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If lots of people planted lots of water dock in their garden ponds, and bred and released dozens of Large Coppers, why would that be a bad thing?

Danny

That's a good question. I'm no expert on releases, but I suspect the rationale for *not* releasing would be along the lines of:

1. This isn't sustainable. Garden ponds are not the natural habitat of the Large Copper. I also believe that the colony at Woodwalton Fen ultimately failed due to a lack of (extensive) habitat. If this didn't work, I don't believe a colony centred on garden ponds would either.

2. It could introduce a higher number of predators (birds) than normal which would not only take Large Copper, but also the other species that were there (first).

Cheers,

- Pete

It's something we don't really think about, but when a butterfly dies out it does so gradually, and there isn't suddenly a big hole. Other species grow to fill the gap, so reinstating the missing butterfly without careful management of the rest of the local ecology creates an imbalance. I would guess that's the reason why most reintroductions don't work. I noticed for instance at Collard Hill, where the large blue has been introduced, that the site isn't nearly as rich in flora or insects as a meadow near Hatch Hill just up the road. As a result it had a better chance at success as there was less competition from other species.

Creating viable but heavily managed hotspots is probably the best way of doing it as this will allow the introduction to spread out naturally at its own pace. Such a technique seems to have worked with brown hairstreak at Ravensroost Meadow, Wiltshire. I think what was done there is that a fenced off pond with a large central island was dug. The island has heavily managed blackthorn in which brown hairstreak are supported. The surrounding hedgerows are also managed with young blackthorn sucker growth allowed to flourish and the butterfly has spread out among these.

Further, marsh fritillary colonies regularly die out due attacks by parasitic wasps, but they quickly become re-established from surrounding areas, presumably before other species take over. Therefore metapopulations are the best way to ensure their survival, and an unoffical release at a single site will ultimately fail. Each species has to be treated differently.

Would the large wetland reserve being created in East anglia, linking up all the fens etc. into one big reserve be a suitable site for another attempt for this species?

Mark