while analyzing our first data set of the male brown hyena
that was collared near the Kaukasib Fountain in 2005 and comparing it to data
retrieved from coastal study sites:
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The inland brown hyena of this study, KHb2m, showed similar activity to
Southern Kalahari brown hyenas. He spent 42.9% of his time inactive, which
corresponds to 42.6% in Kalahari hyenas. Temperatures in inland areas of the
Sperrgebiet are high during the day and brown hyenas need to rest for
thermoregulatory purposes. In contrast temperatures in coastal areas are
moderate as the prevailing south-westerly wind in summer prevents extremely
high air temperatures. Coastal brown hyenas were inactive for only 27.7% and
29.7% of the total time.
Coastal brown hyenas travelled significantly less during the 24 hour period
than the inland brown hyena. It is assumed that inland and coastal hyenas
differ in their movement and activity, mainly related to thermoregulatory
purposes and the distribution of high quality food. Coastal brown hyenas in
this study moved 15.5 to 26.4 km. The inland hyena of this study covered a
greater distance of 46.8 km, ranging from 8.2 to 91.4 km.
The energy that animals require to survive is directly related to the individual
body mass, the time spent active and the distance travelled. The mean field
metabolic rate (FMR) calculations for coastal brown hyenas were 2265
kcal/day and 2512 kcal/day, whereas the inland brown hyena had a FMR of
2861 kcal/day. A trend towards higher energy expenditure can be seen
between coastal and inland brown hyenas, and the distance travelled and
hence the time spent foraging seems to be the most determining factor.
The sample size in this study is low and several other considerations must be
taken into account to obtain reliable information about energy requirements of
brown hyenas inhabiting different habitats. The FMR might differ between
sexes or seasons and could vary with reproductive effort. The energy required
to capture prey can also influence the FMR, and the time interval between
successive GPS fixes should be short to obtain reasonable movement
estimates. Inland hyenas of the Sperrgebiet inhabiting larger home ranges,
therefore, should have higher FMR than coastal ones.
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Environmental Info Centre
The Brown Hyena Research Project’s Environmental Information Centre
moved to Kolmanskop Ghost Town near Luderitz at the beginning of February
2007. We will continue to give presentations at schools and we will improve
on information sharing with visitors.
Collaborations
Namibian Biodiversity Programme
The aim is to continue with the expansion of the Namibian Biodiversity
Database and allow the Brown Hyena Research Project (BHRP) to record
direct observations of biogeospatial data on carnivores and other taxa found
within the brown hyena study area of Sperrgebiet and feedback these to the
Namibian Biodiversity Database.
University of Central Florida
The collaboration continues and Dr. J. Roth obtained a research permit (No
971/2005) for the following reconnaissance project: Measuring allochthonous
inputs to Namib Desert food webs.
Queens University, Canada
Genetic analysis of our samples is done in collaboration with the Queens
University in Canada. Blood and tissue samples have been exported with
valid export and import permits and first results should be available in the first
half of this year.
Raleigh International
Raleigh International venturers continue to participate in the mapping project
University of Pretoria
We collaborated with Mr. Brian Kuhn. The title of his project was: A
palaeozoological and ecological approach to the collection behaviour and
taphonomic signatures of hyaenas. The first progress report was available in
December 2006.
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Planned Project 1
Brown Hyena Conservation along the Orange River
This project contributes to the overall conservation of brown hyenas in the
Sperrgebiet. The SKEP workshop held in Rosh Pinah in March 2006 identified
the need for baseline research and the proposed project will ultimately
contribute to the knowledge about brown hyenas in the Sperrgebiet that is
valuable for tourism and other development planning.
The BHRP aims to obtain extensive knowledge about the brown hyena
population in the entire Sperrgebiet. At present, the coastal area from
Hottentotsbay in the north to Chamais Bay in the south is covered, as well as
a representative inland area (co-funded by SKEP, Nedbank Go Green and
CEPF). The movement, activity and abundance of brown hyenas along the
Orange River is expected to be similar to coastal brown hyenas, as the river
presents a localized and all-year round foraging ground for resident hyenas.
Several site visits have shown that hyena signs are found along the river from
the mouth downriver to Daberas Mine and the mining personnel at the mine
reports sightings on a regular basis. Furthermore a possible denning area was
discovered near the camping site at Hohenfels, which would be a suitable
area to dart hyenas to fit them with GPS collars. The project therefore aims to
obtain the first baseline information about Orange River hyenas and also aims
to detect possible connection with the Richtersveld population to the south of
the river.
Up to date no studies on brown hyenas have been done in the Orange River
area. The brown hyena population is expected to be unique due to the
influence of marine food subsidies on beaches, large herbivore and bird
abundance as a food source along the river and the remaining desert habitat
that is poor in nutrients, but may be of other importance (e.g. suitable den site
habitat, resting site habitat, territory protection). Furthermore it is not known
whether the Namibian river population is geographically separated from the
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South African river population and the analysis of brown hyena movement
through GPS telemetry may detect such pattern.
The objectives are to obtain a first abundance estimate of Orange River
hyenas through camera trapping. Furthermore detailed movement, activity
and habitat use information will be gained through the analysis of GPS data.
The data can be used to create habitat sensitivity maps and can contribute to
brown hyena conservation through development of mitigation strategies in
connection with land use plans.
The projects’ data will contribute to the overall conservation of brown hyenas
in the Sperrgebiet by applying the data in plans for the development of the
area. This can include tourism plans and other activities.
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2623
Planned Project No. 2
Human wildlife conflict with spotted hyenas around the Sperrgebiet
boundary
This project aims to study the spotted hyena population around Garub, near
Aus. This includes, but is not limited to the following:
•
Abundance
•
Home range size
•
Movement and activity
•
Diet composition
•
Habitat use
•
Interspecific relationship with brown hyenas
•
Conflict with humans
Spotted hyenas were first reported in the Garub area at the beginning of the
1990s. It is assumed that they migrated into this area from the north, following
the game species during a period of extreme drought. Since then, incidental
sightings around the mountain Dikwillem and at the water trough at Garub
have been recorded and occurrences of spotted hyena roadkills on the tar
road between Aus and Luderitz indicate that it is a resident population.
Farmers also reported sightings of spotted hyena spoor, although it cannot be
excluded that some of these spoor were of brown hyenas. The BHRP
distributed a carnivore and livestock related questionnaire to farmers in the
buffer zone around the Sperrgebiet and Namib Naukluft Park (with CEPF
funding) in 2004. Some of the outcomes were as follows (based on the
opinions of the participants):
•
Carnivores contributed considerably to cattle, calve, sheep and goat
mortality (up to 70% of the losses)
•
Brown and spotted hyenas were considered a low threat, spotted
hyenas occasionally a high threat to livestock
•
One brown and one spotted hyena were killed on farmland in 2003
•
All carnivore related cattle losses were attributed to spotted hyenas
•
40% of the farmers would not tolerate spotted or brown hyenas on their
farms
23
2624
These results highlight the necessity to carry out a first study on the spotted
hyena population in this area and also to look at the interspecific relationship
between both hyena species.
The objectives of the project are to gain detailed data about spotted hyena
abundance and distribution, and to evaluate true conflict with humans in the
area surrounding the Parks.
The analysis of scat samples will give insight into the spotted hyena’s diet and
will provide baseline information about whether livestock is consumed. Stable
isotope analysis of hair samples of the captured hyenas, their potential prey
species and the investigation of bone material found at den sites will give
further insight into their feeding ecology.
GPS and VHF telemetry will provide data to estimate home range sizes and
the analysis of their movements will indicate the frequency of possible conflict
with humans on adjoining communal and farmland.
The brown hyena clans that have been studied by the BHRP so far, do not
interact with the spotted hyena population around Garub, and the comparison
of those brown hyena clans with the clan around Garub is of basic ecological
interest for the conservation of brown hyenas along the boundary fence of the
Sperrgebiet. Competition with spotted hyenas may either be positive, as their
predatory behaviour may provide brown hyenas with additional carrion, or
negative, as they may compete for the same niche.
Spotted hyena clan structure, foraging and hunting behaviour depends largely
on the habitat, and the Garub spotted hyenas might show a different structure
and behaviour than the ones in, for example, Etosha NP. The data obtained
with this study will allow a first comparative study with other Namibian spotted
hyena populations.
Carnivore conflict with humans often results in financial losses. Nevertheless it
is often difficult to attribute certain livestock losses to specific carnivores and
objective monitoring is therefore of major importance to be able to mitigate the
conflict. At present spotted hyenas are mostly not tolerated outside protected
areas. It is basically unknown, whether the Garub spotted hyenas really pose
a threat to livestock on adjoining farms, and their present persecution may be
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2625
without reason. The results of this study will contribute to the general
understanding of the Garub spotted hyena ecology and behaviour and will
give background data to be able to discuss conflict issues with the affected
parties.
25

Annual Report 2006 Table of contents Annual Report 1. Brown

Transcription

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