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  • roof rafters of a derelict building collapsed on the ground, surrounded by plants
  • Swifts in flight
  • Two hedgehogs nose to nose on grass
  • Common toad resting on a branch

Open Mosaic

Any piece of vegetated land of at least 0.25ha, which has been altered by human activity. Also referred to as brownfield, they can be extremely varied, from former industrial estates to quarries, spoil heaps, disused railway lines, landfill sites and disused airfields.

Unvegetated areas, loose bare substrate and pools may be present with spatial variation, forming a mosaic of early successional communities

Importance for wildlife

They can have as many rare invertebrate species as ancient woodlands, and many act as important ‘reservoirs’ of wildlife. Cycles of disturbance and abandonment combined with low-nutrient soils give rise to a wide variety of habitats, patterns of water temporarily ebbing and flowing and a mini-ark of plant species. Many invertebrates have complex life-cycle needs so they often require two or more habitats close to each other – a ‘mosaic’ of habitats rather than miles and miles of the same.

Important associated species


  • Hedge Accentor (Dunnock) Prunella modularis
  • Common Starling Sturnus vulgaris
  • Song Thrush Turdus philomelos
  • House Sparrow Passer domesticus
  • Herrring Gull Larus argentatus subsp. argenteus
  • Swift Apus apus*


  • Common Pipistrelle Bat Pipistrellus pipistrellus*
  • Soprano Pipistrelle Bat Pipistrellus pygmaeus
  • Hedgehog Erinaceus europaeus

Reptiles and Amphibians

  • Great Crested Newt Triturus cristatus
  • Common Toad Bufo bufo
  • Lizard Zootoca vivipara
  • Slow Worm Anguis fragilis

Bees and Wasps

  • Weevil Hunting Wasp Cerceris quadricincta
  • 5-Banded Tailed Digger Wasp Cerceris quinquefasciata


  • Necklace Ground Beetle Carabus monilis
  • Stag Beetle Lucanus cervus


  • Wall Lasiommata megera


  • Goat Moth Cossus cossus
  • Four-Spotted Moth Tyta luctosa

Mosses and Liverworts

  • Thatch Moss Leptodontium gemmascens
  • Chalk Screw Moss Tortula vahliana


  • Broad-leaved Cudweed Filago pyramidata
  • Red Hemp-nettle Galeopsis angustifolia
  • Annual Knawel Scleranthus annuus
  • Fine-leaved sandwort Minuartia hybrida

*Suffolk Priority species
**Priority - Research Only. Common and widespread but rapidly declining

Factors affecting habitat in Suffolk

  • Despite a growing acknowledgement of the biodiversity value of wildlife-rich brownfields, many local authorities still consider them a priority for development. Loss of habitat clusters is likely to negatively impact wildlife populations as key sites are lost.
  • ’Greening’ is a growing issue, with brownfields being inappropriately restored or remediated for use as public open space. This can involve adding nutrient-rich topsoil and seeding with grass species, alongside tree planting and introducing intense management such as grass cutting. resulting in the loss of early successional habitat features.
  • Neglect of sites can lead to scrub encroachment and the eventual loss of open habitats.

Habitat management advice

  • Some sites will require management to prevent site succession to scrub or woodland, and the loss of open habitats, the management of brownfields differs from traditional conservation management.
  • Avoid rigid management schemes; management should ideally be undertaken in a relatively reactionary manner based on rotational disturbance in response to site monitoring during the early years of management being introduced.
  • Management should be rotational, with only parts of a site managed in a single year to maintain a mosaic, avoiding using a single technique site-wide in a single year. This is essential to retain a habitat mosaic and prevent the homogenisation of a site.

Vision for Suffolk

  1. Improve knowledge of extent and quality of open mosaic habitats.
  2. Maintain the existing extent of open mosaic habitats to ensure no net loss.
  3. Re-create open mosaic habitats as opportunities arise.
  4. Encourage the restoration and improvement of degraded open mosaic habitats.

Where to find further information


  • Derelict ex-military base by Emma Aldous
  • Swifts by Neil Rolph (Flickr)
  • Hedgehogs by Natural England (Flickr)
  • Common toad by Neil Rolph (Flickr)