Introduction

     The knowledge of native invertebrates Invertebrata have recently been enriched just enough to make the preparation of a separate volume of “The Polish Red Data Book of Animals” (PRDBA), covering this group of animals, possible. In the first edition of the PRDBA (1992) the lower animals were, out of necessity, treated marginally. Apart from the generally poorer knowledge of invertebrates, this part of the animal kingdom does no attract as much public attention as vertebrates Vertebrata do, and has a less numerous representation on the lists of protected species and species covered by the EU directives and international conventions. The world and regional „red books” of invertebrates (e.g.,. „The IUCN Invertebrate Red Data Book” 1983; „Threatened Swallowtail Butterflies of the World – The IUCN Red Data Book” 1985) were published much later, one can say – at the second stage, than volumes dedicated to vertebrates, particularly mammals and birds. There are no sufficient data to assume that the obvious dominance of insects and other invertebrates in the world of living organisms, in terms of both the number of species and abundance, will be automatically reflected in the proportion of these animals in the global, regional or national „red books”. It is difficult to suppose that the recognition of the status of small animals and their endangerment (rate of population decline and habitat loss, contraction of the area of occurrence/occupancy) will be ever as good as in the case of vertebrates which are easier to investigate. Many invertebrate groups have not sufficiently been known in terms of taxonomy, and few of the described taxa belong to easily distinguishable. Probably „red books” will favour for a long time the higher animals, easier to identify, stronger appealing to the imagination of people and stronger influencing human life. However, the methodological principles of „red books” – a kind of scientific documents – should be based on the possibly objective perception of species as equivalent biological entities. Assessment of the degree of threat to insects and other invertebrates should be based on similar criteria as those applied to higher animals, though recommendations for their conservation can and should be different because vertebrates and invertebrates are two specific, separate groups, of the very distinct biology of species.
     Why do we care for invertebrates? This question may be posed by each of us because tiny animals are counted in thousands and hundreds of thousands of species, and the numbers of individuals are countless; they have colonised almost all habitats wherever the life has sprang up. This concerns particularly insects dominating world ecosystems (almost 1 million of insect species have been described; Heywood, ex. ed. 1995), which are everyday companions of man, being a nuisance or bringing benefits.
     Reasons for investigating and conservation of invertebrates are practically the same as those which generally underlay science and nature conservation. These animals make up the overwhelming majority of biological diversity, govern ecological processes (energy flow and matter cycle in ecosystems) as a kind of the powerful sanitary service, cleaning our planet of dead organic matter, maintaining natural systems in a state of relative equilibrium and stability. In the huge mass of invertebrates there are species that plague man, transmitting diseases, being parasites of man and livestock, or pests in cultivated fields and farms. On the other hand, many invertebrates, e.g., pollinating insects, insects producing honey, wax, silk, or molluscs and crustaceans being in many regions of the world a valuable source of animal proteins, contribute much to the benefit of man. Knowledge of the practical importance of biological diversity is now far from satisfactory; we are even unable to assess this diversity (e.g., Wilson 1989, 1999); it is unquestionable, however, that it is a big potential capital for present and future generations, if it is not destroyed. In the light of current knowledge we can neither determine nor foresee what benefits in the economy or medicine may be brought in future by particular species, exterminated at an increasingly fast rate. We can say more about ecological consequences of the loss of certain species, particularly those belonging to the group of keystone species, which are of a key importance for the functioning of ecosystems.
     In the mass of insects and other invertebrates one can find many rare species, represented by small populations, sometimes associated with vulnerable and easy to destroy habitats, and for that reason endangered in their existence. Among them there are endemic and unique taxa, particularly interesting for cognitive reasons. Many of these species die unnoticeably as the result of anthropogenic changes in the environment, use of pesticides and over-exploitation (e.g. by collectors, or for trade). The scale and character of this phenomenon are best described in „red books” – specialistic publications, prepared on the initiative of the IUCN/World Conservation Union. Extinctions caused by man create naturally a big problem of ethical nature, particularly because the loss of species is practically irretrievable.
     Anthropogenic extinctions of species are an object of interest of nature conservation and conservation biology, a new branch of science, which stem from nature conservation. Extinctions for natural reasons do not enter within the scope of interest of nature conservation, because they are part of natural biological and evolutionary processes, and random events. The fact of the matter is that sometimes it is difficult to identify factors being involved in extinctions. „Red Books” are attempts to answer such questions and meet species conservation needs; they sort out the problems of anthropogenic threats and species decline and provide practical guidelines for conservation of species.
     The first general list of endangered and extinct animal species of Poland was provided by „The Polish Red List ...” (Głowaciński, ed. 2002), including a little more than 2.5 thousand invertebrate species. The list showed that of this number about 1,280 species had become extinct in the area of Poland (categories EX-EX? = about 200 species) or was in the group of strongly endangered species (CR-VU = about 1,080 species). The present edition of „The Polish Red Data Book of Animals” is more selective in terms of species selection than „The Red List ...” (2002), focusing on extinct species and species of the high risk of extinction, particularly from the CR-EN categories, and on species which attract considerable public attention, and above all arouse interest of scientists and nature conservators. Irrespective of the category of threat, the selection of species was mostly limited to the best known examples of species, treated as representatives of particular taxonomic groups. This largely subjective selection of species was also connected with the limited size of the volume. This limitation was planned from the beginning because, among others, the descriptions of closely connected species of a similar ecological and conservation status would be recurrent and tiresome for a reader. It does not mean, however, that such a full document, describing the population status of all endangered native species would be of no value. It would certainly been useful, particularly for education and conservation practice (e.g., realisation of the National Strategy of Nature Conservation, development of the concept and implementation of the „NATURA 2000” network); however, chances of elaborating such a document are now rather small. Above all, the knowledge of invertebrates is very uneven; there is also little funding available for preparing such a comprehensive elaboration. In addition, we can not neglect the fact that authors-specialists lack the motivation to undertake that kind of work (low prestige of this type of work in the scientific environment, underpayment for intellectual work etc.).
     This book is addressed to a wide group of readers, above all nature conservation service: voivodeship nature conservators, directors of national and landscape parks, foundations acting on behalf of nature and natural environment conservation, competent offices at all levels of government and self-government administration. This book should also serve spatial management planners, Boards of State Forests, other owners of forests, farmers, centres of ecological education, as well as schools and universities. One may hope that it will be helpful in improving law pertaining to conservation of animal species and protection in reserves. It should provide the Ministry of Environment with reliable source materials, useful for realisation of the national strategy of nature conservation and fulfilment of respective obligations at both national and international levels. We recommend, however, critical reading of this book, taking into account considerable variations in animal populations and a need for up-dating information about particular species.