Ostracods had colonized estuaries by the late Silurian

The fossil record of terrestrialization documents notable shifts in the environmental and physiological tolerances of many animal and plant groups. However, for certain significant components of modern freshwater and terrestrial environments, the transition out of marine settings remains largely unconstrained. Ostracod crustaceans occupy an exceptional range of modern aquatic environments and are invaluable palaeoenvironmental indicators in the fossil record. However, pre-Carboniferous records of supposed non-marine and marginal marine ostracods are sparse, and the timing of their marine to non-marine transition has proven elusive. Here, we reassess the early environmental history of ostracods in light of new assemblages from the late Silurian of Vietnam. Two, low diversity but distinct ostracod assemblages are associated with estuarine deposits. This occurrence is consistent with previous incidental reports of ostracods occupying marginal and brackish settings through the late Silurian and Devonian. Therefore, ostracods were pioneering the occupation of marginal marine and estuarine settings 60 Myr before the Carboniferous and they were a component of the early phase of transition from marine to non-marine environments.

Spatiotemporal Variability in Environmental Conditions Influences the Performance and Behavior of Juvenile Steelhead in a Coastal California Lagoon

In California (USA), seasonal lagoons provide important oversummer rearing habitat for juvenile steelhead trout (anadromous Oncorhynchus mykiss). However, key water quality parameters such as temperature and dissolved oxygen concentration can periodically approach or exceed the physiological tolerances of steelhead during the protracted dry season. A field study employing distributed temperature sensing technology, water quality monitoring, habitat mapping, and mark-recapture sampling was conducted to examine how shifting environmental conditions affected the performance and behavior of juvenile steelhead in the Scott Creek estuary/lagoon (Santa Cruz County). Abiotic conditions were driven by episodic inputs of seawater to the typically freshwater lagoon. During midsummer, the water column was vertically stratified which reduced suitable lagoon rearing habitat by approximately 40%. Nevertheless, steelhead abundance, growth, and condition factor were high during the summer and decreased in autumn following lagoon destratification and cooling. Unlike previous work, this study identified limited emigration from the lagoon to riverine habitat during the summer. Instead, juvenile steelhead exhibited crepuscular movement patterns within the lagoon, with peaks in upstream (to upper lagoon habitat) and downstream (to lower lagoon habitat) movement occurring at dawn and dusk, respectively. This study underscores that habitat complexity and connectivity are critical for juvenile steelhead production and persistence and provides insight into steelhead habitat use and behavior in seasonal lagoons.

Identification and fermentative properties of an indigenous strain of Wickerhamomyces anomalus isolated from Rosa roxburghii Tratt

PurposeThe purpose of this paper is to identify and analyse the fermentative properties of a strain of indigenous Wickerhamomyces anomalus (W. anomalus) from Rosa roxburghii Tratt (R. roxburghii).Design/methodology/approachMorphological and molecular methods were used to determine the species of the selected strain W. anomalus C11. The physiological tolerances to glucose, ethanol, citric acid and sulphur dioxide (SO2) were further assessed by checking the growth of cells, and the oenological performances were proved to measure the related fermentative properties of R. roxburghii wines.FindingsThe W. anomalus C11 strain could be grown faster than commercial S. cerevisiae X16 in its logarithmic growth period and had preferable tolerances to glucose, ethanol, citric acid and SO2. Moreover, this strain of native R. roxburghii yeast W. anomalus C11 produced less sulphuretted hydrogen and had a higher β-glucosidase activity. Furthermore, W. anomalus C11 could reduce the volatile acids, reduce the sourness and enhance volatile aroma richness and complexity of R. roxburghii wines including types of aroma and content thereof. Taken together, the R. roxburghii native yeast W. anomalus C11 may have potential for use in R. roxburghii winemaking.Originality/value(1) The fermentative properties of a strain of indigenous W. anomalus (named as C11) from R. roxburghii was evaluated. (2) The strain of W. anomalus C11 had preferable tolerances to glucose, ethanol, citric acid and SO2. (3) This strain of native R. roxburghii yeast W. anomalus C11 produced less sulphuretted hydrogen and had a higher ß-glucosidase activity. (4) W. anomalus C11 could reduce the volatile acids, reduce the sourness and enhance volatile aroma richness and complexity of R. roxburghii wines including types of aroma and content thereof.

Osmoregulatory ability predicts geographical range size in marine amniotes

Species that are distributed over wide geographical ranges are likely to encounter a greater diversity of environmental conditions than do narrowly distributed taxa, and thus we expect a correlation between size of geographical range and breadth of physiological tolerances to abiotic challenges. That correlation could arise either because higher physiological capacity enables range expansion, or because widely distributed taxa experience more intense (but spatially variable) selection on physiological tolerances. The invasion of oceanic habitats by amniotic vertebrates provides an ideal system with which to test the predicted correlation between range size and physiological tolerances, because all three lineages that have secondarily moved into marine habitats (mammals, birds, reptiles) exhibit morphological and physiological adaptations to excrete excess salt. Our analyses of data on 62 species (19 mammals, 18 birds, 24 reptiles) confirm that more-widely distributed taxa encounter habitats with a wider range of salinities, and that they have higher osmoregulatory ability as determined by sodium concentrations in fluids expelled from salt-excreting organs. This result remains highly significant even in models that incorporate additional explanatory variables such as metabolic mode, body size and dietary habits. Physiological data thus may help to predict potential range size and perhaps a species' vulnerability to anthropogenic disturbance.

Intergenerational niche differentiation in filmy ferns (Hymenophyllaceae)

Desiccation tolerance was a key trait that allowed plants to colonize land. However, little is known about the transition from desiccation tolerant non-vascular plants to desiccation sensitive vascular ones. Filmy ferns (Hymenophyllaceae) represent a useful system to investigate how water-stress strategies differ between non-vascular and vascular stages within a single organism because they have vascularized sporophytes and nonvascular gametophytes that are each capable of varying degrees of desiccation tolerance. To explore this, we surveyed sporophytes and gametophytes of 19 species (22 taxa including varieties) of filmy ferns on Moorea (French Polynesia) and used chlorophyll fluorescence to measure desiccation tolerance and light responses. We conducted phylogenetically informed analyses to identify differences in physiology between life stages and growth habits. Gametophytes had similar or less desiccation tolerance (ability to recover from 2 d desiccation at −86 MPa) and lower photosynthetic optima (maximum electron transport rate of photosystem II and light level at 95% of that rate) than sporophytes. Epiphytes were more tolerant of desiccation than terrestrial species in both generations. Despite their lack of greater physiological tolerances, gametophytes of several species occurred over a wider elevational range than conspecific sporophytes. Our results demonstrate that filmy fern gametophytes and sporophytes differ in their physiology and niche requirements, and point to the importance of microhabitat in shaping the evolution of water-use strategies in vascular plants.

The geography of phylogenetic paleoecology: integrating data and methods to better understand biotic response to climate change

Deeper knowledge about how species and communities respond to climate change and environmental gradients should be supported by evidence from the past, especially as modern responses are influenced by anthropogenic pressures, including human population growth, habitat destruction and fragmentation, and intensifying land use. There have been great advances in modeling species’ geographic distributions over shallow time, where consideration of evolutionary change is likely less important due to shorter time for evolution and speciation to occur. Over these shallow time periods, we have more resources for paleoclimate interpretation across large geographic landscapes. We can also gain insight into species and community changes by studying deep records of temporal changes. However, modeling species geographic distributions in deep time remains challenging, because for many species there is sparse coverage of spatial and temporal occurrences and there are fewer paleoclimate general circulation models (GCMs) to help interpret the geographic distribution of climate availability. In addition, at deeper time periods, it is essential to consider evolutionary change within lineages of species. I will discuss a framework that integrates evolutionary information in the form of phylogenetic relatedness from clades of extant closely related species, where and when there are associated fossil occurrences, and the geographic distribution of paleoclimate in deep time to infer species past geographic response to climate change and to estimate where and when there were hotspots of ancient diversification. More work is needed to better understand the evolution of physiological tolerances and how physiological tolerances relate to the climate space in which species occur.

New records of Pimpla Fabricius, 1804 (Hymenoptera, Ichneumonidae, Pimplinae) from Brazilian northeast

We record for the first time the species Pimpla croceiventris (Cresson, 1868), P. golbachi (Porter, 1970), and P. sumichrasti Cresson, 1874, belonging to the Pimplini tribe (Ichneumonidae, Pimplinae), in northeastern Brazil. These species have been recorded in the south and southeast of Brazil, except for P. croceiventris, which has also been recorded in the north of the country. Regarding the development of larvae and its physiological characteristics, Pimpla Fabricius, 1804 is one of the most well-studied genera within ichneumonids. These new distribution records will contribute to the understanding of physiological tolerances in different habitats as well as discoveries of new parasitoid-host interactions in new environments.

Waterlogging tolerance of the threatened grass Arthraxon hispidus and implications for its habitat niche within endangered wetlands in north-eastern New South Wales

Knowledge of a target species’ habitat niche and physiological tolerances is important for conservation planning. However, these factors are not well understood for the threatened annual grass Arthraxon hispidus in New South Wales (NSW). Although the species is widespread in modified environments, recent studies have suggested that several threatened wetland types may represent original native habitat for the species, but documented field examples are lacking and the species’ physiological response to soil moisture is not clear. We undertook a detailed survey of an A. hispidus population within a relatively intact native sedgeland community, and carried out a nursery experiment to test the hydrological tolerances of the species. We found that A. hispidus plants grew more vigorously in poorly drained or waterlogged conditions, suggesting that the species is well-adapted to overcome such stressors, possibly through the formation of adventitious roots, a trait shared by many wetland plants globally. Our field survey confirmed that the A. hispidus population within the study site occurred only within species assemblages that were characteristic of a freshwater wetland formation and that matched descriptions of a listed endangered ecological community. These findings provide a deeper insight into the species’ habitat and threats, and offer a valuable management focus for conservation of A. hispidus as a component of threatened wetland communities in north-eastern NSW.

Discovery of the world’s highest-dwelling mammal

Environmental limits of animal life are invariably revised when the animals themselves are investigated in their natural habitats. Here we report results of a scientific mountaineering expedition to survey the high-altitude rodent fauna of Volcán Llullaillaco in the Puna de Atacama of northern Chile, an effort motivated by video documentation of mice (genusPhyllotis) at a record altitude of 6,205 m. Among numerous trapping records at altitudes of >5,000 m, we captured a specimen of the yellow-rumped leaf-eared mouse (Phyllotis xanthopygus rupestris) on the very summit of Llullaillaco at 6,739 m. This summit specimen represents an altitudinal world record for mammals, far surpassing all specimen-based records from the Himalayas and other mountain ranges. This discovery suggests that we may have generally underestimated the altitudinal range limits and physiological tolerances of small mammals simply because the world’s high summits remain relatively unexplored by biologists.