High Mountain Streams Research Articles

Multidimensional alpha diversities of benthic macroinvertebrate in subtropical high-mountain streams and their driving factors

Multidimensional alpha diversities of benthic macroinvertebrate in subtropical high-mountain streams and their driving factors

Biologically Structured Water (BSW) - A Review (Part 3): Structured Water (SW) Generation, BSW Water, Bioenergetics, Consciousness and Coherence

Natural water sources become partially structured when exposed to cold temperatures, aeration, and sunlight in high mountain streams or kosmotropic ions. Drinking water devices that make structured water utilize methods such as resonance, vortex designs, and static magnets to alter H-bond configurations in liquid water. Other methods, such as the Advanced Oxidation Process (AOP) or vortexing, utilize energy or mechanical methods that are strong enough to break the covalent bonds in liquid water. After water splits into hydronium ions (H30+) and hydroxyl radicals (•OH), these molecular species rapidly reform back into SW water with stable H-bonds. Several companies offer AOP water generators for the remediation of wastewater, industrial water treatment, hydroponic, and agricultural uses. Other companies offer vortex generators for SW drinking water for households and institutions. The final section summarizes the interconnectivity and synchronization between BSW water, bioenergetics, consciousness, and quantum coherence. The continuous layer of BSW water within all cells and covering all biological membranes allows it to capture, store, resonate, amplify, and transmit a wide spectrum of EMF energy that forms the basis of bioenergetics. Application of quantum biology principles to BSW water opens promising research fields potent with solutions to enhance human health and longevity. Other SW and BSW water research areas potentially include environmental and wastewater treatment, medical treatments for age-related diseases, energy generation, and possibly even manipulation of rainfall patterns.

Long-term response of trophic structure and function to dam removal in a subtropical mountain stream

Although dam removal has been considered a viable strategy to mitigate habitat fragmentation within a stream, long-term ecosystem effects after dam removal have rarely been discussed. In an effort to enhance the resilience of the critically endangered Formosan salmon (Oncorhynchus masou formosanus) in response to climate change, a 15-m-high check dam in a subtropical high-mountain stream was half-removed. The aim of this study was to analyze the long-term response of trophic structure and function to dam removal by constructing Ecopath models upstream and downstream of the removed dam at different times. Field surveys for model parameters were conducted for a complete seasonal cycle 1 year before dam removal, 1 and 2 years (short-term) after dam removal and 7 and 8 years (long-term) after dam removal. Both upstream and downstream systems moved toward maturity after dam removal. In the short term after dam removal, more energy can be transferred further up in the food webs. The vitality and diversity of both systems also increased. In the long term after dam removal, although the transfer efficiencies of both systems generally showed a decreasing pattern, the resilience increased. Compared to the upstream system, the effects of dam removal on the downstream system were more evident. In the downstream system, dam removal enhanced the vitality of the Formosan salmon and thus the top-down control. The dominance of detritivory flow in the food web also shifted toward the dominance of herbivory flow. Consequently, the downstream system reached more maturity, and the food web was more closely linked. The ecosystem attributes of the upstream and downstream systems converged, suggesting that the decoupling between upstream and downstream systems resulting from damming disappeared 8 years after dam removal.

Risk Factors in the Natural Habitat of Fish: A Review

Fish can be found in abundance in most bodies of water. Despite the fact that no species has yet been detected in the deepest 25% of the ocean, they are present in almost every aquatic environment, from the abyssal and even hadal depths of the deepest oceans (where they can be found as cusk-eels and snailfish) to the high mountain streams. Habitat destruction is the leading cause of biodiversity loss. The rise in nutrient loading, particularly nitrogen, is one of the main factors contributing to habitat degradation. Trawling diminishes the environment’s complexity by removing sedimentary features and biogenic structures like sponges, bryozoans, and shell aggregates. The construction of dams on tidal rivers has harmed estuarine habitat: estuary community structure, water chemistry, food webs, and loss of freshwater and estuary habitats. Since 1950, the catch of fishes associated with coral reefs has declined by 60% per unit of effort. Ever growing human populations and acidity have significantly impacted fish diversity. The literature reviewed unequivocally demonstrated how anthropogenic effects have altered ichthyofauna and reduced biodiversity in aquatic environments around the globe. Identifying current and potential habitat hazards and the conservation and improvement actions required to eliminate or minimise those concerns is crucial in determining important fish habitats.

Glacier loss and vegetation expansion alter organic and inorganic carbon dynamics in high-mountain streams

Abstract. High-mountain ecosystems are experiencing the acute effects of climate change, most visibly through glacier recession and the greening of the terrestrial environment. The streams draining these landscapes are affected by these shifts, integrating hydrologic, geologic, and biological signals across the catchment. We examined the organic and inorganic carbon dynamics of streams in four Alpine catchments in Switzerland to assess how glacier loss and vegetation expansion are affecting the carbon cycle of these high-mountain ecosystems. We find that the organic carbon concentration and fluorescence properties associated with humic-like compounds increase with vegetation cover within a catchment, demonstrating the increasing importance of allochthonous dissolved organic carbon sources following glacier retreat. Meanwhile, streams transitioned from carbon dioxide sinks to sources with decreasing glacier coverage and increased vegetation coverage, with chemical weathering and soil respiration likely determining the balance. Periods of sink behavior were also observed in non-glaciated streams, possibly indicating that the chemical consumption of carbon dioxide could be more common in high-mountain, minimally vegetated catchments than previously known. Together, these results demonstrate the dramatic shifts in carbon dynamics of high-mountain streams following glacier recession, with significant changes to both the organic and inorganic carbon cycles. The clear link between the terrestrial and aquatic zones further emphasizes the coupled dynamics with which all hydrologic and biogeochemical changes in these ecosystems should be considered, including the carbon sink or source potential of montane ecosystems.

Elevational patterns of trait composition and functional diversity of stream macroinvertebrates in the Hengduan Mountains region, Southwest China

Stream ecosystems in high-mountain regions are susceptible to rapid environmental change, including warming and increased human activities. Understanding elevational patterns of stream communities and underlying drivers can facilitate the development of efficient conservation and management strategies to mitigate the impacts of these changes. Our study investigated elevational patterns of macroinvertebrate trait composition and functional diversity in six streams in the Hengduan Mountains region, Southwest China, which was recognized as one of the global biodiversity hotspots. We were particularly interested in untangling the effects of watershed human disturbance and instream physicochemical factors on elevational patterns of stream macroinvertebrates. Our results showed clear elevational patterns in both trait composition and functional diversity of macroinvertebrate communities. For trait composition, the results indicated that macroinvertebrate traits associated with mobility, habit, and feeding mode exhibited clear elevational patterns. For functional diversity, functional richness showed a positive correlation with elevation, whereas functional divergence had the opposite trend. No significant elevational pattern was detected in functional evenness and RaoQ. Further analyses found that weak human disturbance was the most important driver shaping trait composition and functional diversity of macroinvertebrates. Meanwhile, instream water temperature, primary productivity, and flow velocity also played considerable roles. Our study emphasizes the influence of watershed human disturbance on elevational patterns of macroinvertebrates in high-mountain streams. It also highlights the potential of trait composition and function diversity of macroinvertebrates as indicators for monitoring the ecological status of high-mountain streams.

Comments on the distribution and population estimation of Neurergus derjugini (Urodela, Salamandridae) in western Iran

Basic knowledge of population status is effective for the conservation of many species, especially threatened and endangered species. In this study, we used the Mark-recapture technique (Linconln-Petersen method) as an established method for estimating population in wildlife surveys. Population surveys of critically endangered newts conducted for Neurergus derjugini in the streams of Kurdistan and Kermanshah Provinces, western Iran, at Sarvabad, Marivan, Baneh, Saghez and Nosoud. The study consists of estimating population size by sampling annually for two consecutive years (2018-2019) with each annual sampling consisting of several surveys between May-August. The species has a restricted distribution, occurring at high mountain streams. Our results also reject the occurrence of this species in Sarvabad and Awraman stream habitats and water ecosystems as was stated by former researchers. Distribution information of this species was updated in the region, and all known records are mapped. The results showed that Miri Sour (Marivan) with 1591-1568 and Asnabad (Marivan) with 14-18 specimens as estimated populations were found as most and less populated and suitable habitats respectively.

Divergent nucleic acid allocation in juvenile insects of different metamorphosis modes

Nucleic acids help clarify variation in species richness of insects having different metamorphosis modes, a biological conundrum. Here we analyse nucleic acid contents of 639 specimens of aquatic insects collected from four high mountain streams of Sierra Nevada in southern Spain to test whether the allocation to RNA or DNA content differs during ontogeny between juvenile insects undergoing direct (hemimetabolous) or indirect (holometabolous) metamorphosis. The results show that RNA content as a function of body mass was negatively correlated to insect body length in four out of six and three out of six of the holometabolan and hemimetabolan taxa, respectively. Although no significant differences in RNA content were found between holometabolans and hemimetabolans, the significant interaction between body length and metamorphosis mode for RNA and RNA:DNA indicates a strong ontogenetic component to RNA allocation. In addition, our finding of lower DNA content in holometabolans relative to hemimetabolans agree with the analysis of empirical genome data in aquatic and terrestrial insects, and extend to this class of arthropods the “growth rate-genome size-nutrient limitation” hypothesis that differences in allocation between RNA and DNA may reflect fundamental evolutionary trade-off of life-history strategies associated with high growth rates (and RNA content) in holometabolans at the expense of diminished genome sizes.

The effects of dispersal ability on metacommunity structure of macroinvertebrates in subtropical Chinese high-mountain streams: seasonal shifts in relative contribution of local environment and spatial processes.

It is generally recognized that dispersal mode can affect the relative role of environmental and spatial factors in structuring biotic communities. Disentangling the effects of dispersal mode on metacommunity structuring is essential to understanding the mechanisms of community assembly. Despite high seasonal variation in assemblage structure and phenological features of lotic macroinvertebrates, few studies examined the seasonal changes in the relative contribution of environmental and spatial processes. Here, we used two-season (spring and autumn) investigation data to link dispersal mode with local environmental and spatial factors that regulate macroinvertebrate metacommunity in a Chinese high-mountain stream network. Our aims were (1) to disentangle the relative role of environmental and spatial processes on structuring macroinvertebrate with different dispersal ability (aquatic passive: AqPa, terrestrial passive: TePa, and terrestrial active: TeAc) and (2) to determine seasonal shifts in metacommunity structuring processes. We found that assemblages of TeAc (with highest dispersal capacity) in both seasons were influenced more by environmental filtering than spatial structuring, whereas assemblages of TePa were mainly determined by spatial processes. Unexpectedly, AqPa group showed low spatial control in both seasons, probably due to their underestimated dispersal capacity via animal vector. The relative role of environmental and spatial factors was broadly stable across two seasons for AqPa and TeAc groups, but the TePa showed seasonal differences in the relative role of spatial factors, because of their seasonally changing dispersal capacity. In summary, our study emphasizes the use of dispersal mode for understanding metacommunity structuring mechanisms.

Watershed farmland area and instream water quality co-determine the stream primary producer in the central Hengduan Mountains, southwestern China

As the main primary producer in stream ecosystems, periphyton is the fundamental of stream ecosystems and plays an essential role in maintaining stream biodiversity. The central Hengduan Mountains is one of the famous global biodiversity hotspots. However, for stream biodiversity conservations, the fundamental information about the spatial pattern of stream periphyton and the determining factors in this region remains largely unknown. To fill this gap, we investigated the spatial pattern of periphyton biomass (measured by chlorophyll a) in four typical streams in the central Hengduan Mountains and analyzed the driving factors, with the perspective of watershed land use and instream water quality. The results of our study found that farmland area, instream dissolved silicate (DSi), and water temperature (WT) had significant negative relationships with the stream periphyton biomass in the central Hengduan Mountains. However, the dissolved inorganic phosphorus (DIP) and dissolved inorganic nitrogen (DIN) had non-significant effects on the periphyton biomass in our study. Further analysis showed that the correlation between the ratio of farmland in the catchment and the DSi is non-significant (r = 0.028, P = 0.698), suggesting that the changes in farmland area will not affect the concentration of dissolved silicate in the stream. This reveals that the stream periphyton biomass was co-determined by the watershed farmland area and instream DSi and WT, but not nitrogen or phosphorus. These results highlight the importance of farmland management and instream DSi for stream ecosystems in the central Hengduan Mountains. Our study investigated the spatial pattern of the stream primary producer in the central Hengduan Mountains region and identified the main determining factors, which could improve our understanding of the high mountain stream ecosystems.

Optimised biomolecular extraction for metagenomic analysis of microbial biofilms from high-mountain streams.

Glacier-fed streams (GFS) are harsh ecosystems dominated by microbial life organized in benthic biofilms, yet the biodiversity and ecosystem functions provided by these communities remain under-appreciated. To better understand the microbial processes and communities contributing to GFS ecosystems, it is necessary to leverage high throughput sequencing. Low biomass and high inorganic particle load in GFS sediment samples may affect nucleic acid extraction efficiency using extraction methods tailored to other extreme environments such as deep-sea sediments. Here, we benchmarked the utility and efficacy of four extraction protocols, including an up-scaled phenol-chloroform protocol. We found that established protocols for comparable sample types consistently failed to yield sufficient high-quality DNA, delineating the extreme character of GFS. The methods differed in the success of downstream applications such as library preparation and sequencing. An adapted phenol-chloroform-based extraction method resulted in higher yields and better recovered the expected taxonomic profile and abundance of reconstructed genomes when compared to commercially-available methods. Affordable and straight-forward, this method consistently recapitulated the abundance and genomes of a mock community, including eukaryotes. Moreover, by increasing the amount of input sediment, the protocol is readily adjustable to the microbial load of the processed samples without compromising protocol efficiency. Our study provides a first systematic and extensive analysis of the different options for extraction of nucleic acids from glacier-fed streams for high-throughput sequencing applications, which may be applied to other extreme environments.

Metacommunity Structures of Macroinvertebrates and Diatoms in High Mountain Streams, Yunnan, China

The metacommunity concept has received increasing interest in the past two decades. However, there has been limited research examining metacommunity structure of communities in high mountain streams. These ecosystems are often physically constrained and can display large environmental gradients within a relatively small spatial extent. Here, we examined metacommunity structures of stream organisms in a high mountain region, which is part of the Hengduan Mountains region in the Southwest China. Macroinvertebrates and diatoms were collected from six streams in two opposite aspects of the same mountain with different connectivity between streams. On the west aspect, streams are tributaries of a river (i.e. river-connected) while streams flow into a lake (i.e. lake-connected) on the east aspect. We used Elements of Metacommunity Structure analysis to explore the metacommunity structuring of these two biological models. We also compared the contribution of dispersal and environmental filtering in structuring metacommunities by looking at Euclidean, network, topographic, and environmental distances. Communities of diatoms and macroinvertebrates were structured with clear turnover on both aspects. Further, diatom communities exhibited Clementsian structure on both aspects. Macroinvertebrates exhibited different metacommunity structures on the river-connected aspect (Quasi-Clementsian) and lake-connected aspect (Clementsian). Our results indicated that on the lake-connected aspect, environmental filtering had a stronger association with community dissimilarity than on the river-connected aspect for both macroinvertebrate and diatom communities. Diatom communities were more influenced by environmental filtering on the east aspect with weakened network connectivity compared with those on the west aspect. Our results also emphasized the potential effects of biotic interactions between macroinvertebrates and diatoms on shaping community structures of one other. Given that high mountain streams are scarcely examined, our study provides substantial elements to further understand metacommunity structure and highlights the necessity of future research to reveal the underlying mechanisms of community structuring in these remote ecosystems.

Body P content increases over ontogeny in hemimetabolous macroinvertebrates in a Mediterranean high mountain stream

Differences in elemental stoichiometry among consumers can regulate fundamental ecological processes such as animal production or nutrient cycling within ecosystems. Research to date has established that consumer stoichiometry differs within and across taxa, but the degree to which organismal stoichiometry ranges ontogenetically across life stages or body sizes is poorly understood. To understand patterns of variation in organismal C:N:P stoichiometry, we analyzed the elemental carbon (C), nitrogen (N) and phosphorus (P) composition of 436 aquatic macroinvertebrates across the ontogeny of 13 taxa representing different life history strategies and developmental modes in a high mountain stream. Our results showed that C:N:P stoichiometry varied among taxonomic groups, macroinvertebrate taxa, but not among functional feeding groups. However, stoichiometric variability within taxa was comparable or exceeded those among taxa and was primarily caused by changes in P content. We found undocumented positive relationships between P content and body mass in hemimetabolous taxa, with %P increments ranging from five to eightfold across ontogeny. Overall, findings lend evidence to the idea that phylogenetic relationships may be an important but secondary determinant of C:N:P stoichiometry relative to ontogeny. Elucidating the mechanistic basis for the positive relationship between body mass and P content in hemimetabolous taxa may reveal fundamental differences in the ecology and evolutionary pressure behind hemi- versus holometabolous developmental modes in nature.

Mobile Elements in Ray-Finned Fish Genomes.

Ray-finned fishes (Actinopterygii) are a very diverse group of vertebrates, encompassing species adapted to live in freshwater and marine environments, from the deep sea to high mountain streams. Genome sequencing offers a genetic resource for investigating the molecular bases of this phenotypic diversity and these adaptations to various habitats. The wide range of genome sizes observed in fishes is due to the role of transposable elements (TEs), which are powerful drivers of species diversity. Analyses performed to date provide evidence that class II DNA transposons are the most abundant component in most fish genomes and that compared to other vertebrate genomes, many TE superfamilies are present in actinopterygians. Moreover, specific TEs have been reported in ray-finned fishes as a possible result of an intricate relationship between TE evolution and the environment. The data summarized here underline the biological interest in Actinopterygii as a model group to investigate the mechanisms responsible for the high biodiversity observed in this taxon.

Disturbances in coarse bedload transport in a high-mountain stream channel system (Western Tatras, Poland)

Bedload transport measurements in the formerly glaciated Chochołowski catchment located in the Western Tatras in Poland were performed in the period 1975 to 2018. Measurement of bedload displacement allowed to determine the role of bedload transport disturbances in both system connectivity and sediment transfer. Bedload transport occurred as many as triggered up to several times a year. The longest distances were observed during rain-on-snow events: between 12 m in headwaters and over 100 m in the fluvial valley. Bedload became activated along the entire length of the channel system (10.5 km) every 2 to 5 years when the stream discharge exceeded 10 m3 s−1 (with an average of 1.25 m3 s−1). In such situations, bedload dynamics increased downstream, and stream power was sufficient to overcome local barriers (i.e. boulder and log steps). Downstream increases in bedload dynamics may become disturbed and inverted by sudden snowmelt and locally heavy rainfall. These types of events caused the dynamics of bedload transport to be 190% to 320% greater in the upper part of the studied catchment and to decline in the downstream direction over a distance of 7 km to yield an attenuation effect. The same pattern was observed in local tributaries where the dynamics of bedload transport were 200% higher in the upper part and attenuation was observed along a distance of 1.5 km in the downstream direction. All events of this type cause seasonal disturbances in bedload transport. However, the greatest effect on bedload dynamics was produced by natural deforestation. A 16% decrease in forest cover causes a fluvial system disequilibrium manifested in an intensification of hydro-geomorphologic processes and formation of new landforms.

Elevation shapes biodiversity patterns through metacommunity-structuring processes

Stochastic (e.g., via species dispersal and ecological drift) and deterministic (e.g., via environmental and biotic filtering) processes can produce diversity patterns related to changes in elevation. However, existing studies have not generally examined these processes within a compressive framework. Stream macroinvertebrates are an important and diverse component of freshwater environments in high-mountain systems. By considering metacommunity-structuring processes using Hierarchical Modelling of Species Communities (HMSC), we investigated changes in taxon richness of stream macroinvertebrates along elevational gradients in streams of the Cangshan mountain range in Southwest China. We found that increasing taxon richness along the elevation gradient until the optimum was reached could be modeled using the integrated actions of full structuring processes within the metacommunity modeling. Consistent increases in taxon-richness along the elevation gradient were able to be modeled considering environmental filtering alone. In addition, the importance of structuring processes on shaping communities decreased along spatial hierarchical-scales (from local habitat to mountain-aspect levels). These results suggest that stochastic and biotic-filtering processes can confound environmental filtering in shaping macroinvertebrate communities in high-mountain streams. A comprehensive understanding of the mechanisms underlying elevational biodiversity patterns of riverine communities can be improved through quantitative frameworks (e.g., HMSC) linking metacommunity theory to the real-world systems.

Distribution and Population Structure of Ambystoma altamirani from the Llano de Lobos, State of México, Mexico

Ambystoma altamirani is an endangered salamander found in high mountain streams in the vicinity of México City, and its populations might be threatened by urban growth. Here we report our research on a previously unstudied population of A. altamirani at the Llano de Lobos in the Sierra de las Cruces. The study ran from September 2018 to September 2019. The number of observed individuals was relatively constant across months. The only months when we observed gilled adults were February and July, and the only months when we saw juveniles without gills were January, February, and August, suggesting that the transformation of juveniles to adults takes place twice a year, once in January–February and once in July–August. We observed egg masses in December and January, and larvae from March to May and also in July. The sex ratio was significantly female-biased (about 2:1). We observed A. altamirani at 3 of the 25 permanent sites during the study period. Our comparison of the characteristics of occupied sites with those of unoccupied sites suggests that availability of sunlight (i.e., less cover) and low levels of human impact are important for occupancy by A. altamirani. These findings are consistent with observations of other populations of A. altamirani, suggesting that these characteristics might be important in their management and conservation.

Sediment budget of high mountain stream channels in an arid zone (High Atlas mountains, Morocco)

In an arid zone the sediment budget is predominantly dependent on runoff, which is controlled mainly by the type of rainfall. Sediment budget calculation is one of the indirect methods of estimating channel morphodynamics. This method is advised here since it is not possible to directly measure this important hydrological indicator of environmental dynamics. This is because in small mountain catchments of an arid zone it is impossible to obtain flow rates due to factors such as the amount and size of transported rock debris, as well as the episodic and sudden nature of precipitation events. The research was conducted in 3 catchments (2.95 km2, 7.39 km2, 22.73 km2) situated within the boundaries of the basin of the upper Dades, on the southern slopes of the High Atlas in Morocco. The rivers of these catchments, tributaries to a trunk river Dades, are ephemeral and mostly bedrock depending on lithology of the geology. Three automatic weather stations were installed there. Precipitation events ≥ 10 mm (51 rains in 3 catchments) were used in the analysis. Simple rainfall typology (3 types) was devised for these events. During the research period seasonally repeated (6 times) measurements of topography were obtained from 21 cross-section profiles of streams of different order. These measurements formed a basis for calculating both the intensity of flow in ephemeral rivers (max 69,6 m/s) and the sediment budget. In 70% of analysed channel cross-sections erosion was dominant. The average change of the surface area of the cross-section profile is −82%. The maximum seasonal (between measurements) enlargement of the surface cross-section (erosion) is as high as 128%. The lower catchment, which is predominantly composed of conglomerates, distinctly shows the slightest changes of the cross-section profile surfaces, max 24%. The average volume of channel material displaced at the measurement point is 1.07 m3 (max 9.81 m3). There is evidence that not only high intensity rains, but also less intense but longer lasting rains, amounting to high precipitation totals (type C), may result in the highest channel sediment budgets. Differences between a catchment lithology composed of limestones and marlstones and that composed of conglomerates have only a minor impact on sediment budgets in the first and second order channels, whereas in the channels of the third and fourth order this impact is much higher. It was found that sediment budgets calculated for individual channels were higher for the catchments composed of limestones and marlstones, than for those composed of conglomerates, even though the catchments of different lithology may have had the same number of tributaries. This suggests that the sediment supply from slopes is comparatively larger in the catchments dominated by limestones and marlstones.

Fruit from the Sands: The Silk Road Origins of the Foods We Eat by Robert N. Spengler III

Reviewed by: Fruit from the Sands: The Silk Road Origins of the Foods We Eat by Robert N. Spengler III Martin Jones Fruit from the Sands: The Silk Road Origins of the Foods We Eat. Robert N. Spengler III. Berkeley: University of California Press, 2019. 392 pp., 32 b&w photos, 1 line drawing, 4 maps. Hardcover and eBook US $35, £29; Paperback US $27, £23. ISBN 9780520379268. Fruits from the Sands is an elegantly written and important book. It launches its account from the most pressing issue of life on earth today—how do we feed nine billion plus people without destroying the very ecosystems upon which we rely to provide that food? How have several millennia of food globalization led to a highly interconnected over dependence on global monocultures? Those questions take us directly to an epicentre of ancient food globalization in Central Asia, where the author has over several years made a significant contribution to primary research. That first-hand experience of research in the area allows his pen to bring the region to life, not as an exotic other, but as a thriving and productive heart of the continent. This wonderful combination of first-hand scientific knowledge, a diverse and eclectic awareness of textual sources, and an engaging writing style is reminiscent of Oliver Rackham (2006). Just as Rackham's books are taken off the shelves and dipped into for a long long time, I anticipate the same will be true of Fruits from the Sands. There is a wealth of timeless insight within, supported by a generous section of endnotes and references. Robert Spengler is a leading archaeobotanist of Central Asia, conducting primary research on physical fragments of ancient food plants recovered from archaeological excavations. The focus of much archaeobotanical research around the world has been upon the beginnings of agriculture, around one or another of the "centres of origin" first identified around a century ago by the pioneer crop geneticist Nikolai Vavilov (1926). Spengler's own focus, and the theme of this book, relates to a subsequent episode when crops moved between the Old World centres of origin some millennia after their original domestication, it is presumed through processes of migration, exchange, and trade. This led to a state of "food globalization" in which economic plants initially from the west and the east, the north and the south, were brought together within the same agricultural and culinary systems, a pattern that was widely in place by the end of prehistory. Economic species originally from China were to be found in Europe and from Southwest Asia in China. Asian crops reached sub-Saharan Africa and crops from each of these geographic regions arrived to enrich South Asian food-ways in the Indus Valley. Both the title and the cover image draw attention to one potential agent—the exotic journeys of merchant caravans across the arid Asian sands in pursuit of Silk Road trade. The text within reveals a richer, older story underpinning that transcontinental contact. Up in the foothills of the Tianshan mountains, in the very heart of Asia, Spengler has been working with archaeologist Michael Frachetti on early sites from a time when life existed in an environment very different from that of the arid sands shown in the foreground of this book's cover image. High mountain streams kept the foothills grassy and animals could [End Page 213] graze. There, herders could plant small plots with hardy grain. At sites like Begash in Kazakhstan, these small-scale herders were exchanging seedcorn with their neighbours, so they were able to consume crops from both east and west Eurasia. What is more, this was taking place a full two thousand years before a series of merchants and armies were accompanied by the creators and narrators of a more prominent and familiar history. All this puts Spengler in an excellent position to review and interrogate the familiar traditional story of Silk Road trade and look back in time through his keen archaeobotanical eye to that history's long prelude. He brings his own expertise and an engaging writing style to the task. Part One offers insight into the region whose history and archaeobotany the author knows...

Powerhouses in the cold: mitochondrial function during thermal acclimation in montane mayflies.

Mitochondria provide the vast majority of cellular energy available to eukaryotes. Therefore, adjustments in mitochondrial function through genetic changes in mitochondrial or nuclear-encoded genes might underlie environmental adaptation. Environmentally induced plasticity in mitochondrial function is also common, especially in response to thermal acclimation in aquatic systems. Here, we examined mitochondrial function in mayfly larvae (Baetis and Drunella spp.) from high and low elevation mountain streams during thermal acclimation to ecologically relevant temperatures. A multi-substrate titration protocol was used to evaluate different respiratory states in isolated mitochondria, along with cytochrome oxidase and citrate synthase activities. In general, maximal mitochondrial respiratory capacity and oxidative phosphorylation coupling efficiency decreased during acclimation to higher temperatures, suggesting montane insects may be especially vulnerable to rapid climate change. Consistent with predictions of the climate variability hypothesis, mitochondria from Baetis collected at a low elevation site with highly variable daily and seasonal temperatures exhibited greater thermal tolerance than Baetis from a high elevation site with comparatively stable temperatures. However, mitochondrial phenotypes were more resilient than whole-organism phenotypes in the face of thermal stress. These results highlight the complex relationships between mitochondrial and organismal genotypes, phenotypes and environmental adaptation. This article is part of the theme issue 'Linking the mitochondrial genotype to phenotype: a complex endeavour'.