I come to praise Himalayan Balsam, not to bash it …

In a nature reserve near you, hardy work parties of wardens and volunteers will have ‘bashed’ the dreaded exotic invader Himalayan Balsam (Impatiens glandulifera or HB) all summer. Introduced to Britain in 1839, it is our fastest growing annual plant with beautiful flowers and explosive seed pods loved by children. But according to Natural England and the Environment Agency it:

·         Is a highly invasive annual weed, which can reduce biological diversity by outcompeting native plants for space, light and nutrients

·         Restricts access to the river, leaves autumn river banks bare of supporting vegetation and prone to erosion and the dead plant material increases flood risk.

·       Attracts pollinators away from native species, reducing the genetic diversity of native species and fitness by reducing seed set.

But the charge sheet feels a bit hysterical. Can any plant be this bad? What is the evidence? Once you start to dig a bit, there’s not much. A few short term studies, one that looks at the effect on just a single native species, some that don’t really support the conclusions put about by our conservation bodies at all. Few seem to have been subjected to peer review, a scientific process that allows us to be fairly certain about the results. Indeed given the urgency of the calls to eradicate HB, not much at all. But what do the experts actually say?
A study by Hulme and Brenner[i] showed that more species are present if you remove Himalayan Balsam (HB), but noted ‘in open and frequently disturbed riparian vegetation, many of the species negatively influenced by Impatiens are widespread ruderal[1] species. Thus while several authors recommend its removal such action may only lead to a compensatory increase in the abundance of other non-native species and thus fail to achieve desired conservation goals.’ This doesn’t suggest that there is much effect on the sort of native plants that we might want to conserve. TIckner[ii] compared the competitive ability of nettle and Balsam sometimes our native nettle loses out. But nettle only grows where there are a lot of nutrients – the sort of sites that have little diversity of other native British plants anyway.

Chittka and Schürkens[iii] reported that suggested competition for pollinators might reduce the amount of viable seed set. But they only looked at the effects on Stachys palustris, which is pretty common anyway, and even then it was a one season trial. This is a long way from showing that in a real habitat HB affects the viability of even this one species which is of no real conservation interest, let alone other species. We know that HB has high-sugar nectar and flowers for a long time. But of course it might just support more bees in the medium term leaving the same number of bees available to pollinate other flowers. And finally Tanner[iv] looked at the effect on invertebrates. The evidence was inconclusive and fertile ground for a follow-up study.

I can’t find a scientific paper that looks at the alleged erosion-enhancing effects of HB; all the evidence seems to be anecdotal. HB often inhabits urban river banks where flows are unusually peaked, favouring the sort of erosion that HB is blamed for. It might of course be that HB is just good at colonising river banks that are already prone to erosion and that this is nothing to do with HB.
So there you have it. The studies are generally short-term and focus on the disturbed, urban and the sort of nutrient-rich habitats that HB favours rather than more important plant communities. None of the studies ‘prove’ that HB reduces biological diversity in the long or medium term, or that it is responsible for erosion, or for reducing genetic diversity. Of course, the scientists themselves are honest about pointing these issues out in their paper, and state that more research is needed. But these caveats are never reported in the campaign against HB.
That there is so little hard evidence that HB harms conservation is bad enough. Even worse than this, Wadsworth looked at control strategies and concluded that they are ‘rarely effective in the long term’. Now I’ve ‘bashed Balsam’ myself, enjoyed it, and even met some nice people. It is certainly true that HB gets in the way and takes up a lot of space. There may be a need to remove the plant where it blocks a path. But in an age of austerity should we really be spending millions of hours and millions of pounds fighting an enemy when the case is so weak?

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[1] Scientific name for plants that tolerate disturbance. Examples include docks, dandelions and thistles.

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[i] Hulme and Brenner 2006: Assessing the impact of Impatiens glandulifera on riparian habitats: partitioning diversity components following species removal (Journal of Applied Ecology2006 43, 43–50)

[ii] Tickner et al 2001: Hydrology as an influence on invasion

[iii] Chittka and Schürkens 2001: Successful invasion of a floral market

[iv] Tanner et Al 2013: Impacts of an Invasive Non-Native Annual Weed, Impatiens glandulifera, on Above- and Below-Ground Invertebrate Communities in the United Kingdom

Transporting Burnley into the future

While the big rail money is splashed on London and HS2, and Northern rail electrification is cancelled, what about Burnley? Robbed of direct trains to Manchester in the 1960s and industry in the 1980s, better transport links are now seen as essential if Burnley is to gain from the 'Manchester' effect'.

Lancashire have quietly beavered away with their EU Citizens Rail project to provide a new hourly train service to Manchester appropriately from Manchester Road station, and have funded a new ticket office. Externally it is functional and a bit ugly; clearly not the ‘attractive and iconic gateway to the town’ promised in the brochure. And no sign of the promised ‘coffee cart’. But definitely an improvement on no building; at least you can wait in the dry. The open cycle racks and locked wheelie bin compound shows the comparative priority given to waste and cyclists. The forecourt is overdesigned and over-engineered - a lot of cash has gone into making life difficult for pedestrians in an unimaginative, 1980s way. It’s hard to resist the conclusion that a better job was possible for half the money.

There is no sign of a buses apart from an old bus shelter on the otherwise untouched Blackburn platform, so it’s a walk into town. The diagrammatic map at the station is confusing and one of the good commercial maps now universal in London would've been cheaper anyway. There is the inevitable pedestrian-hostile roundabout. Then a nice canal-side development (visitor centre closed), and a lovely Victorian town hall and theatre, evidence of Burnley’s proud past. But opposite, the unpleasant 1960s Chaddesley House shows the extent of the subsequent architectural and social decline. Occupied, but barely maintained by social services, at least there is a Wetherspoon’s a few doors down to cope with the fallout. And their coffee is good and cheap. In the middle distance looms a vast Tesco Extra. No doubt it was justified as 'edge of centre as it hollowed out the town centre. Only the football club has performed in Burnley in the last couple of decades.

I take the new train. Every hour a 30 year old diesel with a grotty toilet and ripped seats strolls towards Manchester (less than 30 miles) in a leisurely 53 minutes. It dawdles and then stops and inches gingerly across the new single track ‘Todmorden Curve’, delivered late but maybe that was just as well since the current gently rusting trains have only just become available. We pick up speed downhill, but driving is quicker most times of the day and certainly cheaper if you are on your own - £12 return in the peak, or £10 if you can. In the big city, if you want to continue your journey by Metrolink you will need a new ticket; by bus there is theoretically ‘plusbus’, but you have to buy it at the same time as the rail ticket and understand pages of confusing conditions. For instance, it claims to be valid throughout Greater Manchester, but the validity maps only show central Manchester. Very, very few people use Plusbus. We don't want your southern integrated ticketing here, lad.

This is the 'Northern Powerhouse', or 'Northern Powercut' now electrification plans are on hold. But what should we aspire to, what could we reasonably achieve and what should we settle for under the current circumstances?

We can agree that Lancashire have done their best, building a new station building and rail service at a time when resources are difficult to find and spare diesel trains are scarce; they have brought in European funding, and perhaps more importantly expertise. But I think we can all agree that we can and should do better.

A German service between comparable towns in, say the Ruhr or in The Netherlands in the Raandstaat would have modern, airy stations served by up to six modern electric trains every hour. Bus and tram connections would be available at both ends and included in the ticket price and they would even wait for the train (yes, really), but you might not need them as the train would probably continue in a tunnel under the city to your destination. Stations would have ample cycle parking, there would be good cycle and walk maps, cycle hire and certainly and safe and convenient cycle routes. Car drivers would acknowledge your existence, although my experience is that taxi drivers will still moan about you in the pub.

Maybe we can’t have all this now, but Scotland (5 million people) has improved and electrified railways and even built the 30 mile new Borders Line. Compared to this, Greater Manchester and Lancashire (bit over 4 million) has done little apart from build Metrolink tram lines - fine, but not really a solution for longer journeys. There isn’t even  any integrated ticketing worth mentioning even though Manchester owns the tram network. Of course Scotland is not perfect – the Edinburgh tram problems show this, but with a devolved Government, at least they have a choice while the northwest has the odd scrap thrown by the Treasury. With the cancellation of Trans-Pennine electrification, perhaps 30 year-old trains and 30mph is the way forward for Burnley in the foreseeable future. Or maybe not.