Revegetated riparian areas are dominated by weeds, and lack structural diversity and natural recruitment: lessons for restoration practice

• Published in: Restoration ecology Vol. 32; no. 4
• Main Authors: Foley‐Congdon, Eliza, Jellinek, Sacha, Chee, Yung E., Greet, Joe
• Format: Journal Article
• Language: English
• Published: Malden, USA Wiley Periodicals, Inc 01.05.2024; Blackwell Publishing Ltd
• Subjects: animal grazing; Anthropogenic factors; Australia; Browsing; canopy; Community composition; deer; Ecological function; Ecosystem services; ecosystems; exotic species; Ferns; habitat restoration; Human influences; Indigenous species; Introduced plants; Introduced species; Land clearance; Land clearing; land restoration; Leaf litter; plant litter; Plants; Plants (botany); Recruitment; Restoration; Revegetation; Riparian vegetation; Shrubs; Soil characteristics; Species composition; species recruitment; Species richness; Structure-function relationships; target habitat; Urban agriculture; Urban development; Urbanization; Vegetation; Waterways; Weed control; Weeds; Woody plants; Australia
• ISSN: 1061-2971; 1526-100X
• DOI: 10.1111/rec.14098

Riparian areas can be highly biodiverse and provide critical ecosystem services. However, they are frequently subject to anthropogenic impacts such as land clearing, agricultural use, and urban development. Restoration of riparian areas via revegetation commonly improves the health of waterways and surrounding areas, but vegetation outcomes are rarely assessed. Our study compared 10 to 14‐year‐old revegetation to remnant vegetation in riparian areas of south‐eastern Australia to determine if species composition, vegetation structure, and ecosystem function (plant recruitment) differed. We also assessed if the amount of surrounding native vegetation, browsers (including deer, rabbits, and macropods), or soil characteristics influenced native woody plant recruitment at revegetated sites. While native and exotic woody species richness did not differ, native woody plants were less abundant and exotic woody plants twice as abundant at revegetated sites. The ground layer of revegetated sites was dominated by weeds, whereas remnant sites largely comprised native herbaceous plants and leaf litter. Tree heights and tree canopy cover were similar in revegetated and remnant areas, although shrubs and ferns were lacking in revegetation. Native woody plant recruitment was lower at revegetated sites and was negatively associated with browser presence. Our results suggest that while revegetation may have similar species richness and tree cover as remnant areas, weeds often dominate and important structural components such as shrubs and ferns, and ecological processes such as plant recruitment, are lacking. Better consideration of all vegetation strata, reduced browsing pressure and weed control are likely to achieve better revegetation outcomes.