By Dr. Ingrid Wiesel
Darting in and out of shadows, dodging waves and eyes, the shaggy, solitary figure of the strandwolf captures the imagination. For Ingrid Wiesel, once the brown hyena had grabbed her imagination, the hold was permanent. Since 1995, Dr. Wiesel and fellow researchers at the Brown Hyena Research Project have studied the habits of the brown hyena along the southwest coast of Namibia.
For animals and researchers the conditions are difficult. Howling winds, stinging sand and cold air compete with spectacular landscapes, seal colonies, mining, tourism, isolation and inspiration, as the brown hyena seeks to hold on to its place in this ecosystem.
For nearly twenty years, Dr. Wiesel and fellow researchers have methodically and expertly built on what we know about brown hyena and how they survive against competition for space and resources in one of the toughest environments on earth.
The brown hyena is adapted to arid living conditions, and its density is high along the Sperrgebiet coastline. The Sperrgebiet also supports four mainland seal colonies, which provide a permanent, concentrated food source. As other food items are scarce, seals are essential for the maintenance of a healthy and viable brown hyena population. Brown hyenas are at the top of the food chain in the Sperrgebiet, feeding and preying on marine predatory mammals. The balance of this unique predator-prey ecosystem is influenced by many factors, including new and existing land development.
The Brown Hyena Research Project team has been the recipient of several Nedbank Go Green Fund grants. These grants have allowed the researchers to continue to explore the long-term conservation of the brown hyena along the southern coastal Namib Desert, including the Sperrgebiet National Park.
Possible implications of mining to brown hyena conservation
In the early 2000s the greatest outside influence on the environment in the Sperrgebiet was the expansion of mining along the coast. Prospecting along the coast had identified mining sites at 14 diamond bearing beach deposits. The exploitation of these mines was likely to have negative impacts on predators, as it involved disturbance around the food source, and expansion of roads and housing facilities near the coast.
Given these factors, information gathered during this research project could influence decision-making with regard to the development of existing and future mines.
The Brown Hyena Research Project focused on surveying the home range size, habitat use and activity patterns in areas most likely affected by mining disturbance. 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 such as mining.
Three brown hyenas were immobilised and fitted with GPS collars. These three, along with a brown hyena who was previously fitted with a GPS collar, were followed from June 2005 to April 2006. By recording their GPS positions, the researchers were able to calculate home range sizes, evaluate habitat use and determine activity, including evaluating the importance of the coast and the seal colonies with regard to brown hyena activity. Fresh water springs in the area were also monitored.
The Brown Hyena Research Project team found that home range sizes varied significantly throughout the year. However, the coastal area was more frequently used at all times than the inland areas of the home ranges. All brown hyenas were significantly more active at night. Most activity took place around the seal colonies and along beaches, with the with the hyenas’ main foraging ground around the Bogenfels area. Both resident and non-resident hyenas were recorded at fresh water springs, suggesting that such springs might be more important than previously thought.
The study identified that mining disturbance at Bogenfels beach will have an influence on brown hyena foraging activity, but enough alternate food can be found at the Van Reenen Bay seal colony.
It also highlighted that brown hyenas move across the area marked for a future haul-out road to reach other parts of their home range and an important fresh water spring, therefore mitigation measures to avoid road accidents are necessary.
Research in the Sperrgebiet National Park
In June 2004, the Sperrgebiet National Park was proclaimed, making the conservation of the park’s flagship species, the brown hyena, imperative for both ecological and commercial reasons, as tourism is destined to play a growing role in the park.
Researchers embarked upon a study to investigate the complex food-web structure in the Sperrgebiet National Park and its surroundings.
In phase one of this study, nine brown hyenas in coastal areas, including those moving through urban and inland areas, and one nomadic hyena were fitted with GPS telemetry collars. Information gained from these collars regarding brown hyena movements, range, use and overlap, along with the use of camera traps, collection of scat samples and results from previous studies were used to gain a better understanding of the behavioural ecology and habitat used by the Sperrgebiet brown hyenas.
Territory use, defense and habitat preference
Brown hyenas are territorial and defend a common territory boundary. However, home ranges of individual brown hyenas differ in size and often overlap with members of neighbouring clans. Brown hyenas are also solitary foragers and usually meet at active den sites to socialize. It is yet unknown whether and where brown hyenas meet outside the denning period.
Several habitat analyses were performed to investigate whether brown hyenas prefer certain habitat types within the Sperrgebiet National Park and to develop guidelines for the Ministry of Environment and Tourism for the monitoring and conservation of the flagship species, .
Results from phase one of this project provided an interesting insight into the behaviour ecology of brown hyenas living in the Sperregbiet National Park and its surroundings.
The team found that home range sizes varied greatly from several hundred to several thousand square kilometers, with no significant difference in overlapping areas between male/male, female/female and male/female. However, overlaps were significantly greater for brown hyenas belonging to the same clan than between non-clan members.
Brown hyenas mark their territory/home range boundaries with paste marks and latrines. The team calculated that paste marks were on average deposited every 221 metres. It was determined that a home range only becomes indefensible for one individual brown hyena once it exceeds a size of 2559 km2. However, brown hyena clan sizes range from an individual animal to 10 adult animals in a clan, so that larger home ranges become defensible for clan-living brown hyenas.
The Brown Hyena Research Project
The Brown Hyena Research Project is a non-profit organisation based in Lüderitz in the southern Namib Desert in Namibia. Research on brown hyenas (Hyaena brunnea or Parahyaena brunnea) and the conservation of the ecologically unique brown hyena population along the coastal Namib Desert began in 1995 and has since developed into a long-term conservation project.
Brown Hyena Research Project
Sarah Edwards, PhD student
Human-wildlife conflict is a globally intensifying problem, with many of the world’s large carnivores coming into conflict with humans. In southern Namibia, human-wildlife conflict centres on actual or perceived predation of domestic livestock or game by carnivores on commercial farmland. To assess the true extent of conflict in southern Namibia, Sarah Edwards, from the Brown Hyena Research Project used a novel combination of techniques.
Camera traps and non-invasive hair collection techniques were used across five study farms, each bordering either the Sperrgebiet or Namib-Naukluft National Park. Data collected was used to compile the first carnivore inventory for commercial farmland in the south as well as to produce density and relative abundance estimates. Hair collected will be sent for stable isotope analysis, a relatively new technology which will allow the relative contribution of domestic livestock to the diet of carnivores to be assessed. Additionally, farmer questionnaires have been conducted in order to compare the human perspective of the problem to ecological data.
The project recorded eleven carnivore species across the farms, including spotted and brown hyena, leopard and cheetah. Questionnaire results revealed that black-backed jackal are least tolerated by farmers, often being shot on sight. However, larger carnivores are mostly tolerated until a problem arises. Farmers often believed numbers of carnivores on their land to be much higher than camera trapping data indicated.