Surviving climate changes: high genetic diversity and transoceanic gene flow in two arctic–alpine lichens,Flavocetraria cucullata and F. nivalis (Parmeliaceae,Ascomycota)

Aim We examined genetic structure and long‐distance gene flow in two lichenized ascomycetes, Flavocetraria cucullata and Flavocetraria nivalis, which are widespread in arctic and alpine tundra. Location Circumpolar North. Methods DNA sequences were obtained for 90 specimens (49 for F. cucullata and 41 for F. nivalis) collected from various locations in Europe, Asia and North America. Sequences of the nuclear internal transcribed spacer (ITS) + 5.8S ribosomal subunit gene region were generated for 89 samples, and supplemented by beta‐tubulin (BTUB) and translation elongation factor 1‐alpha gene (EF1) sequences for a subset of F. cucullata specimens. Phylogenetic, nonparametric permutation methods and coalescent analyses were used to assess population divergence and to estimate the extent and direction of migration among continents. Results Both F. cucullata and F. nivalis were monophyletic, supporting their morphology‐based delimitation, and had high and moderately high intraspecific genetic diversity, respectively. Clades within each species contained specimens from both North America and Eurasia. We found only weak genetic differentiation among North American and Eurasian populations, and evidence for moderate to high transoceanic gene flow. Main conclusions Our results suggest that both F. cucullata and F. nivalis have been able to migrate over large distances in response to climatic fluctuations. The high genetic diversity observed in the Arctic indicates long‐term survival at high latitudes, whereas the estimated migration rates and weak geographic population structure suggest a continuing long‐distance gene flow between continents that has prevented pronounced genetic differentiation. The mode of long‐distance dispersal is unknown, but wind dispersal of conidia and/or ascospores is probably important in the open arctic landscapes. The high genetic diversity and efficient long‐distance dispersal capability of F. cucullata and F. nivalis suggest that these species, and perhaps other arctic lichens as well, will be able to track their potential niche in the changing Arctic.     

The structure of a triterpenoid ketol from Cetraria nivalis

A triterpenoid ketol isolated from a Norwegian species of Cetraria nivalis is identified as 22α-hydroxy-stictan-3-one, a triterpenoid present in some Pseudocyphellaria lichens.     

Photosynthetic patterns of Cetraria cucullata (Bell.) Ach. at Anaktuvuk Pass,Alaska

Summary The daily photosynthetic patterns of Cetraria cucullata were followed over the 1976 summer period at Anaktuvuk Pass, Alaska. With the exception of rainy peroids, the lichen exhibited a strong diurnal pattern with peak photosynthetic activity occurring between 0300 and 0700 h. This correllated with periods of maximal lichen water retention and the presence of direct solar radiation. When the lichen was moist, a strong gradient in photosynthetic activity was observed with no activity in the lichen bases and maximal activity in the lichen tips.     

A new species of Cymopterus (Umbelliferae) from southern Idaho

A new species,Cymopterus davisii, from alpine areas in the Albion Mountains of extreme south-central Idaho, is described. It has been confused withC. nivalis, with which it is compared. The fruit ofC. davisii are subterete to somewhat compressed laterally and, contrary to the literature, correspond closely to those ofC. nivalis and related species.     

Nutritive value of terricolous lichens for reindeer in winter

Abstract:In contrast to virtually all other species of ruminants, reindeer (Rangifer tarandus) eat substantial amounts of lichens in winter. Several different species of lichens are eaten and most are highly palatable. The chemical composition and the in vitro digestibility of six species of terricolous lichens commonly eaten by reindeer were measured. Ruminal inoculum was obtained in winter from six free-ranging reindeer that had been grazing on natural pastures in northern Norway. Analysis of the plant parts recovered from their rumens confirmed that the animals had been eating a mixed diet that included both lichens and vascular plants. The chemical composition and the in vitro digestibility of the different species of lichens varied considerably between species and genera. Cetraria islandica, C. nivalis andCladonia arbuscula were highly digestible [69–77% dry matter (DM)], Stereocaulon paschale was poorly digestible (43% DM), whereas Cladonia stellaris and C. gracilis had an intermediate digestibility (56–57% DM). Mixing Cladonia stellaris with vascular plants (50:50) had no effect on the in vitro digestibility of the combined substrates. The in vitro digestibility of Cladonia stellaris in inoculum from two captive reindeer which had had no access to lichens was very low (10% DM). This shows that the source of inoculum used for digestibility trials has a major effect on the apparent digestibility of the substrates. Evidently, the extent to which reindeer are able to utilize lichens depends on the species that are selected and on what the animals have been eating recently.     

The lichen cushion: A functional perspective of color and size of a dominant growth form on glacier forelands

Mat-forming lichens dominating high-latitudinal habitats vary in color and geometry. Widespread species are light greenish yellow (usnic acid) and reflect solar radiation, whereas melanic species absorbing most solar wavelengths are spatially more restricted. Color thereby influences lichens’ energy budget and thus their hydration and photosynthetically active periods. By using well-defined cushions from early successional stages on glacier forelands – three melanic^(m) and three usnic^(u) mat-forming lichens with hair-like branches (Alectoria ochroleuca^(u), Gowardia nigricans^(m)), hollow terete branches (Cladonia uncialis^(u), Cetraria muricata^(m)), and flat branches (Flavocetraria nivalis^(u), Cetraria islandica^(m)) – we quantified hydration traits and analyzed how color and cushion size affect water loss rate (WLR) and duration of active periods. Main findings: 1) WLR declined with cushion size and was highest in melanic lichens. 2) Active periods were longer for usnic than for melanic lichens and increased with size in all groups. 3) Size, color, and taxon nested in color significantly influenced WLR and duration of active periods in linear mixed models. 4) Hair lichen cushions had shorter active periods than growth forms with terete or flat branches due to their more open canopy architecture and lower water holding capacity (WHC). 5) WHC measured for isolated branches highly underestimated WHC for intact cushions.     

Low levels of genetic variation within populations of the four rare orchids Gymnadenia cucullata, Gymnadenia camtschatica, Amitostigma gracile, and Pogonia minor in South Korea: indication of genetic drift and implications for conservation

Many terrestrial orchids are relatively rare, and their populations are small and spatially isolated. Population genetics theory predicts that populations of such species, affected historically by random genetic drift, would maintain low levels of genetic diversity and exhibit a high degree of among-population divergence. To test this prediction, I used enzyme electrophoresis. Genetic diversity within populations of the four rare, terrestrial orchids Gymnadenia cucullata (four populations) and its congener G. camtschatica (four populations), Amitostigma gracile (four populations in one region and three in another region), and Pogonia minor (three populations each in two regions) was investigated in South Korea at the landscape level. As predicted, populations of the four species harbor low levels of genetic diversity within populations: the mean percentage of polymorphic loci, %P, the mean number of alleles per locus, A, and the average expected heterozygosity, H _e, were 12.5%, 1.13, and 0.036 for G. cucullata, respectively; 18.2%, 1.18, and 0.067 for G. camtschatica; 3.0%, 1.04, and 0.009 for A. gracile; and 2.7%, 1.06, and 0.014 for P. minor. Except for G. camtschatica (F _ST = 0.000), a significantly high degree of genetic divergence between conspecific populations was detected in the other three species: F _ST = 0.081 for G. cucullata; 0.348 and 0.811 in two regions for A. gracile; and 0.469 and 0.758 in two regions for P. minor. In addition, individuals within populations are highly structured in the four species (overall F _IS = 0.276 for G. cucullata; 0.308 for G. camtschatica; 0.758 for A. gracile; and 0.469 for P. minor), suggesting that selfing, biparental inbreeding, and/or consanguineous mating have occurred in populations of the four species. With the exception of G. camtschatica, an allele at a locus is fixed in a population, whereas alternative alleles with low or high frequencies are detected in another population across the landscape. My results suggest that evolutionary histories of G. cucullata, A. gracile, and P. minor are different from G. camtschatica. Historical genetic drift would be an important force shaping the genetic structure of the Korean populations of G. cucullata, A. gracile, and P. minor. For G. camtschatica on Ulleung Island, relatively higher levels of genetic variation within populations compared to its congener G. cucullata (H _e = 0.067 vs. 0.036) and little evidence of population genetic structure among populations (F _ST = 0.000) suggest that individuals were, presumably, once continuously distributed on Ulleung Island, and populations have recently been isolated by habitat fragmentation through natural succession (e.g,. probably the encroachment of woody vegetation on grasslands) or human-mediated disturbances (e.g., collections). Thus, conservation strategies for the four species should be differently developed in order to preserve genetic diversity in South Korea.     

Detection and Quantification of Snow Algae with an Airborne Imaging Spectrometer

We describe spectral reflectance measurements of snow containing the snow alga Chlamydomonas nivalis and a model to retrieve snow algal concentrations from airborne imaging spectrometer data. Because cells of C. nivalis absorb at specific wavelengths in regions indicative of carotenoids (astaxanthin esters, lutein, β-carotene) and chlorophylls a and b, the spectral signature of snow containing C. nivalis is distinct from that of snow without algae. The spectral reflectance of snow containing C. nivalis is separable from that of snow without algae due to carotenoid absorption in the wavelength range from 0.4 to 0.58 μm and chlorophyll a and b absorption in the wavelength range from 0.6 to 0.7 μm. The integral of the scaled chlorophyll a and b absorption feature (I_0.68) varies with algal concentration (C_a). Using the relationship C_a = 81019.2 I_0.68 + 845.2, we inverted Airborne Visible Infrared Imaging Spectrometer reflectance data collected in the Tioga Pass region of the Sierra Nevada in California to determine algal concentration. For the 5.5-km² region imaged, the mean algal concentration was 1,306 cells ml⁻¹, the standard deviation was 1,740 cells ml⁻¹, and the coefficient of variation was 1.33. The retrieved spatial distribution was consistent with observations made in the field. From the spatial estimates of algal concentration, we calculated a total imaged algal biomass of 16.55 kg for the 0.495-km² snow-covered area, which gave an areal biomass concentration of 0.033 g/m².     

Molecular Genetic Identification Tools for Three Commercially Cultured Oysters (<Emphasis Type="Italic">Crassostrea belcheri</Emphasis>, <Emphasis Type="Italic">Crassostrea iredalei</Emphasis>, and <Emphasis Type="Italic">Saccostrea cucullata</Emphasis>) in Thailand

Abstract Molecular genetic keys for identification of 3 commercially cultured oysters (Crassostrea belcheri, Crassostrea iredalei, and Saccostrea cucullata) in Thailand were developed based on restriction analysis of 18S ribosomal DNA and cytochrome oxidase subunit I (COI). Digestion of the amplified 18S rDNA with Hinf I unambiguously differentiated Crassostrea oysters from Saccostrea oysters and Striostrea (Parastriostrea) mytiloides. In addition, species-specific restriction fragment length polymorphism patterns of C. belcheri, C. iredalei, and S. cucullata were consistently observed when the gel-eluted COI was digested with Mbo I and Dde I. Thirty composite haplotypes were observed across all individuals. Species-specific composite haplotypes were found in C. belcheri (AAAA and AAAB), C. iredalei (AABC and AABU), and S. cucullata (BBCD and BBCE), respectively. The most common composite haplotype of COI in C. belcheri (AAAA), C. iredalei (AABC), and S. cucullata (BBCD) was amplified, cloned, and sequenced. Detection of C. belcheri and C. iredalei based on polymerase chain reaction was further developed using more specific primers (HCO2198 and R372) followed by digestion of a 372-bp product with Mbo I.     

Flavonoid glycosides from Egyptian species of the tribe Asclepiadeae (Apocynaceae,subfamily Asclepiadoideae)

The flavonoids of 11 Egyptian species of the tribe Asclepiadeae (Apocynaceae, subfamily Asclepiadoideae) were studied: Pentatropis nivalis, Pleurostelma schimperi (subtribe Astephaninae), Glossonema boveanum, Solenostemma arghel (subtribe Glossonematinae), Cynanchum acutum, Oxystelma esculentum (subtribe Metastelmatinae), Calotropis procera, Gomphocarpus fruticosus, Gomphocarpus sinaicus, Pergularia tomentosa and Pergularia daemia (subtribe Asclepiadinae). These 11 species were found to produce flavonol glycosides. In addition, flavonol sulphates and disulphates were found in a specimen of P. nivalis. The flavonoids may provide useful taxonomic characters at several levels of classification.     

The Influence of Invertebrate Predators on Daphnia Spatial Distribution and Survival in Laboratory Experiments: Support for Daphnia Horizontal Migration in Shallow Lakes

The behavioural response of Daphnia cucullata to the presence of the pelagic invertebrate predator Leptodora kindtii, and the predation rate of littoral dragonfly nymphs on this species were investigated under laboratory conditions. Results of this study revealed a strong hiding response of Daphnia cucullata in the presence of the predatory cladoceran, L. kindtii, which was similar to the response of Daphnia in the presence of juvenile perch. This suggests that pelagic invertebrate predators may cause Daphnia to hide in the littoral zone which could result in increased exposure to predation by littoral invertebrates. A strong influence of dragonfly nymphs on D. cucullata, both in the presence and absence of macrophytes, was found. The average predation rate of Odonata larvae was about 5 prey ind^–1 h^–1 and did not differ significantly between treatments. Quantification of dragonfly pressure on Daphnia populations will require cross‐verification with field experiments since in the natural conditions Daphnia seeks a shelter in the vegetation stands against predation by Leptodora, despite the occurrence of odonates. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The evaluation of the role of pelagic invertebrate versus vertebrate predators on the seasonal dynamics of filtering Cladocera in a shallow, eutrophic reservoir

An evaluation of the role of invertebrate (Leptodora kindtii) versus vertebrate (juvenile fish) predators in the dynamics of filtering zooplankton (Daphnia sp.) in the pelagic zone of the Sulejow Reservoir was conducted during summer from 1994 to 1996. Leptodora kindtii appeared in high densities (mid-July: 2–6 ind. l^?1) in the pelagic zone. Its predation impact on the dominant filtering zooplankter population Daphnia cucullata, expressed by consumption, was significant and accounted for a reduction of 10 to 51% of Daphnia biomass. Although D. cucullata was a preferred food of juvenile pikeperch in June, due to low biomass, these fish were able to eliminate daily only 0.1–5.4% of Daphnia biomass in the pelagic zone. Thus, the role of juvenile fish in the midsummer decline of D. cucullata density in the pelagic zone seems to be much smaller than that of Leptodora kindtii.     

A new species of cymopterus (Umbelliferae) from northwestern Wyoming

Cymopterus evertii, from Park and Hot Springs counties, Wyoming, is described as new. It appears to be a derivative taxon from what has been calledC. bipinnatus. Data are presented justifying the relegation of the latter name to synonymy underC. nivalis. A key is provided for distinguishingC. evertii from its presumed closest relatives.     

Four new species of Caloplaca from Antarctica

Abstract: Four new species of Caloplaca are described from Antarctica: C. buelliae is parasitic on Buellia, C. iomma has a characteristic deep reddish orange colour on the apothecia, C. psoromatis is parasitic on Psoroma and Pannaria, and C. siphonospora is a parasitic species of mosses, very similar to C. nivalis, but with much shorter spores.     

Ecophysiology of seed dormancy and the control of germination in early spring‐flowering Galanthus nivalis and Narcissus pseudonarcissus (Amaryllidaceae)

Seed dormancy induction and alleviation in the winter‐flowering, moist temperate woodland species Galanthus nivalis and Narcissus pseudonarcissus are complex and poorly understood. Temperature, light and desiccation were investigated to elucidate their role in the germination ecophysiology of these species. The effect of different seasonal temperatures, seasonal durations, temperature fluctuations, the presence of light during different seasons and intermittent drying (during the summer period) over several ‘years’ on seed germination was investigated with outdoor and laboratory experiments. Warm summer‐like temperatures (20 °C) were necessary for germination at subsequent cooler autumn‐like temperatures (greatest at 15 °C in G. nivalis and 10 °C in N. pseudonarcissus). As the warm temperature duration increased, so did germination at subsequent cooler temperatures; further germination occurred in subsequent ‘years’ at cooler temperatures following a second, and also third, warm period. Germination was significantly greater in darkness, particularly in G. nivalis. Dormancy increased with seed maturation period in G. nivalis, because seeds extracted from green capsules germinated more readily than those from yellow capsules. Desiccation increased dormancy in an increasing proportion of N. pseudonarcissus seeds the later they were dried in ‘summer’. Seed viability was only slightly reduced by desiccation in N. pseudonarcissus, but was poor and variable in G. nivalis. Shoot formation occurred both at the temperature at which germination was greatest and also if 5 °C cooler. In summary, continuous hydration of seeds of both species during warm summer‐like temperatures results in the gradual release of seed dormancy; thereafter, darkness and cooler temperatures promote germination. Cold temperatures, increased seed maturity (G. nivalis) and desiccation (N. pseudonarcissus) increase dormancy, and light inhibits germination. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177 , 246–262.     

Preservation of secondary fungal metabolites in herbarium lichen specimens

Fresh picked and herbarium thalli of Cladonia stellaris, C. rangiferina, Allocetraria nivalis, A. cucullata, Cetraria islandica, Peltigera canina, and Nephroma articum epigene lichens were studied using the immune-enzyme analysis. No big difference was observed in the contents of mycotoxin secondary metabolites, i.e., deoxynivalenol, diacetoxyscirpenol, zearalenone, alternariol, citrinin, sterigmatocystin, cyclopiazonic acid, mycophenolic acid, emodin, and PR-toxin. The discovery of these substances in the specimens preserved for several decades shows that lichens have an effective system of conservation of metabolic exchange products.     

Impact of fish predation on coexisting Daphnia taxa: a partial test of the temporal hybrid superiority hypothesis

Fish predation was tested as a factor mediating the coexistence of Daphnia taxa in the shallow, hypertrophic Lake Blankaart. Naturally co-occurring populations of D. galeata and the hybrid D. galeata x cucullata were subjected to different levels of fish predation in in situ enclosures. In control enclosures without fish, the largest taxon D. galeata rapidly became dominant over the intermediate sized D. galeata x cucullata, mainly as a result of higher birth rates. In enclosures with fish, population densities of D. galeata dropped relative to D. galeata x cucullata, due to higher mortality rates. These results are in concordance with the `temporal hybrid superiority hypothesis', and can be explained by a higher vulnerability of the large and more conspicuous D. galeata to the size selective predation exerted by visually hunting planktivorous fishes. After approximately one month, however, population growth rates of D. galeata and D. galeata x cucullata in the enclosures with fish converged, due to a relative reduction in the mortality rate of D. galeata. This suggests that, in the presence of fish, D. galeata may co-exist with hybrids due to a decrease in its relative vulnerability to visual predation with time. Indeed, both D. galeata and the hybrid showed strong reductions in adult body size in the enclosures with fish, but this size reduction tended to be stronger in D. galeata than in D. galeata x cucullata. In addition, turbidity increased in the enclosures with fish and may additionally have reduced the relative advantage of D. galeata x cucullata with regard to mortality caused by visual predation.     

The cryopreservation of Chlamydomonas.

A cryophilic strain of the unicellular green alga Chlamydomonas, C. nivalis was found to be more resistant to the stresses both of freezing and thawing and of shrinkage and rehydration than was a mesophilic strain C. reinhardii. C. nivalis was found to have a higher degree of unsaturation of phospholipid fatty acids. Following freezing and thawing of C. reinhardii there was a direct correlation between reduction in cell viability and loss of membrane selective permeability. Activation of intracellular phospholipases occurred at an early stage of freezing injury. Attempts to cold harden C. reinhardii were unsuccessful. For C. reinhardii methanol was the only effective cryoprotectant for freezing to and thawing from ?196 °C and the effects of cooling rate upon cellular survival are presented.     

Population growth and habitat distribution in cyclic small rodents: to expand or to change?

Habitat selection determined by intraspecific interactions (social behaviour), being either free or despotic, should result in the largest densities in the most favourable habitat at least in late increase and decline phases of cyclic populations. Habitat distribution determined by interspecific effects such as herbivore-plant or predator-prey interactions may result in higher densities in inferior habitats at late peaks and/or declines due to overgrazing of preferred habitats, or invasion of such habitats by specialist predators. An examination of the distributions of the rodent species Clethrionomys glareolus and Microtus agrestis during a population cycle on forest clearcuts at Grimsö, south-central Sweden, demonstrated clear changes towards less preferred habitats during the decline phase, particularly in M. agrestis. Intraspecific competition could be excluded as a cause since the numbers of both species declined simultaneously. There was no sign of overgrazing, while weasels, Mustela nivalis, invaded the preferred M. agrestis habitat during peak–decline. Predation thus appears more important for the local occurrence at early decline, rather than territoriality or other social behaviour. It is concluded that distributions in various habitats do not always reveal any primary habitat selection but, rather, habitat-dependent survival.     

LC–MS/APCI identification of glucoside esters and diesters of astaxanthin from the snow alga Chlamydomonas nivalis including their optical stereoisomers

HPLC methods (LC–MS/APCI and chiral HPLC) were used for the identification of astaxanthin derivatives from the red snow alga Chlamydomonas nivalis collected in Austrian Alps, Slovak High Tatra Mountains and Bulgarian Pirin. We observed a striking difference in the composition of astaxanthin optical isomers in C. nivalis collected in geographically distinct regions. Furthermore, algae from the Pirin Mountains differed in the dominance of astaxanthin diglucoside diesters, suggesting an alternative strategy to enhance cell viability at low temperatures.