Working Report 2009-18 Eurajoki Olkiluoto Study on Species of Ground Beetles and Ants 2008 Jarkko Santaharju Sirkka-Liisa Helminen Rauno Yrjölä February 2009 POSIVA OY Olkiluoto FI-27160 EURAJOKI, FINLAND Tel +358-2-8372 31 Fax +358-2-8372 3709 Working Report 2009-18 Eurajoki Olkiluoto Study on Species of Ground Beetles and Ants 2008 Jarkko Santaharju Sirkka-Liisa Helminen Rauno Yrjölä Environmental Research Yrjölä Ltd February 2009 Base maps: ©National Land Survey, permission 41/MML/09 Working Reports contain information on work in progress or pending completion. The conclusions and viewpoints presented in the report are those of author(s) and do not necessarily coincide with those of Posiva. Eurajoki Olkiluoto study on species of ground beetles and ants 2008 ABSTRACT The species of ants and Ground beetles at Olkiluoto in Eurajoki were studied in the summer of 2008 during two trapping periods: in June and August. The research goal was to clarify the species on Olkiluoto island of the earlier mentioned groups, at least at the family level, and to collect samples for further examination by Posiva. The trapping areas were selected at Olkiluoto in Posiva test monitoring sectors, a part of the trapping areas was the same as the earlier study. Species of ants, depending on their particular species, are a very dominating group of insects. The ants are the most important predators, scavengers and soil movers in Fin- nish forests. It looks as if the biomass of ants may be more than 10% of the biomass of all animals in certain areas of Finnish forests. In Finland there are about 60 species of ants that have been observed. They have been divided into four sub-groups, which are Myrmicinae, Formicinae, Ponerinae and Dolichoderinae. In Finland there are close to 300 species of ground beetles (Carabidae), which are di- vided into dozens of different families. The species, to a great extent, consist mostly of predatory insects that prey on microbes in field layers, but a part of them are specialized in feeding on flora. Ground beetles are usually divided into three groups according to their choice of habitat: Species that favour open biotopes, species that favour forests, and generalist species that can thrive in a variety of environments. Ground beetles also reflect changes in their living environment, and possibly they can be significant as so- called bio-indicators. Pitfall traps were used as the method of research. The preservative fluid used was etha- nol (50%) with dishwashing liquid to remove surface tension. The points were located in various different biotopes in fields, meadows and forests. The data collected was de- fined as a minimum for the family level of Ground beetles and for ants to the species or species pairs. The species of Ground beetles and ants found in the pitfall trap study represented a quite usual range of species for southern Finland and no rare or endangered species were de- tected amongst the individuals defined to their particular species. The number of indi- vidual ants appeared to be higher in biotopes that were predominantly forested with conifers but as far as the amount of species was concerned, the dispersion between dif- ferent biotopes was great. The amounts of species and individuals concerning the ground beetles were higher in open field-and meadow habitats. The differences in sizes amongst the ground beetles are remarkable. The weight of a large individual Carabus hortensis is the same as the weight of several individuals of smaller species together. These species, together with Pterostichus niger & Patrobus atrorufus, make up the ma- jority of the communities of ground beetles in Olkiluoto, both in numbers and in weight. Keywords: ant, beetle, Olkiluoto, Eurajoki, Posiva Eurajoen Olkiluodon maakiitäjäis- ja muurahaistutkimus 2008 TIIVISTELMÄ Eurajoen Olkiluodon muurahais- ja maakiitäjäislajistoa selvitettiin kesällä 2008 kahden pyyntijakson aikana: kesäkuussa ja elokuussa. Tutkimuksen tavoitteena oli selvittää Olkiluodon saaren lajistoa edellä mainituista ryhmistä vähintään sukutasolla ja samalla kerättiin näytteitä Posivan jatkotutkimuksiin. Tutkimuksen pyyntialueet valittiin Olki- luodon alueella olevista Posivan seuranta-koealueista, osa pyyntialueista oli samoja kuin aiemmassa tutkimuksessa. Muurahaislajit, lajista riippuen, ovat hyvin dominoiva hyönteisryhmä. Suomen metsissä muurahaiset ovat tärkeimpiä saalistajia, haaskaeläimiä ja maa-aineksen siirtäjiä. Näyt- täisi siltä, että muurahaisten biomassa saattaa olla jopa yli 10 % eläinten biomassasta tietyissä osissa Suomen metsiä. Muurahaislajeja on Suomessa tavattu n. 60 ja lajit on jaettu neljään alaheimoon, jotka ovat Myrmicinae, Formicinae, Ponerinae ja Dolicho- derinae. Maakiitäjäislajeja (Carabidae) on Suomessa lähemmäs 300 lajia, jotka on jaettu kym- meniin eri sukuihin. Lajit ovat suurelta osin kenttäkerroksessa pieneliöitä saalistavia petoja, mutta osa on erikoistunut myös kasviperäiseen ravintoon. Maakiitäjäiset jaetaan usein kolmeen ryhmään habitaatinvalinnan perusteella: avointen biotooppien lajeihin, metsälajeihin ja generalisteihin, jotka voivat käyttää monia eri elinympäristöjä. Maakii- täjäiset myös heijastavat muutoksia niiden elinympäristössä ja niillä voi mahdollisesti olla merkitystä niin sanottuina bioindikaattoreina. Tutkimusmenetelmänä käytettiin kuoppapyydyksiä. Tutkimuspisteet sijaitsivat vaihte- levissa biotoopeissa, niin pelloilla, niityillä, kuin metsissäkin. Kerätty aineisto määritet- tiin vähintään sukutasolle maakiitäjäisten osalta ja muurahaisten osalta lajiin tai lajipa- riin asti. Kuoppapyydyksistä tavatut maakiitäjäis- ja muurahaislajit edustivat melko tavallista Etelä-suomalaista lajistoa, eikä lajilleen määritetyistä yksilöistä löytynyt harvinaisia tai uhanalaisia lajeja. Muurahaisten yksilömäärät näyttäisivät olevan korkeimpia havupuu- valtaisissa biotoopeissa, mutta lajimäärien kohdalla hajonta eri biotooppien välillä on suurta. Maakiitäjäisten laji- ja yksilömäärät olivat korkeimpia avoimissa pelto- ja niitty- habitaateissa. Maakiitäjäislajien kokoerot ovat huomattavia, ja suurikokoinen Carabus hortensis yksilö on painoltaan samankokoinen kuin useampi pienempien lajien yksilö yhteensä. Se, sekä Pterostichus niger ja Patrobus atrorufus muodostivat pääosan Olki- luodon maakiitäjäisyhteisöstä, sekä yksilömäärältä että painoltaan Asiasanat: muurahainen, maakiitäjäinen, Olkiluoto, Eurajoki, Posiva 1 TABLE OF CONTENTS ABSTRACT TIIVISTELMÄ 1. INTRODUCTION ................................................................................................ 2 2. ECOLOGY OF THE STUDIED SPECIES OF INSECTS .................................... 3 2.1 Ants (Hymenoptera, Formicidae) ..................................................................... 3 2.2 Ground Beetles (Coleoptera, Carabidae) ........................................................ 3 3. MATERIAL & METHODS ................................................................................... 4 4. AREA OF RESEARCH ....................................................................................... 6 5. RESULTS ........................................................................................................ 10 6. REVIEW OF THE RESULTS ............................................................................ 11 7. ACKNOWLEDGEMENTS................................................................................. 16 REFERENCES ........................................................................................................... 17 APPENDICES............................................................................................................. 19 Appendix 1: Olkiluoto ant species summer 2008 ................................................. 19 Appendix 2: Olkiluoto ant species according to trapping spots summer 2008 ..... 20 Appendix 3: Amount of ground beetles on different test dates .............................. 23 Appendix 4: Amount of Ground beetles according to trapping spots on different ... test dates ......................................................................................... 24 2 1. INTRODUCTION The species of ants and Ground beetles at Olkiluoto in Eurajoki were studied in the summer of 2008 during two trapping periods: in June and August. The research goal was to clarify the species on Olkiluoto island of the earlier mentioned groups, at least at the family level, and to collect samples for further examination by Posiva. The trapping areas were selected at Olkiluoto in Posiva test monitoring sectors, a part of the trapping areas was the same as the earlier study (Ranta et al. 2005). Posiva commissioned the study on ant and ground beetles and the study was carried out by the Environmental Research Yrjölä ltd. Jani Helin carried out the supervision of the project on behalf of the client. Jari Siltanen provided his much appreciated assistance on the field. 3 2. ECOLOGY OF THE STUDIED SPECIES OF INSECTS 2.1 Ants (Hymenoptera, Formicidae) Species of ants, depending on their particular species, are a very dominating group of insects. Part of the ant family is equipped with a venom sting located in the abdomen (e.g. Myrmica), when others secrete acid from the abdomen into the wound inflicted with their jaws (e.g. Formica). The ants are the most important predators, scavengers and soil movers in Finnish forests. It looks as if the biomass of ants may be more than 10% of the biomass of all animals in certain areas of Finnish forests. (Hölldobler & Wilson 1994). All species of ants are social insects i.e. they live in communities.