Factors Affecting the Density and Distribution of Wild Dogs in the Kruger National Park

Abstract

African wild dogs ( Lycaon pictus) are a seriously endangered species with only around 5000 individuals left. We examined the factors likely to be affecting the distribution and density of wild dogs living in the Kruger National Park, South Africa. We collected data, by traditional and satellite radio‐tracking, on diet selection, sizes of packs, dispersion and sizes of territories, and patterns of habitat selection for eight packs of wild dogs. In Kruger wild dogs specialize on impala ( Aepyceros melampus) and kudu ( Tragelaphus strepsiceros). They live in packs averaging about nine dogs and inhabit territories of 350–950 km2. Neighboring territories overlap to some extent but packs meet very rarely. The dispersion pattern of food plays only a minor role in determining the density and distribution of dogs in the Kruger; dogs exist at their lowest density where their food is most abundant. This apparent paradox comes about because the dogs seem to avoid areas that, although prey‐rich, are heavily used by lions. This is a sensible strategy because lions are a major cause of dog mortality, accounting for some 39% of natural pup deaths and at least 43% of natural adult deaths. Wild dogs may be conserved most successfully in areas with moderate to low densities of lions and spotted hyenas, and management strategies should be careful not to promote these species to the detriment of wild dogs and other carnivores. The densities of lions and spotted hyenas should be important criteria when considering an area for the reintroduction of wild dogs and other similar sized carnivores.Factores que Afectan la Densidad y Distribución de Perros Salvajes en el Parque Nacional KrugerEl perro salvaje africano ( Lycaon pictus) es una especie en serio peligro de extinción, con una población estimada de solamente 5000 individuos. Hemos examinado los factores que con mayor probabilidad afectan la distribución y densidad de los perros salvajes que habitan el Parque Nacional Kruger en Sudáfrica. Información sobre la selección de alimento, tamaño de grupo, dispersión y tamaño de territorio y patrones de selección de hábitat fué colectada usando métodos tradicionales y seguimiento con satélite para ocho grupos de perros salvajes en el parque. Esta especie se especializa en impala ( Aepyceros melampus) y kudu ( Tragelaphus strepsiceros). Vive en grupos de 9 individuos en promedio y habita un territorio de 350‐950 km2. Territorios vecinos se sobreponen en cierta proporción, pero los encuentros entre diferentes grupos raras veces ocurren. El patrón de dispersión de la comida juega solo un pequeño papel en la determinación de la densidad en lugares donde la comida es mas abundante. Esta aparente paradoja es consecuencia de que los perros parecen evitar zonas que, a pesar de ser ricas en presas, también son muy usadas por leones (Panthera leo). Esta estrategia es sensata, pues esta especie es una de las mayores causas de mortalidad para los perros, alcanzando un 39% de mortalidad natural de los cachorros y al menos un 43% de la mortalidad natural de los adultos. Los perros salvajes podrían ser conservados con mas éxito en zonas con una densidad moderada o baja de leones y hienas manchadas (Crocuta crocuta). Las estrategias de conservación deben ser cuidadosamente estudiadas para evitar favorecer estas especies en detrimento de los perros salvajes y otras especies de carnívoros. La denisdad de leones y hienas manchadas deberá ser un criterio importante cuando se considere una zona para la reintroducción de los perros salvajes y otros carnívoros de similar tamaño.

The Demography and Dynamics of an Expanding, Managed African Wild Dog Metapopulation

“…An alternative explanation for elevated wild dog densities is the statistical artefact of reintroducing wild dogs into areas smaller than their natural home range sizes. Only three of the nine subpopulation sites were larger than the average range of wild dog packs in Kruger (537 km 2 ; Mills & Gorman, 1997) and four were actually smaller than the minimum range size reported (357 km 2 ; Mills & Gorman, 1997). A breeding pair of wild dogs -the minimum required to meet the definition of a pack -in a 50 km 2 reserve (the size of Thanda, the smallest subpopulation site) equates to a density of 4.0 wild dogs/100 km 2 .…”

“…All reserves contained populations of preferred wild dog prey, including impala (Aepyceros melampus) and greater kudu (Tragelaphus strepsiceros), but also nyala (Tragelaphus angasi ) in KwaZulu-Natal. Populations of key wild dog competitors, namely lions (Panthera leo) and spotted hyaenas (Crocuta crocuta) (Creel & Creel, 1996;Mills & Gorman, 1997), were present in all study sites at varying densities. Reserves derived income from various combinations of ecotourism, live game sales and/or hunting, and biodiversity conservation was a primary objective of only two sites.…”

“…Wild dogs are able to coexist with these larger predators by avoiding them both spatially (Mills & Gorman, 1997;Creel & Creel, 2002) and temporally (Saleni et al, 2007). Lion-induced mortality has hampered at least one previous wild dog reintroduction (Scheepers & Venzke, 1995) and has been flagged as a factor likely to limit reintroduction success (Mills et al, 1998).…”

Genetic diversity and spatial genetic structure of African wild dogs (Lycaon pictus) in the Greater Limpopo transfrontier conservation area

“…The area became fragmented during the Zimbabwean land reform programme in the early 2000s and large tracts of natural habitat have been lost in privately owned areas (Lindsey et al 2008). Wild dog packs require large home ranges (from 357 to 930 km 2 ; Mills and Gorman 1997), being mainly limited by prey density, interspecific competition (from lions Panthera leo and spotted hyaenas Crocuta crocuta), and deliberate and accidental human-caused mortality (Mills and Gorman 1997;Creel and Creel 1998;Bach et al 2010). Consequently, many natural areas in Zimbabwe are now too small to maintain viable wild dog populations (Lindsey et al 2004).…”

First Record of the Southern Red-Backed Vole, <em>Clethrionomys gapperi</em>, in Newfoundland: Implications for the Endangered Newfoundland Marten, <em>Martes americana atrata</em>

“…Parallel circumstances have been described for other threatened or endangered carnivores elsewhere (e.g., Coyote predation on Swift Foxes (Vulpes macrotis) (Sovada et al 1998), Coyote predation on San Joaquin Kit Foxes (Vulpes macrotis) (Ralls and White 1995;White and Garrott 1997;Cypher and Spencer 1998), and Lion (Panthera leo) and Spotted Hyena (Crocuta croenta) predation on African Wild Dogs (Lycaon pictus) (Creel 2001;Creel et al 2001)). African Wild Dog densities are actually lowest where density of their major prey is highest, due to intraspecific predation (Mills and Gorman 1997) Changes in prey availability clearly affect densities of carnivores, improving demographic performance (i.e., increased reproductive output and survival (Fuller and Sievert 2001). Furthermore, decreased food resources have been associated with reduced population density or trapper success, enlarged home ranges, and lower reproductive performance of American Marten (Bulmer 1974;Fryxell et al 1999;Poole and Graf 1986;Simon et al 1999;Thompson and Colgan 1987).…”