30 Days Wild – Day 27 – On the Marsh

The majority of my day was spent at one of our occasional staff meetings, a chance to catch up with what other members of staff have been doing, learn about the projects and discuss future direction. Despite their undoubted value, it is often difficult to be sat indoors on a fine day, although on such a warm day being in the shade was not that unwelcome.

After the meeting I went down to as saltmarsh site beside Southampton Water to try to assist with a research project looking at the worrying rates of change along the eroding outer edged of the marshes. Large sections of The Solent coast has a margin of saltmarsh, this narrow strip of habitat has a whole suite of specialised species that live nowhere else. Unfortunately sea level rise and the lack of space for these habitats to migrate inland is meaning they are disappearing as they get squeezed out of existence.

The saltmarsh along Southampton Water is very diverse with lots of the characteristic species of these habitats. The outer edges have banks of shells known as cherniers which can smother the vegetation, if they kill leaving bare mud this can get more easily eroded although it can be recolonised by plants such as glasswort.

glasswort

glasswort colonising mud on the chernier edge

The lack of freshwater makes a saltmarsh somewhat similar to a very arid area and some of the adaptations are similar, for example fleshy and glaucous leaves.

sea purslane

sea purslane growing through the chernier bank

Inland from the shell banks the marshes are very flat, but still have variety in the form of creeks and subtle changes in elevation. These are enough to offer a variety of slightly different niches. In shorter areas sea-spurrey  can be common and its starry flowers are popular with the insects that also live out on the marshes.

sea spurrey

sea-spurrey flower

The higher areas of long-established marshes can have large areas of sea-lavender are very popular with insects and produce large swathes of colour.

sea lavender

sea-lavender in flower

Returning home I had time for a quick look at the meadow.

What’s in My Meadow Today?

There were several small skipper and a meadow brown or two in what is now a very dry meadow. Most of the grasses are brown or yellow, but the deeper rooted perennial herbs are still green and many in full flower. Wandering over the vegetation I found a 7-spot ladybird. This used to be our commonest larger ladybird, before the arrival of the harlequin ladybird from SE Asia, via the horticultural trade.

7 spot ladybird

7-spot ladybird

 

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A Day by the Sea

On Monday Jo and I spent the morning working with the Milford Conservation Volunteers at Keyhaven. Although we mainly work at Blashford Lakes and Fishlake Meadows we have a number of other sites to look after. The reserve at Keyhaven is large, consisting of almost all the saltmarshes and mudflats outside the sea wall between Hurst Beach and the Lymington River. It is an important reserve for nesting gulls and terns in the summer and for waders and wildfowl in the winter. Its value is greatly enhanced by the neighbouring Hampshire County Council nature reserve, together the two reserves make one of the largest areas managed for nature conservation in the county.

The work we were doing was on the one small area of the Trust reserve that is inside the seawall. The wall here used to be a rather porous construction of timber and clay, as a result the land behind it was wet and quiet salty. Since the wall was reconstructed just over 25 years ago the saltwater has been kept out more effectively and the area has become drier and fresher. A lot of species are adapted to live in the narrow habitat band that lies between the saltiness of the sea and truly freshwater, as this habitat is very restricted these species tend to be very local and frequently rare. A time of rising sea level might be thought of as one which would bring benefits to these species, but in fact many are in decline. Our modern seawalls are effectively engineered so that they keep almost all of the saltwater outside and freshwater inside, the fuzzy edge that was the home of the brackish habitat lovers has been squeezed.

I was approached last year by a group of local residents interested in the potential of getting the brackish elements back, by finding a way to get some more seawater onto the marsh. It was really exciting to have such interest in what is often perceived as a dull habitat. Although we are still looking at how they goal might be achieved there is interest in the idea from both Natural England and the Environment Agency.

Monday’s task was to tackle some of the scrub that has established since the site has become fresher so that the former open character can be restored. We coppiced lots of willow and cleared a large area of bramble thicket. Hopefully once there is a more salty regime this will help to limit the regrowth of much of this scrub and encourage brackish marshland habitat.

 

P1090874
Clearing bramble thicket with the Milford Conservation Volunteers, (and collecting rubbish).

 

Listing, Lessons and Speculations

Like lots of people who look at wildlife I cannot resist keeping lists, not usually very thorough and I usually lose interest in about mid-February each year. So far I have kept going and find that I have seen 116 species of birds so far this year, all of them in Hampshire and at least 105 of them on visits to Hampshire and Isle of Wight Wildlife Trust reserves.

Of the 116 species I can see that five of them are introduced alien species (Canada goose, Egyptian goose, Mandarin duck, pheasant and red-legged partridge) and another an introduced population of a former native (greylag).  All of these  have been either introduced for “sport” or escaped from parkland collections.

Of the native species I am struck by the many species that have changed their status radically since I arrived in Hampshire. There are various reasons for this, the white trio of little egret (now breeding), great white egret (soon to be breeding here?) and spoonbill (perhaps likewise), have increased in number and range right across western Europe. The same could be said for Cetti’s warbler, avocet, yellow-legged gull and Mediterranean gull.

Birds of prey have increased, more or less across the board and seeing red kite, marsh harrier and peregrine is not now especially notable and buzzard has spread right across the county rather than being a New Forest bird. All of these species have benefited from a more benign environment, in which they are less exposed to harmful chemicals and suffer less persecution, at least in lowland England. One other species has gained from the same change is the raven, which now nests across most of the county. Goshawk has also colonised the county and benefited similarly, although the population is of escaped , or released, origin.

When I first came to Hampshire in 1978 there was no accepted record of ring-billed gull and I am not sure there was even such a thing as a Caspian gull thought about.

I estimate that if I had been doing the same thing forty years ago my list would most likely not have included at least 14 of those I have seen this year, so more than 10% of my list are birds that would have seemed remarkable then. Of course there would have been some species that I would have expected to see then by mid January, that we have now more or less lost, or at least which now need more particular seeking. For example Bewick’s swan, white-fronted goose, grey partridge, willow tit, corn bunting, yellowhammer and tree sparrow.

So listing may well be a rather pointless exercise in many ways but reflecting upon my list so far certainly tells a story of how much has changed and of course makes one think how much might change in the future. So what might a list in another forty years include?

I suspect we will have established populations of additional alien species, most likely is ring-necked parakeet (I suspect this will happen quite soon), but I think black swan may also get a firmer foothold too and Egyptian goose could become very common. Who knows perhaps even sacred ibis could make it over here in time if the continental populations develop uncontrolled.

Natural colonists that look like becoming regulars include, cattle egret and glossy ibis, both already occasional visitors. It is interesting to note the preponderance of wetland birds that are expanding their ranges. A bit of a wildcard might be the potential for a whole range of essentially  Pacific Arctic species to turn up as winter vagrants. The ice melt along the northern coast of Russia has opened up a route for many previously unconsidered species. The occurrence in Europe in recent years of slaty-backed gull hints at the potential for species to come via this route in years to come.

Unfortunately I think a lot of species are going to get much rarer. Coastal species will be under particular pressure, in forty years time there will be little or no saltmarsh along most of the Solent shoreline and much reduced mudflats, so wintering coastal wader populations will surely be much reduced. Couple this with and increase in “short-stopping”, which means that wintering birds coming from the north and east just don’t come so far in the increasingly mild winters. Overall I think it certain that the Solent will not be nearly so significant for wintering wetland birds.

This discussion of change is only considering the winter, our breeding birds could be in for at least as great a change, who knows I might speculate on this in a later blog.