Irruptive growth patterns are also seen in mammal herbivores with a relatively small body size, or such creatures in Arctic ecosystems which are subject to population cycles. In cases where a single herbivore prey species is dominant in an ecosystem, there is likely to be a strong link with predator species which serves to control the population (see Lotka–Volterra equations). The populations of rabbits and house mice introduced Australia show irruptive growth, for example. A possible reason may be that after drought ends, they reproduce at a rapid rate while predator reproduction is still seasonal in occurrence. This allows for the population to explode and to be limited more by a return of dry conditions than by predators. Invasive species which can reproduce rapidly may show this pattern of growth because when a new area is being colonized predator species are often not present to limit growth, and there is little intraspecific and/or interspecific competition in early settlement of a location which means there is abundant resource availability.