Sunday, 4 December 2016

The Wild Trout Trust and New Forest River Restorations

For some perspective on some of the issues raised by river restorations we contacted the Wild Trout Trust, themselves deliverers or partners in many river restoration projects addressing similar issues to those met by the Latchmore proposal.  As it turns out, they had made an advisory visit in September 2015; this was undertaken by their Conservation Officer, Mike Blackmore.

Their advisory visit programme is "very much focussed on identifying good and poor trout habitat and what can be done practically to make the poor good. Mike looked at a 1 km reach of the Brook and a 500m reach of a tributary, the Thompson's Castle Stream."

Their key findings were:

  • Valuable wild trout habitat is under threat by the status quo condition of the Latchmore Brook and tributaries.
  • Channel incision and accelerated morphological processes as outlined by the JBA Consulting report and as observed during the site visit are limiting the abundance and quality of marginal habitat (important for freshwater invertebrates and juvenile trout). These factors are also likely to be significantly impacting the viability of spawning habitat in the main channel.
  • Reconnecting paleo-meanders will result in a net increase in habitat for wild trout (as a result of increased channel length) and is likely to help protect existing spawning habitat by reducing the rate of channel incision and the magnitude of cut and fill events.
  • The overall paucity of in-stream and low-level bankside woody habitat features significantly limit the abundance, diversity and quality of cover and refuge habitat for trout.
  • Habitat quality and diversity is being significantly reduced by over-grazing and bank poaching by livestock.
  • Further habitat enhancement, including tree planting and the introduction and retention of woody habitat features, will be required to provide a good quality and diverse habitat for wild trout.
  • Improvement in the wild trout population of the Latchmore Brook and the aquatic ecosystem upon which it is dependent will require a significant change in land management including improved protection of the riverbanks from grazing livestock.
Their conclusions recognize the problems with the status quo and acknowledge the benefits of the project to fish species and wildlife. They also suggest measures which would make the habitat optimal for trout species, promotion of stream shading scrub, and fencing to prevent livestock poaching scrub and vegetation bankside, which would fly in the face of traditional forest management, and would even restrict the amenity in ways to which even the protesters would object.  How would Forest users react to the sight of a fenced off stream, with access only through gates?

Scrub does vary over time, and we know that historically there has been, at times, little scrub along stretches of the stream on the open forest.  Even now, there is about a kilometre stretch with next to no riparian shade.  The Commoners often push for active scrub removal to create more grazing (The NFA will usually push for key nectar species to be left where possible), and of course the livestock themselves will have nibbles that hamper growth. 

So, neither the current stream nor the proposed change would be absolutely ideal for fish species, but here's where the point is being missed by objectors' narrow focus.  Habitats are complex.  What benefits some species may be detrimental to others.  The biodiverse rich habitat of the New Forest is not managed solely for any single species.  Scrub removal may warm some of the unshaded water, but this will benefit the Dragonflies, even if it narrows the tolerances for the fish.

Despite the insufficient scrub, both historically and at present, fish tolerate the conditions in the Brook.  Restoring the meanders will recreate the more natural morphology that benefits these species.  The claim that changing the stream will frighten away shy fish, is refuted by many the projects elsewhere aimed at wild fish habitat improvement which restore meanders (some other successful projects go even further and create meanders), including projects directed at fisheries (over 900 in the RRC database), and even more strikingly here in the New Forest, by the fish themselves.  Brown Trout were recorded spawning in a restored section at Harvestslade within three months of the completion of that project.

We thank the Wild Trout Trust for their permission to share their findings (particularly their director, Shaun Leonard who provided the bullet point summary quoted above), and for their candour and generosity in response to our queries.  We commend them for their fine works in implementing and promoting habitat restoration. According to Environment Agency monitoring, their upper Itchen project has produced a four-fold increase in trout biomass, compared to unimproved, control sites.

For further information on some of their projects, and ways to help, on the WTT website: