Use of Telemetry Data to Investigate Home Range and Habitat Selection in Mammalian Carnivores

Abstract

Introduction Management of mammalian carnivore populations, whether to conserve a threatened species or to control the abundance of a noxious one, requires a basic understanding of the ecology and behaviour of a given species. Habitat selection and home range are fundamental processes in the ecology and behaviour of most animals, explaining why most researchers generally investigate them when assessing a species’ needs. Presumably, species should have a higher fitness in habitats that they select or allow them to accomplish basic activities such as foraging and reproduction. Once habitats can be ordered by their relative preference, they can be evaluated as to their relative importance in terms of fitness (Garshelis, 2000). Wildlife managers and conservation biologists can, then, make decisions regarding any habitat modification or population control requirement that may be needed to deal with the species in question. The assessment of either habitat selection or home range requires the collection of data on the animals’ use of space. In theory, different approaches can be used to obtain the data needed to assess habitat selection and home range patterns. One approach may be to obtain the data by following an animal in order to observe its movements and habits. However, this approach is likely to prove very difficult, particularly in areas with thick vegetation or where the animal is active at night or when dealing with a species with secretive habits. There is also the risk that the close proximity of humans could affect the animal’s behaviour resulting in an unrealistic outcome of the study or possibly having a negative effect on the studied animal, like interfering with the hunting success in mammalian carnivores. Another approach may involve obtaining data from transect surveys (Buckland et al., 1993). These surveys record animals in the vicinity of a set of sampling lines or points and therefore tend to yield relatively few sightings, particularly for rare species living in inaccessible environments. Telemetry is without any doubt the most common method to quantify either habitat selection or home range patterns, especially in mammalian carnivore species. Telemetry is a tool or technique used to research wild animal species in the field in order to gain a thorough understanding of that population and its dynamics as well as to identify any potential threats to its survival (White & Garrott, 1990). It is typically used to gather data from distant, inaccessible locations, or when data collection would be dangerous or difficult for a variety of reasons. Wildlife telemetry concerns the use of telemetry techniques to remotely locate wild species and obtain ecological, behavioural and physiological data. It was in the 1960s, when telemetry, specifically radio-telemetry, was first used to study terrestrial wildlife (Craighhead, 1982; Hebblewhite & Haydon, 2010). Since then, wildlife telemetry has contributed significantly to our understanding of fundamental ecological and behavioural processes of many animal species (e.g., Johnson et al., 2006). Advances in wildlife telemetry have made it possible to acquire detailed data on animal’ space use, including habitat selection, home-range size, movement metrics as well as migration timing and routes. Since many wildlife species are secretive and difficult to observe, telemetry has become a valuable tool to learn more about their respective life-histories. Human attitudes vary worldwide towards mammalian carnivore species. The overlap in space-use with human populations results in competition for habitats and resources which is at the heart of most of the conflicts between mammalian carnivore species, especially canids, and humans (Sillero-Zubiri & Switzer, 2004). For instance, canids tend to prey upon a range of livestock, game stock and threatened wildlife, and some of the large-bodied size species may also attack, and on rare occasions, deadly harm humans. Human–carnivore conflicts are among the major causes of population decline in many species (Treves & Karanth, 2003) and can be particularly controversial when the resources concerned have economic value (e.g., livestock) and the carnivore species involved have a high conservation profile (Graham et al., 2005). This is usually the case of large-bodied size carnivore species that usually have extensive space requirements, low reproductive rates and are persecuted by humans (Matthiae & Stearns, 1981). But, while these carnivore species are declining globally, others have not only managed to survive, but to become abundant. Many mediumbodied size generalist carnivores have been able to expand their geographic ranges because they are capable of using human-use areas and anthropogenic resources (Harris & Smith, 1987; Prange et al., 2004). For instance, red foxes (Vulpes vulpes) and coyotes (Canis latrans) may occur not only in rural areas, but also in suburban and occasionally more densely populated urban areas (Atkinson & Shackleton, 1991; Gibeau, 1998; Grinder & Krausman, 2001; Lewis et al., 1999). In this study, we will consider the use of telemetry data to investigate habitat selection and home-range patterns of two mammalian carnivore species. Although both species occur in human-dominated landscapes, their interactions with humans are very distinct, resulting in very different abundance levels and conservation status. However, in both cases, investigations of habitat selection and home-range patterns are fundamental initial steps in the management of their populations. In the following Section 2, we will briefly define key concepts that will be used in this chapter. In Case Study 1 (Section 3), we will use telemetry data to investigate habitat selection and home range of the red fox in Prince Edward Island, Canada. In this case, the species is benefiting from its interaction with human populations. Our objective for Case Study 1 is to show how telemetry data can be used to elucidate the effects of fox-feeding (anthropogenic food resources provided to foxes by humans) on habitat selection and home-range patterns. In Case Study 2 (Section 4), telemetry data will be used to investigate habitat selection and home range patterns of the African wild dog (Lycaon pictus) in Mkhuze Game Reserve, South Africa. Contrary to the red fox, the interaction with humans has had detrimental effects on African wild-dog populations in South Africa and other parts of Africa. Our objective for Case Study 2 is to illustrate the use of telemetry data to assess the success of the establishment part of a reintroduction program of a endangered or threatened carnivore species. For purposes of comparison, we have tried to use the same approaches, methods and data-analysis procedures for both case studies whenever possible. However, differences in abundance levels and current status of red foxes and African wild dogs, as well as data collection, needed sometimes the use of different approaches to achieve the objectives set out for each case study. Section 5 concludes the chapter and comments on the use of radio-telemetry and other similar technologies in ecology and wildlife management