Denso Marston Nature Reserve, Baildon

Wednesday 19th June 2024

Leader: Steve Warrillow

This is a seven acre site made up of woodland, grassland and ponds, in a narrow strip next to the River Aire. We accessed the site from a public footpath that leads down from Otley Road (OS Grid reference SE16503906). At a location with relatively good public transport links, it was good to see that some members had been able to travel to the site by bus. The reserve was created in 1991 when the Denso factory was extended and the adjacent pasture land, which was prone to flooding, was landscaped and turned into the nature reserve. The company entered into a Section 106 Agreement with Bradford Council to ensure the security of the use of the land as a nature reserve. A Friends Group undertake management of the site. One of the main aims of the reserve warden is community involvement, encouraging people of all ages to enjoy nature. There are regular free events at the site such as guided walks.

This evening, reserve manager Steve Warrillow led 13 BBG members on a circuit of the reserve, returning alongside the river. 154 plant taxa were recorded on our visit, including many woodland and wetland species typical of the area. Steve’s infectious enthusiasm has no doubt rubbed off on many of the people he guides around the reserve. Such was Steve’s committment, that he was leading a dawn bird walk the following morning - he wouldn’t have time for much sleep tonight!

At a large pond we saw both Fringed Water-lily (Nymphoides peltata) and White Water-lily (Nymphaea alba). While White Water-lily is a fairly common native plant, Fringed Water-lily, which has smaller leaves, is not native to this part of the UK (it’s possibly native in East Anglia) and is more often seen planted in garden ponds.

There are issues with some non-native invasive plant species which Steve said they are trying to manage. Much of the open water of the pond had become choked by the invasive Water-soldier (Stratiotes aloides). Steve said much of it would soon be removed, but it was impossible to completely eradicate, as was the New Zealand Pigmyweed (Crassula helmsii) which was present nearer the water’s edge.

Also near the pond margin was Bulrush (Typha latifolia), Reed Sweet-grass (Glyceria maxima) and Water Forget-me-not (Myosotis scorpioides). A sample of Nuttall's Waterweed (Elodea nuttallii) was fished out for people to take a look at.

A less often encountered plant we saw here was the native Green Figwort (Scrophularia umbrosa). I have also recently seen this species a little upstream of this site, between Bingley and Hirst Wood, so this may well have arrived naturally. The stems of Green Figwort are strongly four-winged, unlike the more narrow wings of Water Figwort (Scrophularia auriculata) and the leaf margins have more teeth (at least 40 teeth per side compared with Water Figwort which only has up to 32 teeth per side). Another identification feature that can be helpful is that Water Figwort often has two lobes at the base of the petiole which are not seen in Green Figwort.

Other species included Wood Speedwell (Veronica montana), Ground Elder (Aegopodium podagraria), Sweet Cicely (Myrrhis odorata) and Hemlock Water-dropwort (Oenanthe crocata), all in flower. Picking a stem of the invasive Himalayan Balsam (Impatiens glandulifera), Andy demonstrated how to make a flute-like musical instrament from a section of the stem. Steve was pleased to learn the technique and said a group of children who meet at this site, known as the Spider Club, would be overjoyed to learn this too!

There were a number of non-native shrubs to puzzle over. A Dogwood was concluded to be Red-osier Dogwood (Cornus sericea), the leaves having more pairs of secondary veins than the native Dogwood.

Other wildlife we noticed included an adult Moorhen with three juveniles on the pond and Roe Deer (an adult with a juvenile) on the grassy slope on the opposite side of the river. An orange-coloured slime mould called Salmon-eggs (Hemitrichia decipiens) was spotted. Andy said this slime mould was growing on a bacteria which, in turn, was growing on the fungus Turkeytail (Trametes versicolor). The Turkeytail was growing on a fallen log, with Andy pointing out that this made 4 different Kingdoms in that food chain!

Text by Susan

Photographs by Tom