Dragonfly Observations in the Raka Area, Lower Carniola, Eastern
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Dragonfly observations in the Raka area, Lower Carniola, eastern Slovenia, with a note on the behaviour ofSomatochlora meridionalis Nielsen (Anisoptera: Corduliidae) M. Kotarac Marohovih 11, SLO-62000 Maribor. Slovenia Abstract – An annotated list is of 28 given spp. Introduction from 17 localities in the area (alt. 150-300 m). During August 1-10. 1992. the traditional sum- In Slovenia, S. meridionalis of was so far known mer workshop Biology students of the Univer- from NW held the of Raka. a single specimen, taken in Islria in sity of Ljubljana was at village the therefore the the 30 km early 19605. strong populations near Ljubljana-Zagrebhighway, some here interest. with W reported are of some Coupled of the international border with Croatia. The the from recent records northern Italy (Friuli), report ofthe small "odonatological team" is pre- sented here. these could represent an additional evidence for Evaluating the data, it should be the current northward extension of this that based brief range sp. emphasised they are on a very Various of male behaviour outlined in few hours each types are survey, hardly a were spent on sonic detail. one locality. The exceptionally hot summer of 1992. the hottest since decades, dried completely up most Noiul. Vol. No. June 1993 2 odonalol.. 4, I, pp. 1-20, I, other bottom. of the irrigation ditches and small water 5-8 m, modest current, mostly loamy 6 In the bodies for a period ofat least weeks. The tem- shallow sections near the banks, there peratures were 30-35°C during the day, and close are long chains of green algae, reaching the to 25°C in the mornings and evenings. Conse- surface at the low water. The steep banks quently, in the "normal" years species distribu- are regularly cut, therefore there are no tion. abundance and population densities may bushes or trees. deviate considerably from the situation recorded. (7) HrvaSki brod, the Martinek and Racna Some localities have not been checked for the streams, WL 28; 9-VIII-1992. and the Obrh WL larvae. The comments onecology behaviour (8) Kostanjevica, stream, 37; 7- where -VIII-1992. - are given considered of some interest. Same as (8). (10)D.GradiSie, CadraSki potok,WL 27; 7-VIII- — List of localities 1992. Lowland stream in a grassland, The localities are situated at an altitude of 150- overgrown by trees. -300 m a.s.l. (II)Ardro nr Raka. the Lokavec stream, WL 38; (1) Stritovsko jezero, WL 28; 3-VIII-1992. - 5-VIII-1992. - Lowland stream with 2 lake 3 branches. The in the meadow forms Man-made eutrophic (depth m). in a one a natural fed rain and where of and depression, by heavily pool, exuviae Aeshna cyanea stocked with fish, without submerged Anax imperator were found. The other vegetation. It is surrounded by a thick branch flows on the meadow/forest border. vegetation wall, with the usual fishermen (12)Mikote-Koprivnik, the Lokavec stream. WL 10-30 intervals. - The first km entrances at m 38; 2-VIII-1992. (A) from (2) Prilipe, backwaters of Sava R., WL 58; 5- the villageof Mikote is an artificial, 2 yr old -VIII-1992. - It is one of the few backwa- canal, of modest velocity and with some 2 floor ters of the Sava R. preserved in Slovenia, pools (depth 30 cm, width m). The and consists of 2 parts (length 600 and 150 consists of small gravel, covered with mud connected the bank. El chari and m. resp.), by a stagnant water near Typha sp., eo s sp. time less than canal. At the of our visit, 10% Potamogeton natans stands occur locally. of the surface covered with floa- The banks cleared water was are annually. ting vegetation.The vegetation is typical of natural lower section of the stream runs backwaters, submerged vegetation modest. through an oak forest, it is completely shaded Dobra mlaka backwater of the and has (3) nr Skocjan, no aquatic vegetation. Radulja R„ WL 28; 4/8-VII1-1992. - Ac- (!3)Klevevz (castle), Radulja rivulet, WL 18; 4- chan- tually a series of pools, connected by -VIII-1992. nels the between the of Brod- that are dry most of time, fed by (14)SenuSa stream, village Radulja at floods only. Water depth varies -v-podbo£juand the Krka R„ WL38;4-VIII- with the seasons, the surface is covered with -1992. of WL 39; 5-V1II-1992. Lemna sp.. and there is a strong growth (IS)Brestanica, fishpond, submerged vegetation. (16)Krakovski gozd, southern part, WL 38; 3- WL 4- -VIII-1992. — forest (4) DobovSki potok. fishery ponds, 17; Normally a marshy -V1II-1992. - Over-populatedwith fish and with numerous small natural water bodies. probably regularly emptied. Save for the 2 largest streams, it was comple- the time of (5) V. Koren, flint sand pits, WL 38; 7-VIII- tely dry at our visit. -1992. - The depressions in the abandoned (17)Arto, Stagina stream, upward the village. rain WL 39; 6-VIII-1992. sections were filled by water (depth 30- -40 cm. surface up to 200 nr). Potamogeton natans and Eleocharis sp. occur in some of Annotated list of species 50 - = "immense densi- the puddles. Young Libellulidae inslars were (x = > individuals; xx recovered from the bottom mud. ty"! Dobra mlaka nr rivulet. — 4 6 (6) Skocjan. Radulja Calopteryx splendens (Harr.) ssp. (1): , - — 4 — WL 28; 4-VI11-I992. Depth 70cm, width 3 9; (2): cj; (4): x 6. x 9, all at inlet Noinl. Vol. No. 1-20. June I. 3 odonalol.. 4. I. pp. 1993 and outlet; - (6): x 3, x 9; - (7): x 3, x 9; activity of adults on this particular stretch ofthe - - - - (8); x 3, x 9: (9); 2 3: (10): 6<J; stream, resulting in the higher density of larvae. - The slow modest and suit- (12): x 3. x $: (14): x 3. x 9. uniform, to velocity — — 3. $: (7): able bottom allow the larvae C. virgo (L.) ssp. (6): x x x structure to spread 3. x 9: - (9): 7 3. 3 9: - (10): 10 3, 4 9: out, the competition is lower and the survival - - Since the this and in (11) x larvae, x 3, x 9: (12): x 3, x 9: rate higher. development in the former takes than 2 it - (13): I larva, x 3. x 9. species more years, Platycnemis pennipes (Pall.). — (I): x cT.x remains to be seenwhether this process will result — 9. 2 - (2): <3. 9.x (3): in in the cop.; x x cop.; x high emergence rates forthcomingyears. — 9. 3. x 9, I cop.; (6) xx 3. xx xx cop., xx The 2 exuviae were clinging vertically to grass — 3. 9: — (12): 3. few above the At the ovip.; (7): x x x larvae, x stems, a cm water. spot, no - - 9: 3, 9,x horizontal suitable for x 9; (13): x 3. x (14): x x structures, eedysis. arc — cop., x ovip,; (16): xx 3 juv., xx 9 juv. available. Cercion lindenii (Sel.). — (6): 7 <5: — (14): - At (10). (1 and (12 B) Cordulegaster sp. 1 ) I 6. the adults were sighted, at (17) a copula was - 7 noticed. No voucher could be secured. Coenagrion paella (L.). (1): X 6. î. 3 specimens - d: - 9 7 d Somatochlora - cop.; (2): x (3): 5 (4-VIII), (7- flavomaculata (Vander L.). -VIII). (2): X S: - O): I à. - viridulum — (2): x 6 S. meridionalis Nielsen. 5 d. 1 Erythromma (Charp.). (3): cop.; I I — 2 - - - - x 9, cop., ovip.; (3): x <3. ovip. (4- (4): 10 ó: (5): Id: (10): 7 â: (II): — -Vlll), x d (7-VI11); — (6): x d. 4 ovip. 5 â: - (12): 4 â. I 9; - (13): 6 6: - (14): Found only at the 2 backwaters. Those observed S â. — So far a single 5 of this species has at (6) have surely migratedfrom (3). as they have been brought on record from Slovenia, taken in it. been concentrated at the place nearest to 1961 near the city of Piran in NW Istria — 8 At that that far Enallagmacyathigerum(Charp.). (5); 3, (KI ALITA. 1963). time, was by 1 ovip. the northernmost locality known. Recently, how- — 3, Ischnura elegans (Vander L,). (I); x x ever, a number of populations were reported — 3, 9, 5 cop., 5 ovip.; (2) x exuviae, xx x from northern Italy, notably also from the pro- — - - 3; 9, x ovip.; (5): I cop.; (6): I (12); vince of Friuli. N of Udine, where the species 5 PE- 3. co-occurs with S. metallica {Vander L.) (cf. I. — pumilio (Charp.). (5): x 3. I 9. CILE, 1988). Since the Friulian fauna has been Lestes (Flans.). — I 3 in the 1960s and meridiona- sponsa (2): juv., 1 9. thoroughlysurveyed L. — I has been found il is that viridis (Vander L.). (4): I cop.. ovip. lis noi there then, likely — I 3 Aeshna cyanea { Mull.). (II): exuviae, this is another (of the rather numerous) odonate I 9 exuviae; — (16): I 9 juv. species that are currently expanding their range A. grandis (L.). — (1): 2 3; — (2): 13; — northward. Its abundance in the Raka area could (3): 2 3 exuviae, 1 9 exuviae, 2 ovip. be significant also from this point of view. — A. mixta Latr. — is often (16); 1 9. Breeding sites of S. meridional are asso- (L.). — (12 A): 4 ciated with slow the Gomphus vulgatissimus running streams, on grass- F-0 larvae. land/forcst border. Allrecords given here, except Onychogomphus f. forcipatus (L. ). — (I): 19 for localities (3) and (4), would fall within this - 1 - 10 - males juv.; (2): 3; (6): 3, I 9: frame, although were not always sighted 2 1 — (12A): xx larvae, exuviae, x 3, 9; (13): near the water.