The effect of pollinators on the populations of Platanthera in Estonia

Uurimistöö hüpoteesiks oli, et Eesti käokeelte tolmeldajate liigiline koosseis varieerub erinevates populatsioonides, tolmeldajad kujundavad taimede tolmeldamise seisukohast oluliste õietunnuste suurust ja viljumisedukust. Hüpoteesi tõestamiseks teostati 2014. a. suvel kümnes populatsioonis üle Eesti valguspüügid tolmeldajate kohta andmete saamiseks, samades populatsioonides mõõdeti õite kannuste pikkused ja sügisel loeti viljad. Potentsiaalseid tolmeldajaid oli P. bifolia puhul 63 liigist ja P. chlorantha puhul 58 liigist. Pollinaariume kandvaid liike oli viis: S. pinastri, D. porcellus, D. stenochrysis, A. pulchrina, A. tripartita. Enamiku populatsioonide tolmeldajakoosseisude vahel ei olnud suuri erinevusi. Eristusid Kotka, Vana-Nurtu ja Vorbuse teeristi populatsioonid. Erisused võivad olla põhjustatud erinevatest asukohtadest ja biotoopidest. Seega võib öelda, et tolmeldajakoosseisud varieeruvad, kuid mitte suures mahus. Imilondi ja kannuse pikkuse vaheline korrelatsioon osutus enamikel mudelitel nõrgaks, erandiks oli kannuse pikkuse tugev seos pollinaariumidega isendite imilontide pikkustega – mida pikem imilont, seda lühem kannus. Ilmnes P. bifolia kannuse pikkuse kahanemine ida suunas, kuid nõrga mudeli tõttu ei pruugi seos kehtida. Tolmeldajate osas selgus, et S. pinastri imilont kahaneb samuti ida suunas. Imilondi pikkuse erinevused võivad tuleneda toidutaimede erinevustest, mis võivad mõjutada tolmeldaja suurust. Viljumisnäitajate põhjal oli P. bifolia viljumisedukus suurem P. chlorantha omast. Viljumisedukus korreleerus nõrgalt tolmeldajate ohtruse ja elupaiga sobivusega, saadud tulemus ei vasta eeldusele. Siiski on tolmeldajate roll viljumisel oluline, kuna käokeeled ei ole võimelised tolmeldamiseta viljuma. Ebatavaliselt külmast käokeelte õitseajast tingitud andmete vähesus on ilmselt põhjus, miks nõrgad korrelatsioonid mudelitel esinesid. Korduspüügid on vajalikud tulemuste võrdlemiseks.The hypothesis of this study was that the species composition of pollinator communities of Platanthera in Estonia vary in different populations, pollinators shape the size of the spur and fruiting success. To determine which species pollinate Platanthera and to measure their proboscises, we used light traps in summer 2014 to capture moths. Spur lengths were measured and fruits counted. For P. bifolia there were 63 species of potential pollinators, for P. chlorantha 58 species. Species carrying pollinaria were: S. pinastri, D. porcellus, D. stenochrysis, A. pulchrina, A. tripartita. Most of the populations were similar in species composition. Populations that stood out were Kotka, Vana-Nurtu and Vorbuse. Differences in species composition may occur due to different locations and habitats. So pollinator communities do vary in species composition but not extensively. The correlation between spur length and proboscis length was weak in most of the models with an exception of a strong correlation between spur length and the proboscis length of moths catched with pollinaria. But the correlation was alogical, showing that the longer the proboscis the shorter the spur. Fruiting success was higher in P. bifolia. No correlation between fruiting success and pollinator abundance and habitat suitability was found. The role of pollinators is yet considered important, because Platanthera species are’nt able to produce fruits without pollination. The scarceness of data due to abnormally cold blooming period of Platanthera is assumably the reason for weak correlations in most of the models. Additional catches will be carried out to compare the results

Temporal cycles and spatial asynchrony in the reproduction and growth of a rare nectarless orchid, Cypripedium calceolus

The timing and intensity of plant reproduction vary due to internal and external factors. Although this variation has been widely studied in species exhibiting masting (intermittent synchronous reproduction), it has attracted less attention in nonmasting species. Here, we studied intra-individual variation in the flowering intensity and plant size of a nonmasting, rare terrestrial orchid, Cypripedium calceolus, using long-term monitoring data from three populations in Finland and two populations in Estonia. Flowering intensity and plant size showed 2-year cycles, indicating that reproduction and growth were regulated by past costs of reproduction and extensive clonal growth. In addition, flowering intensity and plant size were positively correlated with size from the previous year and were also affected by the weather conditions of spring and of the previous growing season. However, there was little synchrony among plants, suggesting that the climatic control of reproduction and growth is sufficiently low as to be masked by high annual variation in these two vital rates. Together, these results indicate that the reproduction and growth of C. calceolus depend on individual demographic history and past weather conditions and that intrinsic factors can also lead to cyclic fluctuation in reproduction in nonmasting species

Temporal cycles and spatial asynchrony in the reproduction and growth of a rare nectarless orchid, Cypripedium calceolus

AbstractThe timing and intensity of plant reproduction vary due to internal and external factors. Although this variation has been widely studied in species exhibiting masting (intermittent synchronous reproduction), it has attracted less attention in nonmasting species. Here, we studied intra-individual variation in the flowering intensity and plant size of a nonmasting, rare terrestrial orchid, Cypripedium calceolus, using long-term monitoring data from three populations in Finland and two populations in Estonia. Flowering intensity and plant size showed 2-year cycles, indicating that reproduction and growth were regulated by past costs of reproduction and extensive clonal growth. In addition, flowering intensity and plant size were positively correlated with size from the previous year and were also affected by the weather conditions of spring and of the previous growing season. However, there was little synchrony among plants, suggesting that the climatic control of reproduction and growth is sufficiently low as to be masked by high annual variation in these two vital rates. Together, these results indicate that the reproduction and growth of C. calceolus depend on individual demographic history and past weather conditions and that intrinsic factors can also lead to cyclic fluctuation in reproduction in nonmasting species.Abstract The timing and intensity of plant reproduction vary due to internal and external factors. Although this variation has been widely studied in species exhibiting masting (intermittent synchronous reproduction), it has attracted less attention in nonmasting species. Here, we studied intra-individual variation in the flowering intensity and plant size of a nonmasting, rare terrestrial orchid, Cypripedium calceolus, using long-term monitoring data from three populations in Finland and two populations in Estonia. Flowering intensity and plant size showed 2-year cycles, indicating that reproduction and growth were regulated by past costs of reproduction and extensive clonal growth. In addition, flowering intensity and plant size were positively correlated with size from the previous year and were also affected by the weather conditions of spring and of the previous growing season. However, there was little synchrony among plants, suggesting that the climatic control of reproduction and growth is sufficiently low as to be masked by high annual variation in these two vital rates. Together, these results indicate that the reproduction and growth of C. calceolus depend on individual demographic history and past weather conditions and that intrinsic factors can also lead to cyclic fluctuation in reproduction in nonmasting species

Morphological comparison of the parts of the inflorescence important for pollination of the Platanthera species in Estonia

Käesoleva uurimistöö eesmärgiks oli välja selgitada, kas Eesti NSV Flooras toodud Eestis esinevate käokeele liikide kannuse pikkused peavad paika ja teha kindlaks antud liikide kannuse pikkuse varieeruvus. Selleks kogus autor R. Batemani ja R. Sextoni metoodikat eeskujuks võttes andmed kahelehise ja roheka käokeele kannuse ja õie suuruse ning kasvukohtade valgustatuse kohta, teostades koos EMÜ Põllumajandus- ja keskkonnainstituudi Botaanika osakonna töötajatega välitöid. Välitööd viidi läbi üle Eesti, püüdes jälgida, et võimalikult suur osa territooriumist oleks kaetud. Seejärel analüüsiti andmeid ja võrreldi neid mujal Euroopas teostatud uurimistöödega andmetega. Andmete põhjal selgus, et kahelehise käokeele kannuse pikkused jäävad vahemikku 24-45 mm ja rohekal käokeelel 17-37 mm. Mõlemad vahemikud on laiemad Eesti NSV Flooras toodutest. Keskmine kannuse pikkus kahelehisel käokeelel on 32,1 mm ja rohekal 25,2 mm. Olukord, kus kahelehise käokeele kannus on keskmiselt pikem roheka omast, eksisteerib lisaks Eestile ka Skandinaavias, mujal Euroopas, näiteks Briti saartel, on kirjeldatud vastupidist olukorda. Varieteetide esinemist ei täheldatud, samuti hübriidide esinemist populatsioonides, kus kaks liiki kasvasid kõrvuti. Batemani ja Sextoni uurimistöö põhjal uuriti, kas kannuse pikkus ja õie suurus on sõltuvuses taime paiknemisest laiuskraadi suhtes. Ilmnes, et mõlemal liigil on kannuse pikkuse ja laiuskraadi vahel väike korrelatsioon, s.t. kannuse pikkus väheneb lõunast põhja suunas. Õie suuruse ja laiuskraadi vahel otsene seos puudub, küll aga võis täheldada õie suuruse vähenemist ida-lääne suunal rohekal käokeelel ja lääne-ida suunal kahelehisel. Ka kannuse pikkuse puhul eksisteerib vähenemine samadel suundadel. Kontrolliti, kas kannuse pikkus oleneb kasvukoha valgustingimustest. Selgus, et metsas kasvavate ehk varjulisemate kasvukohtade taimede kannuse pikkus on keskmiselt veidi suurem valgusküllastel niitudel ja kadastikes kasvavate taimede kannusest. Käokeele perekond kui kindlatest tolmeldajatest olenevate liikide kogum väärib kindlasti edasist uurimist, kuna aitab mõista paremini evolutsioonilisi protsesse taimede ja tolmeldajate vahel ning nendest protsessidest tulenevat liigirühmade jaotumist maastikus.The aim of this study was to find out if the spur lengths of the Platanthera species in Estonia given in Eesti NSV Floora are correct and to determine the variation in spur lengths of those species. We collected data on spur lengths, the size of inflorescences and the light conditions in the populations of Platanthera bifolia and P. chlorantha. For that field studies were conducted all over Estonia, trying to cover as much of the territory as possible. One flower per inflorescence was collected and the measures taken under binocular. We calculated flower area, data analysis was performed in R package ver. 2.10.1 (2009-12-14) and comparison with the results of other similar studies in Europe. It turned out that the spur lengths of P. bifolia are from 24 mm to 45 mm and for P. chlorantha from 17 mm to 37 mm. Both variations are wider than the ones given in Eesti NSV Floora. The mean spur length of P. bifolia is 32,1 mm and for P. chlorantha 25,2 mm. The situation where the spur of P. bifolia is on average longer than the spur of P. chlorantha exists in Scandinavia, in other parts of Europe, for example in the British Isles, the opposite situation has been described. No hybrids were detected in the populations where the two species grow together. A small correlation for both species was revealed for spur length regressing from south to north. It was found out that there is no such correlation between the size of the inflorescence and latitudinal position, but the size of the infloresence regresses from east to west for P. chlorantha and from west to east for P. bifolia. The same longitudinal trend was revealed with the spur lengths. Spur length’s dependence on the light conditions in the habitation was investigated. It turned out that the average spur length of flowers in woodlands, in darker habitation is a little more than the spur length of flowers in open grasslands and juniper fields. Platanthera genus as an assemblage of species dependent on specific pollinators certainly deserves further studying due to the fact that it helps to better understand the evolutional processes between plants and pollinators and their distribution in the landscape

Temporal cycles and spatial asynchrony in the reproduction and growth of a rare nectarless orchid, Cypripedium calceolus

Abstract The timing and intensity of plant reproduction vary due to internal and external factors. Although this variation has been widely studied in species exhibiting masting (intermittent synchronous reproduction), it has attracted less attention in nonmasting species. Here, we studied intra-individual variation in the flowering intensity and plant size of a nonmasting, rare terrestrial orchid, Cypripedium calceolus, using long-term monitoring data from three populations in Finland and two populations in Estonia. Flowering intensity and plant size showed 2-year cycles, indicating that reproduction and growth were regulated by past costs of reproduction and extensive clonal growth. In addition, flowering intensity and plant size were positively correlated with size from the previous year and were also affected by the weather conditions of spring and of the previous growing season. However, there was little synchrony among plants, suggesting that the climatic control of reproduction and growth is sufficiently low as to be masked by high annual variation in these two vital rates. Together, these results indicate that the reproduction and growth of C. calceolus depend on individual demographic history and past weather conditions and that intrinsic factors can also lead to cyclic fluctuation in reproduction in nonmasting species