Stable Food Sources Research Articles

Technological and Dietary Responses to Holocene Climate Events in the Northern Great Basin

ABSTRACT Environmental instability caused by extended periods of drought no doubt impacted past human populations by limiting economic options and driving changes in social and technological organization. Here we examine two sets of Great Basin sites with occupations spanning the middle and late Holocene droughts: one associated with lowland springs and another with upland springs. We use dietary markers retrieved via starch granule analysis to evaluate whether artifact form relates to resources processed, how changes in tool form might be related to past changes in climate, environment, and social organization, and what, if any, differences mark upland vs. lowland resource use. Our data suggest that changes in tool form track with environmental fluctuations and that in both upland and lowland settings diets focused primarily on tubers and high-return seeds and that these profitable and stable food sources likely anchored populations during periods of drought.

Relative Expression of a Salinity Stress‐Responsive Na+/H+ Exchanger (NHX) in Root and Leaf Tissues of the African Leafy Vegetable, Amaranthus dubius

ABSTRACTAmaranthus dubius, an African leafy vegetable (ALV), is an easy‐to‐grow, annual shrub and a highly nutritious food source, containing elevated levels of essential nutrients in the leaves. Many ALVs, including A. dubius, can tolerate salinity stress, enabling their cultivation on marginal land. However, the widespread propagation of A. dubius as a stable food source has thus far not been realised due partially to the high frequency at which hybridisation occurs, resulting in high genotypic and phenotypic variability. Therefore, to increase the agricultural output capacity of this species on salt‐affected marginal lands, it is important to screen, select and then clonally propagate the identified salinity‐tolerant genotypes to ensure true‐to‐type fidelity in the regenerated population. It is also important, thereafter, to elucidate their underlying gene expression of the stress response. The present study exposed 4‐week‐old A. dubius seedlings to 100, 200 and 400 mM NaCl to determine their degree of salt tolerance. Genotypes were then screened, selected and clonally propagated through cuttings, based on high growth rates and biomass, and salt tolerance. Generally, growth and physiological parameters decreased as substrate salinity increased. However, individual salt‐stressed genotypes demonstrated similar vigour to nonstressed plants and were able to maintain total protein and chlorophyll concentrations despite increasing salinity. The relative expression of an NHX1‐like transcript was quantified in 15 genotypes using degenerately primed real‐time qPCR. The relative expression of the putative NHX1 gene was 6.7 times greater in root tissues of seedlings treated with 400 mM NaCl (10.7 ± 1.8) compared to the roots of untreated seedlings (1.6 ± 1.3), and 2.8‐fold more than leaf tissues harvested from seedlings treated with 400 mM NaCl. Furthermore, the relative electrical conductivity (EC) of root tissues was 10 times greater than the EC of leaf tissues from the same 400 mM NaCl treatment. Numerous genotypes yielded similar chlorophyll content between 200 and 400 mM NaCl treatments, with genotypes salinity‐1 (S1) (3.5 ± 0.2 μg/cm2) and S34 (4.0 ± 0.4 μg/cm2) having the highest concentrations of chlorophyll in the 400 mM group, which was positively correlated with total protein content. Following micropropagation through direct organogenesis, selected clones maintained true‐to‐type traits such as similar chlorophyll, protein and NHX1‐like expression as their parent plants when exposed to 400 mM NaCl. This study revealed that some genotypes demonstrated salt stress tolerance capabilities rivalling established halophytes by regulating the constitutive or inducible expression of an NHX1‐like protein in roots and leaves. The correlation between protein content and NHX1‐like expression was nonlinear and nonproportional, demonstrating the complexity of this response and necessitating further exploration of specific protein families or functional groups conferring salinity tolerance in this species.

A new genomics tool for monitoring Arctic char (Salvelinus alpinus) populations in the Lower Northwest Passage, Nunavut

Harvesting from admixed populations is a common practice in contemporary fisheries. However, monitoring stock health in such mixed-stock fisheries remains challenging, with accurately identifying stock composition a critical first step. Fortunately, genetic tools have improved our ability to quantify stock composition (“genetic stock identification” or GSI). A commercial Arctic char (Salvelinus alpinus) fishery has been proposed for the King William Island region of the Lower Northwest Passage (LNWP), Nunavut, Canada, an area that heretofore has had only subsistence fisheries. Previous studies identified two major char genetic clusters in this region with evidence of stock mixing in some rivers and estuaries. We developed a panel of 181 autosomal single nucleotide polymorphisms and one sex marker using Genotyping-in-Thousands by sequencing (GTseq) to facilitate GSI and sex identification and contribute to development of a sustainable fishery. Applying population genetics and population assignment tests to a pilot set of 48 samples, our panel proved effective in GSI with an assignment success rate of 95.8–100%, and in sex determination with a success rate of 93.6%. Our panel of 182 markers provides a cost- and time-efficient means to perform GSI and sex identification in char in the LNWP, which in turn can be used for effective, continuous monitoring of Arctic char in this region. Collectively, a sustainable Arctic char fishery could bring both long-term revenue and a stable food source to the Inuit community of Gjoa Haven.

Sheep for the soldiers: Stable isotope evidence for sheep management at the Shichengzi fort, Xinjiang and its implications for Han frontier interaction

The territorial expansion of the Han dynasty (202BC – 220AD) created sizeable borderlands, catalyzing interactions between Han military and indigenous communities. At the northwestern periphery of the empire in modern day Xinjiang, military economy reflects the interplay between Han agricultural and indigenous pastoral subsistence. In this study, we sequentially sampled sheep teeth enamel for carbon and oxygen analyses at Shichengzi, a Han dynasty military fort in Xinjiang, attempting to reconstruct the life history of these animals and hence investigate local herding strategies. The sheep isotopic profiles imply that these animals might have been transported to Shichengzi from various locations. Winter foddering and vertical transhumance were the two critical strategies employed to manage Shichengzi’s flocks. While most sheep grazed seasonally along the altitude, a portion of the sheep population were closely managed within the fort, provided with fodder all year round. Seasonal lambing concentrated births in the spring and autumn in an effort to increase livestock survivorship. The variation in sheep isotope profiles denotes an inter-dependent system of provisioning at Shichengzi, where a stable food source could be maintained and relations between border garrisons and local communities actively manipulated. This adaptive military economy was mostly the product of the complex interplay between military demand, the inherent advantages in the indigenous economy and the constraints of the local environment.

No fry zones: How restaurant distribution and abundance influence avian communities in the Phoenix, AZ metropolitan area.

Urbanization is one of the most widespread and extreme examples of habitat alteration. As humans dominate landscapes, they introduce novel elements into environments, including artificial light, noise pollution, and anthropogenic food sources. One understudied form of anthropogenic food is refuse from restaurants, which can alter wildlife populations and, in turn, entire wildlife communities by providing a novel and stable food source. Using data from the Maricopa Association of Governments and the Central Arizona-Phoenix Long Term Ecological Research (CAP LTER) project, we investigated whether and how the distribution of restaurants influences avian communities. The research aimed to identify restaurants, and thus the associated food they may provide, as the driver of potential patterns by controlling for other influences of urbanization, including land cover and the total number of businesses. Using generalized linear mixed models, we tested whether the number of restaurants within 1 km of bird monitoring locations predict avian community richness and abundance and individual species abundance and occurrence patterns. Results indicate that restaurants may decrease avian species diversity and increase overall abundance. Additionally, restaurants may be a significant predictor of the overall abundance of urban-exploiting species, including rock pigeon (Columba livia), mourning dove (Zenaida macroura), and Inca dove (Columbina Inca). Understanding how birds utilize anthropogenic food sources can inform possible conservation or wildlife management practices. As this study highlights only correlations, we suggest further experimental work to address the physiological ramifications of consuming anthropogenic foods provided by restaurants and studies to quantify how frequently anthropogenic food sources are used compared to naturally occurring sources.

High-LD SNP markers exhibiting pleiotropic effects on salt tolerance at germination and seedlings stages in spring wheat

Key messageSalt tolerance at germination and seedling growth stages was investigated. GWAS revealed nine genomic regions with pleiotropic effects on salt tolerance. Salt tolerant genotypes were identified for future breeding program.With 20% of the irrigated land worldwide affected by it, salinity is a serious threat to plant development and crop production. While wheat is the most stable food source worldwide, it has been classified as moderately tolerant to salinity. In several crop plants; such as barley, maize and rice, it has been shown that salinity tolerance at seed germination and seedling establishment is under polygenic control. As yield was the ultimate goal of breeders and geneticists, less attention has been paid to understanding the genetic architecture of salt tolerance at early stages. Thus, the genetic control of salt tolerance at these stages is poorly understood relative to the late stages. In the current study, 176 genotypes of spring wheat were tested for salinity tolerance at seed germination and seedling establishment. Genome-Wide Association Study (GWAS) has been used to identify the genomic regions/genes conferring salt tolerance at seed germination and seedling establishment. Salinity stress negatively impacted all germination and seedling development parameters. A set of 137 SNPs showed significant association with the traits of interest. Across the whole genome, 33 regions showed high linkage disequilibrium (LD). These high LD regions harbored 15 SNPs with pleiotropic effect (i.e. SNPs that control more than one trait). Nine genes belonging to different functional groups were found to be associated with the pleiotropic SNPs. Noteworthy, chromosome 2B harbored the gene TraesCS2B02G135900 that acts as a potassium transporter. Remarkably, one SNP marker, reported in an early study, associated with salt tolerance was validated in this study. Our findings represent potential targets of genetic manipulation to understand and improve salinity tolerance in wheat.

Machine learning in crop yield modelling: A powerful tool, but no surrogate for science

Provisioning a sufficient stable source of food requires sound knowledge about current and upcoming threats to agricultural production. To that end machine learning approaches were used to identify the prevailing climatic and soil hydrological drivers of spatial and temporal yield variability of four crops, comprising 40 years yield data each from 351 counties in Germany. Effects of progress in agricultural management and breeding were subtracted from the data prior the machine learning modelling by fitting smooth non-linear trends to the 95th percentiles of observed yield data. An extensive feature selection approach was followed then to identify the most relevant predictors out of a large set of candidate predictors, comprising various soil and meteorological data. Particular emphasis was placed on studying the uniqueness of identified key predictors. Random Forest and Support Vector Machine models yielded similar although not identical results, capturing between 50% and 70% of the spatial and temporal variance of silage maize, winter barley, winter rapeseed and winter wheat yield. Equally good performance could be achieved with different sets of predictors. Thus identification of the most reliable models could not be based on the outcome of the model study only but required expert's judgement. Relationships between drivers and response often exhibited optimum curves, especially for summer air temperature and precipitation. In contrast, soil moisture clearly proved less relevant compared to meteorological drivers. In view of the expected climate change both excess precipitation and the excess heat effect deserve more attention in breeding as well as in crop modelling.

Morphology of male reproductive organs of the rice field crab Esanthelphusa nani (Naiyanetr, 1984) (Brachyura, Gecarcinucidae)

Abstract The rice field crab is considered a pest that disrupts rice production in paddy fields in tropical regions. The crab is also used as a stable food source by local people in many countries in Southeast Asia. For both of these roles, a good knowledge of the crab’s reproductive biology is necessary to manage populations in their natural habitats. This study aims to investigate the reproductive cycle of adult males of the rice field crab Esanthelphusa nani (Naiyanetr, 1984). Males crabs were sampled monthly in a paddy field; individuals were then anaesthetized and dissected, and their reproductive tract was analysed. The gonadosomatic index (GSI) was evaluated based on the relative weight of the reproductive tract and body weight. The male GSI showed significant temporal difference, with the highest levels in June, August and September. Based on GSI and macroscopic examination, the testis and vas deferens can be classified into three stages of increasing size: (1) resting stage, (2) developing stage and (3) active stage. Microscopic examination revealed that the testis and vas deferens had a tubular structure. Seminiferous tubules in the testis underwent spermatogenesis and spermiogenesis at every stage. The vas deferens consisted of three major regions: anterior, middle and posterior, which showed different types of epithelia. Interestingly, the microscopic structure of the vas deferens was similar among these three reproductive stages. It is also important to note that round-shaped spermatozoa were found in different parts of the reproductive tract, including the seminiferous tubule and vas deferens, as well as in the female seminal receptacle, whereas no spermatophores were found in this species. Overall, this study shows that mature sperms can be found in the reproductive tract of male E. nani throughout the year, indicating that males have prolonged spermatogenic activities.

Energy assessment of different rice–wheat rotation systems

AbstractFood and energy security are important issues that threaten human survival and development. The rice–wheat rotation system provides a stable source of food for more than 20% of the world's population, but there have been no reports on the energy balance of different rice–wheat rotation systems. This study evaluates the energy inputs and outputs of three rice–wheat rotation systems and their energy production efficiency through the study of dry direct‐seeded, wet direct‐seeded, and transplanted rice–wheat rotation systems. The results of the study showed that the average total energy inputs in the dry direct‐seeded, wet direct‐seeded, and transplanted rice–wheat rotation systems were 58,677, 74,083, and 69,022 MJ ha−1, respectively. The production resources with more energy input in rice–wheat rotation system were all related to water and fertilizer. The energy input in the rice season accounts for more than 50.69% of the total energy input in the rice–wheat rotation system. At the same time, rice–wheat rotation production is highly dependent on nonrenewable energy. Among the three rice–wheat rotation systems, the transplanted rice–wheat rotation system had the highest total energy output and net energy, while the dry direct‐seeded rice–wheat rotation had the highest energy use efficiency, energy productivity, energy profitability, and human energy profitability. The results showed that the key to reducing the energy input in the rice–wheat rotation system is to reduce the amount of water and fertilizer. The transplanted rice–wheat rotation system is more suitable for promotion in rice–wheat rotation production areas with good irrigation conditions, while the dry direct‐seeded rice–wheat rotation system is highly compatible with the current development direction of low energy consumption and high energy efficiency in agricultural production and is suitable for promotion in rice–wheat production areas with poor irrigation conditions.

Pine wilt disease and feeding conditions of Japanese squirrels (<i>Sciurus lis</i>) in mountainous green areas where Japanese black pine and Japanese red pine grow

A study was conducted to examine the prevalence of pine wilt disease and the feeding conditions of the Japanese squirrels (Sciurus lis) in mountainous green areas where Japanese black pine and Japanese red pine grow. This study aimed to explore conservation measures for Japanese squirrels and the green areas. Here, we determined that Japanese squirrels clearly preferred Japanese black pine trees in the target area. Feeding remains were visible on black pine trees throughout the study period. Pine cones served as a stable food source for the Japanese squirrels throughout the year. On the other hand, it was shown that pine wilt disease affects the feeding of squirrels. Considering this result and the prevalence of pine wilt disease, it would be appropriate to grow multiple trees in the same place rather than planting isolated trees. This strategy would facilitate the efficient preservation of the pine trees used by the Japanese squirrels and the green areas in which they are located. The lack of pine forests near the target area may lead to a decrease in the local Japanese squirrel population. Therefore, it is necessary to adopt measures to protect the pines, which would simultaneously aid in maintaining the squirrel population.

Feeding habitat of the understory arboreal snail Tikoconus costarricanus (Stylommatophora: Euconulidae) in a tropical montane wet forest, Costa Rica

Introduction: The feeding habitats of land snails are essential for their survival. Some are little known, for example the upper surface of leaves, habitat of tropical arboreal and shrub snails. Objective: To analyze the feeding behavior and preferences in the feeding habitat of the tropical snail Tikoconus costarricanus. Methods: In a humid montane tropical forest in Cartago, Costa Rica, I recorded every 3 to 4 hours the feeding activity and general behavior of individually marked snails on a 2km trail (seven 24-hour visits in May 2010-March 2011). Results: I observed a total of 167 individual specimens and made 781 observations about their behavior and the leaves on which they were found. These snails preferred monocotyledonous leaves with many epiphylls, despite the fact that those leaves were not common in this forest. They avoided ferns, and during the less rainy season, they preferred leaves with many trichomes, although there were few such leaves. On average, they spent 11 hours on each individual leaf and visited two leaves per day. The few snails seen on stems were almost always moving, as opposed to those on the leaf underside. On average they moved a net 65 cm each day. Feeding concentrated around 9:00 am and defecation around 4:20 am. Conclusions: These snails prefer leaves with many epiphylls, where they find good camouflage, moisture and food. The preference for trichomes could be due to mechanical reasons. The lack of seasonality in their behavior may reflect their stable food source in a forest that remains humid year round.

Creation of new varieties of comb-shaped wheat grass (Agropyron pectinatum (Bieb.) Beauv.) as a factor of increasing the efficiency of grass growing in arid conditions

Perennial grasses play the most important role in solving the problem of production of energy-saturated high-protein bulky feed and biologization of agriculture. Perennial grasses are the most affordable and stable source of cheap plant food and a means of preserving soil fertility with intensive farming, which has an anthropogenic negative impact on agroecosystems. Perennial grasses play a special role as a biological means of countering the degradation of biological, water-physical and agrochemical properties of soils, their dehumidification and erosion processes. In arid climates, the most effective species of perennial bluegrass is the comb-shaped Wheatgrass (Agropyron peintforme Roem et Schult.). Compared to two other species used in agricultural practice – Siberian (sand) granary (Agropyron fragile (Roth) P. Candargy) and desert (narrow-leaved) (Agropyron desertorum (Ksch. ex Link.) Schult), the comb-shaped wheat grass is characterized by a wider range of growth, high productivity and environmental plasticity. In the State register of breeding achievements approved for use in Russia as of 2020, only 10 varieties of comb-shaped wheat grass are registered, which limits the effective use of this crop and makes it necessary to intensify breeding work in order to create new varieties with improved economic and useful characteristics. At the Voronezh experimental station, active breeding work is being carried out on perennial grasses to develop new varieties of comb-shaped wheat grass. Currently set up and ready to transfer to a new variety of Pridonskoy, characterized by drought tolerance, high forage and seed productivity and longevity. Thus, when the washed-out slopes were grazed, the abundant participation of the granary in the grass mixture was noted in the third year. From the fifth year, the granary dominated the herbage, and in the 10th-12th year of use, the cenoses were represented only by the granary.

Explosive Radiation of Ant Parasitic Butterflies During the Miocene Aridification of Africa

Extremely spezialized life history strategies are sometimes seen as evolutionary dead-ends. The Afrotropical butterfly genus Lepidochrysops exhibits such a life history. All 137 species are known or assumed to be phyto-predaceous, with caterpillars feeding on plants for the first few instars and later switching to parasitizing ants in the Formicinae, either by consuming ant brood or being fed by the ants through trophallaxis. The only other butterflies that exhibit this phyto-predaceous life history are those in the Palaearctic genus Phengaris (= Maculinea), a group of only a bout 11 species whose caterpillars parasitize ants in the Myrmicinae. We hypothesize that the move into ant nests by species of Lepidochrysops was an adaptive response to the aridification of Africa during the Miocene that facilitated subsequent radiation. Ant colonies have the advantage of providing both shelter from threats like fire and desiccation, as well as a stable food source when vegetation is scarce or unpredictable. To evaluate this hypothesis, we inferred a time-calibrated phylogeny using >400 loci for Lepidochrysops and its closest, non-parasitic relatives. We showed that this clade originated with the emerging Miombo woodlands about 22 million years ago (Mya), and spread to drier biomes as they became available. The diversity of the non-parasitic lineages decreased as aridification intensified around 10 Mya, culminating in an abrupt extinction. In contrast, the phyto-predaceous Lepidochrysops lineage radiated rapidly from around 6.5 Mya when phyto-predation likely evolved, showing the importance of this innovation for diversification and survival during the intensifying aridification of Africa.

The Dietary Importance of Kelp-Derived Detritus to Pelagic and Benthic Consumers along the West Coast of Vancouver Island, Canada

Stable isotope analysis was used to determine the relative dietary importance of kelp-derived detritus to plankton and benthic organisms along a gradient of kelp abundance driven by recovering sea otter populations along the west coast of Vancouver Island (WCVI), Canada. The study used region-specific kelp isotope values (δ13C and δ15N) and season-specific phytoplankton isotope values to model dietary contributions of kelp-derived detritus (KDD). In general, KDD contributions were moderate to high in most plankton size fractions during the summer and decreased during the winter, particularly in the kelp sparse region. Hypothesized regional and spatial (distance from the coast) differences in kelp detritus contributions to zooplankton were not evident. Modeled estimates of the KDD contribution to benthic invertebrates were high (>40%) and independent of the organism size, among regions and between seasons, with the exception of Astraea gibberosa in the kelp abundant region. Local oceanography, natural kelp isotope signature variation, and significant overlap between kelps’ and blooming phytoplankton isotope values led to a large uncertainty in the assessed KDD contributions in benthic organisms. These results highlighted the importance of the KDD as a widespread and stable year-round food source in coastal kelp populated regions.

19세기 이후 러시아의 한반도 주변 조사에 관한 연구: ｢國譯 韓國誌｣를 중심으로

One of the areas of interest that Russian Empire had in Korea was its value as a stable source of food especially beef, as seen in Garin’s travel journal and KOPEИ. Russia named about 200 marine and coastal features of the East Sea via exploration. Most of place names have disappeared, but some remain as marine names near Primorsky state, so toponym users can find those names such as Bukhta Reid Pallada and Zaliv Posiet (Posiet Bay) through Google Earth service. The survey of inland areas seemed to be as an important part as the survey of coastal areas. It is believed that the KOPEИ expresses the direction of the Russian government's interest in Korea. Besides the contents of history, language, administration, and political systems, the contents of the KOPEИ will be sufficiently important enough for geographical research on Korean physical geography, Korea territory, as well as economy and trade until the 19th century.

Composition and assembly of bacterial communities in surface and deeper sediments from aquaculture-influenced sites in Eastern Lake Taihu, China

Although aquaculture provides a stable and high-quality source of food, the environmental effects related to large-scale industrial aquacultural activities have raised concern. To identify the influence of aquacultural activities on sedimentary bacterial communities, we collected surface and deeper sediments from a series of sites subjected to varying intensities of aquacultural activities within Eastern Lake Taihu, China. The associated physicochemical properties were measured, and 16S rRNA gene sequencing was applied to determine the related bacterial communities in sediment. The diversity and composition of bacterial communities within the surface sediments differed significantly from those of the deeper sediment samples. Marked differences were also found between the surface sediments of the aquaculture-influenced and non-aquaculturally influenced sites. More importantly, phylogenetic structure analysis indicated that stochastic processes dominated the assembly of the bacterial communities; yet, the relative contribution of deterministic processes to bacterial community assembly was greater in the aquacultural zones than in the non-aquacultural zones. Furthermore, we identified total phosphorus (TP) as the most important factor driving the assembly of bacterial communities influenced by aquaculture in sediment. These findings provide useful information for ecological assessments and remediation strategies for aquaculture-influenced ecosystems.

To clean or not to clean: Cleaning mutualism breakdown in a tidal environment.

The dynamics and prevalence of mutualistic interactions, which are responsible for the maintenance and structuring of all ecological communities, are vulnerable to changes in abiotic and biotic environmental conditions. Mutualistic outcomes can quickly shift from cooperation to conflict, but it unclear how resilient and stable mutualistic outcomes are to more variable conditions. Tidally controlled coral atoll lagoons that experience extreme diurnal environmental shifts thus provide a model from which to test plasticity in mutualistic behavior of dedicated (formerly obligate) cleaner fish, which acquire all their food resources through client interactions. Here, we investigated cleaning patterns of a model cleaner fish species, the bluestreak wrasse (Labroides dimidiatus), in an isolated tidal lagoon on the Great Barrier Reef. Under tidally restricted conditions, uniquely both adults and juveniles were part‐time facultative cleaners, pecking on Isopora palifera coral. The mutualism was not completely abandoned, with adults also wandering across the reef in search of clients, rather than waiting at fixed site cleaning stations, a behavior not yet observed at any other reef. Contrary to well‐established patterns for this cleaner, juveniles appeared to exploit the system, by biting (“cheating”) their clients more frequently than adults. We show for the first time, that within this variable tidal environment, where mutualistic cleaning might not represent a stable food source, the prevalence and dynamics of this mutualism may be breaking down (through increased cheating and partial abandonment). Environmental variability could thus reduce the pervasiveness of mutualisms within our ecosystems, ultimately reducing the stability of the system.

Food source and feeding habit of Helice tientsinensis from the common reed vegetation in high marsh of Yellow River Delta, China

Investigating the composition of food sources with stable isotope method can provide direct evidence for the top-down control in the coastal wetland. In this study, we examined food source and feeding habit of Helice tientsinensis of common reed (Phragmites australis) vegetation in high marsh of Yellow River Delta. The results showed that the density of crab was (5.5±1.5) ind·m-2, with the behavior of climbing P. australis to feed on the leaves at night. Under the same indoor experimental condition, H. tientsinensis showed feeding preference on fresh leaves of P. aus-tralis. The stable isotope food source analysis showed that the leaves of P. australis were one of the important food sources of H. tientsinensis in the field. There were temporal variations in the proportion of fresh leaves [May: (6.4±4.9)%, July: (5.8±4.9)%, September: (12.5±8.8)%] and dead leaves [May: (12.4±7.8)%, July: (15.5±9.9)%, September: (15.1±9.4)%]. Therefore, H. tientsinensis could inhibit P. australis's growth and affect litter decomposition through feeding disturbance behavior.

Mitogenomics suggests a sister relationship of Relicanthus daphneae (Cnidaria: Anthozoa: Hexacorallia: incerti ordinis) with Actiniaria

Relicanthus daphneae (formerly Boloceroides daphneae) was first described in 2006 as a giant sea anemone based on morphology. In 2014, its classification was challenged based on molecular data: using five genes, Relicanthus was resolved sister to zoanthideans, but with mixed support. To better understand the evolutionary relationship of Relicanthus with other early-branching metazoans, we present 15 newly-sequenced sea anemone mitochondrial genomes and a mitogenome-based phylogeny including all major cnidarian groups, sponges, and placozoans. Our phylogenetic reconstruction reveals a moderately supported sister relationship between Relicanthus and the Actiniaria. Morphologically, the cnidae of Relicanthus has apical flaps, the only existing synapomorphy for sea anemones. Based on both molecular and morphological results, we propose a third suborder (Helenmonae) within the Actiniaria to accommodate Relicanthus. Although Relicanthus shares the same gene order and content with other available actiniarian mitogenomes, it is clearly distinct at the nucleotide level from anemones within the existing suborders. The phylogenetic position of Relicanthus could reflect its association with the periphery of isolated hydrothermal vents, which, although patchy and ephemeral, harbor unique chemosynthetic communities that provide a relatively stable food source to higher trophic levels over long evolutionary timescales. The ability to colonize the deep sea and the periphery of new vent systems may be facilitated by Relicanthus’ large and extremely yolky eggs.

Disentangling the relative influences of global drivers of change in biodiversity: A study of the twentieth-century red fox expansion into the Canadian Arctic.

The poleward range shift of the red fox (Vulpes vulpes)>1,700km into the Arctic is one of the most remarkable distribution changes of the early twentieth century. While this expansion threatens a smaller arctic ecological equivalent, the arctic fox (Vulpes lagopus), the case became a textbook example of climate-driven range shifts. We tested this classical climate change hypothesis linked to an important range shift which has attracted little research thus far. We analysed Canadian fur harvest data from the Hudson's Bay Company Archives (14 trading posts; 1926-1950), testing hypotheses based on changes in summer and winter climates. Summer warming might have triggered a bottom-up increase in ecosystem productivity, while winter warming might have lowered thermal stress, both favouring red fox expansion. Additionally, we evaluated the hypothesis that red fox expansion was driven by the appearance of human sedentary sites (n=110) likely bringing food subsidies into the unproductive tundra. Analysis of red fox expansion chronologies showed that expansion speed was higher during warmer winters. However, the expansions occurred under both cooling and warming trends, being faster during cooler summers in the Baffin Island region. The increasing proportion of red fox in fox fur harvests was best explained by human activity, while generalized linear mixed models also revealed a marginal effect of warmer winters. Generalized additive models confirmed human presence as the most important factor explaining rates of change in the proportion of red fox in fox fur harvests. Using historical ecology, we disentangled the relative influences of climate change and anthropogenic habitat change, two global drivers that transformed arctic biodiversity during the last century and will likely continue to do so during this century. Anthropogenic food subsidies, which constitute stable food sources, facilitated the invasion of the tundra biome by a new mammalian predator and competitor, with long-term consequences that still remain to be understood.