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There be dragons at Spring Park
In late summer, life stirs in the Spring Park pond and a transformation on an almost mythical level takes place each year.
Clinging on to tall vegetation above the pond you can sometimes see evidence of this transformation in the form of dragonfly exuviae. Exuviae are nothing more than the dried outer casing of a young dragonfly. It is what the insect leaves behind when it ends the aquatic stage of its life cycle and turns into the colourful aerial hunter we commonly see. This happens in other species and famously in snakes.
This harmless, dead case provides a clue to what has been living underwater for one or in some cases several years, feeding on the larvae of midges and mosquitoes until the day when something spectacular happens. While underwater the insect has been changing into the adult form, but still trapped in side the larval case.
Ready to undergo a transformation into its adult form, the larvae will climb up a plant stem, out of the water where the case splits open up the back and a dragonfly emerges and flies away to feed. This emergence can take hours – a slow but amazing process during which a dragonfly the length of a pen or pencil escapes from a case only a couple of centimetres long. When it first emerges, its wings are soft but quickly harden to allow flight in a new kingdom above the water.
Look out for different dragonfly and damselfly species (a closely related insect) around the edges of the pond on Spring Park where there are many to observe!
Photo by TJ Gehling
Spores for thought on bracken control
Bracken is one of the worlds most successful plants and each summer it makes itself well known through its dominance of heathlands, grasslands and moorlands.
Bracken is a member of the fern family (The word bracken is of old Norse origin, related to Swedish bräken and Danish bregne, both meaning fern). Although it is a fascinating plant in many ways (its fossil record dates back 55 million years), it poses quite a challenge for biodiversity and the conservation of habitats such as the heath on West Wickham Common.
Bracken is allelopathic meaning it releases chemicals that inhibit both the growth of other plants as well as mycorrhizal development beneficial to fungi and plants. Ticks also thrive in dense bracken and cling on to the fronds of the plant, ready to jump ship to unsuspecting hosts that wade through. Bracken can quickly dominate heathland habitats with little to stop its dominance if left unchecked; each frond contains numerous spores and its creeping rhizomes (underground roots) help it to spread up to a metre a year. It is no surprise that a plant so prolific is complex to manage.
On West Wickham Common, bracken is controlled around the open heath by repeatedly strimming it each year; repeating the process is a way of weakening the root system. This is part of a long process in the management of the site.
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The City of London Corporation has seven green spaces in South London and Surrey covered by three charities: Ashtead Common, Coulsdon Commons and West Wickham Commons. Each charity has its own Newsletter and you can now:
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