Horseshoe Vetch

[Perseus]

Hello,

Horseshoe Vetch

At peak probably a couple of days before the pictures on the lower slopes of
Mill Hill, Old Shoreham.

http://www.glaucus.org.uk/VetchTrail2008.htm#14May

Privet incursions and ground disturbance has caused lots of bare patches. One patch is Tor Grass, Brachypodium, useful for Wall Brown Butterflies.

Adur Butterfly & Large Moth List
http://www.glaucus.org.uk/Butterfly-list2008.html

Cheers

Andy Horton
glaucus@hotmail.com
Adur Valley Nature Notes
http://www.glaucus.org.uk/Adur2007.html
http://www.glaucus.org.uk/Adur2008.html
Adur Valley Nature Notes: May 2008
http://www.glaucus.org.uk/May2008.html
Adur Valley & Downs Gallery
http://www.flickr.com/groups/adur/pool/
View and upload your Sussex Wildlife Images to:
http://www.flickr.com/groups/sussexwildlife/

[champ]

Lovely to see the extent of the plant cover.The flowers certainly show where it is!.

[Piers]

That is an impressive carpet of horseshoe vetch Andy.

What are your thoughts upon the crash in Chalkhill Blue numbers at Mill Hill (compared to a few decades ago)? Clearly supply of suitable food plant is not an issue.

Some sites in Dorset have been ludicrously over grazed which has resulted in total collapse of Chalkhill Blue populations.

The southern slope of St Catherines Hill near Winchester is similarly in a dreadful state although in this case it appears to be the local rabbit population rather than over enthusiastic conservation groups.

All the best,

Felix.

[Perseus]

That is an impressive carpet of horseshoe vetch Andy.

What are your thoughts upon the crash in Chalkhill Blue numbers at Mill Hill (compared to a few decades ago)? Clearly supply of suitable food plant is not an issue.

Some sites in Dorset have been ludicrously over grazed which has resulted in total collapse of Chalkhill Blue populations.

The southern slope of St Catherines Hill near Winchester is similarly in a dreadful state although in this case it appears to be the local rabbit population rather than over enthusiastic conservation groups.

All the best,

Felix.

Hello,

There has NOT been a crash of Chalkhill Blue butterflies at Mill Hill. There has been a small decline (allowing for considerable annual variations) and this can be correlated to Privet incursions, and disturbance by people. Horseshoe Vetch has declined a bit. Decline may be due to annual variations but from my estimate of 4000 on the 3 acres in the 1990s to 3000 or so in 2003. Recent decline in numbers seems to have occurred everywhere. It could be a parasite.

Rabbits do not eat Horseshoe Vetch. Not much does. It is toxic. The cessation of Horse grazing resulted in a small improvement. Cattle grazing caused a problem in the 1950s and the areas have not yet recovered by a long chalk.

Chalkhill Blues at Mill Hill lower slopes are still at 90% of maximum numbers. Alas, the upper plateau is just 40 an acre in a good year which is well below the 800 - 1200 per acre (I go for the lower figure) on the lower slopes in the last good year in 2003.

I have heard about the Dorset sites. My research indicates cattle grazing would inevitably cause a wipe-out. Just how long or how quickly this occurs would be the issue. Eutrophication is the method the scientists say, but I would suggest that ground disturbance would be a factor as well. Humans can do this.

Mill Hill is full of toxic herbs. This is the reason why it is good. The land is unsuitable for grazing.

Horseshoe Vetch is not a grassland herb. Mill Hill is chalkhill herbland on the lower slopes. Horseshoe Vetch can be described as a herb that has a habitat amplitude that extends into chalk grasssland, but its must desirable habitat is the moss layer on chalk. Without grazing, Horsehoe Vetch goes straight to the woodland without an intervening grassland habitat.

The old farmers used to know this and would trash the land with cattle to break up the soil and encourage grasses and eliminate the pesky toxic herbs. It did not happen on Mill Hill because it was traditionally a rabbit warren, but not specially managed like Yorkshire rabbit warrens. Even, on rabbit warrens managed they attempted to remove the butterfly herbs and encourage grasses.

Sheep can be grazed at 0.85 per acre and Horseshoe Vetch can still survive.

Chalkhills Blues in Adur notes:
http://www.ukbutterflies.co.uk/phpBB2/v ... php?p=8761

Mill Hill 2007
http://www.glaucus.org.uk/MillHill2007.html
Shoreham Bank 2007
http://www.glaucus.org.uk/VetchTrail2007.htm

Mill Hill 2008
http://www.glaucus.org.uk/MillHill2008.html
Shoreham Bank 2008
http://www.glaucus.org.uk/VetchTrail2008.htm

Cheers

Andy Horton
glaucus@hotmail.com
Adur Valley Nature Notes (including Shoreham-by-Sea, West Sussex)
http://www.glaucus.org.uk/Adur2008.html
http://www.glaucus.org.uk/Adur2007.html
-----------------------------------------

[Perseus]

PS: A similar conservation grazing cattle wipe out has occurred to the Chalkhill Blue populations and Horseshoe Vetch on the nearby Anchor Bottom. This land may have been fertilised in the 1950s and sown with grasses though.

http://www.glaucus.org.uk/AnchorBottom.html

Shoreham Chalkhill Blue butterflies have been recorded since about 1830. Anchor Bottom was recorded as having 3000 Adonis Blues in the last century.

[Piers]

My apologies Andy, it may well have been this second site that I was thinking of when composing my original post.

Felix.

[Perseus]

My apologies Andy, it may well have been this second site that I was thinking of when composing my original post.

Felix.

Hello Felix,

No apologies necessary. I expect it was the Shoreham Bank. It is typical that unfounded rumours circulate about the good ole days when butterflies abounded.

Because of the work of Colin Pratt and because I am a local, the records for Mill Hill can be discerned.

It is always difficult without accurate recording, and because of the vagaries of both butterflies and weather even the transect counts can mislead. Unfortunately, with few exceptions the Chalkhill Blue numbers have been so denuded that a good site nowadays is a poor imitation of what it should be.



Mill Hill on the lower slopes is still 90% of optimum. The area has shown a 98% decrease since records began in 1830. The area has more comprehensive than could be expected anywhere local history records going back several centuries.

Adur Butterfly & Large Moth List
http://www.glaucus.org.uk/Butterfly-list2008.html

Cheers

Andy Horton
glaucus@hotmail.com
Adur Valley Nature Notes
http://www.glaucus.org.uk/Adur2007.html
http://www.glaucus.org.uk/Adur2008.html
Adur Valley Nature Notes: May 2008
http://www.glaucus.org.uk/May2008.html

[Matsukaze]

Has anyone had much luck at getting this species to germinate? It is one plant I have had a lot of trouble growing from seed.

[Lynn]

Hi The bad news is it is notoriously difficult but it is possible. I reckon best to sow in a ssed tray & sow the seed as soon as it is gathered.

[cecropia117]

I have had no problems germinating Horseshoe vetch seed.

You need to put it in the freezer for a month, then give it some stick between 2 sheets of sandpaper and then sow it.

Always works for me!

[Paul]

I had x4 seedlings out of maybe 20 seeds, collected in the Cotswolds, by leaving the whole seedtray outside for the winter... x3 survived & doing well so far ( I hope the botanical police won't whine)

[chitin]

Yes, leave it outside for the winter or at least in an unheated greenhouse. I once laboriously dehusked some under a dissecting microscope and it made no difference. Two year old seed will also germinate. Can be purchased very cheaply at Emorsgate Seeds who have a website. Surprisingly it will withstand being in a full up pot saucer of water all winter, It has a long root run and cannot be dug up- as if you would. Once Horseshoe Vetch plants get very dry they will not resuscitate, its finis, better to overwater than under.