Dietary analysis reveals the vulnerability of the endangered Maugean skate (Zearaja maugeana) to benthic changes in Macquarie Harbour

2019 ◽  
Vol 70 (5) ◽  
pp. 745 ◽  
Author(s):  
Kay Weltz ◽  
Jeremy M. Lyle ◽  
Justin D. Bell ◽  
Jayson M. Semmens
Keyword(s):  
Environmental Conditions ◽  
Environmental Changes ◽  
Trophic Position ◽  
Credible Interval ◽  
Prey Type ◽  
Stomach Content Analysis ◽  
Small Population ◽  
Fish Farms ◽  
Dietary Analysis ◽  
Isotopic Signatures

Species occupying high trophic positions with a small population size, limited diet and restricted range are vulnerable to extinction. The endangered Maugean skate (Zearaja maugeana) in Macquarie Harbour is potentially threatened by changing benthic environmental conditions (declining dissolved oxygen concentrations and decreased macrofaunal diversity). To inform investigations on potential indirect impacts of benthic environmental changes on the Maugean skate and its prey, non-lethal techniques were used to identify dietary composition and trophic position of the species. The Maugean skate occupies a high trophic position (3.70) in the food web, with both stable-isotope (median 86% contribution to isotopic signatures, credible interval (CI)=44–100%) and stomach-content analysis showing crustaceans, particularly brachyuran crabs (58.5% index of relative importance), as the dominant prey type. Aquaculture feed from salmonid fish farms operating in the harbour was not found to be important in skate diet. This study showed that the Maugean skate consumes a small number of benthic prey species, highlighting its vulnerability to changing environmental conditions in the harbour.

scholarly journals Ontogenetic shift in the trophic role of the invasive killer shrimp Dikerogammarus villosus: a stable isotope study

2021 ◽  
Author(s):  
Francesco Mancini ◽  
Raffaele De Giorgi ◽  
Alessandro Ludovisi ◽  
Salvatrice Vizzini ◽  
Giorgio Mancinelli
Keyword(s):  
Dietary Habits ◽  
Trophic Position ◽  
Ecological Impact ◽  
Central Italy ◽  
Local Conditions ◽  
Dikerogammarus Villosus ◽  
Isotopic Signatures ◽  
Depth Analysis ◽  
Stable Isotope Study ◽  
The Impact

AbstractThe introduction of the amphipod Dikerogammarus villosus in European fresh waters is to date recognized as a threat to the integrity of invaded communities. Predation by D. villosus on native benthic invertebrates is assumed as the key determinant of its ecological impact, yet available information describe the species as a primary consumer as well as a carnivore depending on local conditions. Here, we assessed the trophic position (TP) of D. villosus in Lake Trasimeno, a recently invaded lentic system in central Italy, using the CN isotopic signatures of individuals captured in winter spanning two orders of magnitude in body size. TP estimations were compared with those characterizing the native amphipod Echinogammarus veneris and other representative invertebrate predators. On average, D. villosus showed a trophic position higher than E. veneris, and comparable with that of odonate nymphs. An in-depth analysis revealed that large-sized individuals had a trophic position of 3.07, higher than odonates and close to that of the hirudinean predator Erpobdella octoculata, while small-sized specimens had a trophic position of 2.57, similar to that of E. veneris (2.41). These findings indicate that size-related ontogenetic shifts in dietary habits may per se vary the nature of the interaction between Dikerogammarus villosus and native invertebrates from competition to predation. Information collated from published isotopic studies corroborated the generality of our results. We conclude that intra-specific trophic flexibility may potentially amplify and make more multifaceted the impact of the species on other invertebrate species in invaded food webs.

scholarly journals Clonal selection of Eucalyptus grandis x Eucalyptus globulus for productivity, adaptability, and stability, using SNP markers

2016 ◽  
Vol 65 (2) ◽  
pp. 30-38 ◽  
Author(s):  
D. Torres-Dini ◽  
A. C. P. Nunes ◽  
A. Aguiar ◽  
N. Nikichuk ◽  
C. Centurión ◽  
...  
Keyword(s):  
Eucalyptus Globulus ◽  
Environmental Changes ◽  
Clonal Selection ◽  
Eucalyptus Grandis ◽  
Small Population ◽  
Snp Markers ◽  
Hybrid Population ◽  
Environment Interaction ◽  
Predictive Capacity ◽  
Selection Of

Abstract In Uruguay, reforestations with Eucalyptus sp. is of fundamental importance to supply paper, pulp, and wood production. This study investigates genetic, productivity, stability, and adaptability parameters in the selection of Eucalypts grandis x Eucalyptus globulus full-sib hybrid clones. The study was conducted in a clonal test, repeated in two different soils types, in Rio Negro State, Uruguay. The population was characterized phenotypically for diameter at breast height (dbh) and genotyped for SNP markers (EuCHIP60K chip). Mean dbh was similar between sites and the genotype–environment interaction was simple. We found high genotype correlation in clone performance between environments (0.708), indicating the possibility of selecting the same clones for both study locations. Mean heritability between clones (0.724), coefficient of individual genetic variation (10.9 %), and relative variation (0.916), suggest the possibility of gains (estimated at 3.1 % for both sites together) by selecting clones with higher growth rates. A total of 15,196 SNPs were used to confirm parentage and test a genomic selection model for dbh. The predictive capacity was negative (-0.15) given the small population size (78 individuals). The most adaptable material among the tested study sites presented higher values for SNP heterozygosity. Thus, using molecular markers to identify clones responsive to environmental changes can act as a powerful tool in Eucalyptus breeding programs. The hybrid population showed greater adaptability than E. globulus for this region.

scholarly journals Pathological transitions in myelin membranes driven by environmental and multiple sclerosis conditions

2018 ◽  
Vol 115 (44) ◽  
pp. 11156-11161 ◽  
Author(s):  
Rona Shaharabani ◽  
Maor Ram-On ◽  
Yeshayahu Talmon ◽  
Roy Beck
Keyword(s):  
Multiple Sclerosis ◽  
Phase Transition ◽  
Lipid Composition ◽  
Environmental Conditions ◽  
Structural Changes ◽  
Environmental Changes ◽  
Hexagonal Phase ◽  
Structural Phase ◽  
Structural Modifications ◽  
Transition Points

Multiple sclerosis (MS) is an autoimmune disease, leading to the destruction of the myelin sheaths, the protective layers surrounding the axons. The etiology of the disease is unknown, although there are several postulated environmental factors that may contribute to it. Recently, myelin damage was correlated to structural phase transition from a healthy stack of lamellas to a diseased inverted hexagonal phase as a result of the altered lipid stoichiometry and low myelin basic protein (MBP) content. In this work, we show that environmental conditions, such as buffer salinity and temperature, induce the same pathological phase transition as in the case of the lipid composition in the absence of MBP. These phase transitions have different transition points, which depend on the lipid’s compositions, and are ion specific. In extreme environmental conditions, we find an additional dense lamellar phase and that the native lipid composition results in similar pathology as the diseased composition. These findings demonstrate that several local environmental changes can trigger pathological structural changes. We postulate that these structural modifications result in myelin membrane vulnerability to the immune system attacks and thus can help explain MS etiology.

scholarly journals A three-dimensional view on biodiversity changes: spatial, temporal, and functional perspectives on fish communities in the Baltic Sea

2018 ◽  
Vol 75 (7) ◽  
pp. 2463-2475 ◽  
Author(s):  
Romain Frelat ◽  
Alessandro Orio ◽  
Michele Casini ◽  
Andreas Lehmann ◽  
Bastien Mérigot ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Marine Ecosystem ◽  
Fish Communities ◽  
The Baltic Sea ◽  
Functional Richness ◽  
Holistic Understanding ◽  
The Baltic

Abstract Fisheries and marine ecosystem-based management requires a holistic understanding of the dynamics of fish communities and their responses to changes in environmental conditions. Environmental conditions can simultaneously shape the spatial distribution and the temporal dynamics of a population, which together can trigger changes in the functional structure of communities. Here, we developed a comprehensive framework based on complementary multivariate statistical methodologies to simultaneously investigate the effects of environmental conditions on the spatial, temporal and functional dynamics of species assemblages. The framework is tested using survey data collected during more than 4000 fisheries hauls over the Baltic Sea between 2001 and 2016. The approach revealed the Baltic fish community to be structured into three sub-assemblages along a strong and temporally stable salinity gradient decreasing from West to the East. Additionally, we highlight a mismatch between species and functional richness associated with a lower functional redundancy in the Baltic Proper compared with other sub-areas, suggesting an ecosystem more susceptible to external pressures. Based on a large dataset of community data analysed in an innovative and comprehensive way, we could disentangle the effects of environmental changes on the structure of biotic communities—key information for the management and conservation of ecosystems.

scholarly journals Plant diversity in sedimentary DNA obtained from high-latitude (Siberia) and high-elevation lakes (China)

2020 ◽  
Vol 8 ◽  
Author(s):  
Kathleen Stoof-Leichsenring ◽  
Sisi Liu ◽  
Weihan Jia ◽  
Kai Li ◽  
Luidmila Pestryakova ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Plant Diversity ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
The Arctic ◽  
Mean Annual Precipitation ◽  
Reference Database ◽  
Mean Annual Temperature ◽  
Diversity Assessment ◽  
Recent Climate

Plant diversity in the Arctic and at high altitudes strongly depends on and rebounds to climatic and environmental variability and is nowadays tremendously impacted by recent climate warming. Therefore, past changes in plant diversity in the high Arctic and high-altitude regions are used to infer climatic and environmental changes through time and allow future predictions. Sedimentary DNA (sedDNA) is an established proxy for the detection of local plant diversity in lake sediments, but still relationships between environmental conditions and preservation of the plant sedDNA proxy are far from being fully understood. Studying modern relationships between environmental conditions and plant sedDNA will improve our understanding under which conditions sedDNA is well-preserved helping to a.) evaluate suitable localities for sedDNA approaches, b.) provide analogues for preservation conditions and c.) conduct reconstruction of plant diversity and climate change. This study investigates modern plant diversity applying a plant-specific metabarcoding approach on sedimentary DNA of surface sediment samples from 262 lake localities covering a large geographical, climatic and ecological gradient. Latitude ranges between 25°N and 73°N and longitude between 81°E and 161°E, including lowland lakes and elevated lakes up to 5168 m a.s.l. Further, our sampling localities cover a climatic gradient ranging in mean annual temperature between -15°C and +18°C and in mean annual precipitation between 36­ and 935 mm. The localities in Siberia span over a large vegetational gradient including tundra, open woodland and boreal forest. Lake localities in China include alpine meadow, shrub, forest and steppe and also cultivated areas. The assessment of plant diversity in the underlying dataset was conducted by a specific plant metabarcoding approach. We provide a large dataset of genetic plant diversity retrieved from surface sedimentary DNA from lakes in Siberia and China spanning over a large environmental gradient. Our dataset encompasses sedDNA sequence data of 259 surface lake sediments and three soil samples originating from Siberian and Chinese lakes. We used the established chloroplastidal P6 loop trnL marker for plant diversity assessment. The merged, filtered and assigned dataset includes 15,692,944 read counts resulting in 623 unique plant DNA sequence types which have a 100% match to either the EMBL or to the specific Arctic plant reference database. The underlying dataset includes a taxonomic list of identified plants and results from PCR replicates, as well as extraction blanks (BLANKs) and PCR negative controls (NTCs), which were run along with the investigated lake samples. This collection of plant metabarcoding data from modern lake sediments is still ongoing and additional data will be released in the future.

Paleobiological Implications of the Isotopic Signatures (13C,15N) of Fossil Mammal Collagen in Scladina Cave (Sclayn, Belgium)

1997 ◽  
Vol 48 (3) ◽  
pp. 370-380 ◽  
Author(s):  
Hervé Bocherens ◽  
Daniel Billiou ◽  
Marylène Patou-Mathis ◽  
Dominique Bonjean ◽  
Marcel Otte ◽  
...  
Keyword(s):  
Trophic Position ◽  
Brown Bear ◽  
Extraction Process ◽  
Vegetarian Diet ◽  
Isotopic Abundance ◽  
Preliminary Screening ◽  
Isotopic Signatures ◽  
Extant Species ◽  
Isotopic Abundances

An isotopic investigation of upper Pleistocene mammal bones and teeth from Scladina cave (Sclayn, Belgium) demonstrated the very good quality of collagen preservation. A preliminary screening of the samples used the amount of nitrogen in whole bone and dentine in order to estimate the preserved amount of collagen before starting the extraction process. The isotopic abundances of fossil specimens from still-extant species are consistent with their trophic position. Moreover, the15N isotopic abundance is higher in dentine than in bone in bears and hyenas, a phenomenon already observed in modern specimens. These results demonstrate that the isotopic compositions of samples from Scladina cave can be interpreted in ecological terms. Mammoths exhibit a high15N isotopic abundance relative to other herbivores, as was the case in Siberian and Alaskan samples. These results suggest distinctive dietary adaptations in herbivores living in the mammoth steppe. Cave bears are clearly isotopically different from coeval brown bears, suggesting an ecological separation between species, with a pure vegetarian diet for cave bear and an omnivorous diet for brown bear.

An On-Going Monitoring Project of a New Timber Structure

2013 ◽  
Vol 778 ◽  
pp. 757-764 ◽  
Author(s):  
Francesca Lanata
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Construction Material ◽  
Structural Response ◽  
Timber Structures ◽  
The Real ◽  
Structural Health

Structural design, regardless of construction material, is based mainly on deterministic codes that partially take into account the real structural response under service and environmental conditions. This approach can lead to overdesigned (and expensive) structures. The differences between the designed and the real behaviors are usually due to service loads not taken into account during the design or simply to the natural degradation of materials properties with time. This is particularly true for wood, which is strongly influenced by service and environmental conditions. Structural Health Monitoring can improve the knowledge of timber structures under service conditions, provide information on material aging and follow the degradation of the overall building performance with time.A long-term monitoring control has been planned on a three-floor structure composed by wooden trusses and composite concrete-wood slabs. The structure is located in Nantes, France, and it is the new extension to the Wood Science and Technology Academy (ESB). The main purpose of the monitoring is to follow the long-term structural response from a mechanical and energetic point of view, particularly during the first few service years. Both static and dynamic behavior is being followed through strain gages and accelerometers. The measurements will be further put into relation with the environmental changes, temperature and humidity in particular, and with the operational charges with the aim to improve the comprehension of long-term performances of wooden structures under service. The goal is to propose new improved and optimized methods to make timber constructions more efficient compared to other construction materials (masonry, concrete, steel).The paper will mainly focus on the criteria used to design the architecture of the monitoring system, the parameters to measure and the sensors to install. The first analyses of the measurements will be presented at the conference to have a feedback on the performance of the installed sensors and to start to define a general protocol for the Structural Health Monitoring of such type of timber structures.

scholarly journals Pleistocene Branchiopods (Cladocera, Anostraca) from Transbaikalian Siberia Demonstrate Morphological and Ecological Stasis

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3063
Author(s):  
Anton A. Zharov ◽  
Anna N. Neretina ◽  
D. Christopher Rogers ◽  
Svetlana A. Reshetova ◽  
Sofia M. Sinitsa ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Seasonal Variations ◽  
Environmental Changes ◽  
Daphnia Pulex ◽  
Steppe Zone ◽  
Water Bodies ◽  
Large Branchiopods ◽  
Community Types ◽  
High Diversity

Pleistocene water bodies have been studied using the paleolimnological approach, which traces environmental changes using particular subfossils as ecological proxies, rather than analysis of the paleocommunities themselves. Within a given taphocoenosis, the presence and quantity of animals are related to environmental conditions rather than to community types where relationships between taxa are stabilized during their long-term co-occurrence and are (at least partially) more important than the particular environmental conditions at the time of deposition, which may have experienced significant seasonal and inter-seasonal variations. Here, we analyze Branchiopoda (Crustacea) of two paleolocalities in the Transbaikalian Region of Russia: Urtuy (MIS3) and Nozhiy (older than 1.5 million years). Cladocerans Daphnia (Ctenodaphnia) magna, D. (C.) similis, D. (Daphnia) pulex, Ceriodaphnia pulchella-reticulata, C. laticaudata, Simocephalus sp., Moina cf. brachiata, M. macropopa clade, Chydorus cf. sphaericus, Capmtocercus sp. and anostracans Branchinecta cf. paludosa, and Streptocephalus (Streptocephalus) sp. are found in two localities. With the exception of the last taxon, which now occurs in the southern Holarctic, all other taxa inhabit the Transbaikalian Region. Within Eurasia, the steppe zone has the greatest diversity of large branchiopods and a high diversity of some cladocerans, such as subgenus Daphnia (Ctenodaphnia) and Moina sp. Here we demonstrated that the branchiopod community in shallow steppe water bodies has been unchanged since at least the Pleistocene, demonstrating long-term morphological and ecological stasis.

scholarly journals Sympatric Atlantic puffins and razorbills show contrasting responses to adverse marine conditions during winter foraging within the North Sea

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Katie St. John Glew ◽  
Sarah Wanless ◽  
Michael P. Harris ◽  
Francis Daunt ◽  
Kjell Einar Erikstad ◽  
...  
Keyword(s):  
North Sea ◽  
Environmental Conditions ◽  
Trophic Position ◽  
Survival Rates ◽  
Sympatric Species ◽  
Ecological Niches ◽  
Overwinter Survival ◽  
The North ◽  
Winter Conditions ◽  
The North Sea

Abstract Background Natural environments are dynamic systems with conditions varying across years. Higher trophic level consumers may respond to changes in the distribution and quality of available prey by moving to locate new resources or by switching diets. In order to persist, sympatric species with similar ecological niches may show contrasting foraging responses to changes in environmental conditions. However, in marine environments this assertion remains largely untested for highly mobile predators outside the breeding season because of the challenges of quantifying foraging location and trophic position under contrasting conditions. Method Differences in overwinter survival rates of two populations of North Sea seabirds (Atlantic puffins (Fratercula arctica) and razorbills (Alca torda)) indicated that environmental conditions differed between 2007/08 (low survival and thus poor conditions) and 2014/15 (higher survival, favourable conditions). We used a combination of bird-borne data loggers and stable isotope analyses to test 1) whether these sympatric species showed consistent responses with respect to foraging location and trophic position to these contrasting winter conditions during periods when body and cheek feathers were being grown (moult) and 2) whether any observed changes in moult locations and diet could be related to the abundance and distribution of potential prey species of differing energetic quality. Results Puffins and razorbills showed divergent foraging responses to contrasting winter conditions. Puffins foraging in the North Sea used broadly similar foraging locations during moult in both winters. However, puffin diet significantly differed, with a lower average trophic position in the winter characterised by lower survival rates. By contrast, razorbills’ trophic position increased in the poor survival winter and the population foraged in more distant southerly waters of the North Sea. Conclusions Populations of North Sea puffins and razorbills showed contrasting foraging responses when environmental conditions, as indicated by overwinter survival differed. Conservation of mobile predators, many of which are in sharp decline, may benefit from dynamic spatial based management approaches focusing on behavioural changes in response to changing environmental conditions, particularly during life history stages associated with increased mortality.

scholarly journals An adaptive system for autonomous driving

2020 ◽  
Vol 28 (3) ◽  
pp. 1189-1212
Author(s):  
Martin Zimmermann ◽  
Franz Wotawa
Keyword(s):  
Adaptive Control ◽  
Automotive Industry ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Adaptive System ◽  
Control Method ◽  
Autonomous Driving ◽  
Optimal Selection ◽  
Safe State ◽  
Over Time

Abstract Having systems that can adapt themselves in case of faults or changing environmental conditions is of growing interest for industry and especially for the automotive industry considering autonomous driving. In autonomous driving, it is vital to have a system that is able to cope with faults in order to enable the system to reach a safe state. In this paper, we present an adaptive control method that can be used for this purpose. The method selects alternative actions so that given goal states can be reached, providing the availability of a certain degree of redundancy. The action selection is based on weight models that are adapted over time, capturing the success rate of certain actions. Besides the method, we present a Java implementation and its validation based on two case studies motivated by the requirements of the autonomous driving domain. We show that the presented approach is applicable both in case of environmental changes but also in case of faults occurring during operation. In the latter case, the methods provide an adaptive behavior very much close to the optimal selection.

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