 Central Marsh and Pool is a diverse area where the main flora is common reed , reed sweetgrass , sedges , bulrushes and teasel . Willow trees are particularly important in this habitat as they have over 250 species of insect associated with them . Alder trees support birds such as redpoll , siskin and various tit species . Beyond Central Marsh lies West Marsh Pool , a small area of water surrounded by reedbed , where a number of dragonfly pools have been dug . Plants which thrive in damp areas , such as marsh marigold and meadowsweet , flourish here . 
