Exclude livestock from riverbanks

Overall effectiveness category Evidence not assessed
Number of studies: 1
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Effectiveness
not assessed
Certainty
not assessed
Harms
not assessed

Calculating overall effectiveness category

Background information and definitions

Livestock can negatively impact riverbanks by trampling, which can degrade vegetation, cause erosion and increase sedimentation (Scott et al. 2003). Additionally, livestock can introduce pollutants, such as manure, with negative consequences on water quality (Agouridis et al. 2005). These factors may adversely affect anguillid eel populations in rivers.

Livestock may be excluded from riverbanks by constructing fences or providing bridges over rivers, with the aim of preserving the integrity of riverbanks and maintaining better water quality (McKergow et al. 2003, Scott et al. 2023).

^{Agouridis C.T., Workman S.R., Warner R.C. & Jennings G.D. (2005) Livestock grazing management impacts on stream water quality: a review. JAWRA Journal of the American Water Resources Association, 41, 591–606. https://doi.org/10.1111/j.1752-1688.2005.tb03757.x}

^{McKergow L.A., Weaver D.M., Prosser I.P., Grayson R.B. & Reed A.E.G., (2003) Before and after riparian management: sediment and nutrient exports from a small agricultural catchment, Western Australia. Journal of Hydrology, 270, 253–272. https://doi.org/10.1016/S0022-1694(02)00286-X}

^{Scott A., Cassidy R., Arnscheidt J., Rogers D. & Jordan P. (2023) Quantifying nutrient and sediment erosion at riverbank cattle access points using fine-scale geo-spatial data. Ecological Indicators, 155, 111067. https://doi.org/10.1016/j.ecolind.2023.111067}

Study locations

Key messages

One study evaluated the effects of excluding livestock from riverbanks 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, before-and-after study in New Zealand found no change in shortfin and longfin eel density 8–10 years after building fences, bridges and water troughs to exclude livestock from riverbanks (along with planting bankside vegetation).

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

A replicated, controlled, before-and-after study in 1995 and 2003–2005 in two streams in North Island, New Zealand (Jowet & Richardson 2009) found that installing fences and bridges to exclude livestock, along with planting vegetation, had no effect on shortfin Anguilla australis or longfin Anguilla dieffenbachii eel density. The study does not distinguish between the effects of excluding livestock and planting vegetation. Average density did not differ significantly before and 8–10 years after fences and bridges were installed, and vegetation was planted, for shortfin eels (before: 15 eels/100 m, after: 10–12 eels/100 m) or longfin eels (before: 9 eels/100 m, after: 10 eels/100 m). Average density also did not change significantly over the same period at upstream sites in native forest for shortfin eels (‘before’: 3 eels/100 m, ‘after’: 1–2 eels/100 m) or longfin eels (‘before’: 21 eels/100 m, ‘after’: 5–11 eels/100 m). In 1995–1996, two streams (average 0.9–1.2 m wide) flowing through pasture were restored by building 12 km of fences, five bridges and 12 water troughs to exclude livestock from the stream banks, along with planting of bankside trees and shrubs. One unrestored section of each stream located in native forest was sampled for comparison. Eels were surveyed by electrofishing along one unrestored and two restored sections per stream (each 35–50 m long) before restoration in 1995, and after restoration in 2003 and 2005.
Study and other actions tested
Referenced paper
Jowett I.G., Richardson J. & Boubée J.A.T. (2009) Effects of riparian manipulation on stream communities in small streams: Two case studies. New Zealand Journal of Marine and Freshwater Research, 43, 763-774.

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?

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This Action forms part of the Action Synopsis:

Eel Conservation in Inland Habitats

Related Actions

Actions	Effectiveness	Studies	Category
Exclude livestock from riverbanks  Action Link	Evidence not assessed	1	Synopsis Link
Limit, cease or prohibit harvesting of wild eels for aquaculture Action Link	No evidence found (no assessment)	0	Synopsis Link
Limit, cease or prohibit aquaculture activity Action Link	No evidence found (no assessment)	0	Synopsis Link