Fire and mammal herbivory on arthropods in the protected savannas: A systematic review

Protected areas in the savannas are key global reserves for biological diversity, including arthropods. Fire and mammal herbivory disrupts the diversity of biological organisms that alternately affects the functioning of the ecosystem. The study presents a global synthesis review of arthropod responses to varying intensities of fires and mammal herbivory in the protected savannas. We hypothesise that the intensity of predetermined fires and mammal herbivory has cascading impacts on abundance, species richness and diversity of terrestrial arthropods in the protected savannas. A minimum selection criteria was used to collate relevant literature from electronic databases of previous studies performed in the subtropical regions of Australia, Brazil and South Africa. Arthropod orders were used to group ecological indicators in 84.6%, while the functional traits were used in 15.4% of the studies. The orders included Hymenoptera (i.e. Formicidae), which was used in 81.8% of the studies selected for this systematic review, while Orthoptera, Araneae and Coleoptera were each used in 45.5%, 36.4% and 36.4% of the studies, respectively. In addition, Hemiptera and Lepidoptera were used as indicators in 27.3%, while Blattodea and Diptera were used in 18.2% of the studies. Collembola and functional groups (herbivores, omnivores and predators) were used as indicators in less than 9.1% of the studies. Fire and mammal herbivory significantly influenced the abundance and species richness of Hymenoptera, Lepidoptera, Orthoptera and multi-taxon. However, the response of arthropods (i.e. abundance and species richness) to the intensities of disturbances did not vary significantly at burnt and grazed plots. Conservation implications: A similar response to intensities of disturbance suggests that an array of arthropod orders and functional groups (solely or combined) are indistinguishably affected by fire and mammal herbivory. Thus, arthropods could potentially be a viable ecological indicator to ascertain the magnitude of impacts. Policies encouraging the integration of different intensities of fire and mammal herbivory across protected areas should be encouraged to optimise the conservation of arthropods, including the threatened morphospecies.