家养食草动物粪便中的花粉及菌孢子类型及其对人类活动的指示意义

考古遗址中动物粪化石中的微体植物遗存是重建过去生态环境以及人类活动的重要材料,然而对于能够指示人类活动的粪化石孢粉组合类型及其特征仍然缺乏清楚的认识。本文研究了山羊(Capra aegagrus)、绵羊(Ovis aries)、牛(Bos taurus)、骆驼(Camelus)、牦牛(Bos grunniens)和马(Equus caballus)等几种中国常见的家养食草类动物粪便中的主要孢粉和真菌孢子类型。通过分析这些动物粪便的花粉组合特征,探讨了花粉和菌孢子等微体植物遗存对生态环境及人类活动的指示意义。花粉种类丰度低、一些特征种属花粉(如禾本科、藜科)含量高是家养食草类动物粪便花粉组合的主要特征,可以用于指示人类的饲养行为。家养食草动物粪便中的粪生真菌孢子类型主要有Sporormiella,Sodaria,Pleospora,Coniochaeta,Thecaphora and Dictyosporium。研究表明真菌孢子的分布主要受到动物活动范围的影响,这使得利用粪生菌孢子(如Sporormiella)并结合其他记录来反映人类的饲养或游牧活动成为可能。     

Fungal diversity on dung of tropical animals in temperate environments: Implications for reconstructing past megafaunal populations

Coprophilous fungal spores from sedimentary sequences are increasingly used to reconstruct past herbivore presence and abundance. To provide a modern analogue for extinct megaherbivores in temperate environments, the coprophilous fungal communities on dung of exotic megaherbivores in a temperate environment were compared with those of (semi-)native wild, feral and domesticated herbivores. Six zygomycete, 32 ascomycete and one basidiomycete taxa were identified. A large overlap in community composition was observed between samples from different geographical locations. Dung fungal diversity was influenced primarily by the range size of the herbivore and season of collection. Diet and digestive system were not significant determinants of dung fungal diversity. The dung of exotic megaherbivores is characterised by a dung fungal community similar to that of (semi-)native herbivores, and therefore provides a good analogue for the dung of closely related but now extinct temperate megaherbivores.     

Optimal counting limit for fungal spore abundance estimation using Sporormiella as a case study

The use of non-pollen palynomorphs, and among them spores of coprophilous fungi, has become greatly important in palaeoecological studies. Particularly, the genus Sporormiella has been demonstrated to be the most valuable proxy for the presence of wild and domestic herbivores. This genus could also be used to determine livestock density and reconstruct pastoral pressure during the Holocene. Non-standard counting methods have been established to determine coprophilous fungal spore abundance in sediments. Moreover, these analyses are faced with the recurrent problem of setting the minimum counting sum as small as possible to save time. We researched the reliability of Sporormiella concentration estimates based on different counting sums, using low to high count samples. Box-plots indicate that the variability of inferred Sporormiella concentrations decreases progressively with increasing sums. Statistical comparisons show that the means of box-plots became stabilised after the counts have reached 300–350 exotic marker grains. Moreover, a count of 300–350 exotic marker grains is sufficient to produce a Sporormiella concentration estimate, whatever the amount. Finally, we propose that this counting limit is valid for other fungal spores as well.     

Coprophilous fungi from Morocco

Summary

Fifty-seven species of coprophilous fungi are recorded from 14 dung samples collected from the Souss Valley area of southern Morocco that were incubated in moist chambers. Several new records for Morocco are reported. Evidence for reduced diversity due to the severely degraded nature of the habitats in which the samples were collected is discussed.     

Some coprophilous fungi from Kenya

The occurrence of coprophilous fungi on samples of antelope, buffalo, zebra and hippopotamus dung collected from the Marula Estates in Kenya was recorded. A hundred and seventy three fungal isolates representative of 40 genera and 59 species were identified. Among these species, 23 were Ascomycetes (39%), 30 Deuteromycetes (50.8%), 5 Zygomycetes (8.5%) and 1 Basidiomycete (1.7%). Ascobolus immersus, Coprotus niveus, Iodophanus carneus, Lasiobolus lasioboloides, Podospora anserina, P. australis and Sporormiella minima were the dominant species occurring in the dung of these animals. Notes on infrequent or interesting Ascomycetes include Kernia nitida, Saccobolus versicolor, Sordaria fimicola and others. The interdependence of the vegetation of this area with the fungi occurring on the dung of these animals is discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Molecular Characterization of Coprophilous Fungal Communities Reveals Sequences Related to Root-Associated Fungal Endophytes

This paper reports the use of molecular methods to characterize the coprophilous fungal communities (CFC) that inhabit the dung of four species of mammalian herbivores at two sites, Sevilleta National Wildlife Refuge (SNWR) in New Mexico and Wind Cave National Park (WCNP) in South Dakota. Results reveal that CFC from domesticated cattle (Bos taurus) at SNWR, and bison (Bison bison) and black-tailed prairie dogs (Cynomys ludovicianus) at WCNP were diverse but dominated primarily by members within eight taxonomic orders, including the rarely cultured and anaerobic order Neocallimastigales. In addition, 7.7% (138 of 1,788) of the sequences obtained from all dung samples were at least 97% similar to root-associated fungal (RAF) sequences previously described from blue grama (Bouteloua gracilis), a common forage grass found throughout North America and growing at both study sites. In contrast, 95.8% (295 of 308) of the sequences and four of the total seven operational taxonomic units obtained from pronghorn antelope (Antilocapra americana) dung belonged to the Pleosporalean order. We hypothesize that some herbivore vectors disperse non-systemic (non-clavicipitaceous) fungal endophytes. These dispersal events, it is argued, are most likely to occur via herbivores that occasionally forage and masticate root tissue, especially in arid regions where aboveground vegetation is sparse. The results of this study suggest that some (possibly many) members of the RAF community can expand their ecological role to include colonizing dung.     

Relationships of fungal spore concentrations in the air and meteorological factors

High concentrations of airborne fungal spores are associated with human health concerns. Environmental variables, such as temperature and moisture, can influence growth and reproduction in fungi and airborne spore concentrations can fluctuate seasonally. However, we do not understand how long-term changes in climate affect fungal abundance in the air. Here, we sampled annually (at peak season, in September, over a 20-yr period) for airborne fungal spores in two North American cities (New York and Toronto), and related fungal abundance to local variation in climate. We found that at both locations, the total precipitation during the 2- month period prior to sampling (Jul.–Aug.) was negatively related to observed fungal spore concentrations. Considering that climate predictions for these two regions indicate an increase in drought events in summer, we expect airborne fungal concentrations to increase in future years, potentially exacerbating human health concerns.     

High-resolution palynology reveals the land use history of a Sami <Emphasis Type="Italic">renvall</Emphasis> in northern Sweden

The limited availability of historical and archaeological evidence means that much is still unknown about the development of Sami reindeer herding in Fennoscandia in both the recent and more distant past. To address this problem, high-resolution palynological analyses, ¹⁴C and ²¹⁰Pb dating were undertaken on two adjacent (<25 m apart) peat profiles collected at a recently abandoned reindeer gathering pen (renvall) near Jokkmokk (~66.6°N, 19.8°E) in the boreal forest of northern Sweden. The aim was to assess the impact of Sami reindeer herding on the local environment through a study of pollen, coprophilous fungal spores, microscopic charcoal and sedimentology. The samples collected from within an annex to the renvall indicate cycles of use and abandonment of the pen on a multi-decadal timescale between ~ad 1800–2008, most obviously in the coprophilous fungal spore archive. The pattern and timing of these cycles confirm events previously known only from oral histories. Although the local pollen assemblage zones associated with the phasing of activity were reproducible in a second peat core beyond the boundary of the renvall, the coprophilous fungal spore signal in this paired profile was much less distinctive, possibly due to the typically shorter dispersal distances for these microfossils in comparison to pollen grains.     

Soil fungi invest into asexual sporulation under resource scarcity,but trait spaces of individual isolates are unique

During the last few decades, a plethora of sequencing studies provided insight into fungal community composition under various environmental conditions. Still, the mechanisms of species assembly and fungal spread in soil remain largely unknown. While mycelial growth patterns are studied extensively, the abundant formation of asexual spores is often overlooked, though representing a substantial part of the fungal life cycle relevant for survival and dispersal. Here, we explore asexual sporulation (spore abundance, size and shape) in 32 co-occurring soil fungal isolates under varying resource conditions, to answer the question whether resource limitation triggers or inhibits fungal investment into reproduction. We further hypothesized that trade-offs exist in fungal investment towards growth, spore production and size. The results revealed overall increased fungal investment into spore production under resource limitations; however, effect sizes and response types varied strongly among fungal isolates. Such isolate-specific effects were apparent in all measured traits, resulting in unique trait spaces of individual isolates. This comprehensive dataset also elucidated variability in sporulation strategies and trade-offs with fungal growth and reproduction under resource scarcity, as only predicted by theoretical models before. The observed isolate-specific strategies likely underpin mechanisms of co-existence in this diverse group of saprobic soil fungi.     

Species diversity and community structure of rove beetles (Coleoptera: Staphylinidae) attracted to dung of sika deer in coniferous forests of southwest Japan

Insect communities of mammal dung have been known as excellent model ecosystems for scientific study. Ecological surveys of diversity and seasonal patterns of coprophilous rove beetles in relation to wild mammals have rarely been conducted, although the high potential species diversity and abundance of the rove beetles are known. In order to investigate biodiversity of these beetles, we analyzed species composition, abundance, feeding guild and seasonality of rove beetles that were attracted to sika deer Cervus nippon dung by using dung‐baited pitfall traps for a 1.5‐year study in two plantations (cypress, cedar) and one secondary natural forest (pine) in Fukuoka Prefecture, southwest Japan. Consequently, saprophagous Anotylus sp. (Oxytelinae) was dominant in all forests. Analyses of feeding guild structure showed the number of individuals were dominated by saprophagous beetles, but the number of species were dominated by predatory beetles. Seasonal effects suggested that the species richness and abundance of rove beetles are possibly regulated by scarabaeoid dung beetles. These findings feature one example of a coprophilous rove beetle community.     

The living strategy of nematophagous fungi

The infection structures, trophism, and ecological character of nematophagous fungi are reviewed in this article on the basis of data extracted from the literature and the most recent experiments conducted in this area. Traditionally, nematophagous fungi are classified into four groups according to their modes of attacking nematodes: nematode-trapping fungi using adhesive or mechanical hyphal traps, endoparasitic fungi using their spores, eggparasitic fungi invading nematode eggs or females with their hyphal tips, and toxin-producing fungi immobilizing nematodes before invasion. In the present review, we focus on the first two groups. The living strategies of these nematophagous fungi depend on the diversity of their infection structures, such as different traps and spore types, which determine the modes of infecting nematodes. The diversity of trophic modes of nematophagous fungi is an important prerequisite for fungal survival and activity in soil. The abundance and activity of Hirsutella rhossiliensis and H. minnesotensis, representatives of endoparasites and potential biocontrol agents against nematodes, are highly dependent on environmental factors. Comprehensive understanding of the survival and activity of nematophagous fungi in soil is fundamental for the exploitation of these fungi as successful biocontrol agents.     

Trait‐dependent distributional shifts in fruiting of common British fungi

Despite the dramatic phenological responses of fungal fruiting to recent climate warming, it is unknown whether spatial distributions of fungi have changed and to what extent such changes are influenced by fungal traits, such as ectomycorrhizal (ECM) or saprotrophic lifestyles, spore characteristics, or fruit body size. Our overall aim was to understand how climate and fungal traits determine whether and how species‐specific fungal fruit body abundances have shifted across latitudes over time, using the UK national database of fruiting records. The data employed were recorded over 45 yr (1970–2014), and include 853 278 records of Agaricales, Boletales and Russulales, though we focus only on the most common species (with more than 3000 records each). The georeferenced observations were analysed by a Bayesian inference as a Gaussian additive model with a specification following a joint species distribution model. We used an offset, random contributions and fixed effects to isolate different potential biases from the trait‐specific interactions with latitude/climate and time. Our main aim was assessed by examination of the three‐way‐interaction of trait, predictor (latitude or climate) and time. The results show a strong trait‐specific shift in latitudinal abundance through time, as ECM species have become more abundant relative to saprotrophic species in the north. Along precipitation gradients, phenology was important, in that species with shorter fruiting seasons have declined markedly in abundance in oceanic regions, whereas species with longer seasons have become relatively more common overall. These changes in fruit body distributions are correlated with temperature and rainfall, which act directly on both saprotrophic and ECM fungi, and also indirectly on ECM fungi, through altered photosynthate allocation from their hosts. If these distributional changes reflect fungal activity, there will be important consequences for the responses of forest ecosystems to changing climate, through effects on primary production and nutrient cycling.     

Secretome of the Coprophilous Fungus Doratomyces stemonitis C8, Isolated from Koala Feces

Coprophilous fungi inhabit herbivore feces, secreting enzymes to degrade the most recalcitrant parts of plant biomass that have resisted the digestive process. Consequently, the secretomes of coprophilous fungi have high potential to contain novel and efficient plant cell wall degrading enzymes of biotechnological interest. We have used one-dimensional and two-dimensional gel electrophoresis, matrix-assisted laser desorption ionization-time-of-flight tandem mass spectrometry (MALDI-TOF/TOF MS/MS), and quadrupole time-of-flight liquid chromatography-tandem mass spectrometry (Q-TOF LC-MS/MS) to identify proteins from the secretome of the coprophilous fungus Doratomyces stemonitis C8 (EU551185) isolated from koala feces. As the genome of D. stemonitis has not been sequenced, cross-species identification, de novo sequencing, and zymography formed an integral part of the analysis. A broad range of enzymes involved in the degradation of cellulose, hemicellulose, pectin, lignin, and protein were revealed, dominated by cellobiohydrolase of the glycosyl hydrolase family 7 and endo-1,4-β-xylanase of the glycosyl hydrolase family 10. A high degree of specialization for pectin degradation in the D. stemonitis C8 secretome distinguishes it from the secretomes of some other saprophytic fungi, such as the industrially exploited T. reesei. In the first proteomic analysis of the secretome of a coprophilous fungus reported to date, the identified enzymes provide valuable insight into how coprophilous fungi subsist on herbivore feces, and these findings hold potential for increasing the efficiency of plant biomass degradation in industrial processes such as biofuel production in the future.     

Antiamoebins, myrocin B and the basis of antifungal antibiosis in the coprophilous fungus Stilbella erythrocephala (syn. S. fimetaria)

Antiamoebins I, III and XVI as well as several others in minor amounts were produced by four strains of the coprophilous fungus Stilbella erythrocephala (syn. S. fimetaria) in its natural substrate and in liquid culture. The total antiamoebin concentration in dung was 126-624 microg g(-1) fresh weight, with minimum inhibitory concentrations against most other coprophilous fungi being at or below 100 microg mL(-1). Myrocin B, not previously described from S. erythrocephala, was also produced, but only at low, nonfungicidal levels (< 5.3 microg g(-1)). No other antifungal substances were detected. It is concluded that antiamoebins are responsible for antibiosis in dung colonized by S. erythrocephala.     

What Goes in Must Come out: Testing for Biases in Molecular Analysis of Arbuscular Mycorrhizal Fungal Communities

Arbuscular mycorrhizal (AM) fungi are widely distributed microbes that form obligate symbioses with the majority of terrestrial plants, altering nutrient transfers between soils and plants, thereby profoundly affecting plant growth and ecosystem properties. Molecular methods are commonly used in the study of AM fungal communities. However, the biases associated with PCR amplification of these organisms and their ability to be utilized quantitatively has never been fully tested. We used Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis to characterise artificial community templates containing known quantities of defined AM fungal genotypes. This was compared to a parallel in silico analysis that predicted the results of this experiment in the absence of bias. The data suggest that when used quantitatively the TRFLP protocol tested is a powerful, repeatable method for AM fungal community analysis. However, we suggest some limitations to its use for population-level analyses. We found no evidence of PCR bias, supporting the quantitative use of other PCR-based methods for the study of AM fungi such as next generation amplicon sequencing. This finding greatly improves our confidence in methods that quantitatively examine AM fungal communities, providing a greater understanding of the ecology of these important fungi.     

Dung preference and trophic association of dung beetles (Coleoptera: Scarabaeidae) in the moist forests of the South-western Ghats of the Indian subcontinent

First quantitative dung beetle-feeding trophic network analysis for the Oriental region is carried out by investigating trophic network interaction between dung beetles and mammal dung types in the moist forests of the Western Ghats a global biodiversity hot spot in south-western India. Dung-beetle assemblage associated with the dung of the prominent mammals, such as the macaque, boar, gaur, elephant and deer, showed differences in richness, abundance and composition among different dung types. Most dung beetles were generalists with low resource specificity and community-wide generalist feeding on herbivore and omnivore dung types. Dung beetles in the region displayed high species richness and abundance in boar dung. The high attraction and specificity of dung beetles towards the odoriferous boar dung indicate that the omnivore mammal Sus scrofa has a major role in maintaining the dung beetle community in the forests of the Western Ghats. Network interaction analysis shows that the vast majority in the assemblage are generalist species, and the few specialist species were all with low abundance. Low overall specialisation and low resource partitioning with high species richness is recorded in the assemblage. The assemblage's trophic level preference is reflected in the high dung specificity recorded in the omnivore and herbivore dung types.     

Trophic associations of a dung beetle assemblage (Scarabaeidae: Scarabaeinae) in a woodland savanna of Botswana

Species richness and abundance of dung beetles were assessed across a range of bait types that acted as surrogates for the food resources available in Chobe National Park, Botswana. These bait types were comprised of the dung of pig (omnivore), cattle (ruminant herbivore dropping fine-fiberd pads), sheep (pellet-dropping ruminant herbivore), and elephant (monogastric, nonruminant herbivore producing coarse-fibered droppings), and chicken livers (carrion). Species richness was similar between traps baited with pig, cattle, and elephant dung but was relatively lower in those baited with sheep dung and carrion. In traps baited with pig dung, abundance was relatively greater than in all other bait types. A cluster analysis of species abundance distributions for the 30 most abundant species identified four different patterns of bait type association at a 60% level of similarity. All but 1 of the 15 species in cluster A were attracted primarily to the dung of omnivores and pad-dropping ruminant herbivores (pig and cattle). All seven species of cluster B were attracted primarily to coarse-fibered, nonruminant herbivore dung (elephant). All four species of cluster C were primarily carrion and pig dung associated, whereas all four species of cluster D were carrion specialists. In conclusion, the most abundant species were attracted to all bait types, but most species were largely specialized to different dung types or carrion, with dung attracting the majority of the fauna in terms of both species richness and abundance.     

Vesicular-arbuscular mycorrhizas and soil salinity

This review discusses the growth and activity of vesicular-arbuscular (VA) mycorrhizal fungi in saline conditions. The review includes examination of the effects of high concentrations of salts on the occurrence of VA mycorrhizal fungi in field soils, and on spore germination, growth of hyphae, establishment of the symbiosis and production of spores in controlled conditions. Information on the growth and reproduction of VA mycorrhizal fungi under saline conditions is scarce and is often circumstantial. There is clear evidence that germination of spores and subsequent hyphal growth of some VA mycorrhizal fungi are reduced by increasing concentration of salts. However, in plant growth experiments, experimental designs and methodologies have generally not allowed the direct effects of salinity on fungal growth to be separated from plant-mediated effects. There is a need for controlled studies to investigate the responses of VA mycorrhizal fungi to soil salinity. Research is required which distinguishes between effects on different phases of the fungus lifecycle and which includes in its design the ability to separate direct effects from plant-mediated influences on fungal growth and reproduction.     

Seasonality and photoperiodism in fungi

This review gives a retrospective of what is known about photoperiodism in fungi, which is largely based on reports about seasonal spore concentrations. Relatively few species have been investigated under laboratory conditions, so that our knowledge whether seasonal reproduction in fungi is mainly a direct response to environmental conditions or whether it involves a photoperiodic machinery with memory capacities and a relationship to the circadian system is extremely limited. To form a basis for further experimental endeavors into fungal photoperiodism, we review the reports about endogenous rhythms and photobiology. Finally, we will look at the possibilities of using the fungal circadian model system of Neurospora crassa for future work on photoperiodism.     

Global arbuscular mycorrhizal fungal diversity and abundance decreases with soil available phosphorus

Aim

Arbuscular mycorrhizal fungi (AMF) are widely distributed soil organisms that play critical roles in ecosystem functions. However, little is known about their global distribution and the underlying mechanisms. Here, we aimed to explore distribution pattern and key predictors of AMF diversity and abundance at the global scale.

Location

Global.

Time Period

1987–2022.

Major Taxa Studied

Arbuscular mycorrhizal fungi.

Methods

We investigated the distribution pattern and key predictors of AMF diversity and abundance at the global scale by compiling 654 field studies.

Results

We found that cold climate zones had relatively low AMF diversity. At the ecosystem level, grassland tended to have higher AMF diversity and abundance. Soil available phosphorus (P) and latitude were the most important predictors of AMF diversity. AMF richness and Shannon index decreased with increasing soil available P and latitude. Soil available P and soil pH were the main predictors for global distribution of AMF abundance. AMF colonization rate and spore abundance declined with soil available P and increased with soil pH. Mean annual precipitation was also an important, positive correlate of spore abundance.

Main Conclusions

Our findings highlight soil available P as an important predictor affecting the distribution of AMF diversity and abundance, advancing our understanding of the mechanisms underlying the distribution patterns of mycorrhizal fungal diversity and abundance at the global scale.