Assessing the local effects of riparian restoration on urban streams

Abstract

Riparian zones mediate chemical and biological exchanges between streams and the terrestrial environment. In urban systems, these zones are often heavily modified by removal of native vegetation and bank disruption. Management agencies have made considerable investments into restoring riparian vegetation through replanting. We investigated the potential for riparian plantings to restore invertebrate communities, by comparing open and forested (replanted) reaches over winter within three urban streams in Melbourne, Australia. Clear differences in aquatic habitats, food resources and fauna were evident between reaches. Algal biomass on artificial substrates did not differ significantly between reaches. Open reaches had higher abundances of taxa reliant on autochthonous production as the primary food resources (e.g. gastropods, chironomids and oligochaetes), while forested reaches displayed a higher diversity of invertebrate taxa associated with allochthonous resources. We conclude that riparian plantings may have some positive effects on streams, even without broader catchment improvements in water quality and hydrology.

Ecological Restoration of Streams and Rivers: Shifting Strategies and Shifting Goals

“…g Rate of litter input to stream (Thompson & Parkinson 2011) or rate of leaf retention (Muotka & Laasonen 2002). Abbreviations: ANC, acid neutralizing capacity; EPT, Ephemeroptera, Plecoptera, and Trichoptera.…”

Editorial: Measuring river restoration success: Are we missing the boat?

“…Riparian fencing and planting provides positive outcomes in some agricultural settings, particularly for small streams, although the magnitude of any benefits may be very much context‐dependent and the rate of change slow. Riparian planting can even benefit urban waterways where stormwater does not override influences of increased shade, organic matter delivery and bank stability (Collier, Aldridge, Hicks, Kelly, & Smith, ; Thompson & Parkinson, ). However, small‐scale habitat enhancement with instream structures aimed at resolving broader landscape pressures are typically not successful (Pretty et al, ), for reasons discussed below.…”

Consideration of spatial and temporal scales in stream restorations and biotic monitoring to assess restoration outcomes: A literature review, part 1

“…In Christchurch, New Zealand, invertebrate responses were quite variable after 5 years and had no strong association with the restoration, which was riparian planting with or without channel modification (Suren & McMurtrie, 2005). In three Melbourne, Australia, streams, changes in macroinvertebrate biomass were inconsistent between reaches with riparian planting of at least 15‐year‐old Eucalyptus and Acacia compared to an upstream open reach that lacked native riparian vegetation (Thompson & Parkinson, 2011). However, macroinvertebrate assemblage composition improved and reflected greater inputs of allochthonous detritus in planted reaches.…”

“…However, all the reaches were still dominated by pollution tolerant macroinvertebrate, and Thompson and Parkinson (2011) suggest these urban streams were also affected by previously observed flashy hydrology and high nutrient loads (Walsh et al, 2005). These effects may have been ameliorated by an ongoing drought, but drainage systems carrying stormwater and nutrients bypass the riparian restoration of planting vegetation (Thompson & Parkinson, 2011).…”