Hydrophilous Taxa Research Articles

Testate amoebae as paleohydrological indicators in the boreal and subarctic permafrost mires in the western part of the central Siberian Plateau

Carbon storage capacity of peat deposits in permafrost mires is highly sensitive to climate change which effects might be strongly mediated by mire moisture and permafrost. Thus, it is essential to develop appropriate indicator tools of hydrological regime which can be used for monitoring present and past conditions in these mires. We use testate amoebae to investigate their indicator value to water table depth (WTD) and substrate water content (SWC) and to develop transfer functions for quantitative reconstructions of these environmental characteristics in the permafrost mires on the Central Siberian Plateau. In many cased, direct measurement of WTD in permafrost mires are not possible due to the presence of ice, so that SWC can be used as an alternative characteristic. Overall, 330 surface samples were collected in five study regions together with the corresponding environmental measurements. We find that testate amoebae form diverse assemblages with the species structure strongly controlled by WTD and SWC. We developed two testate amoeba-based transfer functions to reconstruct these characteristics based on Modern Analogue Technique which were assessed using leave-one-out and bootstrap cross-validation. We find that both transfer functions have good predictive power (for WTD: RMSEP = 6.8–7.6 cm, R2 = 0.54, for SWC: RMSEP = 2.0–2.3 %, R2 = 0.74–0.76). The ecological preferences of the majority of testate amoebae were similar to those reported by the studies in lower-latitudes, although some hydrophilic taxa were observed in the drier end of the surface wetness gradient. These data represent an important source for improvement of quantitative reconstructions based on subfossil testate amoebae in permafrost mires.

Climatic control of mat vegetation communities on inselberg archipelagos in south-eastern Brazil

AbstractGranite and/or gneiss inselbergs are excellent examples of geomorphologically stable island habitats, considered as old, climatically buffered, infertile landscapes (OCBILs). However, unlike oceanic islands, their underlying drivers of diversity patterns remain to be investigated. Here, we studied 24 inselbergs in south-eastern Brazil, aiming to understand the role of landscape variables and environmental conditions in the assembly of the characteristic extremophilic mat vegetation communities. We found that beta diversity was largely explained by climatic variables, whereas species richness did not vary among inselbergs. Classic determinants of the diversity of island communities do not generally seem to apply to these plant assemblages. Overall, these communities change along a coast-to-inland gradient that captures increased seasonality with a replacement of more hydrophilic taxa by more drought-tolerant taxa. Changes in species composition in space involved strong species replacement, with several widespread genera locally represented on distinct inselbergs by different narrowly distributed species. Despite the deterministic sorting of taxa based on climatic conditions, a substantial fraction of the beta diversity remained unexplained. This underlines the importance of historical processes, which are easier to notice in stable OCBIL regions, such as range expansion, local extinction, dispersal constraints and allopatric speciation.

Hydrophilic species in the composition of Herbarium Florae Rossicae exsiccatum at herbarium of Uman National University of Horticulture (UM)

Results of processing of hydrophilic species from Herbarium Florae Rossicae (1897–1970) of the historical herbarium of Uman National University of Horticulture are presented (UM). It is found that hydrophilic taxa are represented by 160 species of 70 genera of 30 families of higher spore and angiospermous plants. Quantitative composition of exsiccate of individual collectors and territorial gathering are analyzed. It is found that hydrophilic types of territories in Latvia (collector K. Kupffer), North-West Russia, in particular, surroundings of St. Petersburg (collectors N. Purring and V. Andreev) are most fully represented. On the territory of Ukraine, gathering was made in surroundings of Kiev and Chernigiv region (collectors A. Rakoci and N. Zinger) and in surroundings of Kharkov (collector P. Nalyvaiko). We determined 40 hydrophilic species in the exsiccate composition which are now protected in many European countries. Aldrovanda vesiculosa presented by collections of the founders of exsiccate publication Herbarium Florae Rossicae S. Korzhinsky and A. Rakoci, as well as Caldesia parnassifolia (collectors A. Lorchenko and V. Finn) are now classified as species protected by the Bern Convention. Information on the floristic studies of A. Rakoci (1894 –1903) and P. Nalyvaiko (1891–1897) is presented. It is found that the habitats of the rarest hydrophilic species collected by them for exsiccate Herbarium Florae Rossicae are now lost, so that these samples published more than 100 years ago acquire a memorial value. It is determined that the Cyperaceae family is most fully represented in the exsiccate composition.

Dietary and environmental implications of Early Cretaceous predatory dinosaur coprolites from Teruel, Spain

Coprolites from the Early Cretaceous vertebrate bone-bed at Ariño in Teruel, Spain, were analyzed geochemically and palynologically. They contain various inclusions, such as small bone fragments, abundant plant remains, pollen, and spores. We attribute the coprolites to carnivorous dinosaurs based partly on their morphology together with the presence of bone fragments, and a high content of calcium phosphate (hydroxylapatite) with calcite. Well-preserved pollen and spore assemblages were identified in all coprolite samples and a slightly poorer assemblage was obtained from the adjacent sediments, both indicating an Early Cretaceous (Albian) age. This shows that the coprolites are in situ and also confirms previous age determinations for the host strata. The depositional environment is interpreted as a continental wetland based on the palynoflora, which includes several hydrophilic taxa, together with sparse occurrences of fresh-water algae, such as Ovoidites, and the absence of marine palynomorphs.Although the coprolites of Ariño samples generally are dominated by pollen produced by Taxodiaceae (cypress) and Cheirolepidiaceae (a family of extinct conifers), the sediment samples have a slightly higher relative abundance of fern spores. The distribution of major organic components varies between the coprolite and sediment samples, which is manifest by the considerably higher charcoal percentage within the coprolites. The high quantities of charcoal might be explained by a ground-dwelling species, feeding on smaller vertebrates that complemented its diet with plant material from a paleoenvironment were wild fires were a part of the ecosystem. The state of preservation of the spores and pollen is also more detailed in the coprolites, suggesting that encasement in calcium phosphate may inhibit degradation of sporopollenin.

Controls of isotopic patterns in saprotrophic and ectomycorrhizal fungi

Isotopes of nitrogen (δ15N) and carbon (δ13C) in ectomycorrhizal and saprotrophic fungi contain important information about ecological functioning, but the complexity of physiological and ecosystem processes contributing to fungal carbon and nitrogen dynamics has limited our ability to explain differences across taxa. Here, we measured δ15N and δ13C in needles, litter, soil, wood, fungal caps, and fungal stipes at numerous forested sites in Oregon, USA to determine how functional attributes and biochemical processes may influence isotopic values. Ectomycorrhizal fungi were classified by hydrophobicity of ectomycorrhizae and by patterns of hyphal exploration; saprotrophic fungi were classified into wood decay and litter decay fungi. For δ15N, caps of hydrophobic taxa averaged 8.6‰, hydrophilic taxa 3.2‰, and saprotrophic taxa 0.5‰, whereas needles averaged 3‰ and soil at 5–12 cm averaged 2‰. Caps were higher in δ15N, δ13C, %N, and %C than stipes by 1.7‰, 0.6‰, 1.75%, and 2.61%, respectively, presumably because of greater protein content in caps than stipes. Isotopic enrichment of caps relative to stipes was greater in hydrophobic taxa (3.1‰ for 15N and 0.8‰ for 13C) than in hydrophilic taxa (1.1‰ for 15N and 0.5‰ for 13C). In multiple regressions, 45% of variance in δ15Ncap–stipe and 30% of variance in δ13Ccap–stipe was accounted for by various elemental, isotopic, and categorical variables. We estimated that fungal protein was enriched in 15N relative to fungal chitin by 15‰ in hydrophobic taxa and by 7‰ in hydrophilic taxa. Fungal protein was enriched in 13C by 4.2 ± 0.5‰ relative to carbohydrates. Isotopic signatures of sources and isotopic fractionation during metabolic processing influence both isotopic patterns of sporocarps and the isotopic partitioning between caps and stipes; functional groups differed in processing of both nitrogen isotopes and carbon isotopes.

Analyse pollinique d'une tourbière holocène dans les Montes do Buio : Cuadramón (Galice, nord-ouest de l'Espagne) [Pollen analyse of holocene peat-bog in the Montes do Buio : Cuadramón (Galice, N. W. of Spain)

The palynological analysis of two sedimentary sequences in the same peat bog (denominated Cuadramon I and Cuadramon II, situated at an altitude of 700 m in the Cuadramon mountains (Lugo, N.W. Spain) within the Eurosiberian biogeographical regional framework) has permitted an evolutional knowledge of vegetation during the last nine millennium. Specifically, the intention was to determine the presence, diffusion and expansion of certain taxons, such as Quercus, Corylus, Betula, Alnus, Pinus, and even Fagus, throughout the successive vegetational stages that occurred in this area over a period of time. The ¹⁴C data obtained in this peat bog (8770±170 BP in the CAII-2 zone of Cuadramon II) and others nearby, together with similarity of their palynological zonation, has permitted the establishment of a chronological hypothesis that positions its foundation at the beginning of the Holocene Epoch. Initially, climatic conditions do not appear to have favoured the installation of dense oak forests, but have favoured the expansion of open formations, in which Quercus, Corylus and Betula coexist. The optimum arboreal, in which the major expansion of oak is observed, occurs in the Boreal, beginning around 8770±170 BP. Later on, the Atlantic Period would respond to an arboreal predominance, during which the combination Corylus-Quercus-Betula dominates the landscape and the first signs of an incipient anthropeic activity appears (occasional presence of Cerealia in Cuadramon I). The Subatlantic Period would suppose the substitution of forests for thickets, fundamentally composed of Ericaceae, Calluna and Poaceae. The episodes that imply an arboreal decrease, of both climatic or anthropic origin, entails the increase of Poaceae and Ericaceae, above all, in levels that represent preactual or recent vegetation characteristics. These latter increments are parallel to the expansion of Castanea, the continual presence of Cerealia and the increase of ruderal and hydrophilous taxa. The low relevance of Pinus in the landscape is notable. In contrast, it is a major component of the regional vegetation in other mountains of the Northern Iberian Peninsular. On the other hand, the results obtained in this study, as well as those in other nearby locations, could indicate that Fagus is not an habitual component of Galician vegetation. The representation of Mediterranean taxons such as Oleaceae, taking into account knowledge of the actual climate and vegetation of the zone, could be explained by the capacity of pollen from these taxons to travel long distances from lower latitudes. In synthesis, this palynological study, correlated with those earned out in geographically proximate and well dated chronologically peat bogs such as Lobeiras (Gonzalez, 1996), makes a contribution to the understanding of the evolution of the Holocene vegetation of the Northwest Iberian Peninsula. After taking into account the characteristics of an open landscape together with the fresh and well ventilated nature of the Galician Atlantic climate, it demonstrates the importance of arboreal taxons, represented by deciduous trees : Quercus, Betula and Corylus. A notable factor of the arboreal history of Galicia is, for historic reasons and distance of refuges, the low relevance of taxa such as Fagus and Abies during the Holocene Epoch. The presence of Pinus is also very weak. This behaviour would explain, in part, the importance of Corylus and Betula. The progressive decrease of oak, during the period following its arboreal optimum, benefits Corylus throughout the Atlantic Period in which a discreet presence of cultivated plants and accompanying ruderal was established, observing finally, in the second part of the Subatlantic, the expansion of degradation thickets.

Population genetics of hydrophilous angiosperms

Comparisons between genetic variation and life history and ecological characteristics have been produced for over 400 plant species since the advent of starch gel electrophoresis. Knowledge of how aquatic life histories relate to population genetic structure is lacking, however. Four hydrophilous species — Zostera marina L., Vallisneria americana Michx., Ceratophyllum demersum L., and Ceratophyllum echinatum Gray — have been studied using allozyme estimates of variation within and among populations. At the species level, the percent of polymorphic loci is equal to, or higher than, the average reported for all plant species. At the population level, however, hydrophilous taxa have lower percent of polymorphic loci, fewer alleles per locus, and lower levels of heterozygosity than non-hydrophiles. Except for Z. marina, hydrophilous species show much greater partitioning of variation among populations than non-hydrophiles, particularly when compared with anemophilous species. Explanations for these patterns include sexuality ( Ceratophyllum), extensive clonal spread (all four species), and the greater isolation of freshwater populations (lakes as islands) relative to most terrestrial species and to coastal species such as Z. marina.

'Unless the stereotyped ... pharmacists change their ways, they will become the dinosaurs of the medical team.'

Coprolites from the Early Cretaceous vertebrate bone-bed at Ariño in Teruel, Spain, were analyzed geochemically and palynologically. They contain various inclusions, such as small bone fragments, abundant plant remains, pollen, and spores. We attribute the coprolites to carnivorous dinosaurs based partly on their morphology together with the presence of bone fragments, and a high content of calcium phosphate (hydroxylapatite) with calcite. Well-preserved pollen and spore assemblages were identified in all coprolite samples and a slightly poorer assemblage was obtained from the adjacent sediments, both indicating an Early Cretaceous (Albian) age. This shows that the coprolites are in situ and also confirms previous age determinations for the host strata. The depositional environment is interpreted as a continental wetland based on the palynoflora, which includes several hydrophilic taxa, together with sparse occurrences of fresh-water algae, such as Ovoidites, and the absence of marine palynomorphs.Although the coprolites of Ariño samples generally are dominated by pollen produced by Taxodiaceae (cypress) and Cheirolepidiaceae (a family of extinct conifers), the sediment samples have a slightly higher relative abundance of fern spores. The distribution of major organic components varies between the coprolite and sediment samples, which is manifest by the considerably higher charcoal percentage within the coprolites. The high quantities of charcoal might be explained by a ground-dwelling species, feeding on smaller vertebrates that complemented its diet with plant material from a paleoenvironment were wild fires were a part of the ecosystem. The state of preservation of the spores and pollen is also more detailed in the coprolites, suggesting that encasement in calcium phosphate may inhibit degradation of sporopollenin.