Integrating earth and life sciences in New Zealand natural history: The parallel arcs model

Abstract

Attention is drawn to the parallel arc patterns permeating much of New Zealand biogeographic structure. The fracturing and creation of such parallel arcs by tectonic movement and erosion has brought about vast disjunctions in many plant and animal groups. The major arcs of distribution correlate with zones of tectonic activity such as plate and terrane margins, fracture zones, and belts of granitic intrusion. Other arcs may be the result of evolution along the Tertiary shores of inland bodies of water. The altitude of many communities in New Zealand also appears to conform to biogeographic and tectonic trends, with higher altitude communities having been derived by the uplift of mid-Tertiary lowland-coastal communities. Evolution is interpreted here as proceeding largely by phases of population reorganisation, for example in the formation of Cretaceous hybrid swarms, and “recrystallisation” in which ancient ranges are “frozen”, even in weedy taxa. Such processes correlate spatially with zones of tectonic and physiographic disturbance.