Specific Life History Research Articles

Birds of the World: A global reference for avian life histories and a case study of incompatible taxonomies

Life history accounts and taxonomic monographs are a series of publications covering a higher taxonomic group where each account is a compilation of existing knowledge detailing many aspects of a species life history. These life history accounts are extensively used by researchers, ornithologists and conservationists as a main source for the current state of knowledge of a species. Birds, being one of the more easily seen and studied taxa, have a number of specialized life history accounts where data from a wide variety of disciplines are combined into a single easily accessible resource. The Cornell Lab of Ornithology (CLO) currently manages two of these series focused on different regions of the world, Birds of North America (BNA) and Neotropical Birds (NB). Lynx Edicions has published the Handbook of Birds of the World (HBW), an extensive set of avian monographs covering every species of bird in the world. A recently announced collaboration between CLO and Lynx Edicions provides us with the opportunity to bring together the extreme detail of the life history accounts from Birds of North America with the global coverage of HBW to produce a global, in-depth treatment of every species of bird in the world. The integration of life history information from these existing projects with different underlying taxonomies presents a variety of real-world examples of the challenges to be overcome to bring these life history accounts into alignment and provide the scientific and lay communities with taxonomically accurate and up to date information. The Handbook of Birds of the World currently follows the HBW and BirdLife Taxonomic Checklist v3 (with 11,126 species recognized) while Birds of North America and Neotropical Birds both follow the eBird/Clements checklist of birds of the world: v2018 (with 10,585 species recognized). Of the roughly 11,000 species of birds, nearly 9,500 are direct matches between HBW/BirdLife and Clements at the species or species to subspecies levels. The remaining concept mismatches fall into several basic categories including lump and split differences as well as differences in which subspecies are included or excluded. In this talk we will discuss the challenges we have faced with managing and merging life history accounts where the underlying taxonomies are fundamentally different. With a requirement to ensure that life history accounts remain accurate when the underlying concepts of the original sources differ, we employ a variety of processes, some very labor intensive and some requiring in-depth taxonomic knowledge to produce consolidated species accounts. Existing resources are integral to these type of integrations and in addition to the taxonomies themselves, cross-taxonomy mapping databases such as Avibase are key. Working through this process of consolidating life history accounts highlights the basic need for taxonomic management and publication toolsets built on underlying taxonomic and life history standards. Cross institutional collaboration to produce these toolsets will be key to their development and successful adoption across the biodiversity and taxonomic communities. I will also discuss and propose a set of taxonomic management tools based on taxonomic concepts, some which already exist and are used by bird taxonomists to annually update the Clements Checklist and some which need to be implemented before we can accurately manage and consolidate biodiversity information and the evolving taxonomies on which those data are based.

Coho Salmon Growth in Relation to Natural Turbidity Regimes in a Coastal Stream of Northern California

AbstractWe examined how the growth rate and food consumption of juvenile Coho Salmon Oncorhynchus kisutch varied in relation to natural turbidity regimes in a coastal stream of northern California. Instream sensors were used to continuously monitor the location, turbidity, and temperature exposure of juvenile Coho Salmon fitted with passive integrated transponder tags. We observed that overwinter growth rate and food consumption varied in relation to the duration and magnitude of turbidity and temperature exposure. Growth rate and food consumption were positively associated with low‐to‐moderate turbidity exposures that ranged from >3 NTU to >20 NTU and negatively associated with elevated turbidity exposures that ranged from > 55 NTU to >150 NTU. This shift to negative associations for fish that experienced long exposures at turbidity levels > 55 NTU suggests a threshold for assessing potential risk of impairment. However, our analyses show that the influence of turbidity on consumption and growth rate is complicated by a fish's temperature exposure history, which varies among fish depending on individual movement patterns and duration of residency within different stream reaches. Consequently, Coho Salmon growth reflects the net effect of turbidity, temperature, and other environmental factors that are associated with specific life history patterns. These findings advance our understanding of how natural turbidity regimes may influence Coho Salmon growth and offer insight for assessing biological impairment in streams. Moreover, our findings indicate how knowledge of environmental context is crucial for understanding the applicability of laboratory‐derived turbidity thresholds for fish populations in streams. Such findings corroborate other field‐based studies and add to evidence that laboratory‐derived turbidity thresholds alone may be inadequate predictors of biological impairment to stream fish populations.

Complete mitochondrial genomes of eight seahorses and pipefishes (Syngnathiformes: Syngnathidae): insight into the adaptive radiation of syngnathid fishes

BackgroundThe evolution of male pregnancy is the most distinctive characteristic of syngnathids, and their specialized life history traits make syngnathid species excellent model species for many issues in biological evolution. However, the origin of syngnathids and the evolutionary divergence time of different syngnathid species remain poorly resolved. Comprehensive phylogenetic studies of the Syngnathidae will provide critical evidence to elucidate their origin, evolution, and dispersal patterns.ResultsWe sequenced the mitochondrial genomes of eight syngnathid species in this study, and the estimated divergence times suggested that syngnathids diverged from other teleosts approximately 48.8 Mya during the Eocene period. Selection analysis showed that many mitochondrial genes of syngnathids exhibited significantly lower Ka/Ks values than those of other teleosts. The two most frequently used codons in syngnathid fishes were different from those in other teleosts, and a greater proportion of the mitochondrial simple sequence repeats (SSRs) were distributed in non-coding sequences in syngnathids compared with other teleosts.ConclusionsOur study indicated that syngnathid fishes experienced an adaptive radiation process during the early explosion of species. Syngnathid mitochondrial OXPHOS genes appear to exhibit depressed Ka/Ks ratios compared with those of other teleosts, and this may suggest that their mitogenomes have experienced strong selective constraints to eliminate deleterious mutations.

Sympatric versus allopatric evolutionary contexts shape differential immune response in Biomphalaria / Schistosoma interaction.

Selective pressures between hosts and their parasites can result in reciprocal evolution or adaptation of specific life history traits. Local adaptation of resident hosts and parasites should lead to increase parasite infectivity/virulence (higher compatibility) when infecting hosts from the same location (in sympatry) than from a foreign location (in allopatry). Analysis of geographic variations in compatibility phenotypes is the most common proxy used to infer local adaptation. However, in some cases, allopatric host-parasite systems demonstrate similar or greater compatibility than in sympatry. In such cases, the potential for local adaptation remains unclear. Here, we study the interaction between Schistosoma and its vector snail Biomphalaria in which such discrepancy in local versus foreign compatibility phenotype has been reported. Herein, we aim at bridging this gap of knowledge by comparing life history traits (immune cellular response, host mortality, and parasite growth) and molecular responses in highly compatible sympatric and allopatric Schistosoma/Biomphalaria interactions originating from different geographic localities (Brazil, Venezuela and Burundi). We found that despite displaying similar prevalence phenotypes, sympatric schistosomes triggered a rapid immune suppression (dual-RNAseq analyses) in the snails within 24h post infection, whereas infection by allopatric schistosomes (regardless of the species) was associated with immune cell proliferation and triggered a non-specific generalized immune response after 96h. We observed that, sympatric schistosomes grow more rapidly. Finally, we identify miRNAs differentially expressed by Schistosoma mansoni that target host immune genes and could be responsible for hijacking the host immune response during the sympatric interaction. We show that despite having similar prevalence phenotypes, sympatric and allopatric snail-Schistosoma interactions displayed strong differences in their immunobiological molecular dialogue. Understanding the mechanisms allowing parasites to adapt rapidly and efficiently to new hosts is critical to control disease emergence and risks of Schistosomiasis outbreaks.

The brain of the tree pangolin (Manis tricuspis). IV. The hippocampal formation.

Employing a range of standard and immunohistochemical stains we provide a description of the hippocampal formation in the brain of the tree pangolin. For the most part, the architecture, chemical neuroanatomy, and topological relationships of the component parts of the hippocampal formation of the tree pangolin were consistent with that observed in other mammalian species. Within the hippocampus proper fields CA1, 3, and 4 could be identified with certainty, while CA2 was tentatively identified as a small transitional zone between the CA1 and CA3 fields. Within the dentate gyrus evidence for adult hippocampal neurogenesis at a rate comparable to other mammals was observed. The subicular complex and entorhinal cortex also exhibited divisions typically observed in other mammalian species. In contrast to many other mammals, an architecturally and neurochemically distinct CA4 field was observed, supporting Lorente de Nó's proposed CA4 field, at least in some mammalian species. In addition, up to seven laminae were evident in the dentate gyrus. Calretinin immunostaining revealed the three sublamina of the molecular layer, while immunostaining for vesicular glutamate transporter 2 and neurofilament H indicate that the granule cell layer was composed of two sublamina. The similarities and differences observed in the tree pangolin indicate that the hippocampal formation is an anatomically and neurochemically conserved neural unit in mammalian evolution, but minor changes may relate to specific life history features and habits of species.

Multispecies plant invasion increases function but reduces variability across an understorey metacommunity

Several plant traits have been linked to invasion success in studies involving single alien species or invaded versus non-invaded communities. Less consideration has been given to how invasion by multiple alien species changes community-wide traits and functional structure at landscape scales. Changes to community functional structure by multispecies invasion may have consequences for ecosystem function. Therefore, it is important to identify which traits of naturalized aliens are responsible for optimizing patterns of trait convergence and divergence. Here, we examine if invasion by multiple alien species is related to changes in community-wide functional traits, and patterns of trait convergence and divergence, across an invasion gradient. We collected field data in Victoria, Australia, on traits previously associated with invasion success from 15 × 500 m2 plots. These plots encompassed a range of relative alien cover (~ 3–61%) and represented a multispecies invasion gradient. We tested relationships of each trait to the invasion gradient. We also determined trait convergence and divergence patterns across the gradient, using a trait divergence analysis. Specific leaf area and proportion of annual species significantly increased with the level of invasion. Annual life history and flowering duration maximised trait-convergence, but the two traits had different relationships to the invasion gradient. Specific leaf area, annual life history, leaf dry mass and seed mass maximised trait divergence. Evidence of trait-divergence along the gradient is represented by an increase in functional diversity with invasion level. However, variation in functional diversity was higher in little-invaded communities and stabilised at intermediate and high levels of invasion. Traits (specific leaf area and annual life history) associated with invasion success at a landscape scale are traits promoting rapid life cycle completion, and increases in multispecies invasion leads to an increase in functional diversity but a decline in its variation.

Modeling the effective spawning and nursery habitats of northern pike within a large spatiotemporally variable river landscape (St. Lawrence River, Canada)

AbstractSpawning and nursery habitats are often spatially disjunct as a consequence of specific life history stage habitat requirements and spatiotemporal habitat changes. Nevertheless, free‐swimming larvae originating from spawning habitats must reach productive nurseries to maximize survival. We examined spawning and nursery habitats of northern pike (Esox lucius) over the past 50 yr to investigate how habitat connectivity and hydrological variability interact to alter the distribution of effective spawning habitat. Habitat models coupled to a least‐cost approach were developed to quantify connectivity between habitats in two contrasting regions of the St. Lawrence River (Canada): a riverine corridor lake (~ 46 km) and a large fluvial lake (~ 48 km). Our simulations demonstrate that depending on hydrological conditions, between 3% to 51% of spawning habitat used by adults in the riverine corridor, and 22% to 90% in the lake, allowed larval survival up to the fifth week of development. Although rapid dewatering of spawning habitat is responsible for most spawning losses in the fluvial lake, increasing water currents were responsible for dispersing larvae away from suitable habitats in the riverine corridor. However, stable hydrological conditions led to spatial overlapping of spawning and nursery habitats favoring larval survival and growth. In addition, downstream larval dispersal by low water currents allowed larvae to reach spatially disjunct nursery habitat, especially in the lake. Our results indicate that despite the vast areas of potentially suitable habitats provided by large vegetated floodplains of fluvial lakes, the effective spawning habitats favoring early‐life recruitment are much more heterogeneous and variable both spatially and temporally.

Causes and Consequences of Spatial Within-Host Viral Spread.

The spread of viral pathogens both between and within hosts is inherently a spatial process. While the spatial aspects of viral spread at the epidemiological level have been increasingly well characterized, the spatial aspects of viral spread within infected hosts are still understudied. Here, with a focus on influenza A viruses (IAVs), we first review experimental studies that have shed light on the mechanisms and spatial dynamics of viral spread within hosts. These studies provide strong empirical evidence for highly localized IAV spread within hosts. Since mathematical and computational within-host models have been increasingly used to gain a quantitative understanding of observed viral dynamic patterns, we then review the (relatively few) computational modeling studies that have shed light on possible factors that structure the dynamics of spatial within-host IAV spread. These factors include the dispersal distance of virions, the localization of the immune response, and heterogeneity in host cell phenotypes across the respiratory tract. While informative, we find in these studies a striking absence of theoretical expectations of how spatial dynamics may impact the dynamics of viral populations. To mitigate this, we turn to the extensive ecological and evolutionary literature on range expansions to provide informed theoretical expectations. We find that factors such as the type of density dependence, the frequency of long-distance dispersal, specific life history characteristics, and the extent of spatial heterogeneity are critical factors affecting the speed of population spread and the genetic composition of spatially expanding populations. For each factor that we identified in the theoretical literature, we draw parallels to its analog in viral populations. We end by discussing current knowledge gaps related to the spatial component of within-host IAV spread and the potential for within-host spatial considerations to inform the development of disease control strategies.

Two-tier morpho-chemical defence tactic in Aethionema via fruit morph plasticity and glucosinolates allocation in diaspores.

Fruit dimorphism and the production of glucosinolates (GSLs) are two specific life history traits found in the members of Brassicales, which aid to optimize seed dispersal and defence against antagonists, respectively. We hypothesized that the bipartite dispersal strategy demands a tight control over the production of fruit morphs with expectedly differential allocation of defensive anticipins (GSLs). In dimorphic Aethionema, herbivory by Plutella xylostella at a young stage triggered the production of more dehiscent (seeds released from fruit) than indehiscent fruit morphs (seeds enclosed within persistent pericarp) on the same plant upon maturity. Total GSL concentrations were highest in the mature seeds of dehiscent fruits from Aethionema arabicum and Aethionema saxatile among the different ontogenetic stages of the diaspores. Multivariate analyses of GSL profiles indicated significantly higher concentrations of specific indole GSLs in the diaspores, which require optimal defence after dispersal (i.e., seeds of dehiscent and fruit/pericarp of indehiscent fruit). Bioassays with a potentially coinhabitant fungus, Aspergillus quadrilineatus, support the distinct defensive potential of the diaspores corresponding to their GSL allocation. These findings indicate a two-tier morpho-chemical defence tactic of Aethionema via better protected fruit morphs and strategic provision of GSLs that optimize protection to the progeny for survival in nature.

Demographic responses to climate variation depend on spatial- and life history-differentiation at multiple scales

Long-term demographic data are needed for detailed viability analyses of populations threatened by climate change, but the infeasibility of obtaining such data makes it urgent to assess whether demographic responses to climatic variation can be generalized across populations and species. We used 32 years of demographic data on four species of closely related orchids (genera Dactylorhiza and Gymnadenia), replicated in a coastal and an inland region in central Norway, to test how demographic responses to climate varied among geographical regions and species. We fit generalized linear mixed models (GLMMs) to study climate effects on vital rates and included GLMMs as components in matrix models to examine climate effects on population dynamics. We found that, overall, vital rates and population growth rates of the eight populations responded independently to variation in both temperature and rainfall. Only probability of flowering showed expected regional differentiation in response to climate, despite notable regional climatic differences. Other vital rate – climate relationships were structured by species or a combination of both region and species. The weak clustering of demographic responses to climate variation by species and region demonstrates that effects of climatic variation can strongly depend on variation in local habitat and life history, even among closely related populations occupying similar niches. This highlights the difficulty in transferring data from closely related and/or located populations for viability analyses and for models predicting range shifts, and a general need to account for among-population variation in demographic responses to develop successful conservation and management plans.

Correlates of population genetic differentiation in marine and terrestrial environments

AbstractAimTheory predicts that differences in phylogeographic structure between species should be related to differences in life history, environment, and evolutionary time. Reviews of empirical studies suggest sometimes complex interactions and possibly a preponderance of exceptions to the predicted relationship that greater population genetic differentiation results from lower dispersal potential, as a function of life history. We apply an analytical framework, which controls for effects of environment and time, to test the hypothesis that contrasts in population genetic differentiation are proportional to contrasts in life history traits.LocationGlobal.MethodsWe conducted a meta‐analysis using contrasts of life history traits and population genetic differentiation between synchronously diverging codistributed (SDC) taxa. Because SDC taxa experienced the same environment at the same time, the effects of time and environment are effectively controlled when analysing other causes of genetic differentiation within SDC taxa. This offers the opportunity to rigorously test whether traits favouring greater dispersal potential—such as fecundity, census population size, and duration of the dispersive stage—do lead to lower population genetic differentiation.ResultsWe find a strong inverse relationship between dispersal potential and population genetic differentiation, consistent with predictions. SDC species pairs with similar dispersal potential show similar population genetic differentiation; species with higher dispersal potential have lower population genetic differentiation, relative to species with lower dispersal potential.Main conclusionsSDC comparisons provide a rigorous method for disentangling the factors driving patterns of genetic differentiation in the marine and nonmarine realms. We found broad support for the relationship that higher dispersal potential is associated with lower population genetic differentiation, the specifics of which can be influenced by place, time, and taxon. This relationship appears to be stronger on land than in the sea. However, many factors influence population genetic structure; deviations in measured versus predicted population genetic differentiation may indicate the influence of drift or selection. Too often, too many factors go unmeasured, constraining our ability to disaggregate dispersal syndromes and fully resolve the influence of specific life history characteristics on gene flow.

Key Elements of Photo Attraction Bioassay for Insect Studies or Monitoring Programs.

Optimized visual attractants will increase insect trapping efficiency by using the target insect's innate behaviors (positive photo-taxis) as a means to lure the insect into a population control or monitoring trap. Light emitting diodes (LEDs) have created customizable lighting options with specific wavelengths (colors), intensities, and bandwidths, all of which can be customized to the target insects. Photo-attraction behavioral bioassays can use LEDs to optimize the attractive color(s) for an insect species down to specific life history stages or behaviors (mating, feeding, or seeking shelter). Researchers must then confirm the bioassay results in the field and understand the limited attractive distance of the visual attractants. The cloverleaf bioassay arena is a flexible method to assess photo attraction while also assessing a range of natural insect behaviors such as escape and feeding responses. The arena can be used for terrestrial or aerial insect experiments, as well as diurnal, and nocturnal insects. Data collection techniques with the arena are videotaping, counting contact with the lights, or physically collecting the insects as they are attracted towards the lights. The assay accounts for insects that make no-choice and the arenas can be single (noncompetitive) color or multiple (competitive) colors. The cloverleaf design causes insects with strong thigmotaxis to return to the center of the arena where they can view all the options in a competitive LED tests. The cloverleaf arena presented here has been used with mosquitoes, bed bugs, Hessian fly, house flies, biting midges, red flour beetles, and psocids. Bioassays are used to develop accurate and effective insect traps to guide the development and optimization of insect traps used to monitor pest population fluctuations for disease vector risk assessments, the introduction of invasive species, and/or be used for population suppression.

Bi-parentally Inherited Genetic Evidence for Male-Biased Dispersal in Common Moorhen (Gallinula chloropus).

Dispersal is a life history trait that has relevant effect on both the dynamics and the genetics of species and sex-biased dispersal depends on how resource competition affects each of the sexes. In this study, a total of 210 blood samples including 121 Common Moorhen (Gallinula chloropus) females and 89 males were collected from 18 diverse areas during the breeding season. Based on 8 microsatellite markers analyses, we found that the most genetic diversities from female populations were higher than those from the males, where only 2 male individuals were identified as the long-distance dispersal. Analyses of sex-biased dispersal conducted over all sampling sites indicated that mAI (female mAI = 0.195, male mAI = - 0.265, P = 0.01), FST (female FST = 0.045, male FST = 0.026, P = 0.020), and r (female r = 0.118, male r = 0.064, P = 0.010) in females were all significantly higher than those in males at the 0.05 level, which suggested a male-biased dispersal pattern in this species. Our Mantel test results suggested a significant isolation-by-distance pattern for females but not for males, which corresponded to the more frequent dispersal and gene flow in males than in females. This dispersal pattern could be explained by the special life history trait and mating system that Common Moorhen pair formation occurs before they leave the flock in the spring to establish territories and its females initiate courtship more frequently than males and compete with each other to pair with small males with large fat reserves. The philopatric female could benefit most from knowledge of a particular area because they may win more intrasexual competitions in the breeding season and be able to produce more offspring if they are familiar with the local resources.

Host B chromosomes as potential sex ratio distorters of intestinal nematode infrapopulations in the yellow-necked mouse (Apodemus flavicollis).

The yellow-necked mouse, Apodemus flavicollis, can be considered as a model for genetic polymorphism produced by the frequent presence of supernumerary or B chromosomes (Bs). Host genetic background is rarely taken into account in studies of parasite sex ratio. The main aim of this study was to investigate the range of infrapopulation sex ratios for nematode parasites of the yellow-necked mouse and to determine which factors most influence variation in parasite sex ratios. Six nematode species found in the collected yellow-necked mice were analysed. We confirmed the predominant pattern of female-biased sex ratios in vertebrate parasite infrapopulations. The presence of B chromosomes in host genomes played an important role in infrapopulations of Heligmosomoides polygyrus, Syphacia stroma and Trichuris muris, as hosts with B chromosomes carried a higher proportion of males. The relative increase of males in infrapopulations could result from a shift in parasite life history strategy, induced by adaptation to the specific host genotypes (Bs present). In a meta-analysis with previously published data, the sex determination system was demonstrated to play a significant role in nematode sex ratio variation, as well as specific life history patterns, such as the place of egg hatching.

Drivers of wing shape in a widespread Neotropical bird: a dual role of sex-specific and migration-related functions

A large body of research has shown how avian morphology is shaped by specific behavioral repertoires and life history traits. Yet, the majority of such research has been conducted on birds breeding at north-temperate latitudes. We tested the hypothesis that functional wing traits of Fork-tailed Flycatchers (Tyrannus savana), which migrate within South America, vary predictably between non-migratory and migratory flycatchers. Additionally, due to sex-specific differences in this species (e.g., males perform courtship displays), we explored sex-related variation in wing shape. We applied classic measures of wing shape (e.g., wing loading, length, aspect ratio, pointedness), as well as landmark-based morphometric analysis to describe the wing morphology of Fork-tailed Flycatchers from breeding populations across South America. We found that migratory flycatchers tend to have more pointed wings than non-migratory flycatchers. Additionally, we found that males have wings that are significantly longer, more pointed, with a higher aspect ratio and that are more swept than those of females, regardless of whether they migrate or not. Overall, our results suggest that wing shape of Fork-tailed Flycatchers is the result of a complex set of tradeoffs shaped by selective pressures exerted on both sexes (i.e., the need to forage on the wing, evade predators and migrate efficiently), as well as sex-specific behaviors (e.g., the need for males to execute acrobatic displays).

Phylogenetic analysis and genetic structure of the seahorse, Hippocampus fuscus from the Arabian and Red Sea based on mitochondrial DNA sequences

The unique body morphology and specialized life history traits make seahorses excellent flagship species for many issues in marine conservation and biological evolution. In this study, the complete mitochondrial genome of Hippocampus fuscus was determined. Phylogenetic analyses showed that H. fuscus had a close genetic relationship to Hippocampus reidi, which give us a new insight into the speciation and dispersal among seahorse genus. A total of 843 base pairs of cytochrome b (Cytb) gene and a 646 base pairs of cytochrome oxidase I (COI) gene were obtained from 36 H. fuscus and 26 H. reidi from three populations. Population genetic analysis revealed a relatively high genetic diversity across the populations of H. fuscus compared with H. reidi. Neighbour-joining (NJ) tree of COI and Cytb gene sequences showed that H. fuscus haplotypes formed one cluster. The result of median-joining network of haplotypes based on COI and Cytb indicated a lack of structure in populations of H. fuscus. This study addressed the information about the evolution history and genetic structure of an Arabian seahorse H. fuscus, which provides insight into the genetic conservation and sustainable management for this species.

Movement patterns and home range size of tigerfish (Hydrocynus vittatus) in the Incomati River system, South Africa

Historical data suggested that the tigerfish (Hydrocynus vittatus) of the Incomati River migrates upstream and downstream as part of their life history. It has been suggested that this movement was a prerequisite for successful spawning in inundated floodplains in Mozambique. Recent advances in aquatic radio telemetry provided a reliable mechanism to monitor fish movement and increase knowledge of the ecology of tigerfish. From 04 January 2003 to 22 December 2003, 41 tigerfish in the Incomati River system were fitted with radio transmitters to record movement patterns and estimate home range size. On average, each fish was tracked 72 times, and the total number of fixes was 2971 over the study period, including 1322 summer fixes and 1649 winter fixes. The mean longest distance travelled by tigerfish was 730 m (range = 75 m to 3200 m). The home range size varied between individual fish, but on average fish stayed within a defined home range of 48 846 m2. Tigerfish showed high site fidelity to specific habitats within specific activity zones and movement occurred primarily within these defined zones. Differences in movement pattern, longest distance travelled and home range size could not be attributed to the sex or size of the fish. No large-scale movement patterns associated with specific life history activity were observed; thus, previous reports of large-scale downstream migrations and spawning migrations appear to be invalid. The presence of weirs in the study area impedes free fish movement as these weirs create migration obstructions.Conservation implications: River regulation such as damming, water abstraction, obstructive barriers and channel modification may have a detrimental impact on the survival strategy of this species. Implementation of these results in a management policy will provide a reliable basis for species specific requirements such as upstream reservoir release management; minimum flow volumes required for downstream ecosystem maintenance and management and planning of structures obstructing natural flow.

Evaluation of land surface phenology from VIIRS data using time series of PhenoCam imagery

Land surface phenology (LSP) has been widely retrieved from time series of various satellite instruments in order to monitor climate change and ecosystem dynamics. However, any evaluation of the quality of LSP data sets is quite challenging because the in situ observations on a limited number of individual trees, shrubs, or other plants are rarely representative of the landscape sampled in a single satellite pixel. Moreover, vegetation indices detecting biophysical features of vegetation seasonality are different from (but related to) the specific plant life history stages observed by humans at ground level. This study is the first comprehensive evaluation of the LSP product derived from Visible Infrared Imaging Radiometer Suite (VIIRS) data using both MODIS LSP products and observations from the PhenoCam network across the Contiguous United States during 2013 and 2014. PhenoCam observes vegetation canopy over a landscape at very high frequency, providing nearly continuous canopy status and enabling the estimate of discrete phenophase using vegetation indices that are conceptually similar to satellite data. Six phenological dates (greenup onset, mid-greenup phase, maturity onset, senescence onset, mid-senescence phase, and dormancy onset) were retrieved separately from daily VIIRS NDVI (normalized difference vegetative index) and EVI2 (two-band enhanced vegetation index) time series. Similarly, the six phenological dates were also extracted from the 30-min time series of PhenoCam data using GCC (green chromatic coordinate) and VCI (vegetation contrast index) separately. Phenological dates derived from VIIRS NDVI and EVI2 and PhenoCam GCC and VCI were generally comparable for the vegetation greenup phase, but differed considerably for the senescence phase. Although all indices captured green leaf development effectively, performance discrepancies arose due to their ability to track the mixture of senescing leaf colors. PhenoCam GCC and VCI phenological observations were in better agreement with the phenological dates from VIIRS EVI2 than from VIIRS NDVI. Further, the VIIRS EVI2 phenological metrics were more similar to those from PhenoCam VCI than from PhenoCam GCC time series. Overall, the average absolute difference between the VIIRS EVI2 and PhenoCam VCI phenological dates was 7–11 days in the greenup phase and 10–13 days in the senescence phase. The difference was smaller in forests, followed by grasslands and croplands, and then savannas. Finally, the phenological dates derived from VIIRS EVI2 were compared with MODIS detections, which showed a good agreement with an average absolute difference less than a week except for the senescence onset. These results for the first time demonstrate the upper boundary of uncertainty in VIIRS LSP detections and the continuity to MODIS LSP product.

Smooth lumpsucker Aptocyclus ventricosus in the northwestern Sea of Japan: distribution and some life history traits

Abstract This paper is focused on horizontal, vertical, and temperature-dependent distributions, size composition of bottom and mid-water trawl catches, and biomass estimations of smooth lumpsucker Aptocyclus ventricosus (Pallas) (Cyclopteridae) within the Russian Exclusive Economic Zone (EEZ) of the northwestern Sea of Japan. This species is distributed very widely throughout the study area inhabiting both near-bottom layers and water column. It is less abundant in small bays and in the northern Tatar Strait (north to 50°N). Despite wide bathymetric (0 to 940 m) and temperature (-1.1 to +12.2 °C) ranges this species occurred mainly within the lower mesopelagic zone of 400-800 m depths and cold temperatures of -0.5-1°C. In the near-bottom layer catches of smooth lumpsucker were represented by fish with TL 5-45 cm (mean 28.1 cm, dominant lengths 29-37 cm) while in water column its TL varied 4 to 41 cm with mean 17.9 cm, most abundant were fish with TL 8-15 and 24-31 cm; the difference is associated with specific life history aspects of the species considered. Recent increase of smooth lumpsucker biomass in the study area was observed with estimated value of 3000 t in the northern Primorye.

Plasticity in physiological condition of female brown bears across diverse ecosystems

Variation in life history strategies facilitates the near global distribution of mammals by expanding realized niche width. We investigated physiological plasticity in the spring body composition of adult female brown bears (Ursus arctos) across 4 diverse Alaskan ecosystems. Brown bears are a highly intelligent omnivore with a historic range spanning much of North America, Europe, and Asia. We hypothesized that body mass, fat mass, lean mass, and total caloric content would increase across populations with increasing food resource availability. Throughout their range, brown bears enter a period of torpor during winter months, decreasing their metabolic rate as an adaptation to this period of reduced food availability. They also give birth to and nourish offspring during this time. Due to this specific life history strategy, we further hypothesized that proportional body fat and the proportion of total calories derived from fat would be consistent across populations. Our results supported our first hypothesis: body, fat, and lean masses, and caloric content of bears across populations increased with the quality and abundance of available food. However, the proportional body fat content and proportion of calories from fat differed across populations indicating population-specific strategies to meet the demands of reduced seasonal food availability, offspring production and rearing, and climate as well as some plasticity to respond to environmental change or ecosystem perturbations. Investigations of body condition and energetics benefit from combined assessments of absolute, proportional, and caloric metrics to understand the nuances of brown bear physiological dynamics across and within populations.