The Flora of Wilden Marsh

 

It’s often a mistake for people with or without historical knowledge of a site’s uses to assume too much about its current value. The number of people living around Wilden Marsh that think the area is an under managed industrial wasteland surprises me. People have long memories and will often recall the dark days of industrial dereliction and misappropriation of lands along the Lower Stour Valley. Thankfully, the days of heavy industry being able to dispose of its troublesome waste legally on the Wilden wetlands have passed. The marsh still suffers from treated sewage effluent inflow, land drainage runoff, and all manner of rubbish floating down the River Stour to the River Severn, but at least things are being done to minimise the effects of these types of pollution; although, well meaning efforts do tend to progress slowly. It can be a mistake rushing towards decisions without proper consideration of their likely positive and negative effects.

Many times I have stood on surrounding hills, inspecting the marsh through binoculars, when people have approached me with their views of what is happening down there on the marsh. The majority of these people were not aware of my connection to the marsh, so our conversations gave me an interesting insight into people’s perceptions of the Reserve;  these range from: they ought to to do something with that unused land – build houses on it, perhaps; someone is making a packet from all the trees that are being felled; I’m going to complain to the council about the horrible flies breeding in that fetid wasteland; those poor cows have been abandoned – and it goes on and on a similar vein. Wilden Marsh is a highly and expertly managed site, and the fact that some people can’t see this, I think, is a credit to our comprehensive and well researched management plan.

The reserve’s most important habitats for botanical and nature conservation exist within a complex matrix of floodplain wetlands – ie. marshy grassland and mire, mesotrophic fen/ swamp, wet woodland (alder and willow carr) and open water (ditches, pools, scrapes). Other habitats such as dry broadleaf woodland, dry mesotrophic/acidic grassland and scrub are considered to be of secondary importance. 

The important vegetation types are mesotrophic fens and damp neutral grassland, along with transitions between these and areas of carr. The flora includes many species which are rare or uncommon in Worcestershire, notably Marsh Cinquefoil, Marsh Pennywort (Hydrocotyle vulgaris), Fen Bedstraw (Galium uliginosum), Marsh Valerian (Valeriana dioica), Marsh Arrowgrass (Triglochin palustris), Lesser Reedmace, Sea Club-rush (Scirpus maritimus), Star Sedge (Carex echinata) and Lesser Tussock Sedge. Tall fen vegetation in the centre of the site has an especially rich flora with an abundance of Lesser Water Parsnip, Great Water Dock and commoner tall helophytes. Parts of the neutral grassland have flourishing colonies of Southern Marsh Orchids progressing further along the northern marsh each year; these have now reached the swamp at the far north of the site. Pollarded Crack Willow (Salix fragilis) and White Willow (S.alba) line some of the ditches. The two main areas of carr woodland are dominated by Alder (Alnus glutinosa) and Crack Willow. Scrub, mainly of Grey Sallow (Salix cinerea), invades the marshy grassland near some of the carr. 

Marshy Grassland/Mire 

The highest quality marshy pastures occur in the northern compartment. These tend to be complex mosaics of rush pasture with localized transitions to acidic mire communities. The dominant vegetation is a tussocky mix of soft and sharp-flowered rush (Juncus acutiflorus) interspersed with grass sward of Yorkshire fog (Holcus lanatus) and bent grasses (Agrostis sp.). 

Mesotrophic swamp/Fen 

Sedge or reed-dominated vegetation is dispersed throughout the reserve, but is prominent along the margins of drainage ditches or where these have become partially blocked – particularly to the south in wood pasture compartment and northern section bordering the settlement lagoon, where there is deep (and dangerous) silt. Though not as rich in plant species as the marshy grasslands, this habitat supports a range of emergent and semi-aquatic plants, the dominant species of which include lesser pond sedge (Carex acutiformis), reed sweet-grass (Glyceria maxima), reed canary grass (Phalaris arundinacea) and, locally, common reed (Phragmites australis), reed mace (Typha latifolia) and lesser reed mace (Typha angustifolia).  Characteristic broad-leaved herbs are water mint (Mentha aquatica), tufted forget-me-not (Myosotis laxa), common skullcap (Scutellaria galericulata), lesser water parsnip (Berula erecta), marsh speedwell (Veronica scutellata), marsh marigold (Caltha palustris). Among the scarcer plants are: wood club-rush (Scirpus sylvaticus) and bladder sedge (Carex vesicaria) – both uncommon in Worcestershire; and the local marsh willow-herb (Epilobium palustre). Tall fen/swamp vegetation on this site is prime habitat for wetland birds such as sedge warbler (Acrocephalus schoenobanus) and water rail (Rallus aquaticus) and excellent for dragonfly species. 

Wet Woodland – Alder Carr, Willow Carr and Sallow Scrub 

There are areas of wet woodland where alder forms the dominant canopy tree. Mostly in the form of coppice woodland, the ground flora here comprises shade tolerant species including ferns and mosses, but also tracts of lesser pond-sedge swamp. Characteristic plants occurring include: creeping jenny (Lysimachia nummularia), yellow loose-strife (L. vulgaris), black-currant (Ribes nigrum), red-currant (Ribes rubrum), and gypsywort (Lycopus europaeus). Unfortunately, however, much of the field layer has been overrun by invasive Himalayan balsam (Impatiens glandulifera) and nettle (Urtica dioica), due to drying out of the peripheral parts of the reserve, as a result of a reduced ground-water table over recent years. Though it contains similar field-layer flora, willow carr is of generally lesser botanical importance, and sallow is invasive on the sedge-swamp at the southern end of the reserve.

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The Fauna of Wilden Marsh

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I have not gone into any great detail in this blog, about the variety of Wilden Marsh fauna; so, whilst relaxing in the midday heat of a bar at the port of Paphos, with a few pints of beer to sustain me, I will attempt correct my oversight. 

One of the main considerations leading to Wilden Marsh being designated a Site of Special Scientific Interest (SSSI) is the nationally important populations of resident and migratory bird species it supports. The total number of bird species recorded on the SSSI is greater than 200, of which about 50-60 breed annually. The uncommon and notable birds regularly visiting or breeding within the northern section of the Marsh include: lesser spotted woodpecker (Picoides minor), grasshopper warbler (Locustella naevia), reed bunting (Emberiza schoeniclus), willow tit (Parus montanus), marsh tit (Parus palustris), woodcock (Scolopax rusticola), skylark (Alauda arvensis), cuckoo (Cuculus canorus), water rail (Rallus aquaticus) and barn owl (Tyto alba). Kingfisher (Alcedo atthis), grey wagtail (Motacilla cinerea), yellow wagtail (Motacilla flava) and sand martin (Riparia riparia) are also known to occur along the watercourses. There are many historical records of several other notable and uncommon species which may still occasionally be found on this part of the Marsh, particularly if they are regular visitors to the southern half. Many of these records are of waders and waterfowl from a time when the settling pools in the former lagoons supported large areas of standing water. However, snipe (Gallinago gallinago), curlew (Numenius arquata), lapwing (Vanellus vanellus) and common sandpiper (Actitis hypoleucos) have been recently recorded in the lagoons over winter and spring periods. Half a dozen great cormorants (Phalacrocorax carbo), known as the great black cormorant across the Northern Hemisphere, overwinter here on the marsh. There is a 16+ bird heronry on the island, hidden within mature grey willow scrub overlooking an open area of swamp and marshy grassland. The reserve is important for a number of reptiles and amphibians with grass snake (Natrix natrix), common lizard (Lacerta vivipara), great crested newt (Triturus cristatus),smooth newt (Triturus vulgaris), common toad (Bufo bufo) and common frog (Rana temporaria) having been recorded in this part of Wilden Marsh. Great crested newts are known to breed in various ponds and ditches across the northern end of the SSSI. 

Some of the mammals recorded include otter (Lutra lutra), stoat (Mustela ermine), American mink (Mustela vison), hedgehog (Erinaceus europaeus), bank vole (Clethrionomys glareolus), field vole (Microtus agrestis), common shrew (Sorex araneus), fox (Vulpes vulpes), muntjac (Muntiacus reevesi), bats (various species), and badgers (Meles meles), the latter living sett within the northern part of the Marsh and along Stour Hill. As with many watercourses, there are also historical records of water vole (Arvicola amphibious). The last time I saw a water vole on the marsh was along a water ditch feeding the south pool. I noticed grass stems chewed in the characteristic V shape, and mounds of fresh bullet shaped droppings. Eventually, after many visits, I saw a water vole swimming in this section of the drainage ditch with a grass stem in it’s mouth. Water shrew (Neomys fodiens) is known to occur at the southern end of the Marsh but as yet has not been recorded from the northern part. 

The varied habitats on Wilden Marsh support a large number and diversity of invertebrates including over 200 species of beetle, 23 species of butterfly, 19 species of spider, 14 species of dragonfly and damselfly and several species of moth, bee, ant, bug and fly. Notable of these include the diving beetle (Hydaticus seminiger) which has become rare in the midlands, (Carabus granulatus), Dytiscus circumflexus and the longhorn beetle (Pyrrhidium sanguineum). More common species include cinnabar (Tyria jacobaeae) – a National BAP species, small heath (Coenonympha pamphilus), purple hairstreak (Quercusia quercus), holly blue (Celastrina argiolus subsp. Britanna), small copper (Lycaena phlaeas) and marbled white (Melanargia galathea subsp. serena) butterflies. It should also be noted that Bombus humilus, a National BAP species, has been recorded at the southern end of Wilden Marsh and so may occur on the northern part of the site also.

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Hoo Brook Pasture Improvement

Walking through Hoo Brook Pasture yesterday I shot this image with my iPhone camera. The cattle worked this pasture in May and the first week of June this year, and similarly last year. For many years the growing season produced swathes of willow and alder scrub, 2.5 metres high Himalayan balsam, thistles, nettles and a sea of ragwort in this area. Three years ago, this pasture was Hoo Brook Wood.

The cattle ate all the Himalayan balsam here last year, and I cut the thistles and dug-up the ragwort during June and July of this year; buried ragwort seeds have already taken advantage of the sunlight to germinate, sprout, and replace some of those I removed. There is now considerably less thistle and a small amount of Himalayan Balsam.

I can see slight improvement in this often wet pasture, but at least another 3 years of grazing, trampling, invasive plant removal, and cowpatting are needed before the soil really begins to show any uniform microbial diversity and activity. There is a lot of building rubble and other rubbish buried in this area alongside Hoo Brook.

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Tulip

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Portraits

Billy Bull and Wayne grazing around South Pool this evening.

 

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I will miss these ocean sunsets

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Views from my window

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