Desert Elephant Conservation Logo

 

Home

About Desert Elephants

News & Reports

Projects

Families & Clans

Study Area & History

Publications & Media

Related Links

Photo Album

Donate

Who We Are

Contact Us

News

Vision Image

2015

2014

2013

2012

2011

 

2015 Report

Desert-dwelling Elephants in the Hoarusib, Hoanib, and Uniab Rivers.

Ministry of Environment and Tourism research and collection permit #2026/2015.

Dr. Rob Roy Ramey

Dr. Laura M. Brown

Wildlife Science International, Inc.

Desert Elephant Conservation

PO Box 386

Nederland, CO 80466

USA

robroyrameyii@gmail.com

laura@desertelephantconservation.org

+1 303 718 6686 USA cell

+ 264 81 406 4040 Namibia cell


25 February 2016

1) Current status of the Hoanib and Hoarusib elephant subpopulation

As of December 2015, the number of adult desert-dwelling elephants inhabiting the lower Hoanib and Hoarusib Rivers has been reduced by approximately 30% of what it was ten years ago when we began our research (Figure 1). Just 31 remain in this subpopultion. In short, more elephants are dying due to human causes than of natural causes, and at a rate that exceeds their rate of reproduction. These ongoing losses are putting this world-renown and economically important desert-dwelling elephant subpopulation at risk of extirpation. The results below are based upon exact counts of known individual elephants from our photographic database.

Summary:

14 died of human causes:

9 shot illegally

4 shot by MET as problem animals or wounded animals

1 died of complications from radio-collar (not part of our study)

11 died from natural or unknown causes

7 disappeared with fate unknown

32 KNOWN LOSSES (2006-2015)

A total of 31 elephants remain as of December 2015, including 10 calves that have been born and survived since 2006. (See Table 1 for details.)


1.1) Hoarusib

With 6 elephants residing below Puros, and 9 in the upper Hoarusib, the total for the Hoarusib subpopulation is 15.

In the lower Hoarusib River (below Puros), just 6 elephants remain. This group is made up of:

2 females who are quite old (40+ years) and

4 male offspring (ages 8, 13, 15, and ~23).


During a reconnaissance trip in November with IRDNC to the Upper Hoarusib (Ongongo, Otjiu West, and Upper Gorge), we documented the fate of 13 out of 15 "missing" elephants known to us previously from the lower Hoarusib and Hoanib Rivers:

- Eight (8) of the “missing” elephants emigrated into the upper Hoarusib gorge above Puros, with some going as far as Ongongo. A new calf was found with this group, bringing the total in the Upper Hoarusib to 9. The composition and ages are as follows:

4 adult females (ages 13, 18, 28 and 40+),

3 calves/juveniles (ages 1, 5 and 9),

1 young bull (age 19), and 1 breeding bull (age ~28).

- Five (5) of the "missing" elephants were dead (3 illegally shot, and 2 shot by MET after elephant/human conflict).

- Two (2) "missing" elephants remain unaccounted for and are presumed dead.


Only two calves have survived in the Hoarusib River since 2008 (7 have been born, but 5 did not survive past 3 months of age). In contrast, 5 calves have been born in the Hoanib River since 2007 and all have survived.


Observations of livestock in the lower Hoarusib and Skeleton Coast Park

Large numbers of cattle (200+) were observed in the lower Hoarusib during the drought for emergency grazing. Trail camera images showed herds of cattle far into Skeleton Coast Park (within 13km of the ocean). This is a concern because we have observed that elephants generally avoid cattle and their herders (who, by the way, were not present), thus reducing available habitat for the elephants.


In addition, feral donkeys have colonized the lower Hoarusib River in Skeleton Coast Park (between the coast and the poort, 13km inland). They are also reproducing, with two foals observed.

1.2) Hoanib

In the Hoanib River west of Sesfontein there are only 16 elephants remaining:

6 breeding females (ages 15, 16, 20, 28, 40+, 40+)

8 calves/juveniles (ages 2, 3, 4, 4, 5, 5, 9, 11)

2 adult males (ages 24 and 32).

No new calves have been born since 2013.

The number of males in the lower Hoanib is alarmingly small: only 2 bulls of breeding age, and one is only in his early twenties and just had his first musth. One of the resident bulls we had known for many years (WKM-14 "Papa G") died after falling from a steep embankment, possibly during a fight with another male (as reported by MET in July 2015).

There are 5 elephants from the Hoanib that have “gone missing” over the past several years (2 adult males, and 3 subadult orphans, incuding 1 male and 2 females). It is unknown whether these individuals have emigrated or died.

During the course of our ten year study, no elephants from the upper Hoanib catchment (upstream of Khowarib Schlucht), or from the mountains north of Warmquelle (Otjomatemba area), have been documented to overlap in range with the Hoanib elephants west of Sesfontein. While there may have been historic movements between these areas, our observations and data over the past decade suggest that these are now separate subpopulations.


1.3) Combined results for the Hoarusib/Hoanib subpopulation:

Briefly, the decline of the Hoarusib and Hoanib subpopulation between 2006 and 2015 may be seen in the following numbers:

14 adult females in 2006; 12 adult females in 2015

7 breeding-age bulls in 2006; and 4 breeding-age bulls in 2015

By comparison, when Garth Owen-Smith hiked from Omutati through the Upper Hoarusib Gorge to Puros in October 1970, he observed over 80 elephants.



Figure 1. Hoarusib-Hoanib subpopulation trends from 2002 through 2015. (Data prior to 2006 are from K. Leggett.) Although one breeding bull died in 2014, there is an increase in breeding bulls as a result of 2 sub-adult males that have now reached breeding age, plus re-discovery of one breeding age male that emigrated to Upper Hoarusib. Overall however, the total number of elephants in the Hoanib and Hoarusib clans has declined from 45 in 2008, to 31 in 2015, a 30% decline over seven years. With only 4 breeding age bulls, two of whom are known offspring of clan females, there is concern that inbreeding could become a problem.

1.4) Uniab River

In the Uniab River, the desert-dwelling elephant subpopulation that primarily inhabits the Palmwag Concession Area and immediate surroundings appears to be stable. There are approximately 48 individuals in this subpopulation. (An exact number for the Uniab is pending additional analysis of photographs.). Elephants in the southern part of the Palmwag Concession tend to exhibit more defensive behaviors (skittish or aggressive), presumably due to ongoing harassment when they venture outside of the fence into settlement areas. Their future will depend upon the good will and tolerance of local people outside the concession when they encounter these elephants.

2.0) Elephant mortality documented in 2015

As mentioned earlier, a bull about 40 years old (WKM-14 "Papa G") died after falling from a steep embankment in July 2015. Staff at Wilderness Safaris Hoanib Camp reported the death to MET in Sesfontein who then investigated the scene and removed the tusks. MET staff reported that WKM-14 may have been in a fight with another male at the time he fell to his death.

Five other deaths were recorded of known individual elephants in the Upper Hoarusib, including 3 illegally shot in the vicinity of Otjiu West and Ongongo, and 2 shot by MET due to human/elephant conflict (between 2013-2015).

Also, a calf born near Ongongo in late December 2015 died within a week of birth. The cause is unknown.

Significance

The ongoing loss of elephants in Skeleton Coast National Park and western Kunene region threatens the future of this world-renown, desert-dwelling elephant population.

Not only is this population important in its own right as a part of Namibia's biodiversity heritage, but is essential to tourism, investment by conservancies and private tourism ventures, and stories in the press and documentary film productions (both of which yield tourism). If concerted effort is not applied to prevent further human-caused mortality of these desert-dwelling elephants, their fate will surely be extinction.

Table 1. Documented loss of desert-dwelling elephants in the Hoarusib and Hoanib Rivers from 2006-2015.


2006

WKF-17 shot illegally, died in Hoarusib ~1km downstream of Puros.

WKF-17a2 died from starvation after mother was illegally shot and died near Puros.

WKM-8 last seen in Hoanib in 2006, fate unknown.

WKM-11 last seen in Hoanib in 2006, fate unknown.


2008

WKF-8a3 calf born and died within 3 months in Hoarusib.

WKM-23 last seen in Hoanib in 2008, fate unknown.


2009

WKF-16a4 calf born and died within one month in Hoarusib.

WKM-10 strongly suspected of being illegally shot based on holes in carcass and fact that GPS satellite transmitter was stolen.


2010

WKF-11a1 died from unknown cause in Hoanib (near Mudorib borehole), anthrax suspected.


2011

WKF-4 ("Clarissa") died from unknown cause in Hoanib; offspring formed an orphan group and subsequently disappeared.

WKF-8 killed a tourist in Puros Campsite and then shot by MET as problem animal.

WKF-14 ("Lucy") died at Puros from unknown problem that developed under radio-collar (collared by MET in 2009).

WKF-18 ("Rosa") shot illegally in Gomatum River area, died in Hoarusib ~1km downstream of Puros.

WKF-19 died from unknown cause in Hoanib, offspring formed an orphan group and subsequently disappeared.

WKM-16 last seen in 2010, illegally shot near Otjiu West.


2012

WKF-4a3 orphaned in 2011 in the Hoanib and has not been seen since 2013.

WKF-4a5 orphaned in 2011 in the Hoanib and has not been seen since 2013.

WKF-19a1 orphaned in 2011 in the Hoanib and has not been seen since 2013.

WKM-7 ("Mr. Sneaky") shot by MET as problem animal at Puros.


2013

WKF-1 last seen in upper Hoarusib and reported by game guard as illegally shot northeast of Ongongo.

WKF-12a1 ("Bullethole's boy") illegally shot near Ongongo.

WKF-13 Illegally shot and wounded in Hoarusib upstream of Puros, alone because mother and brother were shot as problem animals, disappeared and presumed dead.

WKF-16a5 born and died within two months in Hoarusib.

WKM-3 ("Grandpa") illegally shot in Gunamib River, bullet fragments recovered from carcass in 2014 and turned over to MET.

WKM-13 ("Japie") was last seen in poor condition, died possibly of illness or old age near Hoanib Floodplain (and the bones examined in 2014 revealed worn teeth.)

WKM-26 ("Rosa's grandson") was last seen in 2011, shot by MET at Otjiu West as a problem animal for blocking road.


2014

WKF-1a2 an orphan of WKF-1, shot illegally (bullet wounds in foot) near Otjiu West, subsequently killed by MET.

WKF-7a6 born in Hoarusib and died within one month; found scavenged by hyenas.

WKF-11a2 ("Wrinklehead") died from unknown cause in Hoanib (near East President borehole), anthrax strongly suspected.

WKM-21 ("Policeman") shot by MET near Puros due to leg injury from an unknown source.


2015

WKM-14 ("Papa G") Died from fall off embankment in Hoanib.

WKF-2a3 calf born and died within a week, between Ongongo and Otjiu West.

 

Figure 2: Map of the approximate home range of Hoarusib-Hoanib (green) and Uniab (blue) elephant subpopulations. Migration routes between the Hoarusib and Hoanib are indicated by the connecting lines. Mean annual rainfall is portrayed by isoclines. These are the same subpopulations as studied by Viljoen (1987, 1988, 1989), Legett (2006), and Leggett, Brown, and Ramey (2011), with occassional, temporary movements outside these home ranges, as described by Lindeque and Lindeque (1990).

Acknowledgements

We are grateful for the information and assistance we received from the following: Ministry of Environment and Tourism; people, staff, and game guards of the Purros, Sesfontein, Torra, Anabeb, Ongongo, and Otjiu West Conservancies; Desert Lion Conservation; Rhino Rangers; Kunene Conservancies Safaris; TOSCO; Okahirongo Lodge; Ondjamba Safaris, Wilderness Safaris (the staff at Hoanib Camp and Rhino Camp); Palmwag Lodge; Khowarib Lodge; Fort Sesfontein guides; Etendeka Concession; Rivendell Lodge; W.W. Automotive; Off Road Centre; Tiger Wheel and Tyre; Into Nature Productions; Land Cruiser Club of South Africa; and Integrated Rural Development and Nature Conservation (IRDNC).


Literature Cited

Leggett, K.E.A. 2006. Home range and seasonal movement of elephants in the Kunene Region, Northwest Namibia. African Zoology. 41(1):17-36.

Leggett, K.E.A., L.M. Brown, and R.R. Ramey. 2011. Matriarchal associations and reproduction in a remnant subpopulation of desert-dwelling elephants in Namibia. Pachyderm 49:20-32.

Lindeque, M. and Lindeque, P.M. 1991. Satellite tracking of elephants in northwest Namibia. African Journal of Ecology 29:196–206.

Ramey, E.M., R.R. Ramey, L.M. Brown, and S.T. Kelley. 2013. Desert-dwelling elephants dig wells to purify drinking water. Pachyderm 53:66-72.

Viljoen, P.J. 1987. Status and past and present distribution of elephants in Kaokoveld, South West Africa/Namibia. South African Journal of Zoology 22:247-257.

Viljoen, P.J. 1988. The ecology of the desert-dwelling elephants Loxodonta africana (Blumenbach, 1797) of western Damaraland and Kaokoland. PhD. Thesis, University of Pretoria, South Africa.

Viljoen, P.J. 1989. Spatial distribution and movements of elephants (Loxodonta africana) in the northern Namib Desert region of the Kaokoveld, Southwest Africa/Namibia. South African Journal of Zoology 219:1-19.

 

 

2014 Report

 

Desert-dwelling Elephants in the Hoarusib, Hoanib, and Uniab Rivers.

 

Ministry of Environment and Tourism research and collection permit #1870/2014.

 

Dr. Rob Roy Ramey and Dr. Laura M. Brown

Wildlife Science International, Inc.

Desert Elephant Conservation

PO Box 386

Nederland, CO 80466

USA

robroyrameyii@gmail.com

laura@desertelephantconservation.org

+1 303 718 6686 USA cell

+ 264 81 406 4040 Namibia cell

 

31 January 2015

 

 

1) Current status.

The results below are based upon exact counts of known individual elephants from our photographic database.

 

Hoanib and Hoarusib subpopulation

The number of adult desert-dwelling elephants inhabiting the lower Hoanib and Hoarusib Rivers subpopulation has been reduced by approximately 30% of what it was ten years ago when we began our research (Figure 1). Ongoing adult mortality, both natural and human-caused, coupled with low rates of reproduction and survival of offspring, and emigration, have put this world renown and most studied desert-dwelling elephant subpopulation at risk of extirpation.

 

Just 6 resident elephants (only 2 breeding females with their male offspring) remain in the lower Hoarusib River and 17 elephants remain in the lower Hoanib River.

 

No calves have survived in the Hoarusib River since 2007 (four have been born but none have survived past 3 months of age). In contrast, 5 calves have been born in the Hoanib River since 2007 and all have survived.

 

Briefly, the decline of this subpopulation between 2006 and 2014 may be seen in the following numbers:

13 adult females in 2006; 11 adult females in 2014

 

7 breeding bulls in 2006 and 2 breeding bulls in 2014

 

By comparison, when Garth Owen-Smith hiked from Omutati through the Upper Hoarusib Gorge to Puros in October 1970, he observed over 80 elephants. In October 2014, we drove through the upper Hoarusib Gorge and observed zero elephants.

 

Figure 1

 

Figure 1. Hoarusib-Hoanib subpopulation trends from 2002 to 2014. Data prior to 2006 are from K. Leggett.

 

 

Uniab River

In the Uniab River, the desert-dwelling elephant subpopulation that primarily inhabits the Palmwag Concession Area and immediate surrounding area, appears to be stable. There are approximately 45 individuals in this subpopulation. (An exact number for the Uniab will be provided after analysis of photographs is complete). Elephants in the southern part of the Concession Area tend to exhibit more defensive behaviors (skittish or aggressive), presumably due to ongoing harassment when they venture outside of the fence into settlement areas. Its future will depend upon the good will and tolerance of people outside of the concession area when they encounter these elephants.

 

Elephant mortality documented in 2014

In October 2014 a 9-year old male elephant died in the Hoanib River, 1.4km downstream of the East Presidents borehole. We alerted MET about this mortality. Anthrax was suspected based on the fact that no wounds were found on the carcass and uncoagulated purple blood issued from trunk and opened body cavity beginning 2 days after death. To our knowledge, the carcass was not tested but the tusks were removed by MET. Other elephants were documented by trail camera to have visited the carcass multiple times while passing upstream or downstream.

 

A mature bull was shot by MET in September 2014 after reports from locals that the bull was injured in a fight with another bull. Although the animal was clearly wounded, residents interviewed could not identify the individual(s) who reportedly witnessed the fight between bulls. Given that the bull wounded was the only breeding bull left in the lower Hoarusib, and that no witnesses could be named, this report by Puros residents appears to be questionable.

 

Emigration

A group of former resident elephants not seen since 2012 were briefly observed and photographed near the Upper Hoarusib gorge by the tour guide, David Rey. His photograhs allowed us to identify the individuals. It is unknown where these elephants currently reside. A trip to the upper Hoarusib tributaries failed to locate this group. Reports of elephants in the upper (western) tributary remain inconclusive due to a lack of identifying photographs and description of unique individually identifying characteristics.

 

Significance

The ongoing loss of desert-dwelling elephants is having an impact on the biodiversity within Skeleton Coast National Park and the Namib Desert. This loss of biodiversity in turn affects tourism, including investment by conservancies and private tourism ventures, documentary film productions (that yield tourism), and the sustainability of this world-renown population.

 

 


2) Sources of elephant mortality and disappearance: 2006-2014.

 

Fate of adult females:

2 shot illegally (WKF-17 in 2006, WKF-18 in 2011, both found ~1km downstream of Puros)

 

1 wounded, recovered, but alone and disappeared (WKF-13, wounded upstream of Puros in 2012)

 

1 shot by MET as problem animal (WKF-8, killed a tourist in Puros Campsite in 2011)

 

1 died from unknown problem that developed under radio-collar (WKF-14, at Puros in 2011)

 

2 died from unknown causes in 2010 and 2011 (WKF-4, WKF-19 bones found in Hoanib, offspring formed an orphan group in 2011)

 

3 emigrated (WKF-1, 2, and 12 emigrated early in 2012 and were observed briefly based on photographs from upper Hoarusib in 2014 but left the area immediately after)

 

Fate of calves:

1 died after mother (WKF-17) was shot in 2006

 

5 died from unknown causes (one was found scavenged hours after death in 2014)

 

Fate of juveniles and subadults:

3 orphaned in 2011 in the Hoanib and have not been seen since 2012 (WKF-4a3, 4a5, and 19a1)

 

2 died from unknown causes but anthrax strongly suspected (WKF-11a1 in 2010, and 11a2 in 2014)

 

1 disappeared (WKF-18a1 orphaned and not seen since her mother was shot in 2011)

 

Fate of bulls 2006-2014:

2 shot illegally: WKM-3 (died in Jan. 2013, slug remains found in carcass in 2014) and WKM-10 (died in 2009; strongly suspected as being shot based on holes in carcass and fact that GPS satellite transmitter was stolen).

 

2 shot by MET: WKM-7 in 2012 as problem animal, and WKM-21 in 2014 due to injuries.

 

1 died possibly of old age or illness (WKF-13 in 2013 was last seen in poor condition, and the bones examined in 2014 revealed very worn teeth.)

 

6 unknown fates (WKM-8 last seen in 2006; WKM-11 last seen in 2005; WKM-23 last seen in 2008; WKM-16 last seen in 2010; and WKM-25 last seen in 2011; WKM-26 was last seen in 2011)

 

 

3) Elephant metapopulation structure and its significance to the conservation of desert-dwelling elephants.

Numerous published scientific papers and data have shown that elephants have a metapopulation structure. These metapopulations are composed of multiple, demographically-independent female subpopulations, that are in turn made up of clans, bond groups, and resident family groups led by elephant matriarchs (Van Aarde 2005; Van Aarde and Jackson 2007; Olivier et al. 2009; Leggett et al. 2011; Ahlering et al. 2012). Female subpopulations are linked by the movement of males among them and potential for immigration or emigration of females (although female movements appear to be very limited).  Yet despite this modern knowledge, an outdated perception persists in Namibia that elephants live in large, relatively unstructured populations and are effectively managed as such (i.e. Martin 2009).

 

There are two elephant metapopulations in Namibia: one in the Northwest (including Etosha National Park), and the other in the Northeast (including Caprivi, Khaudom, northern Botswana, and southeastern Angola).

 

This is basically what the hierarchy of a metapopulation looks like in northwestern Namibia:

 

-  Metapopulation (Northwest Namibia)

                       

- Subpopulations (e.g., Hoarusib-Hoanib; Uniab, and others...)

 

- Resident family groups (females and offspring) and resident bulls

 

In northwestern Namibia, this is an issue of some significance to the conservation and management of elephants. On the one hand, conservation of a metapopulation requires that female subpopulations be identified and managed as demographically independent groups, whereas, an unstructured, homogeneous population can be managed as a single demographic unit. Problems can arise with the decline and loss of female subpopulations if a metapopulation is managed as a unstructured population (i.e. as single demographic unit). And the problem may go unrecognized if data on density and numbers are gathered without this knowledge.

This problem is particularly acute in the western desert-dwelling elephant subpopulations. There, the Kunene River subpopulation was 26 in 1970 and extirpated (poached) by 1980.  And now, the Hoanib-Hoarusib subpopulation is at risk because of ongoing losses of elephants, coupled with low reproductive rates and mortality of adult females. Only 17 elephants remain in the Hoanib and only 6 in the Hoarusib (2 old females with their 4 male offspring). While the desert-dwelling Uniab River subpopulation (residing mainly in the Palmwag Concession Area) appears stable at approximately 45 individuals, that number, if combined with the Hoarusib and Hoanib, would mask the magnitude of the latter's decline. Similarly, recent surveys of elephants in the transitional areas (between the desert and Etosha) have produced estimates, however, those estimates will remain difficult to interpret until the underlying number and distribution of female subpopulations and family groups are determined.

The type of population structure described above is typical in elephants, as well as many other social species. It confers a survival advantage to females and their offspring through knowledge of stable home ranges, migration routes, and location of critical food and water resources during times of drought. In the desert, preservation of matriarchal females is essential so that this knowledge can be passed on to future generations of elephants, and therefore, maximize their chances of survival.

 

4) Desert-dwelling elephants are not a genetically unique species, or subspecies, however, they are a behaviorally adapted desert-dwelling ecotype, one of only two such ecotypes remaining in Africa.

It is known that desert-dwelling elephants in Namibia are not a distinct species (or subspecies) from Savannah elephants (Loxodonta africana). There is no evidence that they are genetically different from elephants that are found in transitional habitat with higher rainfall to the east. A number of male elephants have been documented to move between the western desert and the wetter areas to the east (e.g. between the Upper Hoarusib and Etosha; Leggett 2006; W. Kilian, pers. comm.), thus providing potential genetic exchange. Recently, several of these bulls have been shot or disappeared.

 

What sets these desert-dwelling elephants apart is the fact that there are well-documented resident family groups, and bulls, with relatively consistent home ranges that have learned how to live year-round in the extreme desert through behavioral adaptation rather than genetic adaptation (Viljoen 1987, 1988, 1989; Leggett 2006; Leggett et al. 2011; Ramey et al. 2013). Intelligence, long life spans, sociality, and the capacity for learning and innovation are the key behaviors that have allowed the elephants to colonize and persist in this desert. Their persistence, even in the face of extreme drought,

 

"illustrates the ultimate capacity of the African elephant to adapt to marginal conditions;"

 

and

 

"without an intimate knowledge of the location of the widely scattered water-holes and food resources it is doubtful if any elephant would survive for long in the desert. This probably explains the elephants’ reluctance to leave individual home ranges, even if more favourable conditions develop in adjacent areas." (Viljoen 1987).

 

The fact that desert-dwelling elephants have behaviorally adapted so well to the desert is underscored by the following observations: they remain in the desert even during severe drought, and persist even when livestock and other wildlife perish. No elephants in the Horusib/Hoanib/Uniab study area died as a result of drought during the extreme drought of 1976-1981 (Viljoen 1987). More recently, none perished from the 2013 drought that killed many livestock and wildlife (although one calf was documented to have died, possibly from an injury).

 

However, it is important to recognize that desert-adaptation is tenuous. We emphasize that if these elephants are extirpated, colonization of the desert by elephants from transitional areas to the east (or nearby desert-dwelling subpopulations) will be a very slow process, if it happens at all, because of the learning required to successfully survive and reproduce in the desert. It is a slow process of exploration and discovery to learn the locations of food and water during lean times, and of migration routes and navigation through the desert. If this knowledge is lost, it can only be regained through an extended process of exploration, trial and error. That process took nearly a decade to fully develop in the Hoarusib, where elephants were poached out in 1981 (Leggett et al. 2011), and may have been accelerated by recolonization by remaining elephants from the lower Hoanib. With increasing human settlement surrounding the desert and low numbers in the desert-dwelling subpopulations, such recolonizations would likely take longer in the future, if they occur at all.

 

Therefore, it is of utmost importance that conservation of desert-dwelling elephants be not simply about maintaining numbers. It must also preserve the knowledge and experience of older individuals on ways to survive in this extreme environment. That knowledge is acquired by matriarchs and dominant bulls, and passed on to their offspring. Therefore, it is imperative that adult mortality, and human-caused sources of mortality in particular, be identified and curtailed, if desert-adapted elephants are to survive into the future.

 

Ecological setting

Desert-dwelling elephants inhabit the extremely arid ecoregions of the Namib Desert and Kaokoveld Desert (Dasman 1973; Viljoen 1987; Olson et al. 2001; Linder et al. 2012; Sayre et al. 2013; Chevalier et al. 2014) and immediately adjoining areas (Viljoen 1987; Leggett et al. 2011; Figure 2). Rainfall in their home ranges averages less than 150mm per year, and elephant use is concentrated along ephemeral riverbeds and short distances outside of them (typically less than 20km, unless migrating between rivers). When the wet season arrives, longer distance movements can occur, including transient movements into transitional areas (Lindeque and Lindeque 1991; Leggett 2006; J. Cloete pers. comm.). Although Lindeque and Lindeque (1991) questioned the distinctiveness of northwestern elephant populations as described by Viljoen (1987) (i.e.  "three separate geographic groups and no contact between these groups"), we now know that limited contact does occur, and therefore Lindeque and Lindeque's (1991) observations were consistent with a contemporary view of elephant metapopulation structure (and that Viljoen's definition of no contact was too strict). In summary, desert-dwelling elephants are a collection of subpopulations in a unique ecological setting that have been linked primarily by movement of adult bulls and more rarely by the immigration or emigration of females.

 

Although resident elephants inhabiting the western Huab and Ugab were not studied by Viljoen, Leggett, or us (until recently), they should be considered desert-dwelling elephants because they exist in a similar ecological setting. These subpoulations should not be confused with elephants that primarily inhabit transitional areas to the east (i.e. farming areas). If included, this would bring the current number of desert dwelling subpopulations to four.

 

Desert dwelling elephants were not always this restricted in range and numbers. As noted previously, desert-dwelling elephants occurred along the Kunene River until they were shot out in 1980 (Viljoen 1987; Leggett et al. 2011). Archeological evidence and early reports from explorers indicate that historically, elephants occurred as far south as the lower !Khuiseb and Swakop Rivers (see Viloen 1987 for documentation of historic distribution; and Kinahan et al. 1991 and Kinahan 1996 for discussion of !Khuiseb River archeological sites). Thus, the current north-south distribution of desert dwelling elephants in Namibia is less than half of what it was before European settlement. And historical accounts of elephant numbers, compared to current estimates, indicate an even steeper decline.

 

The only other desert-dwelling elephants are found in Mali and those elephants are currently at risk because of a civil war occurring there.

 

The significance of a metapopulation structure is threefold:

First, the demographic trends in subpopulations may be different due to local conditions: some subpopulations may be increasing, while others are decreasing, for entirely different reasons that are related to local conditions. Therefore, if one were to only look at the overall trend across the entire metapopulation (i.e. the entire Northwest), local differences and their causes affecting subpopulations (i.e. Hoarusib-Hoanib, Uniab, Huab, or Ugab), would be missed.

Second, subpopulations do not necessarily overlap human political jurisdictions such as conservancy boundaries. That means that there will be shared responsibility for the conservation and management of specific subpopulations among jurisdictions. For example, the range of the Hoarusib-Hoanib subpopulation includes the Purros and Sesfontein conservancies, as well as Skeleton Coast Park and northern Palmwag concession area. And in that subpopulation, most of the elephant mortality has occurred in the Puros conservancy. The Uniab subpopulation primarily inhabits the Palmwag and Etendeka concessions, but also ranges into parts of Torra Conservancy and the Skeleton Coast Park. Simply put, a problem with loss of elephants in one area can have demographic implications for more than one jurisdiction, and consequent loss of income for conservancies that depend upon them.

And third, with the loss of so many bulls from the desert-dwelling subpopulations, and increasing human settlement on the eastern edge of the desert, there is a growing risk that there are not enough number of bulls to breed the remaining female elephants. What bulls are there may be closely-related, therefore, inbreeding is a potential problem.

 

Figure 2

 


Acknowledgements

We are grateful for the information and assistance we received from the following: Ministry of Environment and Tourism, Purros and Sesfontein Conservancies, Desert Lion Conservation, Kunene Conservancies Safaris, TOSCO, Okahirongo Lodge, Ondjamba Safaris, Wilderness Safaris (the staff at Rhino Camp and Hoanib Camp), Palmwag Lodge, Rivendell Lodge, W.W. Automotive, Off Road Centre, and Integrated Rural Development and Nature Conservation (IRDNC).

 

 

Literature Cited

 

Ahlering, M.A. L.S. Eggert, D. Western, A. Estes, L. Munishi, R. Fleischer, M. Roberts, J. Maldonado. 2012. Identifying source populations and genetic structure for savannah elephants in human-dominated landscapes and protected areas in the Kenya-Tanzania borderlands. PLoS ONE 7(12): e52288. doi:10.1371/journal.pone.0052288.

 

Chevalier, M., R. Cheddadi, and B.M. Chase. 2014. CREST (Climate REconstruction SofTware): a probability density function (PDF)-based quantitative climate reconstruction method. Climate of the Past 10:2081-2098.

 

Dasman, R. 1973. A system for defining and classifying natural regions for purposes of conservation. IUCN Occasional Paper No. 7. International Union for the Conservation of Nature and Natural Resources. Morges Switzerland. 55 pages.

 

Kinahan, J. 1996. Human and domestic animal tracks in an archaeological lagoon deposit on the coast of Namibia. The South African Archaeological Bulletin 51(164):94-98.

 

Kinahan, J., Pallet, J.,Vogel, J.Ward, J. and M. Lindeque. 1991. The occurrence and dating of elephant tracks in the silt deposits of the lower !Khuiseb River, Namibia. Cimbebasia 13:37-43.

 

Leggett, K.E.A. 2006. Home range and seasonal movement of elephants in the Kunene Region, Northwest Namibia. African Zoology. 41(1):17-36.

 

Lindeque, M. and Lindeque, P.M. 1991. Satellite tracking of elephants in northwest Namibia. African Journal of Ecology 29:196–206.

 

Leggett, K.E.A., L.M. Brown, and R.R. Ramey. 2011. Matriarchal associations and reproduction in a remnant subpopulation of desert-dwelling elephants in Namibia. Pachyderm 49:20-32.

 

Linder, H.P., H.M. de Klerk, J. Born, N.D. Burgess, J. Fjeldsa, and C. Rahbek. 2012. The partitioning of Africa: statistically defined biogeographical regions in sub-Saharan Africa. Journal of Biogeography 39:1189-1205.

 

Martin, R.B. 2009. The elephants of north-western Namibia: Options for management. Unpublished report. 81 pages.

 

Olivier, P.I., R.J. Van Aarde and S.M. Ferreira. 2009. Support for a metapopulation structure among mammals. Mammal Review 39(3):178-192.

 

Olson, D.M., E. Dinerstein, E. D. Wikramanayake, N.D. Burgess, G.V.N. Powell,

E.C. Underwood, J.A. D’amico, I. Itoua, H.E. Strand, J.C. Morrison, C.J. Loucks, T.F. Allnutt, T.H. Ricketts, Y.Kura, J.F. Lamoreux, W.W. Wettengel, P. Hedao, and K.R. Kassem. 2001. Terrestrial Ecoregions of the World: A New Map of Life on Earth. Bioscience 51(11):933-938.

 

Ramey, E.M., R.R. Ramey, L.M. Brown, and S.T. Kelley. 2013. Desert-dwelling elephants dig wells to purify drinking water. Pachyderm 53:66-72.

 

Sayre, R., P. Comer, J. Hak, C. Josse, J. Bow, H. Warner, M. Larwanou, E. Kelbessa, T. Bekele, H. Kahl, R. Amena, R. Andriamasimanana, T. Ba, L. Benson, T. Boucher, M. Brown, J. Cress, O. Dassering, B. Friesen, F. Gachathi, S. Houcine, M. Keita, E. Khamala, D. Marangu, F. Mokua, B. Morou, L. Mucina, S. Mugisha, E. Mwavu, M. Rutherford, P. Sanou, S. Syampungani, B. Tomor, A. Vall, J. Vande Weghe, E. Wangui, and L. Waruingi. 2013. A New Map of Standardized Terrestrial Ecosystems of Africa. Washington, DC: Association of American Geographers. 24 pages.

 

Van Aarde, R.J. 2005. Assessment of seasonal home-range use by elephants across Southern Africa’s seven elephant clusters. Unpublished report. Conservation Ecology Research Unit Department of Zoology& Entomology, University of Pretoria, Pretoria, South Africa.

 

Van Aarde, R.J. and T.P. Jackson. 2007. Megaparks for metapopulations: Addressing the causes of locally high elephant numbers in southern Africa. Biological Conservation 134:289-297.

 

Viljoen, P.J. 1987. Status and past and present distribution of elephants in Kaokoveld, South West Africa/Namibia. South African Journal of Zoology 22:247-257.

 

Viljoen, P.J. 1988. The ecology of the desert-dwelling elephants Loxodonta africana (Blumenbach, 1797) of western Damaraland and Kaokoland. PhD. Thesis, University of Pretoria, South Africa.

 

Viljoen, P.J. 1989. Spatial distribution and movements of elephants (Loxodonta africana) in the northern Namib Desert region of the Kaokoveld, Southwest Africa/Namibia. South African Journal of Zoology 219:1-19.

 

2013 Report

2013 Research Report

Update on Desert Elephants in the Hoarusib, Hoanib, and Uniab Rivers.

1) Population Status

Summary
The decline of the elephant subpopulations in the western desert continues. There are fewer elephants in the study area than when Viljoen (1988) documented their numbers at the height of poaching and drought during the war years of the early 1980’s. The major contributing factor has been the ongoing mortality and disappearance of adult elephants, and a very low reproductive rate. These elephants are one of only two desert-dwelling populations in Africa (the other is in Mali), and have been an important draw for tourists to the Puros, Sesfontein, and Anabeb Conservancies, and the Palmwag Concession area.

Results and Discussion
As of December 2013, the number of female elephants in the Hoarusib River has gone down again.  Only two adult females remain in the once popular area of the river below Puros.  One female (WKF-13), who had a wound in her left rear in 2012 but recovered, has been missing since September 2013.  She was, according to a lodge owner in the Hoarusib, the last of the elephants that migrated annually from the Kunene, until that migration ceased in 1990 (when the remaining family groups along the lower Kunene River were poached out). She was the sole survivor of her family group, and never produced a calf.  After her mother (WKF-8) was shot in 2011, she remained mostly alone, a condition that is very unnatural for female elephants and which may have contributed to her disappearance.

The two remaining females (WKF-7 and WKF-16 “Left Fang”) have only male offspring surviving, so after these females pass on, there will be no female lineage to carry-on the Hoarusib clan.  On 11 August 2013, WKF-16 gave birth to a male calf, but it died a couple months later according to local Puros guides, possibly from a foot injury sustained from very long treks through the mountains.

Also, in response to the drought, a large number of cattle (200-300) were utilizing the permanent water in the lower Hoarusib, into Skeleton Coast Park. Donkeys were also observed in the riverbed, deep within the Park and just 13 km from the coast.  If the cattle are allowed to persist in the river, it is unlikely that elephants will re-colonize this narrow riverbed. By comparison, in 2006 there were eight resident breeding female elephants (with 7 young) in the Hoarusib, several transient bulls, and the dominant adult male WKM-10.

It is also very important to note that the upper Hoarusib gorge, 25 km upstream of Puros, no longer has resident elephants, and the remaining family group of elephants in the lower Hoarusib no longer migrate through there into the upper Hoarusib drainage.  Moreover, local residents in the villages along the road C3707 between Orupembe and Opuwo reported to us that no elephants have been seen in that area for years, and no sign was found by us, which means the lower Hoarusib elephants no longer migrate into the upper Hoarusib basin during the wet season (above Otjiu West) as they had in years past.

The total number of resident elephants in the lower Hoarusib at the end of 2013 was just six total: 2 adult females, 3 juvenile males, and 1 bull (WKM-15).
The fates of elephants lost in the Hoarusib River in recent years are as follows:
WKF-13  disappeared in 2013, presumed dead.
WKF-18  died of bullet wounds, just downstream of Puros, in June 2011.
WKF-8    shot by MET as a problem animal after death of tourist at Puros camp in 2011.
WKF-14  died of unknown cause at Puros in June 2011 (collared by MET in 2009).
WKF-12  disappeared and not seen since 2008.  Presumed dead.
WKF-17  died of infection from bullet wounds, just downstream of Puros, in 2006.
WKM-10 died of apparent bullet wounds downstream of Puros in December 2009.

None of the offspring of the deceased females have survived, except for the family of WKF-14, who now stay almost entirely in the Hoanib River.

In the Hoanib River, west of Sesfontein, there are only six breeding females, as of December 2013 (WKF-11, WKF-3, WKF-21, WKF-15, WKF-20, WKF-22.) This number is down from eight in 2007. A male calf was born to a 14 year-old first-time mother (WKF-22) in October 2013, making nine offspring, plus the six females, a total of 15 in the breeding herd of the Hoanib.

An orphan group of three adolescents (WKF-4/a3, WKF-4/a5, WKF-19/a1) that was in the Hoanib in 2011 and 2012 was not seen in 2013. They were the offspring of the well-known family group led by the matriarch "Clarissa" (WKF-4) who died of unknown cause in 2011. The three orphans went missing in 2013, and despite an enormous amount of searching on our part they were not located. It is unknown whether they have died, but no sightings have been reported for almost a year.

Two of the oldest bulls in the Hoanib also died in 2013.   The short-legged “Grandpa” (WKM-3), who was an iconic one-tusked old bull, was found dead in January 2013 near the junction of the Gunamib and Hoanib rivers.  It was presumed that he had died of starvation from loss of teeth (a condition of old age), however, further analysis of the carcass and teeth revealed that they were still in good condition and his stomach had been full at the time of death, so starvation / old age / tooth loss was not the cause.  The cause of death remains unknown.

The other old bull of the Hoanib, “Japie” (WKM-13), was missing as of December 2013, and in May 2014 a carcass matching his description was reported near the floodplain.  No tusks were present at the very decayed carcass, and cause of death remains unknown.
There are now only four resident bulls in the Hoanib: WKM-14, WKM-21, WKM-20 and WKM-6.

The total number of resident elephants at the end of 2013 was: 6 adult females, 9 juveniles and calves, and 4 bulls (19 total).

The following is known about the fate of the adult elephants lost in the Hoanib River in recent years:
- WKF-4  “Clarissa” disappeared in 2011, presumed dead.  Skull located in 2013.
- WKF-19  (adult female in Clarissa's group) disappeared in 2011. We discovered in November 2013 that a female elephant skull that was collected around that time by Sesfontein residents now resides at Camel Top campsite near Sesfontein. It presumably belongs to WKF-19.
- WKF-4/a3, WKF-4/a5, WKF-19/a1 (the orphans of WKF-4 and WKF-19) have been missing since early 2013.
- WKF-11/a1 (oldest daughter of WKF-11) died of unknown cause in 2010 near Mudorib borehole.
- WKF-1 and WKF-2 have not been seen since January 2012. Although their whereabouts are not known, this family group used to periodically leave the Hoanib and return after several months (the only family group known to do this). They were not seen in 2013.
- WKM-3  “Grandpa” died in January 2013 near Gunamib/Hoanib junction; cause unknown.
- WKM-13  “Japie” disappeared in 2012 and a decomposed carcass fitting his age and description was discovered on the north bank of the floodplain in May 2014.  The tusks were not with the carcass. Cause of death is unknown (we observed from his carcass that he died with a full set of teeth and a full stomach, so old age and starvation can be ruled out.)

 

In the Uniab River drainage, a concerted effort was made to census elephants in the Palmwag concession in November-December 2013.  The resulting total was 44 elephants, mostly females and young in five family groups.  We are currently compiling a book of individual identifications from photographs, but the general family group composition is as follows:

Kawaxab group A = 12
adult females = 5
juveniles = 3
calves = 2
adult males = 2 (one in musth)

Kawaxab group B = 7
adult females = 3
juveniles = 1 (male)
calves = 1
young males = 2

Uniab Group A = 8
adult females = 4
juveniles = 2 (one female + one male)
calves = 1
young males = 1

Uniab group B = 12
adult females = 7
juveniles = 3
calves = 2

Mrs. Floppy Ear group = 5 (from Johan Cloete, guide at Rhino Camp)
adult females = 1
juveniles = 2
calves = 2

It is important to note that the ratio of adult females to adult males is highly skewed in this drainage, with 20 adult females to only 2 adult bulls (plus 3 sub-adult males). 

Palmwag Pool Bar Bull:  On 3 December 2013 a resident bull about 30 years of age, that was frequently seen coming into the lodge area and campsite at Palmwag, was observed to have six coils of heavy wire wrapped tightly around his rear leg, with a couple of meters of wire trailing.  MET was alerted and a retired veterinarian was sent to dart the animal and remove the wire. (The MET staff veterinarians were unavailable at the time.)  The bull went down on his brisket and died of asphyxiation during the darting.

 

Figure 1. Mortalities of adult (reproductive age) female elephants in the Hoarusib and Hoanib Rivers from 2006 - 2012. The degree of association is indicated by line thickness (six family groups were resident in 2009).

We have documented the loss of 10 breeding females from the Hoarusib/Hoanib subpopulation who died or disappeared (three were shot, 4 died of unknown cause, and 3 missing/presumed dead).

The total number of females and young in the Hoarusib and Hoanib has declined from 33 in 2009, to 31 in 2011, and is now only 20 as of December 2013, with the majority residing in the Hoanib.  The number of mature bulls has also declined from 10 in 2009, to 8 in 2011, to now only 5 in 2013.

The total population number in the study area (Hoarusib/Hoanib/Uniab) have declined as follows:
1980 (Viljoen) = 86 elephants; 1983 (Viljoen) = 70 elephants; 2009 = 74 elephants; and 2012 = 64 elephants; 2013 = 69 elephants (although this current number is skewed towards younger, non-reproductive elephants).

 

Morbidity and mortality in 2012-2013
One "problem" bull was shot at Puros in October 2012. This was male WKM-7.
The oldest bull elephant of the Hoanib, WKM-3, died in the Gunamib in December 2012. The cause of death is unknown, but it is estimated that he was close to 50 years old. Another old bull, WKM-13, was missing in 2013 and his carcass was reported in May 2014.

A female in the Hoarusib (WKF-13) who was wounded in 2012 went missing in 2013 and has not been seen since. Two skulls were located in 2013 in the Hoanib and are presumed to be from two missing females (WKF-4 and WKF-19) who went missing in 2011.

Births in 2012-2013
One female calf was born in the Hoanib in 2012 and a male calf was born in the Hoanib in October 2013. (Another male calf born in the Hoarusib in August 2013 died after 2 months.) These births are inadequate to make up for adult/juvenile losses. Long intervals between calves (~8 years) in the desert population, and a higher rate of calf mortality (~60 %) compared to elephant populations in Etosha, limit the natural recruitment of offspring into the breeding population.

Prospects
There has been no immigration into this population. Fewer females in the Hoarusib and Hoanib Rivers also translate to fewer bulls in residence, and therefore, fewer opportunities for elephant viewing. Additionally, increased cattle grazing in the Hoarusib downriver of Puros to Leylands Drift, along with fewer elephants and the loss of resident lions in 2010, has resulted in tour guides now avoiding the area. Fewer tourists to a conservancy means reduced income to a model conservancy that has traditionally drawn substantial tourism to its desert elephants and lions.

The downward trend in the Hoarusib and Hoanib Rivers can only be reversed in two ways: 1) stop adult mortality, 2) eliminate sources of human-elephant conflict that have led to mortalities (particularly in the Hoarusib).  It may also be timely to consider the potential for an experimental translocation of family group(s) from a nearby transitional area (e.g. Khorixas) to augment the desert-dwelling population.

Motorcycles in the Hoanib:
On November 18, 2013 at 1155hrs, just downstream of the Obias, a group of 9 motorcycles and two chase cars came up the Hoanib River while we were observing WKF-22's family group with its new calf. The elephants became very agitated as the loud rumble from the motorcycles came upriver and passed. We later observed that the motorcycle tracks were all over the riverbed and seemed to specifically avoid the 4x4 vehicle track. 

Motorcycles pose a severe hazard to elephants and people in the Hoanib, as well as other rivers with elephants. This hazard extends to tourists, guides, and local people who may encounter elephants after they have been recently agitated by motorcycles.  Additionally, with motorcycles riding uncontrolled in the riverbed, a violent encounter between a motorcyclist and elephant seems inevitable. With so few elephants remaining in the Hoarusib and Hoanib Rivers, it would be an unnecessary tragedy for the loss of human life and any additional losses of elephants to occur as a result of motorcycle tours. For these same reasons, motorcycle tours are not allowed in Namibia's National Parks.

Scientific publications resulting from this research
In 2013 we published our third paper, Desert-dwelling African elephants (Loxodonta africana) in Namibia dig wells to purify drinking water, in the scientific journal Pachyderm (The Journal of the African Elephant, African Rhino and Asian Rhino Specialist Groups). Our two previous research papers included: Matriarchal associations and reproduction in a remnant subpopulation of desert-dwelling elephants in Namibia (Leggett, Brown, and Ramey 2011) and Evolution of mammals and their gut microbes (Ley et al. 2008).

 

Acknowledgements
We are grateful for the sharing of information and assistance we received from the following: Ministry of Environment and Tourism, Purros and Sesfontein Conservancies, Desert Lion Conservation, Kunene Conservancy Safaris, Okahirongo Lodge, Ondjamba Safaris, Wilderness Safaris (the staff at Rhino Camp, Hoanib Camp, and Palmwag), IRDNC, Aqua Services & Engineering, DG Ecological Consulting, and Namibia Nature Foundation.

 

Literature Cited

Leggett, K.E.A., L.M. Brown, and R.R. Ramey (2011) Matriarchal associations and reproduction in a remnant subpopulation of desert-dwelling elephants in Namibia. Pachyderm 49:20-32.

Ley, R.E. M. Hamady, C. Lozupone, P. Turnbaugh, R.R. Ramey, S. Bircher, M.L. Schlegel, T.A. Tucker, M.D. Schrenzel, R. Knight, and J.I. Gordon (2008) Evolution of mammals and their gut microbes. Science 320:1647-1651.

Ramey, E.M., R.R. Ramey, L.M. Brown, and S.T. Kelley (2013) Desert-dwelling elephants dig wells to purify drinking water. Pachyderm 53:66-72.

Viljoen, P.J. (1988) The ecology of the desert-dwelling elephants Loxodonta africana (Blumenbach, 1797) of western Damaraland and Kaokoland. PhD. Thesis, University of Pretoria, South Africa.

 

 

2012 Report

24 October 2012

We filmed an elephant calf being born in the Hoanib River, a miraculous experience that few ever get to see. We will post photos and more info when we have a better connection.

23 October 2012

Report from the Hoarusib River, Namibia.

We (Rob and Laura) arrived in Namibia on the evening of 15 October and spent 3 days in Windhoek sorting out the well-worn Land Cruiser, buying food for a month in the bush, and loading it all into the vehicle. Repairs had been done to the Land Cruiser while we were away, and it was running pretty good, but then a fuel leak was discovered which delayed departure for an additional day. Many thanks are due to Debbie Gibson and Colin Craig for their generous hospitality in Windhoek.

From Windhoek to Purros is about 800 km (~500 miles), a grueling 2-day drive in 90-degree heat (with no air conditioning) over rugged roads.  Finally, on the evening of 20 October we pulled into Purros, in the Hoarusib valley, where we immediately investigated a report that a male elephant had been shot the day before by MET (Ministry of Environment and Tourism). According to the locals, the young bull had become a problem in the village, so MET was called to assess the situation. As the young bull apparently could not be scared off and was considered aggressive, he was shot.

All that remained of the carcass was skin (the meat and bones had been hauled away and donated to another village in need) but one ear remained from which we were able to determine the identity of the elephant. He was a young bull we knew as M7, or “Mr. Sneaky”, about 18 years old, and the son of the tuskless female, F8, who was shot by MET in 2011. F8 was also considered a problem animal after she allegedly killed a tourist in the Purros campsite.  M7 had been collared by MET in 2010 for a mark-resight study of the Kunene population.

M7 Carcass Ear

M7 Carcass Ear

We had had a number of interactions with M7 over the past few years, as he was curious and more than once had come up to our vehicle to check us out. One time, in 2008, while we were sitting quietly watching the elephants, he came over and sniffed our tires with his trunk, then gently tapped his tusks on the hood of the car. He pulled back abruptly at the sound, and quickly felt his tusks with his trunk, making sure they were ok. Another time, when we were napping in the car with our feet out the windows, he snuck up alongside the car in the dark. Just as he was reaching out his trunk to sniff Rob’s bare feet, Rob bolted awake, giving a fright to humans and elephant alike. M7 was never aggressive with us, just curious, and unfortunately for him, not afraid of people or vehicles.  But for the local people who travel mostly on foot and live in mud and wattle houses, an elephant wandering around at night can be frightening, even if he means no harm.  Although we have the luxury of traveling in the relative protection of a vehicle by day, we know the feeling of vulnerability when lying in a nylon tent at night hearing the heavy footfalls of elephants coming close, and the sound of branches being snapped off.

The sad reality is that animals like elephants and lions can bring tourists and their dollars to a region, but it’s the local people who must live on a daily basis with the potential danger these animals pose.  Finding the right balance is not easy.

Now that F8 and M7 are gone, there remains just one elephant in this family. She is known as F13, and is also tuskless like her mother. We heard from the Purros locals that F13 was in the lower region of the Hoarusib, alone, and had a nasty wound on her backside.  The cause of the wound was unknown, but according to one local, possibly a bullet. After much searching through dense thickets, we found her down river below Leyland Drift, on her own.  Her wound is now abscessed (about 6-8 inches in diameter and 1-2 inches in height), and weeping green pus. Photos were emailed to the veterinarian in Etosha to determine whether there is a need for treatment. Hopefully F13 will recover and join up with other elephants, like she did in 2011 after the death of her mother. We noticed for the first time that F13 has one white/blue eye, which is unusual.  It is not known whether she has always had this, or if it is recent and indicates a possible malady. Old photos will be consulted.

F13 White Eye....... F13 with wound

F13 White Eye
F13 with wound

A second family of Hoarusib elephants, led by “Fanny” (F7) and “Left Fang” (F16), were found in the lower Hoarusib River below Purros. With them were their offspring: Fanny’s two juvenile males (7/a4 and 7/a5), and “Yabo” (M9) the teenage son of Left Fang.  All 5 looked healthy, and Left Fang appears to be pregnant. This family group is resident in the Hoarusib, and seen regularly. They have a route through the mountains that makes a detour around Purros.

F16 Left Fang

F16 Left Fang

A third family of resident Hoarusib elephants, “Rosa’s” family, have been wiped out or disappeared. Rosa, who was one of the stars of Martin Colbeck’s BBC film “Elephant Nomads,” was shot by persons unknown and died in the Hoarusib in 2011. Her oldest daughter (F17) also died in the Hoarusib back in 2006, after being shot through the trunk and dying of infection. At that time Rosa adopted both of her grandsons (17/a1 and 17/a2), but a2, less than a year old, was not able to thrive without mother’s milk and soon died. The older son, 17/a1, was seen by us in 2011, after Rosa’s death, tagging along with Fanny and Left Fang’s group.  This year he is no longer with them and has not yet been seen by us. Nor have we had any sightings of Rosa’s second daughter (18/a2) since Rosa’s death a year ago.  Rosa’s companion “Bullethole” (F12), has also not been seen by us in a few years, but she may be in the Upper Hoarusib River area that she and Rosa used to frequent.

At this time, there remain just 7 elephants in the Hoarusib River at Purros and below: Fanny and Left Fang’s group (total of 5), an adult male “Slit Ear” (M15) who is Fanny’s oldest son and now independent, and the tuskless female F13. There are 2 family groups that migrate between the Hoanib and Hoarusib, but according to the locals, they have not been seen in the Hoarusib since 2011.

2011 Report

Recent mortality in the Hoarusib-Hoanib elephant population:

In 2011, five adult females were lost (died or disappeared) from the Hoarusib-Hoanib elephant population. In 2010, one sub-adult female (not yet reproductive) also died. A total of 11 reproductive adult females remain. The total number of adult females and dependent offspring was 31, compared to 33 in December 2009. We observed a total of eight adult bulls, all of which were known to us. Additional focused educational and conservation efforts will be needed to prevent further mortality, especially mortality of females which are critical to maintaining the viability of this population. With the recent loss of females, the conclusions of our recent publication on this population applies more than ever: “The combination of past poaching and a severe desert environment underscore the need to reduce female mortality, whether it is from human-elephant conflict, poaching or disease.”

2011 mortalities:

1) In June 2011, WKF-14 (Western Kunene Female 14, aka “Lucy”), the matriarch of the largest Hoanib-Hoarusib migratory family group, died along the Hoarusib River approximately 200m north of Purros. The sex of this animal was erroneously reported as male, but further investigation determined otherwise. WKF-14's radio collar was functioning, so MET will have the data on her movements prior to death, that could help reveal a cause of death.

2) In August 2011, WKF-8 was shot by MET as a problem animal after allegedly killing a tourist at the Purros Conservancy Campsite.

3) In September 2011, an adult female elephant (WKF-18 as determined from ear photographs) died of gunshot wounds in the Hoarusib River approximately 3km downstream of Purros. This female died in the same location (within approximately 50m) where a dominant bull (WKM-10) died in December 2009 of suspected gunshot wounds. In 2006, this adult female had nursed the orphan calf of WKF-17 (her daughter, based on DNA data). That calf subsequently perished, and WKF-18 was last seen by us in 2009 upstream of the Upper Hoarusib Gorge. It is therefore possible that she was shot and wounded well upstream of where she died.

4 and 5) Two adult females, WKF-4 (the iconic matriarch of the Hoanib, aka “Clarissa”) and WKF-19 (who joined her group early in 2009), have not been seen since June 2011 and were unaccounted for during our survey. Their offspring (WKF-4/a3, WKF-4/a5, and WKF-19/a1) have formed an “orphan group” in the Hoanib River. Their ages range from 6 to 13 years old. We made multiple observations of this orphan group during the course of our survey. Because WKF-4 and WKF-19 have not been present with their offspring, and have not been seen in many months, they are presumed dead. WKF-4 also had a new calf, born in 2010 that is unaccounted for and presumed dead. The last report we have of WKF-4 and her calf alive was from 17 January 2011 (information on last sighting provided by Dieter Risser).

2010 mortalities:

In January of 2010, a sub-adult female, 12 years old and not yet reproductive, died in the Hoanib River, downstream of the Mudorib junction. From photographs of the carcass (provided by P. Stander of Desert Lion Conservation) we identified her as WKF-11/a1. The cause of death is unknown, however, anthrax was ruled out based on tests performed by MET.

Fig 1, recent mortalities diagramFigure 1. Recent mortalities of adult females elephants in the Hoarusib-Hoanib subpopulation.
Thickness of lines indicate degree of association among individuals. The three family groups in the
center migrate seasonally between the Hoarusib and Hoanib Rivers. Only females of reproductive-age
are shown.

Reproduction:

1) At the time of our November 2011 survey, there were five new calves in the population that had been born in 2010 and 2011:

WKF-15/a3 (born in 2010)
WKF-11/a3 (born in 2010)
WKF-2/a2 (born in 2011)
WKF-3/a2 (born ~August 2011)
WKF-20/a1 (born ~August 2011)

Based on our published data from this population, one third of calves die before the end of their first year. We are inspecting photographs provided by others to determine if more calves may have been born and subsequently died between the time of our December 2009 and November 2011 surveys (as noted above, the calf of WKF-4 is presumed dead.)

2) One female, born in 2001, came of breeding age and produced her first calf in 2011. She is now re-numbered as an adult: WKF-20 (formerly WKF-15/a1).

3) If there is no additional mortality, a total of five additional females should be of reproductive age by 2014:

WKF-4/a3
WKF-1/a2
WKF-3/a1
WKF-14/a1
WKF-18/a1

Uniab River elephants

We took ID photographs of two groups totaling 35 elephants in the Uniab River drainage, including one female that had been collared by MET. Fourteen were in the Khowaxis River north of Palmwag (5 adult females, 7 dependent offspring, and 2 adult bulls, observed on 14 November 2011), and 21 were at Upper Achab Spring south of Rhino Camp (~6 adult females, 13 dependent offspring, and 2 adult bulls, observed on 19 November 2011). Based on reports from staff at Rhino Camp, it is likely that this is the total number of elephants inhabiting the Uniab River drainage, although the southern group may pass into and out of the area. Future comparison of photographs taken in the Palmwag Concession Area with our photographic database will allow us to test these alternative hypotheses and document movements of family groups and individuals. These will also serve as a basis for local guides to individually identify elephants and family groups.

The Significance of Desert Elephant Population Structure to Their Conservation

There seems to be a perception that the elephants in northwestern Namibia comprise a single population. Our data show that this is not the case for the elephants inhabiting the Hoarusib and Hoanib River drainages west of the 100mm rainfall line (e.g. west of Sesfontein), and those inhabiting the Uniab River drainage. Twelve years of observational data gathered during this long-term research project (by ourselves and Leggett), as well as earlier data gathered by Viljoen from 1978 and 1981, show that these are more accurately two separate subpopulations of elephants, made up of resident family groups (e.g. breeding herds), with little or no immigration or emigration of females. Mature bulls, on the other hand, frequently range over a far greater area that may include more than one of these female subpopulations, thus providing a genetic linkage between them.

The type of population structure described here is typical in elephants as well as many other social species. It confers a survival advantage to females and their offspring, through knowledge of stable home ranges, migration routes, and location of critical food and water resources during times of drought. Although elephants are unique in their high degree of intelligence and sociality, this type of population structure with resident female subpopulations and roving males, is not unique to elephants and is found in many other species.

The significance of this population structure is twofold:

First, the demographic trends in female subpopulations may be different due to local conditions: some subpopulations may be increasing, while others are decreasing, for entirely different reasons. If one were to only look at the overall trend of the meta-population, these local differences and their causes, would be missed. Thus, the fundamental demographic unit for management of females is the subpopulation, and because bulls range over a wider area, their management may span multiple female subpopulations.

Second, female subpopulations do not necessarily overlap human political jurisdictions, such as conservancy boundaries. That means that there will be shared responsibility for the conservation and management of specific subpopulations among jurisdictions. For example, the range of the Hoarusib/Hoanib subpopulation includes the Purros and Sesfontein conservancies, as well as Skeleton Coast Park and northern Palmwag concession area. The Uniab subpopulation primarily inhabits the Palmwag and Etendeka concessions, but also ranges into parts of Torra Conservancy and the Skeleton Coast Park. Simply put, a problem with loss of elephants in one area can have demographic implications for more than one jurisdiction (and consequent loss of tourist income for conservancies).

Although our study involves a limited area and two well-defined female subpopulations in the arid western Kunene, we predict that similar patterns will be found in the surrounding areas as additional data are gathered (e.g. by W. Killian of MET who is currently leading a large-scale satellite tracking study). Our results are consistent with patterns found in Etosha by Killian, whose long-term research and satellite tracking studies there have established the existence of western and eastern elephant subpopulations. One valuable aspect of the current satellite tracking study and ground surveys (such as ours) will be to describe the movement patterns of female subpopulations in the area in between Etosha and the desert subpopulations (e.g. Hoanib/Hoarusib, Uniab, Huab and Ugab drainages). When those data are combined with the identification of known individuals and their family groups from the ground, strong inferences can be made about the overall number and home ranges of elephants inhabiting these intermediary subpopulations. This will be a positive and lasting contribution to their effective long-term management.

Acknowledgements

We are grateful for the sharing of information and assistance we received from the following: Ministry of Environment and Tourism, Purros and Sesfontein Conservancies, Desert Lion Conservation, Kunene Conservancies Safaris, Okahirongo Lodge, Ondjamba Safaris, Wilderness Safaris (the staff at Skeleton Coast Camp, Rhino Camp, and Palmwag), IRDNC, Aqua Services & Engineering, DG Ecological Consulting, and Namibia Nature Foundation.

Fig-2, Map of study area

Figure 2. Map of study area showing the approximate range currently used by desert-dwelling
elephants in the Hoarusib-Hoanib (light blue) and Uniab (dark blue) female subpopulations. Migration
routes between the Hoarusib and Hoanib are indicated by the connecting thin (light blue) lines. The
northernmost extent of the Hoarusib subpopulation, upstream of the Orupembe-Opuwo road, overlaps
with at least one other subpopulation in that area. Mean annual rainfall is portrayed by isoclines.



   

 

 

 


©Copyright 2012 Desert Lion and Elephant Conservation, Inc.