A thread 👇 Managing for urban butterflies.
If you want roadside verges buzzing with life & brimming with butterflies - or if you've mourned the loss of a habitat blitzed by mowers - this is for you. We look at positive solutions to urban grassland management ...
Q1. What's an urban butterfly? This is need-to-know as we'll see... According to the UK Butterfly Monitoring Scheme there's 28. Let's whizz through them in family groups... PIERIDAE: 1. Orange-tip 2. Brimstone 3. Large white 4. Small white 5. Green-veined white @UK_CEH @JNCC_UK
They eat nettles as kids, they overwinter as butterflies - it's the NYMPHALIDAE. 6. Small tortoiseshell 7. Peacock 8. Comma 9. Red admiral 10. Painted Lady [if you don't know about their migration, look it up - mind boggling!] @_BTO @DrJudyStone
Here come the skippers or the HESPERIIDAE if you want to impress... 11. Dingy 12. Essex 13. Large 14. Small 15. Grizzled. These are easy wins to protect but also super sensitive to mismanagement... think coal mine canary of the verge... we'll come on to that... @LissaKEvans
Introducing the SATYRIDAE: 16. Marbled white 17. Small heath 18. Speckled wood 19. Wall brown 20. Meadow brown 21. Gatekeeper 22. Ringlet. We're getting there now ... register almost done ...
- and finally, the last of our urban butterflies - 23. Purple hairstreak 24. Green hairstreak 25. Small copper 26. Common blue 27. Holly blue 28. Brown argus. I've little doubt some others appear in urban environments, but we've got a data set for these 28 ...
28 urbanites of the UK's 59 species. Let's give them nectar... say, wallflower, clover, knapweed, marjoram, lavender, verbena, a garden buddleia. Good stuff. Flying start. But we've forgotten something... and it's VITAL! ... it's the reason why populations have CRASHED e.g. ...
That's a snapshot of some of the 28... when I looked at the data for all 28... well, it was pretty bleak - small wins for small white and comma - everything else, curtains... so, I worked out how to fix it. First we need just TEN more plants...
1. Blackberry 2. Cock's foot grass 3. Nettle 4. Nasturtium 5. Birds Foot Trefoil 6. Oak 7. Garlic mustard or Cuckoo flower 8. Sorrel 9. Alder buckthorn or Buckthorn 10. Rock rose. Plant those and you've catered for all 28 urban CATERPILLARS. They're often forgotten! @Ecothrifty
Next up - we need new verge management. Councils & highways presuppose managing for butterflies and pollinating insects will be expensive. But the reverse is true ... why? because wildflowers like it TOUGH... truth be told we don't need "paradise verges" ...
... we just need councils to take away the grass clippings. Year 1 & 2: mow 4-6 times like they do today but *remove* the clippings = nutrients GONE! Year 3 onwards: mow March & Sept; you won't need to mow more than that, no nutrients onsite = short grass. Images: @PhilSterling3
Short grass & low nutrients = wildflowers thrive. Sure, scatter some wildflower seed if you like; get that nectar flowing! Maybe chuck in a bit of yellow rattle which steals nutrients from grasses and keeps them short. By year 3 you are down to just two mows ... @gillians_voice
One last thing for: 1. 10 of the 28 that need grass as a caterpillar foodplant inc. the skippers 2. the 12 that overwinter as caterpillars on their foodplant 3. the Essex skipper who overwinters as an egg on a grass stem 4. the 8 that overwinter as pupae... LEAVE SOME UNMOWN!
Does the maths work? Here's an example: North Dorset County Council reduced their mowing bill by 11k a year. Although a cut & collect mower costs £35.5k, they were spending £36k on mowing annually. Now, every 3.5 years they could buy a new cut and collect mower.
So, what can you do? Plant 10 caterpillar food plants & a nectar source that flows from Spring to Autumn. But, above all else, and the reason I've written this - ask your council to start cut and collect with some standing crop left all year on rotation. Do that, and we all win!
Additions: 1. Well managed grasslands sequester carbon, win win 2. Cut and collect mower [£35.5k] includes trailer! 3. Theory works in rural locations too 4. Tweet 6 = Lycaenidae 5. I speak about these ideas here: http://shorturl.at/krHP1  6. Thanks for so much interest 🙌👊🦋🐛🌼
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