Brilliant Volunteers

As I have noted many times on this blog, Blashford Lakes would not be anything like as good a site without the invaluable input from our great volunteer team. Our volunteers help out with a range of tasks and do some projects in their entirety.

Over the last week we have had volunteer educators helping with school groups river dipping in the rain, reptile and butterfly surveyors, office administration and our Tuesday and Thursday working parties.

The rarest habitat at Blashford Lakes is the Lichen Heath, perhaps because of its industrial origin it is not actually designated, but it is home to many nationally rare species which form an assemblage which needs looking after.

lichens

Lichen Heath close-up

The importance of the area rests on it having very low nutrients, but over time nutrients fall from the sky and collect in the upper layers of the soil as mosses, lichens and small plants die. The obvious conclusion is that it will slowly disappear and turn into nutrient poor acid grassland. So how to keep some areas to true Lichen Heath? The answer is probably to strip off the surface layer and get down to the bare sandy surface and let it colonise once more. This seems very drastic and it feels wrong to be stripping off what is still a diverse sward with lots of interesting species. We started doing this in a small way on Tuesday, doing six small trial plots which we can monitor, if it looks a good technique we can extend it more widely in the years to come.

Lichen heath before

Lichen heath before surface stripping

Lichen heath after

Lichen heath after surface stripping

We chose sites where there were small bramble or birch trees that needed removing anyway and piled up the material on the northern side of the scraped area to provide some variation in the surface topography and potentially warm nesting sites for the many species of bees, ants, wasps etc. that call the heath home.

The rain this last week is what allowed us to work on the heath as it meant the lichens absorbed water and so could be walked on gently, in dry conditions they would just crumble to dust under foot, which is why we ask visitors not to walk on it. Even in wet conditions it is intolerant to trampling so we do as little as possible out there. So it was a treat whilst we were there to see some of the special species that grow on the heath including the two rare bird’s-foot trefoils.

hairy bird's foot

Hairy bird’s-foot trefoil

 

slender bird's foot

slender bird’s-foot trefoil

On Thursday the volunteers were back on the task of clearing Himalayan balsam and pink purslane from along the Dockens Water. These two invasive alien species can muscle out native species, but can be controlled by pulling them up to prevent seeding. After several years of doing this we have made great progress and balsam is now no more than occasional where once it was the dominant plant. Along the way when doing such tasks we come across other things of interest, one such find was a mating pair of lime hawk-moth.

lime hawk pair mating

Lime-hawk moth pair

Some discoveries though are less welcome and one such was an American skunk cabbage plant, the first I have ever heard of along the Dockens Water. This plant has been a big problem in wetland sites across the New Forest and the subject of an eradication program, so finding it here is a worry. I suspect that somewhere up stream someone has it planted around their pond and the seeds are escaping to grow in the wild.

skunk cabbage

skunk cabbage, a young plant without the huge leaves and yellow flower that attracts water-gardeners.

Our last chance find was made by Geoff, one of our most regular volunteers who photographed this crab spider which had ambushed a bee visiting a daisy flower.

spider

Crab spider with bumble-bee prey on ox-eye daisy.

I will endeavour to do a wildlife update for the week later, I know we have received a number of fabulous photographs from visitors.

 

Progress Against an Invader

Thursday at Blashford is volunteer day and we had a good turn out of fourteen for our first Himalayan balsam pull of the year. After many years of pulling this plant we have very significantly reduced the population and it is nowhere the dominant plant. The advantage of doing the first sweep early in the season is that we remove a significant number of plants but also get an idea of where the main problem areas are and so where to concentrate on our later visit. Pleasingly we found no more than a couple of hundred plants on about half the length of the stream, enough to suggest that there is still a seed source upstream  somewhere but not so many that it is having a serious impact on native wildlife.

The common terns are finally taking some interest in the rafts on Ivy Lake, although they are still not really taking control of any in numbers sufficient to deter the black-headed gulls. I tried putting out another raft during the afternoon in the hope that a new one might tempt them in. The gulls often just loaf around on the rafts, but have the annoying habit of bringing reeds and sticks and leaving them scattered  over the surface. I suspect they are mostly young adults, as the older birds started nesting a couple of weeks ago, a few may eventually build a proper nest, but in the meantime their practice efforts are putting off the terns.

Generally things were quite across the reserve, most of the birds are now nesting or getting ready to do so. Our visitor form North America, the Bonaparte’s gull is still to be seen, although it does not now attract more than the occasional admirer. I did manage to get a slightly better picture of it, which does show a couple of the differences from black-headed gull. You can see the slightly smaller size and overall thinner, more “pointed” look. Now that it is getting a summer plumage hood you can also see that this is blacker than that of black-headed gull, which is actually chocolate brown.

Bonaparte's gull

Bonaparte’s gull (right)

A very noticeable feature of the past week has been the huge increase in the numbers of damselflies around the reserve. Common blue and azure damselflies are now out in numbers, but the large red damselfly, typically the commonest spring species is very hard to find, perhaps due to the very poor April weather last year.

 

 

From Around the World to Blashford (unfortunately!)

It is the time of year when reserve officer’s thoughts turn to invasive plants, yes we can be a bit boring like that! Anyway after weeks of building tern rafts today the volunteers had a walk along the Dockens Water to look for Himalayan balsam. This plant used to dominate long stretches of the stream shading out other species but several years of pulling it up is showing real dividends, it is not gone, but for long stretches there is little or none to be found now. The seed are only viable for two or three years so pulling it up before it flowers for this time should have seen it gone, but a few always seem to hide away and get missed, so it never quiet disappears.

Although the balsam has got much rarer it is noticeable that we are seeing more of another invasive alien plant, the pink purslane, this time hailing from North America. Hopefully it will not become as much of a problem as the balsam, but we are pulling it up, just in case it has plans for a take over!

pink purslane

pink purslane

We came across a few other plants that do not belong, highlighting that garden plants are getting thrown out and establishing themselves all the time and, probably some of them will become invasive in time. One of the new ones today was star of Bethlehem, I doubt this will become a problem, but you never know and every garden escape is growing where a native plant could have been, so in a small way they all impact upon out native flora.

 

There should have been a picture of star of Bethlehem here , but it would not load!

Of course alien plants do not just impact upon other plants, they also reduce the native plants available for insects and other species to feed upon. Plants support lots of other wildlife, often specific to single species, native plants support a native fauna. By contrast alien plants tend to support a range of species that live in that plant’s native range and usually do not occur here. Some alien species will support some of our native fauna, but usually not much, which is why they do so well, there is not much eating them!

The warm sunshine today did bring out quite a few insect, I actually saw two species of dragonflies for the first time this year, which just shows how slow the season has been so far. The species were broad-bodied chaser and downy emerald. I did not get pictures of either of them though, but I did get one of a snail-killing fly,

snail killer

snail-killing fly

and a weevil.

weevil

weevil