See discussions, stats, and author profiles for this publication at: http://www.researchgate.net/publication/266079915 The ecology and conservation of the Bog Hawker Aeshna subarctica WALKER, 1908 (Odonata: Aeshnidae) of Latvia ARTICLE · JANUARY 2012 DOWNLOADS VIEWS 30 15 1 AUTHOR: Martins Kalnins JSC Latvijas valsts meži 25 PUBLICATIONS 23 CITATIONS SEE PROFILE Available from: Martins Kalnins Retrieved on: 13 September 2015 40 The ecology and conservation of the Bog Hawker Aeshna subarctica ... The ecology and conservation of the Bog Hawker Aeshna subarctica WALKER, 1908 (Odonata: Aeshnidae) in Latvia Mārtiņš Kalniņš Nature Conservation Agency, Baznīcas iela 7, LV-2150, Sigulda, Siguldas novads, Latvia; e-mail: [email protected] KALNIŅŠ M. 2012. ThE ECoLoGY AND ConservatioN oF ThE BoG Hawker AESHNA SUBARCTICA WALKER, 1908 (oDonata: AEShNIDAE) IN Latvia. – Latvijas Entomologs 51: 40-57. Abstract: The Bog hawker or Subarctic hawker, Aeshna subarctica WaLKEr, 1908, is a declining and already regionally extinct species in some areas in Europe. Published and all known unpublished data have been used to present and analyse its distribution, population size, habitat selection, and conservation status. The distribution of A. subarctica has been mapped using a basic grid of 5x5 km squares in the Baltic grid system. In total, A. subarctica has been recorded from 21 squares and 21 localities occurring sparsely or in small concentrations over a large part of the country apart from its western territories. The majority of the recent localities are situated in northern and southern Latvia. The known pattern of the species’ distribution partly results from the abundance and density of appropriate habitats and possibly a climatic influence. however, this also may be a consequence of an insufficient and uneven odonatological exploration of the country. A. subarctica has mostly been recorded in primary habitats in Latvia, such as raised bogs with bog pools, lakes and lakes within fens and bogs. The flight season of theA . subarctica in Latvia ranges mainly from August to September. The conservation measures are suggested. Key words: odonata, Aeshna subarctica, distribution, habitat selection, conservation, Latvia. Introduction is already regionally extinct in some areas in Europe. In Europe, it currently The Bog hawker or Subarctic exists mostly in rather localised areas, hawker, Aeshna subarctica WaLKEr, at individual and scattered localities or 1908, is a circumboreal species, in their small concentrations (Djikstra occurring throughout central and 2006). Available habitats continue northern Europe, Eurasia and Japan to decline due to the drainage of (Dunkle 2000, Djikstra 2006, Paulson wetland areas and climatic changes 2009). however, it is declining and (Raeymaekers 1998, Salmiņa 2010). Latvijas Entomologs 2012, 51: 40-57. 41 Pollution and overgrowth of habitats projection (TKS-1993) of Latvia. The also may threaten the survival of this final map is based on 1:50000 scale species. Therefore, A. subarctica satellite maps available for Latvia, has been classified as Least Concern published in 1999–2000 by the State (LC) species in the European Red Land Service of the Republic of List of Dragonflies (Kalkman et al. Latvia. 2010), and in the European Union The data on habitats (inter alia also as Least Concern species with photo) were collected by the author the decreasing population trend and others in the field. Potential (Kalkman et al. 2010). habitats, such as raised bogs with The aim of this paper is to bog pools and lakes, lakes within summarize the knowledge of fens and bogs and post-excavation the distribution and habitats of peat bogs were examined. Visual A. subarctica in Latvia. This dragonfly search for imagines and exuviae is not protected in Latvia, but so far was made. Egg laying microhabitat the data on it have not been analysed and substratum was registered when and the species’ current population egg-laying females observed. Data status has not been assessed. on particularly protected nature territories come from the website of the Nature Conservation Agency Methods (Nature Conservation… 2011). The quantitative field data The analysis of distribution on dragonflies exuviae in Lielais and habitat preference is based on: Ķemeru tīrelis Bog were collected in (a) all published data, (b) author’s 16 sampling plots on 16 and 19 July unpublished data collected between 2007. The survey of dragonflies and 1999 and 2010, (c) unpublished data the evaluation of vegetation were collected by entomologists before carried out within a 100 m long and 2011. Both historical and recent data, a 5 m wide transect in each sampling in total 31 records of A. subarctica, plot. The percentage of the coverage of were included in a Microsoft office different vegetation forms, the impact Access geodatabase prepared by the of trees, the dragonfly species and the author. number of individuals were evaluated The distribution of A. subarctica in each 20 metres in the transect. The has been mapped using a basic grid habitat groups were chosen for the of 5x5 km squares in the Baltic grid arrangement of sampling plots by system on a Transverse Mercator maps at the landscape level, choosing 42 The ecology and conservation of the Bog Hawker Aeshna subarctica ... the most typical habitats, but transects are concurrent with district names, used by were chosen by ten categories of the author in previous papers (Kalniņš 2007, vegetation developed by the author’s 2008). and as well as by accident. Each transect was run through two times, i.e. back and forth and all exuviae Results were collected. The quantitative field data on Twenty one locality of dragonflies imago were collected in A. subarctica has been recorded Grabatiņš Lake and Meistars Lake. in Latvia so far. Geographical The survey of dragonflies were coordinates are only given for carried out within a transect along several localities, localisation of lake bank. All observed specimens which could be difficult. Vegetation were counted. The length of bank of descriptions concern a zone inhabited Grabatiņš Lake is 300 m, of Meistars by A. subarctica. Lake is 550 m. The areas measured on 1. Lielauce Lake (Auce orthophoto maps, scale 1:10 000 from d.). August of 1949, Aessub: 1 the third cycle (2007-2008) of aerial female was caught (Spuris 1952; photography (Latvian Geospatial 1956). Information about locality Information agency) using Arc GIS (vegetation) was not described in 9 software. Geographical coordinates detail in the original publication, the are only given for several localities, data on vegetation concern its current localisation of which could be composition. The lake is large and difficult. Vegetation descriptions rich in diverse habitats and one part concern a zone inhabited by of lake are fen (~200 ha). The locality A. subarctica. has had PPNT status since 1999. It is situated in the nature reserve “Vīķu Explanations of abbreviations: Aessub purvs” and in the NATURA 2000 area – Aeshna subarctica, PPNT – particularly (site code: LV0504700). protected nature territory, d. – district, vill. – 2. Complex of bog pools S of village. The number of observed imagines or Gārgaļu Lake and at the NE part of collected exuviae of A. subarctica (Aessub) is given after the date of observation and large Lielais Ķemeru tīrelis Bog followed by references or the author of (Tukums d.). Large (~5000 ha) unpublished data, as e.g. (M. Kalniņš). The active raised bog with large regions are named according to the Law complexes of bog pools. Vegetation on administrative territories and populated with Sphagnum cuspidatum and areas (2008). Some of the regional names Sphagnum sp., Eriophorum sp., Latvijas Entomologs 2012, 51: 40-57. 43 Rhynchospora alba, Scheuchzeria with numerous bog pools and small palustris, Ledum palustre, Vaccinium lakes. Vegetation with Sphagnum uliginosum, Calluna vulgaris and cuspidatum and Sphagnum sp., Andromeda polifolia (Table 1). Eriophorum sp., Rhynchospora 06.08.2003, Aessub: 1 female caught alba, Scheuchzeria palustris, Ledum (M. Kalniņš); 18.07.2007, Aessub: 11 palustre, Vaccinium uliginosum, exuviae near five bog pools (Table Calluna vulgaris and Andromeda 1) (M. Kalniņš) (Kalniņš, Medne polifolia. The locality has had PPNT 2007). Since 2006 a project for the status since 1973. It is situated in restoration of the bog’s hydrological the Gauja National Park and in the regime – earlier seriously disturbed NATURA 2000 area (site code: due to drainage – has been carried out LV0200100). resulting in an increased water level 5. Pekšu Lake (Pārgaujas d.). that will certainly improve the habitat A eutrophic lake (~10 ha) with rich conditions for A. subarctica (Ķuze, and diverse vegetation – Phragmites Priede 2008). The locality has had australis, Typha sp., Equisetus sp., PPNT status since 1973. It is situated Menyanthes trifoliate, Nuphar lutea, in the Ķemeri National Park and in Nymphaea sp., Potamogeton sp. the NATURA 2000 area (site code: and others. 09.08.1999, Aessub: 1 LV0200200). individual (M. Kalniņš) (Kalniņš 3. Pakujezers Lake near et al. 2007). The locality has had Ezerkalni (Baldone d.). A PPNT status since 1973. It is situated dyseutrophic lake (~1 ha), bordered in the Gauja National Park and in by a wide (5–10 m) Sphagnum the NATURA 2000 area (site code: zone with Sphagnum cuspidatum, LV0200100). Carex limosa, Eriophorum sp., 6. Grabatiņš Lake in Rhynchospora alba, Calluna vulgaris Grabatpurvs Bog (Krimulda d.). and Andromeda polifolia. 01.06.2008, Active raised bog (~250 ha), with Aessub: 1 exuviae (M. Kalniņš). relative small (~50 ha) open (non- 4. Sudas Bog, SE part, SE owergrown) area and two small from Velna Lake env. near small lakes. Grabatiņš Lake is a dystrophic bog pool (Līgatne d.). 17.06.2006, lake (~0.6 ha), bordered by a narrow Aessub: 2 exuviae (M. Kalniņš); (1–5 m) Sphagnum zone with Carex Sudas Bog, Central part, Salas Lake limosa. 31.07.2005, Aessub: totally env. near small bog pool 19.06.2006, 10 individuals recorded and 3 exuviae Aessub: 1 individual (M.