Case Study: Breen Wood, Co. Antrim

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  • A deciduous forest lying on the north facing slope of a river 6 miles from Ballycastle
  • Breen Wood is a Special Area of Conservation- 36 hectare site
  • One of the few deciduous woodlands remaining in Ireland
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Abiotic Components

  • Lies between 130 and 190m between sea level
  • High rainfall totals of 1600mm a year
  • Average temperatures are 4°C in January and 15°C in July
  • Podzols are poor quality due to basalt parent rock which is low in nutrients
  • High rainfall and sloping relief ensure leaching is significant
  • As a result range of plants and animals is smaller than expected in deciduous forest- 200 year old oak trees in Breen Wood are half the size they should be
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Biotic, Energy Flows and Trophic Structure

First Level

  • Autotrophs are mainly oak and downy birch forming a 20m canopy layer above ground- below some shrubs such as hazel and holly and ground layer: ferns, brambles, bilberry and mosses as well as wood-rush, wood-sorrel and ferns on soil. Bluebells and anemones can grow in spring due to lots of light. All these fix solar energy via photosynthesis

Second Level

  • Heterotrophs mainly herbivores- usually limited due to harsh climate mainly of one of the 15 species of butterfly including Orange Tip and Speckled  Wood as well as the red squirrel

Third Level

  • Birds including omnivores such as gold crests and the great and blue **** which consume seeds and insects such as the butterflies

Fourth Level

  • Omnivores and carnivores such as sparrow hawks and buzzards and badgers who also eat fruit and nuts as well as foxes and stoats who conusme rodents and eggs
  • 90% of energy is lost due to respiration and excretion so fourth level is smallest
  • Detritivores such as birch bracket fungi and earthworms decompose DOM but is limited due to slow decompsotion and acidic soils
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Nutrient Cycling

  • Few decomposers so decomposition is quite slow so may take years before leaves fully breakdown and transfer via decay pathway to soil store
  • High rainfall and cool summer temps. with sloping relief means there is high leaching
  • Basalt bed rock does not release many nutrients via weathering, leaving main input to come from precipitation
  • Good uptake of nutrients from soil into biomass- each autumn trees shed leaves to reduce moisture loss via transpiration during winter, leaving fresh leaf litter via fallout pathway to litter store
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