August 2025

I had thought that the Dave Lofthouse Glade might be ready for its annual meadow mow, but in mid month I found it to be quite colourful. There was a scattering of the yellow flowers of Bristly Oxtongue and the Creeping Thistle was flowering again. It appears that the return of rain this month has given these a new lease of life. I have been scattering seeds of Meadow Vetchling there in recent years and this month I found it in flower for the first time. That brings the list of species that have been seen there since meadow management began to 147, this year's total to 52 species and the number found on the day to 35. It will need mowing before the end of September with the arisings racked off. I'm hopeful that Merton Greenspaces will help with this, saving much hand labour.

I did the monthly bird count on the 18th. The geese moult was over and many of them were feeding out in the public park or the grasslands of the ex-golf course, those from the public park making their way back to the lake as dog walkers arrived when the gates were opened at 06:50. The 80 Greylags continued to outnumber the 50 Canada Geese and 20 Egyptian Geese. The Mute Swan pair has been remarkably successful, with seven well-grown cygnets. The three Cormorants and two Great-crested Grebes suggest that the fish populations may have recovered somewhat from the recent dearth. A sole Grey Wagtail was feeding along the lakeside promenade. This species is now established and breeding and also often spotted in the brook.

I have continued to prune back around the edges of the perimeter path where potentially invasive Brambles grow. It's possible to remove this year's arching stems, so preventing them leapfrogging out into the adjacent grassland, whilst leaving the flowering and fruiting spurs to be enjoyed by people and by birds. Sadly, the heavy pruning by Idverde at just the wrong time of year removed flowering and fruiting spurs, not only of Bramble, but also Dog Rose, Honeysuckle, Elder, Blackthorn, Wild Cherry and Hawthorn. These aren't invasive and can be pruned back, if necessary, once the fruits have been consumed. The significant early summer drought has left the birds with less natural food than usual and, sadly, there will be little fruit for them in the autumn also. There's also an aesthetic point, which will be a matter of preference. Pruning with machine tools lends itself to "tidy" clean-edged shrubbery in places where an irregular edge would look more natural. 

There is a heavy acorn crop this year, unfortunately mainly infected by the Knopper Gall wasp. Fortunately some acorns escape infection and are carried off by Jays and Squirrels and buried. Those not later dug up and in the right growing conditions will germinate and potentially colonise. 

 

July 2025

There are two species of bird on the lake that increased greatly when there was a recovery of waterweeds some ten years ago: Mute Swans and Coots, both of which feed on the submerged waterweed. On the 3rd, I noted a third species, not observed before. In the early morning, the geese that feed on the surrounding grasslands make their way to the lake and there were Canada Geese and Greylags there. The Canadas were upending to gather a fresh growth of Fennel Pondweed and consuming it, but the Greylags weren't; an interesting difference in the feeding ecology of these two. It could be that the drought left the geese short of their early morning bite from the grassland and that those Canada Geese were making up for the shortage, but it's interesting nevertheless that the Greylags seemed to lack the ability.

The water in the brook downstream of the cafe was a series of pools with just a trickle of flow on the 4th, accounting for the Water Striders seen there, a species of calm waters. And there was a new species of plant for the park, Elegant Clarkia, growing beside the brook. This is a garden annual originating in California and it remains a mystery how it arrived in this odd situation.

There was just a little easing of the drought on the 8th when there was around 10 mm of  rain, but then we were straight back into another hot dry week. Sadly, the high temperatures and nutrient pollution in the lake led to a significant bloom of blue-green bacteria and water clarity declined greatly early in the month, as has happened in previous years with blooms. I could see the floating clumps of Oscillatoria and the abundance of Aphanizomenon flos-aquae, which is dispersed through the water. Both of these are known sometimes to be toxic. At the beginning of the month the lake level was below the crest of the outfall weir, so practically no water, polluted by blue-greens or not, went down the brook from the lake. However, the old pipe that issues near the toilet block continued with a trickle. This pipe carries the surface water drainage from much of Home Park Road, so clearly there are springs or leaks in this area that provide a tiny flow even in drought times. After the 8th, water flowed down from the weir in the new course of the brook for a day or two, and it was noted that this was milky in appearance and that there were some suds where it flowed over an obstruction. This is typical of lake water with algal blooms and was, therefore, not the result of a single pollution incident, rather of an ongoing situation in the whole lake.

I did my regular lake water sampling on the 11th, when I found the cause of that colour in the brook: a bloom of a blue-green bacterium, confirmed by microscopic examination as Aphanizomenon flos-aquae, This species is unusual, as the individual filaments clump together to form shapes that are visible to the naked eye floating dispersed throughout the water body, looking much like finely-chopped grass cuttings (see the magnified image). I have found this species in a wide range of months (April to December) every year since I first noted it blooming in 2018 and it bloomed also in May and August 2019, September 2021, June 2022 and August 2024 as well as this month. On these occasions I found some pondweeds and plenty of microscopic animals, such as water boatmen, water fleas, water mites and the copepod Cyclops, nor was any unusual fish mortality observed, suggesting that the blooms of this species were not very toxic on those occasions. When Aphanizomenon runs out of nutrients or oxygen it can die off and be seen more obviously as bright green scum accompanied by a turquoise coloration in the water. That's what was seen in the incident after the 8th. Another species, Oscillatoria, bloomed this Spring, between February and April, and was still present, if in reduced numbers. Like Aphanizomenon it can be identified without a microscope as it lives in the top layer of sediment and the oxygen given off by its photosynthesis causes ugly globs of sediment to float to the surface. It has bloomed previously in the Spring of 2023. 

There was a much more significant pollution of the brook with a blue-green bloom on the 23rd and 24th. This was reported in the Putney News on the 30th: https://putney.news/2025/07/30/anglers-campaigners-point-to-aeltc-after-mystery-lake-spill/?bclid=IwQ0xDSwL2pR1leHRuA2FlbQIxMQABHulJqMo3Iii5nqGBCfckoVWQiSx05tP9MFqsrh9_MqfKPsfxeHiiC9_33oxb_aem_G1OERC3RHjGQ-i_NZoyIuw&sfnsn=scwspwa 

This article is remarkably good journalism, but it speculates beyond the present incident, with its headline "Many now believe the spill may have originated from drainage linked to the All England Lawn Tennis Club (AELTC), and fear it may foreshadow far more serious pollution if the club’s expansion plans are approved." We just don't know whether the cause was a spill and we have great reservations about the water quality implications of the AELTC proposals, but that is not our present concern. Here, I focus on the incident around the 24th. 

Before recounting this recent incident, I repeat the occasion when a dog was left partially paralysed by exposure to a bloom in the brook in early September 2022, when I confirmed the organism to be Dolicospermum, which bloomed in August and September that year. The dog was poisoned by the contaminated water of the brook. The samples for blue-greens commissioned by LB Merton in late September, well after the incident, confirmed only Microcystis aeruginosa in high numbers. I had found a tiny amount of Microcystis in previous years and it was there in September 2022, but did not bloom. I am confident it was not the cause of the dog poisoning. It is not identifiable without a microscope. Dolicospermum also requires a microscope for determination and it has been found between June and September in other years, but not since 2022. 

I was out of town on 23rd July, when there were reports of a flow of milky-grey or turquoise water, foaming where turbulent, in the whole length of the brook and of a dog under treatment as a result of exposure to the water. It was first reported where the downstream pipe discharges into the River Wandle at Earlsfield, and the Environment Agency was alerted. Photographs the following day confirmed that it came from the stilling pool which lies below the outfall weir in Ashen Grove Wood, just upstream of the public park. An angler visited the lake later on the 24th, confirming that the milky-grey water was flowing over the lake outfall weir, it was foul-smelling and there were fewer birds by the lakeside promende than usual, and he also reported to the Environment Agency. There were no signs of dead birds or fish. The Council was alerted by the Friends of Wimbledon Park, and posted extra warning notices on the 24th, and also contacted the Environment Agency.

It emerged later that the Watersports Centre had been carrying out visual inspections for blue-green bacteria each morning over the previous month to decide which parts of the lake were appropriate for "wet" activities. This was following a blue-green bloom on Putney Heath, so apparently my previous alerts sent to senior officers of LB Merton did not result in any such action. My most recent alert was an email to the Chief Executive reporting the bloom of Oscillatoria on 1st May this year. 

The dog was affected by entering the polluted water of the brook and kept under observation by a veterinarian on the 24th and discharged unharmed. The dog owner had acted prudently.

Some further background.

Blue-green blooms are most numerous in summer, when light levels and water temperatures are high, but the key factor is excessive levels of plant nutrients dissolved in the water. I have compiled nutrient determinations by myself (most recently through FreshWaterWatch, a citizen science scheme) by the anglers and a very few by others. These results show that the lake has often had moderate or high phosphate concentrations, which could lead to blooms if it were not for the low concentrations of nitrogen. Many blue-greens are able to fix nitrogen, so surviving or even thriving where plants would find the low concentrations limiting. This year, phosphate measurements declined from high levels in April and May to low levels this month, so phosphate appears to have become limiting this month, perhaps causing the mass death of Aphanizomenon, but that's speculation on my part.

The breaking of the drought, accompanied by overtopping of the weir and a flow down the Brook after months of no more than a trickle, clearly explains why a bloom appeared in the Brook on the 8th. Press reports then described thunderstorms at the Wimbledon Championship. The drought returned after that, but there was much more rainfall on the 19th which sent a flood down the brook. On my return home on the 26th, my rain guage showed that 40mm of rain had fallen in the previous week. However, that flood didn't show a bloom. Photographs of the brook taken by Paul Johnson show it was running dirty, but with no colouration  on the morning of the 23rd, yet the first report right down at Earlsfield that evening shows that the bloom originated that day and quickly filled the whole length of the brook. Photos also show that there was a visible bright green scum on the lake beside the promende on the 24th.

The visible bloom was over by the time I was able to take water samples on the afternoon of the 26th, but my samples confirmed that Aphanizomenon was still present dispersed throughout the water of both the lake and the brook, just no longer super-abundant, as it was on the 11th. No other blue-green species was evident then. We, and the dog, had been lucky as the bloom seems not to have been very toxic.

The origin of the nutrient pollution that is a pre-requisite of a bloom remains uncertain, it 
can be excessive bird feeding, atmospheric deposition, bird defecation, and sources in the catchment coming down the tributary pipes, none of which are monitored, including the drain from the AELTC site. It's reprehensible that Merton owns and manages the site and runs the watersports yet does no substantial monitoring, and that AELTC remains silent on what goes down its drains. I, and the anglers, publish our information (me most recently as part of my representations on the AELTC overdevelopment proposals), but we have neither the access nor the resources to monitor the sources.

With a microscope, blue-green bacteria are readily monitored in water samples, as I have been doing for some eight years but, unfortunately, testing for toxicity requires specialist methods not available to the ordinary environmental scientist and an innocuous bloom can turn toxic. Effectively, we are using dogs as a test species, which is not an appropriate approach. This means that precaution is required.

Since I wrote this, it appears that Thames Water have inspected the site. The first occasion was late at night, perhaps on the 24th and certainly that week. On the second occasion, the evening of the 30th, a local lawyer spoke to the TW operatives parked up by the Home Park Road entrance to the public park, who said they were investigating the reports of pollution. I would comment, rather late. I have previously sought to help TW with their investigation of local incidents, finding them unreceptive, but I tried again, getting an incident number 01242268.

 

 

June 2025

As I have monitored the results of meadow and hedgerow management in the park, tensions have arisen.

I did some experimental management of the hedgerows in early June. Some was in the 35-year-old hedgerow on the Tube line boundary between the Revelstoke Road car park and Horse Close Wood. This was established as a joint project between the Wimbledon Park Residents' Association and LB Merton tree officers and is still remembered by some of the school children who did the planting, now in their mid 40s. I also experimented along the 80-year-old hedgerow on the boundary with the ex-golf course north of the Athletics area. Both places had been butchered in the winter with the use of a heavy flail, leaving unsightly broken branch stumps. There were but two advantages of this. First, is the cost, the flail doing work much more cheaply than hand trimming. Second, is the avoidance of the bird breeding season, so avoiding breaking the law by harming the nests of breeding birds. 

Since this butchering of the hedges, the plants had grown back and flowering stems of Bramble, Dog Rose and Native Honeysuckle were showing at the edges of the hedges. The fruits of the earlier-flowering Hawthorn and Blackthorn and the odd late Holly fruits were ripening. A few of the rose stems projected appreciably clear of the edge of the hedge, but there were many arching branches of Bramble without flowers, as is typical. This species flowers on one-year-old stems. These flowerless stems would threaten passers-by if left. So, my experimental management cut back mainly these threatening Brambles, whilst sparing the flowers and fruit, except in exceptional places where these branches stood out from the hedgerow edge. A few Dog Roses were in flower and had arched out, but these weren't long enough to intrude and I left them for people to enjoy, intending to cut them back once the flowers were over. As the work was solely on stems projecting clear of the hedge and was by hand, it was assured not to affect bird nests. Some of the Blackbirds, Song Thrushes, Robins, Dunnocks and Wrens were repeat-nesting after losing their first or second attempts and others had fledged young successfully and were embarking on their second nest of the year. I didn't search for these nests, as it's difficult to find nests in the dense shrubbery and so a search would risk disturbing them, but the birds' behaviour confirmed their presence in the hedge. My experiments confirmed that intrusive growth clear of the hedge could be removed in a responsible way. 

Then, on 11th June, I was surveying the hedge on the boundary of the golf course and was disturbed to find that almost all of the flowering and fruiting stems that weren't any threat to passers-by had been cut off, leaving a straight edge with only a tiny fraction of the previous flowers and fruit. Clearly, someone had decided that the hedgerow needed pruning. They were wrong. Going on round, I found that the same pruning had been done on the eastern hedgerow as well. Not only that, but this trimming went well into the edge of the dense shrubs and alarm calls from Robins and Blackbirds told me that they were in distress. I cannot confirm what was the cause of that, but suspect it was disturbance of nests and their contents. Also, the flowers and fruit removed were no longer there for passers-by to appreciate, nor as sources of nectar and pollen for pollinating insects, nor for birds to consume the ripe fruits later in the season. Wanton harm to the wildlife and its habitat. Now, of course, if you don't survey a hedge before managing it you cannot confirm the presence of breeding birds. Failure to look is failure to find. It's commonplace for people to manage bird breeding habitat in such a way and technically they are not breaking the law. In my view, however, the choice not to look breaks the spirit of the law. At best these hedgerows have been impoverished by the management, at worst protected species have been harmed.

I will be making submissions on the future of our Merton parks in the current consultation. I don't believe that talking to local park users and seeking ways to balance the desires of all park users needs be any more expensive than is management by rote, as goodwill generates voluntary help. And we have a team of Community Payback Scheme people who could carry out sensitive management work with hand tools and could benefit from understanding why this is done. 

As I did the monthly bird count on the 17th, I noted the Dave Lofthouse Glade in Horse Close Wood. The management work by the Friends is paying off. The early colour from Dandelions. Jack-by-the-hedge, Cow Parsley and Yellow-flag Iris has died back to be replaced by Creeping Buttercup, White Clover, Hybrid Hedge Bindweed, Hogweed, Meadow Buttercup and Hedge Woundwort. It looks like a wildflower meadow, even before the summer plants get going. The Cuckoo Flowers in the little triangle near the White Pavilion have died back and the grass flowers of Yorkshire Fog are prominant there now with just the odd Cat's-ear, Germander Speedwell and Nipplewort. The meadow beside the perimeter path south of the brook is also showing a few meadow species, the most interesting of which was a new listing for the public park, Wild Carrot. This species is most abundant in old meadows, so it is nice to find it here. It doesn't like acid soils, being found rather on the chalk in places south of here. So, yet another indication indication that there are no thoroughly acid soils in the heritage landscape. A single Pokeweed plant was seen growing at the base of a Railway Poplar just north of where the brook leaves the park. The odd individual Pokeweed has been seen in the park previously and they can last several years, if not tidied away.

Another nice finding was a Nurseryweb Spider in the veteran oak plot. The mother spider makes a nest around her egg sac and guards her nest whilst the spiderlings are growing. 

Give their great decline, it was good to see that Swifts still commute long distances to catch insects flying over the lake. Numbers are typically very variable, and they come and go, but seeing 20 at once was good. For other birds, much of the song is over, with birds intent on rearing their young, but it was good to hear Stock Doves and Song Thrushes on all sides of the public park. There were just a few Blackbirds in song, but many Wrens, a Blackcap beside the tube line in the east and a Chiffchaff in Horse Close Wood. There was a Great Spotted Woodpecker feeding its young in Horse Close Wood. I wonder if the pre-emptive spraying for possible Oak Processionary Moth has affected any of those species that feed caterpillars to their nestlings. My totals for both Blue and Great Tits were lower than they have been in most past years, but all manner of other things are possible explanations. It will be difficult to prove any adverse effect.

The Egyptian, Greylag and Canada Geese had arrived in the park for their annual moult, when they are flightless for about a month. There were some 120 Greylags, 50 Canadas and 40 Egyptians, all with their still flightless young of the year. At these times, they feed nearer to the lake, so they can retreat to safety out on the water when disturbance arrives in the public park (and also on the ex-golf course where the set-up for corporate hospitality is under way). There were 5 Great-crested Grebes on the lake, and three Grey Herons on the edge, suggesting that some fish are breeding naturally. Sadly, the incipient Heronry seems to have come to nothing this year.

I did the lake water sampling on the 19th. At 26 C, the water was well above the previous warmest June temperature and one degree above the highest in any month before. Sadly the water quality was low. The nutrient story was the same as usual: low nitrate and high phosphate, still suggesting that the lake is nitrate-limited. The Oscillatoria blue-green remained prominent, and the fauna was dominated by Daphnia magna, the big water-flea. People still set their dogs into the water, disregarding the warning notices about "blue-green algae". Myself, I'm careful to avoid exposure to the Oscillatora and I wash thoroughly on return home. Of course, the main risk is Weil's Disease, so it's essential that no open wound is exposed to the water. I found two other blue-greens, but so far not blooming. There was also quite a lot of Ulva lactuca, the miss-named "sea lettuce", and just a little Fennel Pondweed and Rigid Hornwort. I expect that the pondweed will increase and be cleared by the watesports people again, so exascerbating the nutrient problem. Many midges had emerged from the lake recently, leaving their larval exoskeletons behind. It was difficult undertaking a "kick sample" in the brook, as there was only a trickle of water, in many places flowing below the gravel surface, but I did find a large number of mosquito larvae alongside the usual water lice and shrimps. More like pond fauna than that of a brook. 

May 2025

A great time to see spring flowers and birds. I did the monthly lake water sampling on the 15th and bird count on the 22nd. I saw the first Swifts hawking insects over the lake on the 15th, although doubtless they returned earlier than that. So, migration was over, the Swift being the last.

As happens at this time of year, the geese were mostly out on the grass of the Great Field in the early morning before the arrival of the first dogs off the leash sent them to the security of the lake. The gates were opened at 06:20 and the geese had moved within 10-minutes of that. All the geese species had goslings, several groups of Greylags, but fewer of Canada and Egyptian. We have yet to see any Mandarin ducklings, now the second spring they have been present, it should be just a matter of time.

Many wild flowers were seen in May. By arrangement with the parks contractors, a small, triangular, grassy slope by the steps at the south-east corner of the tennis courts is left for two species to flower. First came the pale pink Cuckoo Flower from late April through to mid May and that was followed by Germander Speedwell at the end of May. Both of these are perennials and so the appropriate management is as a meadow: mowing and then raking off the resulting hay in summer, once the flowering is over. Around the edges of the wooded areas Cow Parsley was in full flower, going over to seed by the end of the month in the hot, dry conditions. It was the same story with Stinking Iris, a specialist for dry shade, with flowering quickly over.

The same meadow management is applied to the grassland strip between the perimeter path and the railside hedges on the south-eastern side of the park. In both places it is taking time for the flowers that have long been supressed by scheduled mowing to return, but we have more than daisies to enjoy. Dandelion, White Clover and Creeping Buttercup flower there, "weeds" where they invade a tidy lawn or cottage garden border, but here wildflowers. These meadows have been managed appropriately following good consultation between Idverde contract staff and the Friends of Wimbledon Park, but sadly this is the exception. And, even here, not all is well. The edges of both places have been sprayed. Sadly, this is the case also for the perimeter of the stadium, where a good range of plants colonise and would soften the ugly, bare bases of the Leyland Cypressus were they given a chance. If allowed, Ivy would green the bare ground, the Herb Robert, Sow thistles, thistles, Round-leaved Crane's-bill, Creeping Buttercup and Black Nightshade are modest plants, showing promise in April, withered and dying from the spray in May

Dog roses were in flower both where they colonised naturally, as in the hedgerow beside the golf course in the north and below the Veteran Oak, and where planted beside Horse Close Wood and in the newer hedgerows. By the end of the month Bramble was just beginning to flower in these same places.

The vegetation of the brook was looking good, with the planted Yellow-flag Iris and Brooklime and the naturally colonised Watercress. In the protracted drought there is but a trickle of flow in the brook most of the time, much of that deriving from surface water drainage from the Home Park Road suburbs, rather than the lake outflow where there is a small residual flow down the Eel pass only.

At the end of April topsoil and grass seed were spread over the worst of the bare patches in the Great Field, a great boon for the Feral Pigeons that gleaned much of the seed. One hopes that the grass seed wasn't treated with insecticide. Sadly, the drought prevented any germination.

The watering of the bowling green was a boon for the Starlings commuting to and from their nests with food, and later bringing the fledglings to it. Perhaps an act of desperation, as the grassland invertebrates elsewhere had been decimated by the drought or forced to go down in search of moisture. This will affect other species, like Blackbirds, that risk predators at this time of year to venture out of shelter to find food in the open grass. 

 

Consultation

There is a consultation under way on the future of Merton's parks, with Idverde's contract coming to an end soon. One fears a continuation of one-size-fits-all actions, perhaps inevitable in a cost-effective contract. Nevertheless, many problems could be overcome with improved consultation with parks users and friends groups. Here, I relate how consultation has worked well for those wanting a more natural aspect to the vegetation of the park and lack of consultation has not.

The natural character of the park has suffered from failures of consultation and by continuation of past practices. It's all too easy to mow much more frequently than is required by the use. A place where this happens is the Crazy Golf area. This is one of the best grasslands in the park, but that is hidden when it's scalped to a schedule and the hay left on the surface as a thick mulch, suppressing the regrowth of wildflowers. Meadow management is needed here and the results celebrated. Raking off such big areas could be done if the mowing was on a meadow schedule, coordinated with volunteers or the Community Payback team. Alternatively, it could be mown with a machine equipped with a grass collector, so obviating the need to rake off. 

Another excess was the use of a flail machine to cut back the hedgerows around the perimeter of the park. It's great that this is done in the winter, so avoiding the bird breeding season, but that leaves garish scars there until late spring growth comes to cover them up.That winter hedgerow work would be much more sensitively done with hand tools, perhaps again by the Community Payback team, with help from volunteers. Hedgerow work in the bird breeding season needs to be much more sensitive, which is only possible with careful use of hand tools. This also allows the flowering and fruiting branches to be spared and to be enjoyed, being pruned back once the birds have taken the fruit.

When the Lofthouse Glade was developed at the eastern end of Horse Close Wood, the Friends of Wimbledon Park asked for the heavier management, the meadow cut, to be included within the maintenance contract. The Friends would do the raking off and spot control of invading trees and shrubs. Without this cooperation and coordination, the Friends are left cutting the meadow with hand tools, an onerous task. 

A difficult issue is the spraying of  "weeds" around the paths, fences, standard trees, seats, notice boards... well everywhere that a mowing machine cannot easily access. Some people resent the unsightly dead grass that results and don't like the idea of their children getting contaminated when investigating the flowers unaware they have just been sprayed. In most cases the contract could redefine some of those "weeds" as wildflowers, tidied by hand or a strimmer once the flowering is over, and we can accept some vegetation at the edge, between paved paths and grassland, again cut back occasionally. Pathside plants once provided food for House Sparrows, but now we have neither the sparrows nor the plants. Needless spraying beside the hedge in the north beside the ex-golf course has prevented establishment of the valuable hedge-bottom wildflowers that grow there naturally, instead there's a strip of dead grass from the spraying. Hedge bottom plants need cutting back, but not very often. Merton's parks contract need employ no weedicides.

A one-size-fits-all approach also applies to schemes that are rolled out across Merton's parks. These schemes are efficient and so deliver improvements in a cost-effective way. There are also one-off initiatives led by elected members, a valuable connection between local democracy and action. Sadly, however, there is little or no consultation with local volunteers on these borough-wide initiatives. Trees arrive unannounced and at odds with a long-term local programme of planting. That programme was developed using volunteers planting to fill the gaps left by the 100-year-old poplars that are going one by one as they become dangerous and to provide a wooded boundary, reflecting the Capability Brown heritage. It was designed in co-ordination with Merton tree officers. This Council-volunteer partnership thought through what species to plant and where, raised the finance and the planting was done by volunteers. Clearly the institutional memory of Merton Greenspaces is poor, or this local initiative is seen as trivial, for whatever reason there is no consultation with locals. 

Perhaps the most gross problem, however, comes from schemes imposed upon the park by Merton's development planning. AELTC needed to prove a "biodiversity net gain" in their proposed gross overdevelopment of grass courts on the golf course. Unable to prove the gain within their area, they needed places to flag up as "gain" nearby. There's been no real consultation on these proposals in the public park, which were developed late, inadequately described, and buried amongst hundreds of other documents, nor any acknowledgement that there are existing programmes of work in the park. These proposals would deny most of the lakeside promenade to the public. New path diversions are proposed. Without consultation, we don't know if park users really want to see the promenade wholly devoted to watersports? And, if we want this, are the proposed path diversions designed for disabled access? Another AELTC idea is for Horse Close Wood car park. There has long been a proposal to return this back to woodland, but, hidden away in the "gain" is a proposal to upgrade the car park for continued vehicle use. Other planting proposed by AELTC affects places that are part of the 10-year community tree planting. It would be great to get some capital investment into the park, 100 years after it was originally laid out, to refresh tired facilities and reflect community wishes. Locals will be able to help find constructive projects, after all it's our park. But the urgency of statutory planning approval dictates that we will not have a consultation on the proposals, we are meant to simply welcome them. 

I could go on. It's difficult to consult, it takes time and needs willingness. The most vital test of the success of Merton's parks going forward in these cash-strapped times, will be a willingness to discuss and consult, and to work together with locals. 

The meadow triangle

Cuckoo flower

 

April 2025

There seems to have been a radical change to the lake water. The Oscillatoria that arrived this spring has persisted. After arriving in February, there were just a few floating clumps during the dry period in late March and the first half of April, but the return of westerly winds on 17th April led to a visible accumulation of this blue-green beside the promenade on the public side of the lake, around the watersports jetties, dissipated again by the 19th with the return of easterlies. So, the obvious signs of this bloom migrate around the lake with the prevailing wind, but it remains there on the lake bed and floating up to the surface. The experts tell us that blooms are often poisonous with liver or nerve toxins known collectively as cyanotoxins which are typically observed in at least half of the blooms analyzed (see, for example review papers by Prof Linda A. Lawton). Determining toxicity, however, requires specialist analytical methods, inaccessible to the ordinary laboratory or citizen scientist, so one should be precautionary and assume all blooms are toxic to animals, especially dogs, but also us. Oscillatoria is the fourth species of bloom-forming blue-green bacteria found in the lake recently. It is urgent to deal with the excess nutrients in the lake to return it to better health. LB Merton and AELTC assume that the solution lies in "de-silting", but without citing any peer-reviewed science to justify this assumption. My reading of the literature suggests that the preferred method of removing sediment from the lake would make the situation much worse, rather than better. It's surely time for AELTC to spend just a little money actually studying where the excess nutrients come from and looking at the existing published studies for the soluion.

I have taken part in the citizen science Waterblitz, Big River Watch and Freshwater Watch whenever one is run. They did this on 25th-28th April and I took part. As usual the lake scored high on Phosphate at 0.35 ppm, but as unpolluted for Nitrate, also 0.35 ppm. This tells us that nitrate is the limiting nutrient and helps to explain why Blue-green bacteria do well in the lake, as they can fix atmospheric nitrogen. The Anglers have been monitoring lake water quality on and off since late 2022 and you should consult their website for their results, but suffice to say that they agree that phosphate levels are high (indeed their kit gives consistently higher phosphate than the citizen science kit). Unfortunately, the anglers' nitrate measurements, whilst agreeing that there isn't much are mainly zero, which makes no sense. I suspect their kit is not sensitive enough for nitrate. Helpfully, the anglers also measure ammonia and most of their measurements of it show no pollution.

That's the bad news, but the good news is that there's much to celebrate in the park. The native Bluebells, Dog's mercury, Lords-and-Ladies, Wild cherries, Hawthorn and Jack-by-the-hedge are flowering in the woodlands and hedgerows. Stock doves, tits, Green and Great-spotted woodpeckers, Chiff-chaffs, Starlings and Blackcaps are breeding. Bees are collecting pollen and nectar from those native plants and also from Green alkanet. None of these plants are named in the lists of "pollinator friendly" plants pushed by the popular media, but the bees have the answer. There's a pair of Mandarin ducks on the lake again this spring, and the male has been on his own recently, so the female is probably on a nest in one of the few veteran trees that AELTC have spared in their tree works. After months without any, a pair of Great-crested grebes has returned to the lake to join the Tufted ducks, Pochards, Grey herons and Mute Swans. The grebes give us hope that the fish may be breeding successfully again.

March 2025

With the arrival of spring, Blackthorns were in flower early in the month. The temporary ponds were drying up, for example the one beside the Lofthouse Glade