[thedoc]

Dear Chris,

Love your podcast been listening to it driving down the full length of the country - good driving audio - keeps you awake, alert and amused. Thank you.

I do have a question - at this time of year, late March - early April, the verges and central reservations of roads get covered in white, pin-sized blossoms - I've stopped and looked at the plants and they are a scurvy grass

This is normally found on beaches, but have clearly found a successful niche on the side if main roads - I'm sure salting the roads is a major factor in this

My question is: given the ubiquity of this plant - has this plant been spread by the road salting or has it propagated along the sides of the roads following these narrow salty corridors?

It appears to be a single species - or are there species I have yet to find?

Any help in answering this would be gratefully received

Keep up the good work,

Edward

Dr Edward Draper
Asked by Edward Draper


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[Mazurka]

I understand that the Highways Agency have looked into this (partly as they have to keep on top of vegatation to prevent drains blocking up etc). and appears to be a relatively new phenomenon - with the spread really being noticed in the late 1980's.  This may be coupled with improvements in road ice prediction systems (such as the one operated by Vaisala) and more systematic application of grit.

There is little doubt that it has spread along the salty corridors of major roads rather than by spreading of grit contaminated with scurvey seed.

I would suggest that anyone who has been unfortunate enough to stand next to a major highway in the rain will have experienced spray from passing vehicles and how this turbulence could spread seed along roads.   

[Lmnre]

Do motorways create a microclimate?

In some ways, yes.

the verges and central reservations of roads get covered in white, pin-sized blossoms

Likewise

Ticks are drawn to carbon dioxide and use it as target to find mammals. Often you will find a concentration of ticks along the side of the roads due to the exhaust fumes from cars (carbon dioxide among them).

source

[CliffordK]

There is also the well documented effect called "Urban Heat Island".  Cities, perhaps due to the large dark colored asphalt area tend to be a couple degrees warmer then the surrounding countryside.