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1.
BMC Geriatr ; 24(1): 627, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39044146

RESUMO

BACKGROUND: The demographic changes affecting Switzerland and other European countries, including population ageing, will continue to challenge policymakers in building accessible, affordable, comprehensive and high-quality long-term care (LTC) systems. The purpose of this paper is to investigate how Switzerland's LTC system compares to other European countries, in order to inform how to respond to the increasing need for LTC. We carried out a descriptive study using secondary data from key national and international organizations. METHODS: By comparing the financing, workforce, service delivery and need for LTC in Switzerland, Germany, Italy, Norway and the United Kingdom, we described similarities and differences in these five European countries between 2005-2019. Thirty-three indicators within five domains were analysed: (1) Population statistics and health expenditure, (2) Need for LTC, (3) LTC financing, (4) LTC service delivery, and (5) LTC workforce. RESULTS: Switzerland has the highest life expectancy in comparison to the other four high-income countries. However, similarly to other countries, the years lived with disability are increasing in Switzerland. Switzerland's public expenditure on LTC as a share of GDP is lower than that of Norway and Germany, yet out-of-pocket expenditure on LTC is highest in Switzerland. Switzerland has the highest proportion of persons receiving formal LTC both in institutions and at home. Switzerland has had the most pronounced increase in the proportion of over 65-year-olds receiving LTC at home. Even though more than fourfold more persons receive care at home, Switzerland still has more workforce in LTC institutions than in home-care. In comparison to Germany and the UK, Switzerland has a lower number of informal carers as a proportion of 50-year-olds and over, as well as fewer nationally available services for informal carers compared to Germany, Italy, Norway and the UK. CONCLUSIONS: Our comparative study corroborates the importance of improving the affordability of LTC, continuing to support the movement towards home care services, improving the support given to both the professional workforce and informal carers, and improving the amount and quality of LTC data. It also provides a valuable contrast to other European countries to support evidence-informed policymaking.


Assuntos
Assistência de Longa Duração , Humanos , Assistência de Longa Duração/tendências , Assistência de Longa Duração/economia , Suíça , Noruega/epidemiologia , Idoso , Alemanha/epidemiologia , Reino Unido/epidemiologia , Itália/epidemiologia , Gastos em Saúde/tendências , Masculino , Feminino , Expectativa de Vida/tendências , Idoso de 80 Anos ou mais
2.
Mol Ecol ; 26(2): 571-588, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27882647

RESUMO

Human activity has more than doubled the amount of nitrogen entering the global nitrogen cycle, and the boreal forest biome is a nitrogen-limited ecosystem sensitive to nitrogen load perturbation. Although bryophyte-associated microbes contribute significantly to boreal forest ecosystem function, particularly in carbon and nitrogen cycling, little is known about their responses to anthropogenic global change. Amplicon pyrosequencing of the ITS2 region of rDNA was used to investigate how fungal communities associated with three bryophyte species responded to increased nitrogen loads in a long-term fertilization experiment in a boreal Picea abies forest in southern Norway. Overall, OTU richness, community composition and the relative abundance of specific ecological guilds were primarily influenced by host species identity and tissue type. Although not the primary factor affecting fungal communities, nitrogen addition did impact the abundance of specific guilds of fungi and the resulting overall community composition. Increased nitrogen loads decreased ectomycorrhizal abundance, with Amphinema, Cortinarius, Russula and Tylospora OTUs responding negatively to fertilization. Pathogen abundance increased with fertilization, particularly in the moss pathogen Eocronartium. Saprophytic fungi were both positively and negatively impacted by the nitrogen addition, indicating a complex community level response. The overshadowing of the effects of increased nitrogen loads by variation related to host and tissue type highlights the complexity of bryophyte-associated microbial communities and the intricate nature of their responses to anthropogenic global change.


Assuntos
Briófitas/microbiologia , Florestas , Micorrizas/classificação , Nitrogênio/análise , DNA Espaçador Ribossômico/genética , Ciclo do Nitrogênio , Noruega , Árvores
3.
Microb Ecol ; 72(2): 295-304, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27147245

RESUMO

High amounts of driftwood sail across the oceans and provide habitat for organisms tolerating the rough and saline environment. Fungi have adapted to the extremely cold and saline conditions which driftwood faces in the high north. For the first time, we applied high-throughput sequencing to fungi residing in driftwood to reveal their taxonomic richness, community composition, and ecology in the North Atlantic. Using pyrosequencing of ITS2 amplicons obtained from 49 marine logs, we found 807 fungal operational taxonomic units (OTUs) based on clustering at 97 % sequence similarity cut-off level. The phylum Ascomycota comprised 74 % of the OTUs and 20 % belonged to Basidiomycota. The richness of basidiomycetes decreased with prolonged submersion in the sea, supporting the general view of ascomycetes being more extremotolerant. However, more than one fourth of the fungal OTUs remained unassigned to any fungal class, emphasising the need for better DNA reference data from the marine habitat. Different fungal communities were detected in coniferous and deciduous logs. Our results highlight that driftwood hosts a considerably higher fungal diversity than currently known. The driftwood fungal community is not a terrestrial relic but a speciose assemblage of fungi adapted to the stressful marine environment and different kinds of wooden substrates found in it.


Assuntos
Ascomicetos/classificação , Basidiomycota/classificação , Microbiologia da Água , Madeira/microbiologia , Adaptação Fisiológica , Ascomicetos/isolamento & purificação , Basidiomycota/isolamento & purificação , Biodiversidade , Biologia Computacional , DNA Fúngico/genética , Ecossistema , Análise Multivariada , Oceanos e Mares , Análise de Sequência de DNA , Especificidade da Espécie
4.
Biotechnol Lett ; 38(3): 425-34, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26543036

RESUMO

OBJECTIVES: Efficient enzymatic saccharification of plant cell wall material is key to industrial processing of agricultural and forestry waste such as straw and wood chips into fuels and chemicals. RESULTS: Saccharification assays were performed on steam-pretreated wheat straw under ambient and O2-deprived environments and in the absence and presence of a lytic polysaccharide monooxygenase (LPMO) and catalase. A kinetic model was used to calculate catalytic rate and first-order inactivation rate constants of the cellulases from reaction progress curves. The addition of a LPMO significantly (P < 0.01, Student's T test) enhanced the rate of glucose release from 2.8 to 6.9 h(-1) under ambient O2 conditions. However, this also significantly (P < 0.01, Student's T test) increased the rate of inactivation of the enzyme mixture, thereby reducing the performance half-life from 65 to 35 h. Decreasing O2 levels or, strikingly, the addition of catalase significantly reduced (P < 0.01, Student's T test) enzyme inactivation and, as a consequence, higher efficiency of the cellulolytic enzyme cocktail was achieved. CONCLUSION: Oxidative inactivation of commercial cellulase mixtures is a significant factor influencing the overall saccharification efficiency and the addition of catalase can be used to protect these mixtures from inactivation.


Assuntos
Catalase/metabolismo , Glucose/metabolismo , Lignina/metabolismo , Oxigenases de Função Mista/metabolismo , Celulases/metabolismo , Cinética , Oxirredução , Caules de Planta/metabolismo , Triticum/metabolismo
5.
New Phytol ; 206(4): 1238-46, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25678224

RESUMO

Rates of peat growth and carbon (C) accumulation in a Sphagnum-dominated boreal peatland in south-east Norway were compared over two time periods each 17 yr long, that is, an earlier period from 1978 to 1995 and a recent period from 1995 to 2012. Our research was based on 109 peat cores. By using exactly the same study area and sampling protocols to obtain data for the two time periods, we were able to obtain a clear picture of the spatio-temporal patterns of peat accumulation. We show that peat growth and C accumulation were significantly higher in the recent than in the earlier time period. Interestingly, nitrogen (N) deposition was lower in the recent than in the earlier time period, while precipitation increased in the recent time period. Temperatures did not show any consistent trends over the time periods. Although our data do not allow assessment of the relative importance of declining N deposition vs increasing precipitation as drivers of peat accumulation, our results suggest that peatland C sequestration is not significantly inhibited by N pollution at current precipitation and N deposition levels.


Assuntos
Carbono/metabolismo , Clima , Nitrogênio/metabolismo , Solo , Taiga , Áreas Alagadas , Geografia , Modelos Lineares , Noruega , Chuva , Temperatura , Fatores de Tempo
6.
New Phytol ; 205(4): 1587-1597, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25483568

RESUMO

Soil conditions and microclimate are important determinants of the fine-scale distribution of plant species in the Arctic, creating locally heterogeneous vegetation. We hypothesize that root-associated fungal (RAF) communities respond to the same fine-scale environmental gradients as the aboveground vegetation, creating a coherent pattern between aboveground vegetation and RAF. We explored how RAF communities of the ectomycorrhizal (ECM) plant Bistorta vivipara and aboveground vegetation structure of arctic plants were affected by biotic and abiotic variables at 0.3-3.0-m scales. RAF communities were determined using pyrosequencing. Composition and spatial structure of RAF and aboveground vegetation in relation to collected biotic and abiotic variables were analysed by ordination and semi-variance analyses. The vegetation was spatially structured along soil C and N gradients, whereas RAF lacked significant spatial structure. A weak relationship between RAF community composition and the cover of two ECM plants, B. vivipara and S. polaris, was found, and RAF richness increased with host root length and root weight. Results suggest that the fine-scale spatial structure of RAF communities of B. vivipara and the aboveground vegetation are driven by different factors. At fine spatial scales, neighbouring ECM plants may affect RAF community composition, whereas soil nutrients gradients structure the vegetation.


Assuntos
Fungos/fisiologia , Raízes de Plantas/microbiologia , Polygonaceae/microbiologia , Solo , Regiões Árticas , Biodiversidade , Fungos/classificação , Modelos Lineares , Dados de Sequência Molecular , Análise de Sequência de DNA
7.
Mol Ecol ; 24(24): 6289-302, 2015 12.
Artigo em Inglês | MEDLINE | ID: mdl-26547806

RESUMO

Ectomycorrhizal (ECM) fungi are important for efficient nutrient uptake of several widespread arctic plant species. Knowledge of temporal variation of ECM fungi, and the relationship of these patterns to environmental variables, is essential to understand energy and nutrient cycling in Arctic ecosystems. We sampled roots of Bistorta vivipara ten times over two years; three times during the growing-season (June, July and September) and twice during winter (November and April) of both years. We found 668 ECM OTUs belonging to 25 different ECM lineages, whereof 157 OTUs persisted throughout all sampling time-points. Overall, ECM fungal richness peaked in winter and species belonging to Cortinarius, Serendipita and Sebacina were more frequent in winter than during summer. Structure of ECM fungal communities was primarily affected by spatial factors. However, after accounting for spatial effects, significant seasonal variation was evident revealing correspondence with seasonal changes in environmental conditions. We demonstrate that arctic ECM richness and community structure differ between summer (growing-season) and winter, possibly due to reduced activity of the core community, and addition of fungi adapted for winter conditions forming a winter-active fungal community. Significant month × year interactions were observed both for fungal richness and community composition, indicating unpredictable between-year variation. Our study indicates that addressing seasonal changes requires replication over several years.


Assuntos
Biodiversidade , Micorrizas/classificação , Polygonaceae/microbiologia , Estações do Ano , Microbiologia do Solo , Regiões Árticas , DNA Fúngico , Sequenciamento de Nucleotídeos em Larga Escala , Micorrizas/genética , Raízes de Plantas/microbiologia , Análise de Sequência de DNA
8.
Proc Natl Acad Sci U S A ; 109(36): 14488-93, 2012 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-22908273

RESUMO

In terrestrial ecosystems, fungi are the major agents of decomposition processes and nutrient cycling and of plant nutrient uptake. Hence, they have a vital impact on ecosystem processes and the terrestrial carbon cycle. Changes in productivity and phenology of fungal fruit bodies can give clues to changes in fungal activity, but understanding these changes in relation to a changing climate is a pending challenge among ecologists. Here we report on phenological changes in fungal fruiting in Europe over the past four decades. Analyses of 746,297 dated and geo-referenced mushroom records of 486 autumnal fruiting species from Austria, Norway, Switzerland, and the United Kingdom revealed a widening of the annual fruiting season in all countries during the period 1970-2007. The mean annual day of fruiting has become later in all countries. However, the interspecific variation in phenological responses was high. Most species moved toward a later ending of their annual fruiting period, a trend that was particularly strong in the United Kingdom, which may reflect regional variation in climate change and its effects. Fruiting of both saprotrophic and mycorrhizal fungi now continues later in the year, but mycorrhizal fungi generally have a more compressed season than saprotrophs. This difference is probably due to the fruiting of mycorrhizal fungi partly depending on cues from the host plant. Extension of the European fungal fruiting season parallels an extended vegetation season in Europe. Changes in fruiting phenology imply changes in mycelia activity, with implications for ecosystem function.


Assuntos
Agaricales/crescimento & desenvolvimento , Clima , Carpóforos/fisiologia , Aquecimento Global , Estações do Ano , Europa (Continente) , Geografia , Modelos Estatísticos , Reprodução/fisiologia
9.
Mol Ecol ; 23(3): 649-59, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24320873

RESUMO

There is growing evidence that root-associated fungi have important roles in Arctic ecosystems. Here, we assess the diversity of fungal communities associated with roots of the ectomycorrhizal perennial herb Bistorta vivipara on the Arctic archipelago of Svalbard and investigate whether spatial separation and bioclimatic variation are important structuring factors of fungal community composition. We sampled 160 plants of B. vivipara from 32 localities across Svalbard. DNA was extracted from entire root systems, and 454 pyrosequencing of ITS1 amplicons was used to profile the fungal communities. The fungal communities were predominantly composed of Basidiomycota (55% of reads) and Ascomycota (35%), with the orders Thelephorales (24%), Agaricales (13.8%), Pezizales (12.6%) and Sebacinales (11.3%) accounting for most of the reads. Plants from the same site or region had more similar fungal communities to one another than plants from other sites or regions, and sites clustered together along a weak latitudinal gradient. Furthermore, a decrease in per-plant OTU richness with increasing latitude was observed. However, no statistically significant spatial autocorrelation between sites was detected, suggesting that environmental filtering, not dispersal limitation, causes the observed patterns. Our analyses suggest that while latitudinal patterns in community composition and richness might reflect bioclimatic influences at global spatial scales, at the smaller spatial scale of the Svalbard archipelago, these changes more likely reflect varied bedrock composition and associated edaphic factors. The need for further studies focusing on identifying those specific bioclimatic and edaphic factors structuring root-associated fungal community composition at both global and local scales is emphasized.


Assuntos
Biodiversidade , Micorrizas/genética , Raízes de Plantas/microbiologia , Polygonaceae/microbiologia , Microbiologia do Solo , Regiões Árticas , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Consórcios Microbianos , Análise de Sequência de DNA , Svalbard
10.
Mol Ecol ; 22(2): 368-83, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23190367

RESUMO

Although bryophytes are a dominant vegetation component of boreal and alpine ecosystems, little is known about their associated fungal communities. HPLC assays of ergosterol (fungal biomass) and amplicon pyrosequencing of the ITS2 region of rDNA were used to investigate how the fungal communities associated with four bryophyte species changed across an elevational gradient transitioning from conifer forest to the low-alpine. Fungal biomass and OTU richness associated with the four moss hosts did not vary significantly across the gradient (P > 0.05), and both were more strongly affected by host and tissue type. Despite largely constant levels of fungal biomass, distinct shifts in community composition of fungi associated with Hylocomium, Pleurozium and Polytrichum occurred between the elevation zones of the gradient. This likely is a result of influence on fungal communities by major environmental factors such as temperature, directly or indirectly mediated by, or interacting with, the response of other components of the vegetation (i.e. the dominant trees). Fungal communities associated with Dicranum were an exception, exhibiting spatial autocorrelation between plots, and no significant structuring by elevation. Nevertheless, the detection of distinct fungal assemblages associated with a single host growing in different elevation zones along an elevational gradient is of particular relevance in the light of the ongoing changes in vegetation patterns in boreal and alpine systems due to global climate warming.


Assuntos
Briófitas/microbiologia , Ecossistema , Fungos/genética , Altitude , Biomassa , DNA Fúngico/genética , Ergosterol/análise , Fungos/fisiologia , Variação Genética , Noruega , Análise de Sequência de DNA
11.
Mol Ecol ; 22(19): 5040-52, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23962113

RESUMO

The main gradient in vascular plant, bryophyte and lichen species composition in alpine areas, structured by the topographic gradient from wind-exposed ridges to snowbeds, has been extensively studied. Tolerance to environmental stress, resulting from wind abrasion and desiccation towards windswept ridges or reduced growing season due to prolonged snow cover towards snowbeds, is an important ecological mechanism in this gradient. The extent to which belowground fungal communities are structured by the same topographic gradient and the eventual mechanisms involved are less well known. In this study, we analysed variation in fungal diversity and community composition associated with roots of the ectomycorrhizal plant Bistorta vivipara along the ridge-to-snowbed gradient. We collected root samples from fifty B. vivipara plants in ten plots in an alpine area in central Norway. The fungal communities were analysed using 454 pyrosequencing analyses of tag-encoded ITS1 amplicons. A distinct gradient in the fungal community composition was found that coincided with variation from ridge to snowbeds. This gradient was paralleled by change in soil content of carbon, nitrogen and phosphorus. A large proportion (66%) of the detected 801 nonsingleton operational taxonomic units (OTUs) were ascomycetes, while basidiomycetes dominated quantitatively (i.e. with respect to number of reads). Numerous fungal OTUs, many with taxonomic affinity to Sebacinales, Cortinarius and Meliniomyces, showed distinct affinities either to ridge or to snowbed plots, indicating habitat specialization. The compositional turnover of fungal communities along the gradient was not paralleled by a gradient in species richness.


Assuntos
Biodiversidade , Micorrizas/genética , Raízes de Plantas/microbiologia , Neve/microbiologia , Microbiologia do Solo , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Micorrizas/classificação , Noruega , Polygonaceae/microbiologia , Análise de Sequência de DNA , Solo/química
12.
Ecol Evol ; 13(8): e10401, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37600486

RESUMO

An urgent aim of ecology is to understand how key species relate to climatic and environmental variation, to better predict their prospects under future climate change. The abundant dwarf shrub bilberry (Vaccinium myrtillus L.) has caught particular interest due to its uphill expansion into alpine areas. Species' performance under changing climate has been widely studied using the climatic space-for-time approach along elevation gradients, but potentially confounding, local environmental variables that vary along elevation gradients have rarely been considered. In this study, performed in 10 sites along an elevation gradient (200-875 m) in W Norway, we recorded species composition and bilberry performance, both vegetative (ramet size and cover) and reproductive (berry and seed production) properties, over one to 4 years. We disentangled effects of local environmental variables and between-year, climatic variation (precipitation and temperature), and identified shared and unique contributions of these variables by variation partitioning. We found bilberry ramet size, cover and berry production to peak at intermediate elevations, whereas seed production increased upwards. The peaks were less pronounced in extreme (dry or cold) summers than in normal summers. Local environmental variables explained much variation in ramet size and cover, less in berry production, and showed no relation to seed production. Climatic variables explained more of the variation in berry and seed production than in ramet size and cover, with temperature relating to vegetative performance, and precipitation to reproductive performance. Bilberry's clonal growth and effective reproduction probably explain why the species persists in the forest and at the same time invades alpine areas. Our findings raise concerns of the appropriateness of the climatic space-for-time approach. We recommend including both climatic and local environmental variables in studies of variation along elevation gradients and conclude that variation partitioning can be a useful supplement to other methods for analysing variation in plant performance.

13.
New Phytol ; 195(4): 844-856, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22758207

RESUMO

Bryophytes are a dominant vegetation component of the boreal forest, but little is known about their associated fungal communities, including seasonal variation within them. Seasonal variation in the fungal biomass and composition of fungal communities associated with three widespread boreal bryophytes was investigated using HPLC assays of ergosterol and amplicon pyrosequencing of the internal transcribed spacer 2 (ITS2) region of rDNA. The bryophyte phyllosphere community was dominated by Ascomycota. Fungal biomass did not decline appreciably in winter (P=0.272). Significant host-specific patterns in seasonal variation of biomass were detected (P=0.003). Although seasonal effects were not the primary factors structuring community composition, collection date significantly explained (P=0.001) variation not attributed to locality, host, and tissue. Community homogenization and a reduction in turnover occurred with the onset of frost events and subzero air and soil temperatures. Fluctuations in the relative abundance of particular fungal groups seem to reflect the nature of their association with mosses, although conclusions are drawn with caution because of potential methodological bias. The moss-associated fungal community is dynamic, exhibiting seasonal turnover in composition and relative abundance of different fungal groups, and significant fungal biomass is present year-round, suggesting a winter-active fungal community.


Assuntos
Biomassa , Briófitas/microbiologia , Fungos/crescimento & desenvolvimento , Fungos/genética , Estações do Ano , Ergosterol/metabolismo , Fungos/classificação , Variação Genética , Modelos Lineares , Noruega , Fotossíntese , Análise de Sequência de DNA
14.
Mol Ecol ; 21(8): 1897-908, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22590726

RESUMO

We investigated changes in the root-associated fungal communities associated with the ectomycorrhizal herb Bistorta vivipara along a primary succession gradient using 454 amplicon sequencing. Our main objective was to assess the degree of variation in fungal richness and community composition as vegetation cover increases along the chronosequence. Sixty root systems of B. vivipara were sampled in vegetation zones delimited by dated moraines in front of a retreating glacier in Norway. We extracted DNA from rinsed root systems, amplified the ITS1 region using fungal-specific primers and analysed the amplicons using 454 sequencing. Between 437 and 5063 sequences were obtained from each root system. Clustering analyses using a 98.5% sequence similarity cut-off yielded a total of 470 operational taxonomic units (OTUs), excluding singletons. Between eight and 41 fungal OTUs were detected within each root system. Already in the first stage of succession, a high fungal diversity was present in the B. vivipara root systems. Total number of OTUs increased significantly along the gradient towards climax vegetation, but the average number of OTUs per root system stayed unchanged. There was a high patchiness in distribution of fungal OTUs across root systems, indicating that stochastic processes to a large extent structure the fungal communities. However, time since deglaciation had impact on the fungal community structure, as a systematic shift in the community composition was observed along the chronosequence. Ectomycorrhizal basidiomycetes were the dominant fungi in the roots of B. vivipara, when it comes to both number of OTUs and number of sequences.


Assuntos
Basidiomycota/genética , DNA Fúngico/análise , Ecossistema , Raízes de Plantas/microbiologia , Polygonaceae/microbiologia , Análise de Sequência de DNA/métodos , Basidiomycota/classificação , DNA Espaçador Ribossômico/análise , Camada de Gelo , Micorrizas/genética , Noruega , Especificidade da Espécie
15.
Am J Bot ; 99(9): e344-6, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22922400

RESUMO

PREMISE OF THE STUDY: The perennial feather moss Hylocomium splendens is one of the most widely distributed and common bryophytes in the Northern Hemisphere and has, because of its capacity to grow under a wide range of environmental conditions, been used as a biomonitor for atmospheric metal deposition in Europe. METHODS AND RESULTS: We present a multiplex approach for the analysis of 14 microsatellite markers tested on 194 H. splendens gametophytes. Ten of the markers are developed recently, and are presented for the first time in this paper, whereas four were previously developed but have not been used for population genetic investigations. CONCLUSIONS: The microsatellite markers reported here will provide a powerful tool for further research on population genetic structure in H. splendens.


Assuntos
Bryopsida/genética , Repetições de Microssatélites/genética , Primers do DNA/metabolismo , DNA de Plantas/genética , Dados de Sequência Molecular , Noruega
16.
Biol Lett ; 7(2): 273-6, 2011 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-20961882

RESUMO

Most basidiomycete fungi produce annual short-lived sexual fruit bodies from which billions of microscopic spores are spread into the air during a short time period. However, little is known about the selective forces that have resulted in some species fruiting early and others later in the fruiting season. This study of relationships between morphological and ecological characteristics, climate factors and time of fruiting are based upon thorough statistical analyses of 66 520 mapped records from Norway, representing 271 species of autumnal fruiting mushroom species. We found a strong relationship between spore size and time of fruiting; on average, a doubling of spore size (volume) corresponded to 3 days earlier fruiting. Small-spored species dominate in the oceanic parts of Norway, whereas large-spored species are typical of more continental parts. In separate analyses, significant relationships were observed between spore size and climate factors. We hypothesize that these relationships are owing to water balance optimization, driven by water storage in spores as a critical factor for successful germination of primary mycelia in the drier micro-environments found earlier in the fruiting season and/or in continental climates.


Assuntos
Basidiomycota/crescimento & desenvolvimento , Esporos Fúngicos/crescimento & desenvolvimento , Basidiomycota/fisiologia , Noruega , Reprodução , Estações do Ano , Fatores de Tempo , Água
18.
Proc Biol Sci ; 277(1685): 1169-77, 2010 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-20008050

RESUMO

Most macrofungi produce ephemeral fruit bodies during autumn but some have adapted to spring fruiting. In this study, temporal changes in the time of spring fruiting in Norway and the UK during 1960-2007 have been investigated by statistical analyses of about 6000 herbarium and field records, covering 34 species. Nearly 30 per cent of the temporal variation in fruiting could be ascribed to spatial and species-specific effects. Correcting for these effects, linear trends towards progressively earlier fruiting were detected during the entire period in both Norway and the UK, with a change in average fruiting day of 18 days over the study period. Early fruiting was correlated with high winter temperatures in both countries, indicating that the observed phenological changes are likely due to earlier onset of spring. There were also significant correlations between climatic conditions in one year and timing of fruiting the following year, indicating that below-ground mycelia are influenced by climatic conditions over a longer time period before fruiting. Fruiting dates were, however, not strictly related to changes in vernal accumulated thermal time. Our results indicate that global warming has lead to progressively earlier fruiting of spring fungi in northwest Europe during the last half century.


Assuntos
Mudança Climática , Fungos/fisiologia , Estações do Ano , Noruega , Fatores de Tempo , Reino Unido
19.
Oecologia ; 163(4): 921-33, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20425124

RESUMO

Plants of low stature may benefit from the presence of large herbivores through removal of tall competitive neighbours and increased light availability. Accordingly, removal of grazers has been predicted to disfavour small species. In addition to this indirect beneficial effect, the population dynamics of plants is strongly influenced by variation in external conditions such as temperature and precipitation. However, few studies have examined the interaction between large herbivores and inter-annual variation in climate for the population dynamics of small plant species not preferred by herbivores. We studied three populations of the perennial herb Viola biflora exposed to different sheep densities (high, low and zero) for 6 years in a field experiment. Plants were also impacted by invertebrate and small vertebrate herbivores (rodents). Rates of growth were marginally higher at high sheep densities, and during warm summers both survival and growth were higher when sheep were present. Thus, while the height of tall herbs was positively related to July temperature, it was less so in the treatments with sheep, suggesting that sheep reduce the negative effects of interspecific competition for this small herb. Life table response experiment analyses revealed that the population growth rate (lambda) was slightly lower in the absence of sheep, but between-year variation in lambda was larger than variation among sheep density treatments. lambda was negatively related to July temperature, with an additional negative effect of vertebrate grazing frequency (sheep or rodent grazing). The evidence from this 6-year study suggests that the population dynamics of Viola biflora is determined by a complex interplay between climate and grazing by both large and small herbivores.


Assuntos
Clima , Comportamento Alimentar , Ovinos , Viola , Animais , Ecossistema , Noruega , Dinâmica Populacional
20.
Oecologia ; 161(1): 77-85, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19412704

RESUMO

Herbivores shape plant communities through selective foraging. However, both herbivore selectivity and the plant's ability to tolerate or resist herbivory may depend on the density of herbivores. In an alpine ecosystem with a long history of grazing, plants are expected to respond to both enhanced and reduced grazing pressures, and the interaction between plant traits and changes in species abundance are expected to differ between the two types of alteration of grazing regime. To understand the mechanisms behind species response, we investigated the relationship between sheep selectivity (measured in situ), plant traits and experimentally derived measures of change in species abundance as a response to the enhancement (from low to high density) or cessation (from low to zero density) of sheep grazing pressure over a six-year time period for 22 abundant herb species in an alpine habitat in south Norway. Sheep selected large, late-flowering herbs with a low leaf C/N ratio. Species that increased in abundance in response to enhanced grazing pressure were generally small and had high root/shoot ratios, thus exhibiting traits that reflect both resistance (through avoidance) and tolerance (through regrowth capacity) strategies. The abundance of selected species remained stable during the study period, and also under the enhanced grazing pressure treatment. There was, however, a tendency for selected species to respond positively to cessation of grazing, although overall responses to cessation of grazing were much less pronounced than responses to enhanced grazing. Avoidance through short stature (probably associated with increased light availability through the removal of tall competitors) as well as a certain amount of regrowth capacity appear to be the main mechanisms behind a positive response to enhanced grazing pressure in this study. The plant trait perspective clearly improves our insight into the mechanisms behind observed changes in species abundance when the disturbance regime is altered.


Assuntos
Ecossistema , Comportamento Alimentar/fisiologia , Desenvolvimento Vegetal , Ovinos/fisiologia , Animais , Carbono/análise , Modelos Lineares , Nitrogênio/análise , Noruega , Plantas/química , Dinâmica Populacional , Especificidade da Espécie
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