DEFINITIONS OF TERRITORIALITY USED IN THE STUDY OF VARIATION IN VERTEBRATE SPACING SYSTEMS

Both species and populations within species display variation in spaci ng patterns, and the number of published reports documenting this vari ation is increasing rapidly. The potential for instructive comparisons is high, but the comparative approach requires common terminology. Va gue or implicit definitions of spacing systems undermine the rigour of comparisons. Papers were reviewed that examined interspecific and int raspecific variation in spacing systems to determine the degree to whi ch definitions currently produce a common terminology. This report des cribes and classifies the 48 conceptual and operational definitions of territoriality found in the literature. Only 12% of the papers gave a n operational definition of territoriality. The single criterion of 'd efended area' was used in 50% of the papers, and the other 50% used ot her definitions which often consisted of multiple criteria. These defi nitions were variants of three main themes: defended area, exclusive a rea, and site-specific dominance, and authors used up to three criteri a to define territoriality. Conceptual and operational definitions dif fered because different questions were asked and because of logistical problems, such as collecting the same data on different species or po pulations. The taxonomic group being studied also seemed to determine which type of definition was chosen. Although defended area was used m ost often across four classes of vertebrates, researchers studying mam mals chose spatial criteria, for example, amount of home range overlap , more often than researchers studying other taxa. Workers pursuing re search in this area can enhance their contribution by using clear conc eptual and operational definitions of territoriality, making them expl icit at the outset.