Clear bankside vegetation

How is the evidence assessed?
  • Effectiveness
    not assessed
  • Certainty
    not assessed
  • Harms
    not assessed

Study locations

Key messages

  • One study evaluated the effects of clearing bankside vegetation on anguillid eel populations in inland habitats. The study was in New Zealand. 

COMMUNITY RESPONSE (0 STUDIES)

 

POPULATION RESPONSE (1 STUDY)

  • Abundance (1 study): One replicated, controlled study in New Zealand found that clearing bankside vegetation, along with removing in-stream woody debris, led to higher elver density, lower longfin eel density and similar numbers of shortfin eels compared to uncleared stream sections. 

BEHAVIOUR (0 STUDIES)

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A replicated, controlled study in 2001–2002 in a stream in North Island, New Zealand (Jowett et al. 2009) found that clearing bankside vegetation, along with removing in-stream woody debris, led to higher elver density, lower longfin eel Anguilla dieffenbachii density, and similar numbers of shortfin eels Anguilla australis compared to uncleared stream sections. Results are not based on tests of statistical significance. After six months, cleared stream sections had higher average densities of elvers (1.7 elvers/m) and lower average densities of longfin eels (0 eels/m) than uncleared sections (0.8 elvers/m, 0.2 eels/m). Overall, similar numbers of shortfin eels were caught in cleared (total 11 eels) and uncleared sections (total 10 eels). In November 2001, bankside vegetation was cleared (including overhanging branches of larger trees/shrubs), and in-stream woody debris removed, from five 15-m-long stream sections. Immediately upstream of each cleared section, a second 15-m section was left uncleared and used as a comparison. Eels were surveyed monthly in each stream section from December 2001 to May 2002 by electrofishing. Stop nets were placed at the ends of each section to stop fish escaping. Eels <100 mm length (elvers) were not identified to species.

    Study and other actions tested
Please cite as:

Cutts V., Berthinussen A., Reynolds S.A., Clarhäll A., Land M., Smith R.K. & Sutherland W.J. (2024) Eel Conservation in Inland Habitats: Global evidence for the effects of actions to conserve anguillid eels. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Eel Conservation in Inland Habitats

This Action forms part of the Action Synopsis:

Eel Conservation in Inland Habitats
Eel Conservation in Inland Habitats

Eel Conservation in Inland Habitats - Published 2024

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