Movement and space use in three sympatric lacertid lizards (Acanthodactylus): Inter- and intraspecific comparisons

Competition can be keen within and between closely related species but can be reduced when sympatric individuals differ in resource use. To determine how sympatric, closely related species coexist, we examined movement and activity of foraging individuals, developing detailed profiles for males of three species (Acanthodactylus boskianus, A. dumerilii and A. scutellatus) and for female A. boskianus in arid sub-desert steppes of southern Tunisia. All three species were active concurrently with different peak activity times. Males varied markedly in their movement, as did A. boskianus sexes. Interspecifically, male A. boskianus moved most frequently, for the most time, covering the greatest distance and searching the largest area, while male A. dumerilii moved the least often, travelled the shortest distances and intensively searched small areas. Acanthodactylus scutellatus males generally were intermediate between the other species but dug more frequently and had movement rates comparable to A. boskianus. Intraspecifically, A. boskianus females moved less frequently, for a smaller percentage of time, covering shorter distances and searching smaller areas than male A. boskianus. Habitat use varied among species and by sex within A. boskianus. Differences in movement and activity likely reflect differences in resource use that promote coexistence between and within species.