SPATIAL ECOLOGY STUDIES IN FREE RANGING ANIMALS

Spatial Ecology STUDIES IN FREE RANGING ANIMALS

M Jeri Imansyah

Habitat loss and fragmentation are currently the most serious threats to wildlife worldwide, so it is important to understand how patterns and processes of landscape change will cause individual populations and species to respond to these broad-scale modifications (Blumstein & Fernandez-Juricic 2004; Collinge 2001). Spatial heterogeneity processes directly affect ecological systems (Gardner et al. 1989). The spatial arrangement of individuals within a population will reflect aspects of its behavior and ecology, and is important in determining population persistence and gene flow within and between sub-populations (Brown & Downhower 1988; Johnson 2000). Thus, the dynamics of an animal population depends not only on birth and death rates, but also on an animal’s ability to move into or out of a population (Dasmann 1964). Determining the number of individuals persisting in an area is a basic question in ecology, but it is more important to understand how an animal responds to changing landscape conditions, regardless of whether it is at the individual, population or community level (Lawson et al. 2006).

Krebs (1999) pointed out that spatial ecology as a science aims to understand the ecological processes that determine the location of individuals, which are rarely spread evenly over the landscape. Collinge (2001) concluded that spatial ecology is an ecological study, which centers upon understanding how landscape configurations influence the community and population dynamics of organisms. Spatial ecology is at the very core of the science of ecology (Boyce & McDonald 1999). Whitaker and Shine (2003) stated that studying spatial ecology can contribute at least three potential benefits; first, a better understanding of movement and habitat selection by the animal, second, giving information regarding animal-human interactions, and third, as an aid in assessing the response and role of an animal in regards to their habitat. Collinge (2001) emphasized that empirical studies in spatial ecology beneficially links conservation biology research to practical mechanisms for species management and conservation planning. In studying spatial ecology, authors included studies of dispersal (e.g. Olsson & Shine 2003), movement and activity area, habitat use, activity patterns (Fitzgerald et al. 2002; Piepgras & Lang 2000), diets (Thompson & Thompson 2001; Whitaker & Shine 2003), and anthropic habitat changes (Pearson et al. 2005; Martin et al. 2001; Fitzgerald et al. 2002).

Dispersal is the movement of an individual from its natal area to an unoccupied and suitable area within which it is able to establish its own home range. Caughley and Sinclair (1994) emphasised that migration is not the equivalent of dispersal. Greenwood and Swingland (1984) described dispersal as being caused by the need for an individual to search for food sources. Lebreton et al. (2003) studied the importance of dispersal as a mechanism in reproduction.

It is essential in studying spatial ecology to investigate dispersal patterns. Dispersal is recognized as a key process in ecology, evolution, and conservation and it is important to understand the consequences to an animal’s behaviour as it responds to the habitat (van Dyck & Baguette 2005). Dispersal can affect the dynamics and persistence of populations, distribution and abundance, community structure, gene flow, local adaptation, speciation, and the evolution of life-history traits (Lebreton et al. 2003; Roper et al. 2003). Thus, dispersal is one of the most critical events in the life of most animals and one of the most important processes affecting the ecology and evolution of populations (Roper et al. 2003).