Termite (Isoptera) diversity of riparian forests, adjacent woodlands and cleared pastures in tropical eastern Australia

Abstract

The Fitzroy River (Central Queensland) has the second largest ocean-flowing catchment in Australia and retains relatively extensive remnant woodlands. However, clearing of the more fertile alluvial plains is proportionally much greater. Typically, forested habitat on the alluvial plain is restricted to narrow riparian corridors and small remnants on the adjacent terraces. Riparian forests are known to be important repositories of biodiversity in cleared and uncleared landscapes. However, little is known about the invertebrates of these habitats. Termites are ecosystem engineers promoting soil health and organic decomposition, and keystone taxa by virtue of mound and nest construction, and the hollowing of living trees. A comparison of the termite fauna of riparian forests and vegetation of the adjacent terraces (either remnant woodlands or cleared for grass-dominated pastures) was made at five locations in the Fitzroy River basin. Terrace pastures had fewer species than terrace woodlands while termite encounters within the riparian forests were lowest. Termite assemblages also differed between the three vegetation types. Some species showed zonation patterns. These patterns may relate to ecosystem drivers such as frequency of flooding in relation to life history parameters (e.g. arboreal or ground nesting). Termite species distribution also appeared to be coupled to resource availability such as presence of live and dead wood and percentage cover of litter, grass and dung. To retain natural levels of termite diversity and functionality, it is recommended that land managers retain both riparian forests and adjacent woodlands in a matrix with cleared pastures.