Terrestrial Invertebrates in the Riparian Zone: Mechanisms Underlying Their Unique Diversity

Riparian areas are biologically rich ecosystems, but they are highly threatened across the globe. Invertebrates represent a large proportion of the animal diversity within riparian areas, perform various ecological functions, and serve as bioenergetic links between aquatic and riparian food webs. Although many studies have been done on riparian taxa, this is the first synthesis of invertebrate ecology in riparian areas. We first discuss five characteristics of riparian zones that may support specialist riparian invertebrates: high rates of disturbance, elevated nutrient and water availability, increased vegetation and microhabitat diversity, strong microclimate gradients, and unique food resources. We then review how these mechanisms change with distance from the stream (lateral gradients) and position within a catchment (longitudinal gradients) and the resulting effects on the riparian community. Finally, we highlight gaps in our current knowledge and offer suggestions for future research.