It's been a good year for the rose hips. Elderberries are also fat and super-abundant, while blackberries are still weighing down bushes long after the season's crop would normally be picked and made into jam.

This autumn's bumper growth of hedgerow fruits is just one outcome of the miserable summer in Britain. In the countryside, as well as gardens, nature has gone berserk. With nettles sprouting up to 8ft-tall, you know something unusual is happening.

And the season which – in recent years – has been marked by everything starting up to a month earlier than the norm, has this time begun later than usual. In many places, the wildlife still thinks it's summer.

Even in parts of the high Pennines, for example, long purple stems of buddleia are only now in full bloom, creating an unexpected boost for butterflies such as Peacocks and Red Admirals which depend on it for food.

It's all the fault of the jet stream, which governs the British summer. This usually creates wet conditions known as Icelandic lows to the north of Britain through July and August, and brings Azores highs that provide us with long days of summer sun. This year, however, the jet stream moved south and we got the Icelandic lows.

This has given 2008 the seventh wettest summer since records began, according to the Met Office, and rainfall in the first half of September equals the worst recorded for the same period, which was back in 1918.

The effect on nature has been dramatic. In woodland, liverworts and mosses which would normally dry in summer are still flourishing. Some plants like wood cranesbill and forget-me-nots have flowered twice, the second flowering – say botanists – because the weather has fooled them that it's springtime again.

Dragonflies, virtually absent in July and August, have been coming out in swarms in late-September, when normally they would be much harder to find.

Meanwhile, it looks like a bumper year for fungi. Alan Braddock, recorder for the Mid Yorkshire Fungus Group, believes that the wet summer and mild temperatures have provided perfect conditions for growth. One wood that he surveys at Hartley Bank, an old colliery on the banks of the River Calder, was "absolutely full of fungi."

Edible species such as hedgehog fungus are growing prolifically in their traditional habitat of beech woods, probably because the trees have enough moisture for their roots and there is more left for the fungi.

Many species of butterfly have suffered adversely because of the wet summer, according to Butterfly Conservation's recorder for West and South Yorkshire, Roy Bedford.

It's been a bad year for the Small Skipper and even more disastrous for one of the most popular species, the Common Blue. At one site in Wakefield he regularly surveys he expected to count 600 Common Blues this year, but saw only one.

"They spend their chrysalis time underground with ants, and would normally emerge in early August. But there was a huge downpour most of them drowned before they have a chance to get out."

However, most of the group of butterflies known as "Browns" have benefited from the deluge. The field grasses which contain their food plants are long and luscious because of the rain. Another butterfly which has bucked the trend is the Speckled Wood, again because moisture has helped the grasses on which it feeds.

The effect on bird life has been harder to establish, with information still coming in, but the huge crop of berries is likely to be beneficial. However, the high rainfall has made life difficult not only for some rarer migrant species but also for birdwatchers.

Steve Wadsworth, warden of the RSPB reserve at Fairburn Ings, says the September floods there seriously affected the passage of wading birds returning south. There was not much mud for them to feed on, and they went off in search of food in flooded fields – well away from the reserve's bird hides and birdwatching visitors.

Information about this autumn's events is being gathered by around 50,000 observers around the UK for a project known as Nature's Calendar, run jointly by the Woodland Trust and the Centre for Ecology and Hydrology.

The Woodland Trust's Steve Marsh says that many autumn events have been late to start this year. "And unfortunately it's looking like we will have a pretty dreary autumn, where the colours are golden, rather than lots
of reds. The forecast doesn't look like providing us with the dry, cold and sunny weather that would bring out the tints and give us a classic autumn fireworks display in our woods."

If you would like to get involved in recording the changes seen in autumn, as well as other seasons, visit the UK Phenology Network's website at www. naturescalendar.org.uk

Autumn Nature Events

Today: Mid Yorkshire Fungus Group (MYFG). Fungus Foray at Fountains Abbey. Meet in Studley car park by the lake. Tel 07801 557 388.
Tomorrow: Tree Seed Collection. A walk in the woods. 1pm-3pm, Lady Wood, Ravensthorpe, near Mirfield. Book on 01484 234073.
October 5: Bishop Wood, near Wistow, North Yorks. MYFG Fungus Foray. Booking essential. Tel 01904 631975.
Aysgarth Falls National Park Centre, Wensleydale. Seed Collecting Day. 10.30am-3pm. Booking on 01969 662910.
October 11 & 12: Painting Fungi workshop, RHS Harlow Carr, Harrogate. Bookable on 01423 724680.
October 11: Swinsty Reservoir. MYFG Fungus Foray, from visitors' car park west of B6451. Tel 01937 587922.
October 12: Bolton Abbey. Two-hour fungus trail, from Cavendish Pavilion, 2pm. Book on 01756 751690.
October 19: "Discover & Do", Dales Countryside Museum, Hawes, 11am-4pm. Children over eight. Tel 01969 666210.
October 25: Middleton Woods, South Leeds. MYFG Fungus Foray. From Middleton Town Street. 0113 2641407.
October 27: Autumnwatch, BBC2 from October 27 for two weeks, Monday to Thursday.
October 29: Fungi of Grass Wood walk, from Quarry Car Park, Grass Wood, near Grassington, 2pm-5pm. Book on 01756 751690.
November 2: RHS Harlow Carr, Mushroom Day. Book on 01423 724680.