HEATHLAND - A WASTE OF SPACE?
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HEATHLAND MOTHS PAUL WARING I would like to introduce some of the moths that may be found on heathland, describe a little bit about their biology and make some key points regarding heathland moths and about heathland management issues as they affect moths and other invertebrates. These moths can be considered as a 'flagship' group for all the other invertebrates for which heathland is their only, or only major habitat. They are the species that are going to benefit most from the conservation of our remaining heathland and for which re-creation of heathland may be particularly beneficial. General overview One of the features that reveals itself when heathland invertebrates are studied is the extent to which heathland habitats form a continuum. In some cases moths seem to have as much difficulty recognising heathland as people do. There are species that are closely associated with heathlands in the strict sense, as lowland Vegetation dominated by dwarf shrubs, particularly ericaceous species, and others that occur in a wider ränge of habitats. There are moths that are widely recognised as heathland species that are found in relatively few heathland habitats, but which also occur on chalk downland. This pattern of distribution reveals something of the way that moths approach heathland. For many species, the key requirements are hot, low-lying places, usually with dry areas and often with micro-climates that are measurably hotter than their associated local climates. Often these micro-climates are more typical of climates recorded at latitudes many miles further south. The acidity, or even the presence of ericaeous shrubs are not important factors to some of our heathland moths. Some species will feed on heathers (Erica and/or Calluna) whilst others will feed on the plants that grow amongst the heather matrix. National statuses of heathland moths Within the British list for the macro-moths, or larger moths, there are approximately 37 species which could be regarded as particularly associated with heathland. For these species heathland is at least a major, if not the only, habitat they occupy. These species are listed in the accompanying Table (see Table 1) , showing the national status for each, as per Waring (1994 & in press). The national status categories for macro-moths in Britain are defined as follows: Red Data Book (RDB) categories (for those species recorded from 15 or fewer 10km squares since 1980 or in rapid decline): RDB1 - Critically endangered - 50% chance of extinction in 10 years based on various criteria, particularly the rate of decline and perceived threats RDB2 - Endangered - 20% chance of extinction in 20 years, based on rate of decline and perceived threats RDB3 - Vulnerable - 10% chance of extinction in 100 years, based on rate of decline and perceived threats
Trans. Suffolk Nat. Soc. 34 (1998)