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Wednesday, 2 April 2014

Book Review- 'The Sixth Extinction'

Review: ‘The Sixth Extinction: An Unnatural History’ by Elizabeth Kolbert; Bloomsbury, 2014.


On one fateful day 66 million years ago, the Earth’s gravitational field captured an asteroid. It was travelling at around seventy thousand kilometres per hour on a flat trajectory. It slammed into the Yucatan Peninsula and generated a white-hot, supersonic shock-wave which was directed mainly northward. The author of this book quotes a geologist who said: “Basically, if you were a triceratops in Alberta, you had about two minutes before you got vaporized (sic)”. Trillions of tons of sulphur- rich material were blasted into the air, which led to a condition analogous to a ‘nuclear winter’. Whole orders, families, genera and species of plants and animals went extinct – most famously the non-avian dinosaurs. It took the world millions of years to recover from these catastrophic circumstances – but they are probably why we’re here, rather than some descendant of the dinosaurs.

There had, in fact, been four mass extinction events before the one described above. The most devastating was probably the one at the end of the Permian, some 252 million years ago when around 96% of all living things went extinct – although the reasons for that event are not as well understood. When interviewed recently (http://www.theguardian.com/theobserver/2014/mar/09/elizabeth-kolbert-whole-world-becoming-zoo) the author of this book, Elizabeth Kolbert, stated that life on Earth is “contingent” i.e. subject to chance or unforeseen circumstances. The title of her book is based on the rapidly growing consensus among scientists that we’re now living through the sixth extinction event in the history of life on Earth – and that our own species, Homo sapiens, is directly responsible for it. Our current epoch is increasingly being referred to as the “Anthropocene” because our species is now so dominant and has so modified the planet’s surface and atmosphere that the fate of the biosphere is now in our hands.

Elizabeth Kolbert is an American journalist and author. She is best known for her book on climate change, ‘Field Notes from a Catastrophe’ (2006), and as an observer and commentator on environmental matters for the ‘New Yorker’ magazine. This present book is brilliant, lucid, very readable, scientifically up-to-date, tragic and utterly terrifying. We learn that although certain species, such as the Great Auk and the Dodo, have been deliberately exterminated through over-exploitation in the recent past, more recent losses can be directly attributed to our gross and ruthless modifications of the planet’s surface and atmosphere – in particular there are direct links between species’ extinction and climate change. For example, carbon dioxide is soluble in water and produces a weak acid. As the CO2 content of the atmosphere increases, the oceans become more acidic. This affects the viability of organisms that use calcium in their body plans; shellfish and corals are particularly badly affected. In tropical waters, reefs formed by corals provide ecological niches for thousands of non-coral species; if corals are damaged or killed, all of those dependent species are put at risk as well. Tropical rain forests contain hundreds of different tree species. Each tree species has specific habitat requirements and also provides niches for many other species of plants and animals. As temperature rises, trees which produce few seeds and/or are slow growing are at a serious disadvantage, and, consequently, so are their attendant species. Trees which produce lots of seeds and/or are fast growing can move uphill to cooler climes. But even the latter are still at risk because many rain forests are now so fragmented that there are limited spaces for them to move to.

The much vaunted ‘globalisation’ is a serious problem too. Many organisms have been (often inadvertently) transported around the world and have caused havoc in places in which they do not belong. Currently, Central American amphibians and North American bats are being wiped out by imported fungal diseases.
I took away two surprising ideas from this book:
1. This is undoubtedly the first extinction event in history which is being studied, in meticulous detail, by elements of the causal agent! In her research for this book, Ms Kolbert interviewed many scientists working in the field and accompanied some of them on their field trips. The ingenuity and dedication of these scientists is often astonishing.

2. Time scales can often be difficult, or impossible, to grasp; who can get their head round 66 million years – let alone 252 million years – for example? It is now, more or less, agreed that when humans migrated out of Africa, they exterminated large animals (mammoths, giant ground sloths, moas etc.) everywhere they went. Kolbert interviewed a paleobiologist, named John Alroy, who described this ‘megafauna extinction’ as a “geologically instantaneous ecological catastrophe too gradual to be perceived by the people who unleashed it.” The ominous fact is, though, that extinctions are currently happening within single human lifetimes. 
 
This is an important but scary book. Brace yourself and read it!

Dave Bishop, March 2014

Note: This review first appeared in 'Manchester Climate Monthly'. To find out more about Manchester's premier climate journal, you should e-mail the editor, Marc Hudson, on mcmonthly@gmail.com.

PS: I tried to add a picture of the cover of this book to top of this article but, for some unknown reason, this - bleep, bleep, bleep, bleeping - software wouldn't let me!! 

Tuesday, 22 October 2013

The Fallowfield Loop and 'Greening the Greenways'




The Fallowfield Loop (‘Floop’) is an off-road cycle path, pedestrian and horse riding route from Chorlton-cum-Hardy through Fallowfield and Levenshulme to Gorton and Fairfield in Manchester. It is part of the National Cycle Network of routes and paths developed and built by the cycling charity Sustrans. It is part of National Route 6 of the National Cycle Network which, when complete, will connect London and Keswick in Cumbria.

At 8 miles long the Fallowfield Loop is thought to be the longest urban cycleway in Britain. It was previously part of the old ‘Manchester Central Station Railway’, built in the 1890s and closed in 1968.

 The line had lain derelict for many years until the late 1990s, when a group of cyclists started campaigning for its conversion to a traffic free ‘greenway’ across south Manchester. That group, together with supporters from local civic societies and other community groups, formally became the ‘Friends of the Fallowfield Loop’ in June 2001. The route is now mostly owned by Sustrans, a charity which specialises in building off-road cycle routes. They have partly funded conversion of the route, together with Manchester City Council, Sainsbury’s and others.

The overall aim of the ‘Friends’ is to encourage and support all the partners in the Fallowfield Loop route to provide and maintain a first-class community resource and to encourage As many people as possible to use it.

The Floop creates a linear park and wildlife corridor, linking parks and open spaces. It has an interesting flora – some of which may represent all that’s left of the lost, ancient rural landscape of South Manchester. Some of the intriguing plants that I have found, over the last few years, include:

Hedge Parsley (Torilis japonica) – which is by no means uncommon nationally but is very rare in South Manchester – presumably because its precise habitat requirements are now only met by one little patch of ground by the Floop (?)
 
The scarce, pink-flowered bindweed hybrid Calystegia x howittiorum (although the exact identity of this plant needs to be confirmed).



Royal Fern (Osmunda regalis)


A Sphagnum moss (S. capillifolium)

 

The presence of the latter two plants suggest that the surrounding land was probably once much boggier – and it’s a miracle, really, that they have survived.
An evergreen, Chinese Honeysuckle (Lonicera henryii). This latter plant is obviously a garden escape – but I’ve never found it anywhere else.




Because of my interest in the Floop’s flora, I was delighted to learn, recently, of Sustrans’ ‘Greener Greenways’ project which started this spring (2013) and is a 3.5 year project that they are running in England on certain sections of their cycling routes. The project is funded by the Esme Fairburn trust and has allowed Sustrans to employ two ecologists to run the project. The outline of the project is in stages, beginning with the baseline surveying of the ecological status of 280 kilometres of cycling routes. The chosen sections are not all that Sustrans owns, or has management liability for, but they represent the majority of its holdings and hence some very significant sections.

The roll out of the programme will allow Sustrans to systematically build up their knowledge of the biodiversity of their greenways. They are aware that many of their volunteers have an interest and expertise in this field and hope to engage with that pool of enthusiasm and knowledge as the projects develops.
Once the 280kms of survey have been completed, mapped and analysed – the findings will inform Sustran’s ecology team and allow them to develop fuller management plans for the designated routes. They believe that this will allow them to make very practical but balanced decisions on work priorities for the routes and the wildlife corridors they run through. In turn, these plans will help to contribute to work plans that Sustrans staff and volunteers will be able to share.
Ultimately, Sustrans would like to recruit Wildlife Champions from their volunteer team and/or the local communities along their greenways. Potentially each champion could take on such a role for any given one kilometre stretch of greenway and help to monitor and to care for its wildlife. Sustrans believes that this will represent a great chance to engage with local communities who, in turn, can help them to enhance and protect some wonderful local habitats.

Initial surveys are being undertaken by a paid ecologist. These surveys will not supersede any work already done by any individual volunteers but they are intended to lead to a Phase One baseline. It should be noted that any additional information, that any volunteer or supporter of Sustrans might have, and is willing to share, would be considered very beneficial by the Ecology team. If you have any of this knowledge and think that Sustrans should know about it then, please contact Mike Dagley* of Sustrans in the first instance (for contact details, see below).
The timetable for the Phase One baseline survey is as follows:

August 13-14th Fallowfield Loop, Manchester
September 17-18th Chester Millennium Greenway

November 5-7th Hadrian’s Cycleway, Cumbria
Later this year Sustrans intend to develop Management Plans and specific recommended actions for each route. As well as informing Sustrans about the more nuanced management of their routes, opportunities will be created to form partnerships with Wildlife Trusts, local conservation groups, volunteers and all interested in making more of the ‘linear parks’ that these routes represent.

*Mike Dagley

Volunteer Coordinator

Sustrans Northwest England

5th Floor, 30-32, Charlotte Street

Manchester M1 4FD

0161 923 6050

0161 923 6053 (direct)

0787 645 3773


Dave Bishop, October 2013

References:

The Friends of the Fallowfield Loop: http://fallowfieldloop.org/
  

Thursday, 26 September 2013

Review: Manchester Festival of Nature, Heaton Park, Saturday 7th September 2013



Here, better late than never, is my review of this event earlier in the month.

According to the flyer which advertised the event, it was part of the: “BBC Summer of Wildlife”. Nevertheless, the small print on the flyer informed us that it was: “... not being organised or run by the BBC”. The BBC link appeared to consist of an opportunity to: “Meet Naomi Wilkinson from CBBC’s Wild!” Unfortunately, I seem to have missed that opportunity (drat!).
The actual organisers were Manchester City Council in collaboration with Red Rose Forest, Manchester Museum, the University of Manchester, the Environment Agency and Greater Manchester Local Records Centre.

My main involvement was with the latter organisation - which is in the midst of an important 3 year project called ‘Grey to Green’ (http://www.gmwildlife.org.uk/grey_to_green/). The aim of this Heritage Lottery funded project is to: “... encourage and train local people to identify and record wildlife. The project operates across the whole of Greater Manchester with a particular focus upon residents in Tameside, Manchester, Salford and Wigan.” The Grey to Green team has been running ‘bioblitzes’ at various wildlife rich sites, throughout this region, all year.  A ‘bioblitz’ is an event at which a group of naturalists attempts to identify as much of a particular site’s wildlife, as possible, in an approximately 24 hour period. This particular Heaton Park bioblitz was incorporated into the main ‘Festival of Nature’ event. It actually started the evening before when bats, moths and other nocturnal wildlife were detected and recorded. Other groups of plants and animals were recorded on the day of the main event. My contribution was to work with other botanical enthusiasts to record the site’s flowering plants and ferns. I’ve been involved with this project all year and it’s given me the opportunity to investigate and record samples of Greater Manchester’s wild vegetation from Prestwich to Wilmslow and from Wigan to Broadbottom. Even prior to any significant analysis of the data, I think that it may be possible to draw a few very tentative conclusions (at least about the plant life) – but more on that later.
The main festival event itself was, as these things usually are, a bit of a mixed bag. I confess that I didn’t get round to visiting many of the stalls that were present because I spent a lot of my time in the field. Nevertheless, I did get to speak to two ladies on the Environment Agency stall who wanted to hear people’s views on their organisation’s management of local rivers and river valleys.  As it happens, a number of wildlife groups in the Mersey Valley had discussions with the EA last year (2012) about their management of the river banks. The EA were prepared to enter into dialogue and this is currently leading to some very positive outcomes for the Mersey Valley’s biodiversity. I learned from the two ladies at the festival that the EA are now actively soliciting comments on the issues facing local river basins through a consultation. You can find out more on the consultation website at: www.environment-agency.gov.uk/challengesandchoices . If you have any opinions on this subject, please contribute to the consultation – I certainly will be.

I also had an interesting chat with a postgraduate student from the University of Manchester who is in the process of completing a PhD on freshwater algae; he had some nifty little microscopes with screen displays – so that I could see what the microscopic plants, that he was studying, looked like.
There seemed to be a lot of silly, vaguely wildlife-related, things for little kids to do. Children, with whiskers painted on their cheeks, and wearing sparkly cardboard ‘bunny ears’ rushed around stroking stuffed foxes and badgers and viewing various hapless living creatures in a variety of tanks and cages.  I am, of course, a bit of a curmudgeonly old git – but even I don’t disapprove of little kids doing silly things and having fun on a Saturday afternoon! Nevertheless, these silly things are supposed to fill them with enthusiasm for wildlife. Do they? I wonder if the council has ever checked? To my knowledge, the Council has been running these types of events for around a generation now. I wonder how many little kids, who were persuaded to construct and wear sparkly bunny ears 20 years ago, are now enthusiastic and knowledgeable naturalists? I hope that my scepticism is unfounded. If you are an enthusiastic and knowledgeable naturalist, and were inspired to become one through making and wearing sparkly bunny ears 20 years ago, please comment on this post and put me right!

One peculiar and unaccountable aspect of this festival was a tent full of drummers (!) What their remorseless, monotonous, interminable thumping had to do with wildlife, I will probably never know. For a while they could be heard all over the park and I narrowly escaped being driven completely mad. I briefly toyed with the idea of applying a penknife to all of the percussive surfaces in the tent – mercifully, I came to my senses and realised that I didn’t really want to go to prison for drumicide (there is, of course, no such crime as “drumicide” – I made it up!).
The ‘star’ of the show was, of course, Heaton Park itself – or rather it should have been. It is, I believe, the biggest park in Manchester. Nevertheless, the bits that I saw were not very biodiverse and maximising their biodiversity did not appear to have any sort of priority. As far as I was able to tell there were three main types of habitat in the park: lots of obsessively mown grass, some overgrown, gloomy tree plantations and some unmanaged, scruffy bits. The dominant flora was a rather dismal assemblage of (all too common) plants which, I’m afraid, I could have, more or less, predicted before I laid eyes on it. I can recite species off the top off my head: Common Nettle, Broad-leaved Dock, Creeping Buttercup, Meadow Buttercup, Yorkshire Fog Grass, Timothy Grass, Soft Rush, Greater Plantain, Ribwort Plantain etc., etc., etc.  The ubiquity of this assemblage, in so many sites in Greater Manchester, is, I fear, an indicator of how species-poor our local biodiversity has become.  

Significant populations of the two alien, vegetable thugs, Himalayan Balsam and Japanese Knotweed, were evident in a number of places. It is possible to control the former, if the will exists to do so, but controlling the latter can be difficult and expensive.
The most interesting plant find of the day was also an alien. It occurred on a little patch of disturbed ground in the midst of a sea of closely mown grass. The plant in question turned out to be Cape-gooseberry (Physalis peruviana - see photo above). This species is unrelated to gooseberries but is, in fact, a member of the tomato family. Its fruits are like miniature yellow tomatoes and are edible. It’s originally from South America but I believe that it’s now grown commercially for its fruits in various parts of the world (e.g. South Africa). I’m not sure if it’s grown on any significant commercial scale in the UK. This was only the second time that I’ve seen this plant, in the wild, in Manchester. Curiously, I found my first one, in Hulme, about a week before.  I looked it up in the ‘Bible’ i.e. Prof. Clive Stace’s monumental ‘New Flora of the British Isles’ (3rd ed., 2010). I learned that it is: “Intr[o]d[uced]-nat[uralise]d; imported as minor fruit and casual on tips, nat[uralised]d in Herts; occasional in Br[itain], mainly S[outh] ...”

So do my two finds suggest that it’s moving north? Some authorities believe that some alien plants, will respond to climate change by doing so in the near future. Well, no - to advance such a hypothesis, on the basis of two finds, would be ridiculous! But ask me again in a few years time.
I learned on the grapevine that this event had cost the Council around £10,000. I rather wish that they’d spent the money on improving the park for wildlife.

Dave Bishop, September, 2013    

Friday, 30 August 2013

Unravelling the Web of Life

Marc Hudson, of Manchester Climate Monthly, has just sent me the following link to a sad and terrifying piece by the Canadian biologist, Neil Dawe:

http://www.oceansidestar.com/news/web-of-life-unravelling-wildlife-biologist-says-1.605499

Please read it!

It may seem overly dramatic to compare the Mersey Valley to the wilds of Canada - but my experience of our local green haven, over the last 40 years or so, is eerily similar. We have lost so many species over that time and all we've got now is a species-poor tangle of nettles and brambles.

I've come to the conclusion that there is no such thing as 'progress' any more - just accelerating environmental destruction.


Dave Bishop, August 2013

Sunday, 18 August 2013

Bat and Moth Night, Chorlton Ees and Ivy Green, 10th August 2013



When I emailed Dave Bishop to enthuse about the Bat and Moth Walk last Saturday evening he asked me if I would write a short account for the FOCM blog.

Here goes………….

My first thought - read Dave's account of last year's Bat & Moth night and smile smugly (no that's not the word I was looking for) I mean contentedly that we had much better fortune this year.

The humour of Dave's description of last year's event did make me smile "Everyone seemed perfectly happy to stand around in the dark and the pouring rain, in a flooded car park, chatting about bats and moths - while the subjects of these conversations were sensibly tucked up in their little bat and moth beds. Eventually sense prevailed and we all went to the pub"

On the night of 10th August 2013 we were blessed with fine weather and an amazing turn out of people to look at and learn about bats and moths AND we did not see the inside of a pub at all.


Our evening started with an introduction to moths lead by Ben Smart. Ben had kindly brought some moths which he had caught locally in his own garden the previous night. It was wonderful to see some of the more colourful and unusual moths which can be found in our local area. The moths included the stunning Red Underwing which has upperwings which are perfectly camouflaged against tree bark in order that the moth can rest unnoticed on a tree and vibrant red underwings which it can flash to startle any predator which disturbs it. Other lovely colourful moths which Ben had brought along for us to see were a Bloodvein, an Orange swift and a Canary-shouldered Thorn. Moths such as the Pale Prominent were really interesting shapes and others like the little Antler moth had very distinctive markings (well, like antlers really) which give them their names. Some were so well camouflaged and "twig like" that we all had to look and then look again to even see them whilst they were resting on their twigs.

 
I have to confess to rather liking the Dingy Footman which does seem like a rather disrespectful name to give to a lovely silky moth with pale edges to its wing which make it look like it has a halo. As someone who is very keen on moths, I was in my element and it was lovely to see how enthusiastic and pleasantly surprised many people seemed when they saw just how varied and colourful many of our British moth can be.

A moth trap (light trap) was set up on one edge of Ivy Green car park and Ben ran this trap for us whilst the bat walk took place.


 The Bat walk was lead by Richard Gardner. Richard gave us some background information about our UK bats and the types of bats which we may expect to encounter on our walk with him. The group had some bat detectors to share out and Richard explained to us all how these worked by converting bats ultrasonic echolocation calls into sound at a frequency which we could hear. He explained how echolocation worked for bats and what their calls would sound like when we listened to them using bat detectors. I was really keen to practise using my own bat detector which I had recently purchased and it was so useful to have an expert on hand to confirm the identification of the bats.

I think that we all liked hearing the "feeding buzzes" which can be heard through the detectors as the bats close in on their insect prey.
 
Richard also gave us some really interesting "Bat Facts"

A tiny Pipistrelle bat can eat 2000 - 3000 midges per night (we were both amazed and very grateful for this!)

 Bats fly with their hands. Their wings are made of a thin membrane which stretches across the bones which in our bodies would form our hands.

Bats mate before they hibernate in the winter but the female bats delay the subsequent fertilisation and do not "become pregnant" until the following spring.

We saw and heard both Common and Soprano Pipistrelle bats flying over Chorlton Brook. Common Pipistrelle's peak echolocating frequency is around 45KHz and Soprano Pipistrelle's peak echolocating frequency is around 55KHz. We tuned the bat detectors when were heard the echolocation calls in order to tell which one of the two types of Pipistrelle we were listening to. We could also see the bats when they flew into a clear area where they were silhouetted against the sky. We marvelled at how tiny and agile they were.

 
After leaving the Brook and heading across the meadow, we arrived on the banks of the Mersey where we heard more Pipistrelles and in addition we saw and heard Daubenton's bats. The sound heard through at bat detector for these bats differ. Pipistrells produce a sound which is often described as a "wet slap". Daubenton's bats sound is a faster "dry click" (a bit like a fast two stroke engine!).

The Daubenton's bats could just be seen skimming the surface of the Mersey, "gaffing" insects from the river. Gaffing is a term which means that the bat is using its feet to grab insects as it is flying along very close to the water.

 
After some excellent "batting" we returned to the Ivy Green car park to investigate the moths which were being attracted to the light trap. Large Yellow Underwings were flying around the light and the dark yellow colour of their underwings could be clearly seen. Amongst the other moths there were more Dingy Footman, Pale Prominent an attractive "micro-moth" called a Mother of Pearl moth which had pale iridescent wings. My absolute favourite was a Sallow Kitten moth. I saw this species of moth later in the week and thanks to Ben's excellent moth identification and explanations, I was very pleased to be able to recognise the moth again when I saw it.


 My thanks go to both Richard and Ben for this very enjoyable event. I would love to learn more about moth identification and if you are likeminded and would like to take up moth identification (and very importantly) submitting records for the moths which you see in the Manchester area, then perhaps you could let me or Dave Bishop know. If there is enough interest it would be wonderful to draw upon Ben's experience and expertise to learn more about identifying these wonderful insects.
 
Debbie Wallace

Thanks to Ian Brusby for the wonderfully atmospheric photographs that he took, on the night, in the car park - Ed.

Thursday, 15 August 2013

Wildlife Activities at Heaton Park, 7th September 2013




There's a Manchester Festival of Nature being held at Heaton Park on Saturday 7th September. All are welcome and it's FREE!

As well as the wildlife focussed family activities the Greater Manchester Local Record Centre will be running a series of 'bioblitzes' in the park as part of their 'Grey to Green' project. For those people who may not know what I'm talking about, a bioblitz is an event at which the participants attempt to identify as much wildlife as possible, on a particular site, over a limited period of time. If you're interested in finding out more, have look at the following page:

http://www.gmwildlife.org.uk/news/index.php

Bioblitzes are great fun and to join in, participants do not need any experience. For more details contact either me (davegbishop@aol.com) or Matt Holker (matthew.holker@tameside.gov.uk) of the 'Grey to Green' team.

Dave Bishop, August 2013

Tuesday, 6 August 2013

A Walk from Chorlton to Didsbury in July


When Transport for Greater Manchester destroyed the wonderful plants and habitats of the Lower Hardy Farm SBI, with their hideous Metrolink-to-the-Airport bridge, they also closed off the path, on the south side of the river, which leads eastward towards Didsbury and Stockport. Recently, though, they have re-opened this path and on Tuesday  9th July 2013 I seized the opportunity to walk it again and re-visit those of my favourite spots which haven’t been destroyed by ‘progress’ ... yet.

The weather was gorgeous and the day felt to me to have a particularly pleasing, summery ‘savour and flavour’ to it.

The first part of the walk took me past Sale Golf Course. Now here’s a thought - have you ever noticed how much green space in Greater Manchester is devoted to golf courses? If it has never occurred to you, just try flicking through the ‘Manchester A to Z’;  there appears to be a golf course on nearly every page (apart from the City Centre of course!); some pages show two – or even three. I just thought I’d point this out – particularly as golf courses are not particularly biodiverse. If we had as many biodiverse spaces as golf courses then, perhaps, we wouldn’t be in the midst of a biodiversity crisis (?)

Beyond the golf course there’s a large electricity sub-station with extensive open space around it.  I’ve known this area for at least 30 years and it’s always had an interesting flora. I think this is mainly due to the fact that, sometime in the past, a load of limestone chippings were spread over it. Part of this space is open and the other part now has a rather sparse birch wood growing on it. On the open part is a sign saying ‘Private Land’. Although I’ve never been stopped from entering site, I always experience a slight ‘frisson’ when stepping over the rusty barbed wire perimeter. I calm myself by pretending that I’m the great early 19th century Manchester botanist, James Crowther. James, a warehouse porter from Hulme, would range miles on his botanical expeditions and was often chased by gamekeepers - who tended to mistake him for a poacher. James usually managed to out-run the gamekeepers but there’s no doubt that, these days, they’d catch me easily! I also suppose that if, on that Tuesday in July, anyone had intercepted me I would merely have been ordered off the site. James, on the other hand, probably risked being transported to Botany Bay (how horribly ironic that particular fate would have been for him!).

There were numerous Common Spotted Orchids (Dactylorhiza fuchsii) on the site. In spite of the name, these are not as common around here as the members of the Marsh Orchid group (also in the genus Dactylorhiza). They are slim and delicate and often have dark spots on the leaves – which are probably the origin of the common name.
 

Also present on this site were small patches of Mouse-ear Hawkweed (Pilosella officinarum). These have delicate little, lemon- yellow, dandelion-like flowers. The patches have runners and small leaves with white hairs (I assume that these leaves are supposed to resemble the ears of mice ...).


Is Mouse-ear Hawkweed really a ‘Hawkweed’? That name should possibly only apply to plants in the genus Hieracium. But Pilosella and Hieracium are closely related (Professor Stace informs us that “evidence for [their] distinctness is equivocal”). Nevertheless, there is at least one ‘true’ Hawkweed on the site. At present, I can’t name this plant and would probably have to send off a specimen for full identification. You see, Hawkweeds are one of the most difficult groups in the British Flora. Apparently, all Hieracium flowers are female and the plants reproduce via an asexual process called ‘apomyxis’. One of the consequences of this process is that it gives rise to a multiplicity of similar, but distinct, forms known as ‘apomictic microspecies’ (no, I don’t understand any of this either – I’m just parroting what I’ve read - and I realise that I’m in very deep water here!).


 
Prof. Stace, in his magisterial ‘New Flora of the British Isles, tells us that, “411 microspp. are currently recognised in the British Isles.” Even he doesn’t give a full account but divides the genus up into 15 sections.  A simpler account, in a book called ‘Wild Flowers of Britain & Ireland’ by M. Blamey, R. Fitter and A. Fitter, gives three main types of Hawkweed: Leafy, Few-leaved and Basal Leaved. I think that the plants under discussion are probably of the Few-leaved type. We used to have at least two of the ‘Leafy’ type on Lower Hardy Farm (one of them, I believe, quite rare) but, as noted at the beginning of this piece, that wonderful place has now been destroyed.

The open part of the sub-station site shows every sign of being rabbit nibbled. As I noticed this, as if on cue, a rabbit appeared. It has always puzzled me as to why rabbits occur much more frequently on the south side of the river than on the north side. I’m a little disappointed that, in the middle of the night, the rabbits don’t go ‘hippity-hoppity’ across the footbridges, like characters in a Beatrix Potter story ... but they probably don’t ... oh well ...

A bit further on, a large wild rose bush marked an entrance to the Kenworthy Woods site. I identified the bush as Sweetbriar (Rosa rubiginosa). Our wild roses have such beautiful flowers, but they only last for a few weeks each year. As you can see from the photograph, the hoverflies appreciated the lovely flowers too.

 

Less than a hundred yards beyond the rose bush, I encountered, on the upper bank, the creamy white flowers of Common Valerian (Valeriana officinalis). I believe that the ‘officinalis’ part of the scientific name translates as “of the shop” – by implication, the apothecary’s shop – for this is a herb with medicinal properties. In her book, ‘A Modern Herbal’ (1931) Mrs M. Grieve tells us that extracts of Valerian can be used to treat disorders of the nervous system. I have a species of Valerian growing in my garden (I’m not sure which species it is because the magpies long ago stole the label). This plant certainly has an effect on the nervous systems of cats. Last winter I noticed that the soil of the site where the Valerian grows was so compressed it was almost shiny. One day I caught a small black cat rolling frenziedly around on this patch of ground. Valerian is a perennial which dies down in the winter and at that time of year nothing is visible. So I must assume that the cat’s nervous system was being stimulated by the scent of the plant’s dormant roots lying just below the surface.

 

A long stretch of upper bank was dominated by the huge leaves of Butterbur (Petasites hybridus). In my mind this plant is highly characteristic of the Mersey Valley. I believe that generations of local kids have known it as “wild rhubarb” – although the resemblance is superficial. It is, in fact, related to the Hawkweeds I encountered earlier – not rhubarb! Both Hawkweeds and Butterbur are members of the great Dandelion/Daisy family – the Asteraceae. In the case of Butterbur, the flowers appear before the leaves and these leaves don’t appear until the flowers have died away. In many parts of the UK, only the male flowers are present. In these cases they reproduce vegetatively, presumably forming clonal patches and spreading via pieces of root breaking off and forming new patches. In this part of the North West both male and female flowers occur and the females produce seeds (not sure how viable they are though). Both male and female flower heads are odd pinkish, almost ‘fungoid’ looking things. Once the female flower heads are fertilised they elongate into long tassels which are easy to spot in March/April.



I walked further and by this time the sun was getting hotter. On the opposite bank I noted two gentlemen striding along deep in conversation. They were smartly dressed and their only concession to the weather was to have doffed their suit jackets and to have donned Panama hats. There was something rather Edwardian about them. They fitted in well with the fine Edwardian houses of West Didsbury just visible through the trees.

On my side of the river I spotted something ominous on the lower bank – a specimen of the alien Giant Hogweed (Heracleum mantegazzianum). This is a member of the Carrot family – the Apiaceae. It is closely related to our native Hogweed (Heracleum sphondylium). Members of this family tend to have the same general form with white or yellow flowers arranged in a flat head or ‘umbel’. H. mantegazzianum is as monstrous as its sinister, buzzing name. It’s about twice as big as our native species and its great hollow, hairy stems are covered in sickly looking reddish-brown patches. The leaves have a spiky outline and the compound umbels are huge. But even more monstrous is its effects on human skin. By coincidence, I was talking to a Polish lady recently who had encountered this plant on a visit to Russia. Somehow she had brushed against it and it had raised blisters on her arms. Soon these blisters had turned to infected ulcers for which she had required medical treatment.

 
Giant Hogweed is a native of the Caucasus Mountains. It’s certainly a dramatic plant and that’s probably why Victorian gardeners introduced it into British gardens. What they didn’t realise, until it was too late, is that it’s very invasive (as well as toxic!). Now Greater Manchester river valleys are full of it. It’s certainly common in the Croal-Irwell and the Bollin Valleys but 2013 is the first year that I’ve begun spotting it in the Mersey Valley too.

Eventually I arrived in Northenden for lunch. I like Northenden – it’s a pleasant riverside settlement. Or, rather, it probably was just a few decades ago. Now, like hundreds of other settlements, in Greater Manchester and the rest of the UK, it’s being steadily ‘ruined-by-progress’. Surrendering our landscapes to the motor car and handing property developers so much power over our built environment and green spaces were never good ideas and future generations will curse us for these follies.  In a front window I spotted a sign saying: “Save Northenden Library”. The sign prompted the gloomy reflection that perhaps our society is now in the process of abandoning ‘real’ progress. Things like public libraries and universal education and the National Health Service were truly progressive – now our political masters want to either sell them off to the highest bidder or to dump them all together; why are we putting up with this?

After lunch I walked down Ford Lane, past Northenden’s fine old sandstone church, and still muttering darkly to myself about the state of the world. I cheered up a bit when I spotted a Polypody (Polypodium sp.) fern growing on an earthen bank at the base of a hedge. I expect to see these ferns growing on walls or, occasionally, on trees – so this was an unusual sighting. There are three species of Polypody in the British flora: Common, Intermediate and Southern. To cut a very long story short, the species around here usually turns out to be Intermediate Polypody (P. interjectum). The picture below, by the way, is of a specimen that I found on a wall near my house a couple of years ago - it's a better picture than the one that I took on the day of the walk.


 
I continued on until I reached Simon’s Bridge and crossing this bridge, I arrived at the head of Stenner Lane, Didsbury. In base of the hedge, by the side of this lane, is a patch of a plant called Dog’s Mercury (Mercurialis perennis). I always make obeisance to this plant as I pass it as it’s an indicator of ancient woodland. At one time the floodplain of the Mersey would have been fringed with woodland – and in this district, this plant may be all that is left of those old woods. Recently, a fellow member of the Manchester Field Club told me that the doyenne of local botanists, the late Audrey Franks, discovered this little patch of Dog’s Mercury long before I did.



A few yards further on the leaves of Ramsons (Allium ursinum) appear in the hedge bottom and beyond that Ivy (Hedera helix) appears. I suspect that this mixture of plants implies that this hedge has a complex history and that one end is much older than the other.

A couple of years ago I found a plant called Ivy Broomrape (Orobanche hederae) growing on the Ivy covered bank of a ditch within about 2 miles of this spot.  Broomrapes are parasites which have no chlorophyll and derive all of their nutrients from the roots of their hosts. The plant on the bank is the only Broomrape that I have ever found around here and now I scan every patch of Ivy I encounter for more. I had no luck on this particular day but a few days later Mike Pettipher, of the Altrincham Naturalists, sent me an amazing photograph of a huge patch of Broomrape (probably O. hederae) growing on the banks of the Bridgewater Canal somewhere between Stretford and Manchester city centre. I haven’t had a chance to go and see this plant yet and will probably have to wait until next year now.
And so to Fletcher Moss and a nice cold drink in the park’s excellent cafe.

And then I caught the number 23 bus back to Chorlton.

Dave Bishop, August 2013