Krill (Euphausiacea) demography and variability in abundance and distribution

2000 ◽  
Vol 57 (S3) ◽  
pp. 151-167 ◽  
Author(s):  
Volker Siegel
Keyword(s):  
Energy Flow ◽  
Environmental Changes ◽  
Population Level ◽  
Survival Strategies ◽  
Detailed Knowledge ◽  
Species Survival ◽  
Flow Through ◽  
Abundance And Distribution ◽  
Geographical Locations

Among euphausiids, there are many species that are represented by enormous numbers of individuals and are of considerable importance to various ecosystems, as well as to human exploitation. Considerable progress has been made regarding quantitative aspects of krill biology. This detailed knowledge about krill population parameters is necessary to answer questions about the importance of euphausiids to energy flow through certain ecosystems. This information also helps in assessing the importance of seasonal or long-term climate effects on variation in euphausiid populations because variability is not simply noise. Hypotheses have been developed as to how large seasonal or latitudinal environmental changes affect species survival strategies in poor conditions and maintenance of a stable population level. This paper discusses aspects of the spatial distribution with regard to seasonal and interannual changes, developments to define genetically distinct populations, and results of long-term variability in krill abundance and biomass for various species in different geographical locations.

scholarly journals Climate change drives mountain butterflies towards the summits

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dennis Rödder ◽  
Thomas Schmitt ◽  
Patrick Gros ◽  
Werner Ulrich ◽  
Jan Christian Habel
Keyword(s):  
Climate Change ◽  
Life History ◽  
Climate Warming ◽  
Environmental Changes ◽  
Range Shifts ◽  
Solar Irradiation ◽  
High Mountain ◽  
Detailed Knowledge ◽  
Annual Range

AbstractClimate change impacts biodiversity and is driving range shifts of species and populations across the globe. To understand the effects of climate warming on biota, long-term observations of the occurrence of species and detailed knowledge on their ecology and life-history is crucial. Mountain species particularly suffer under climate warming and often respond to environmental changes by altitudinal range shifts. We assessed long-term distribution trends of mountain butterflies across the eastern Alps and calculated species’ specific annual range shifts based on field observations and species distribution models, counterbalancing the potential drawbacks of both approaches. We also compiled details on the ecology, behaviour and life-history, and the climate niche of each species assessed. We found that the highest altitudinal maxima were observed recently in the majority of cases, while the lowest altitudes of observations were recorded before 1980. Mobile and generalist species with a broad ecological amplitude tended to move uphill more than specialist and sedentary species. As main drivers we identified climatic conditions and topographic variables, such as insolation and solar irradiation. This study provides important evidence for responses of high mountain taxa to rapid climate change. Our study underlines the advantage of combining historical surveys and museum collection data with cutting-edge analyses.

Population viability and spatial fish reproductive strategies in constant and changing environments: an individual-based modelling approach

1997 ◽  
Vol 54 (10) ◽  
pp. 2235-2246 ◽  
Author(s):  
C LePage ◽  
P Cury
Keyword(s):  
Reproductive Strategies ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Reproductive Function ◽  
Population Level ◽  
Population Viability ◽  
Natural Systems ◽  
The Individual ◽  
Modelling Approach

A spatially explicit individual-based model (IBM) helps to explain how two reproductive strategies, described as obstinate and opportunist, may be acting at the population level. Factors such as the spatial structure and the dynamics of the environment, the shape of the reproductive function, and spawning season duration are considered. Five simulations are presented to explore the importance of these factors in the success of two reproductive strategies experiencing in a first step, a constant, and in a second step, a changing environment. Simulations show that the obstinate strategy is characterized by high inertia and mainly selects optimal environmental conditions in the long term, whereas the opportunist strategy maintains diversity in site choice and allows the individual to explore environmental variability. Under drastic environmental changes, only a population combining both strategies avoids extinction. A low percentage of opportunists (about 1%) coupled with a high proportion of obstinates (about 99%) ensure population viability. Similar percentages have been observed in nature for philopatric species. The respective percentages of inertia and innovation that are needed in the functioning of natural systems are discussed.

scholarly journals Living evidence of a fossil survival strategy raises hope for warming-affected corals

2019 ◽  
Vol 5 (10) ◽  
pp. eaax2950 ◽  
Author(s):  
Diego K. Kersting ◽  
Cristina Linares
Keyword(s):  
Climate Change ◽  
Environmental Changes ◽  
Survival Strategies ◽  
Survival Strategy ◽  
Ecological Role ◽  
High Recovery ◽  
Recovery Capacity ◽  
Fossil Corals

Climate change is affecting reef-building corals worldwide, with little hope for recovery. However, coral fossils hint at the existence of environmental stress–triggered survival strategies unreported in extant colonial corals. We document the living evidence and long-term ecological role of such a survival strategy in which isolated polyps from coral colonies affected by warming adopt a transitory resistance phase, in turn expressing a high recovery capacity in dead colony areas. Such processes have been described in fossil corals as rejuvenescence but were previously unknown in extant reef-builder corals. Our results based on 16 years of monitoring show the significance of this process for unexpected recoveries of coral colonies severely affected by warming. These findings provide a link between rejuvenescence in fossil and extant corals and reveal that beyond adaptation and acclimatization processes, modern scleractinian corals show yet undiscovered and highly effective survival strategies that help them withstand and recover from rapid environmental changes.

Coming into the Country: Early Paleoindian Hunting and Mobility

1988 ◽  
Vol 53 (2) ◽  
pp. 231-244 ◽  
Author(s):  
Robert L. Kelly ◽  
Lawrence C. Todd
Keyword(s):  
New World ◽  
Environmental Changes ◽  
Raw Materials ◽  
Initial Population ◽  
Detailed Knowledge ◽  
Hunter Gatherers ◽  
Common Response ◽  
Lithic Raw Materials ◽  
Level Of Processing

Hunter-gatherer adaptations to long-term fluctuations in regional resource structure require mechanisms to cope with periodic subsistence stresses. Among documented groups, a common response to such stress is temporary movement into adjacent occupied areas-moving in with "relatives" when things go wrong. However, in the case of early (ca. 12,000-10,000 B.P.) Paleoindian groups in the Americas, the availability of neighboring groups with a detailed knowledge of local resource geography could not be relied upon. Post-Pleistocene environmental changes and the low initial population of the New World are important factors conditioning a lifeway characterized by a dependence on hunting (though not exclusively of megafauna), and by high residential, logistical, and range (territorial) mobility. Early Paleoindian groups had to adopt a subsistence technology that could be employed regardless of the specific resource microstructure. In some regards, Paleoindians seem to have behaved like tropical foragers while in others like arctic collectors. Use of high quality lithic raw materials from large quarry sources, reliance on a bifacial technology, limited use of caves and rockshelters, and a low level of processing of food products for storage all may be indicative of such a subsistence technology, which would have been unlike that of any modern hunter-gatherers.

Designing a CRM Framework for online & offline sports footwear retailers

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Rodrigo Cueva ◽  
Guillem Rufian ◽  
Maria Gabriela Valdes
Keyword(s):  
Environmental Changes ◽  
Customer Relationship ◽  
Business Strategies ◽  
Economic Sectors ◽  
Running Shoes ◽  
Brick And Mortar ◽  
Key Factor ◽  
On Line ◽  
The Impact

The use of Customer Relationship Managers to foster customers loyalty has become one of the most common business strategies in the past years.  However, CRM solutions do not fill the abundance of happily ever-after relationships that business needs, and each client’s perception is different in the buying process.  Therefore, the experience must be precise, in order to extend the loyalty period of a customer as much as possible. One of the economic sectors in which CRM’s have improved this experience is retailing, where the personalized attention to the customer is a key factor.  However, brick and mortar experiences are not enough to be aware in how environmental changes could affect the industry trends in the long term.  A base unified theoretical framework must be taken into consideration, in order to develop an adaptable model for constructing or implementing CRMs into companies. Thanks to this approximation, the information is complemented, and the outcome will increment the quality in any Marketing/Sales initiative. The goal of this article is to explore the different factors grouped by three main domains within the impact of service quality, from a consumer’s perspective, in both on-line and off-line retailing sector.  Secondly, we plan to go a step further and extract base guidelines about previous analysis for designing CRM’s solutions focused on the loyalty of the customers for a specific retailing sector and its product: Sports Running Shoes.

scholarly journals Responses of Vertebrate Wildlife to Oil and Natural Gas Development: Patterns and Frontiers

2021 ◽  
Author(s):  
A. D. Chalfoun
Keyword(s):  
Natural Gas ◽  
Anthropogenic Activities ◽  
Spatial Scales ◽  
Habitat Type ◽  
Population Level ◽  
Low Frequencies ◽  
Natural Gas Development ◽  
The Usa ◽  
Oil And Natural Gas

Abstract Purpose of Review Anthropogenic activities can lead to the loss, fragmentation, and alteration of wildlife habitats. I reviewed the recent literature (2014–2019) focused on the responses of avian, mammalian, and herpetofaunal species to oil and natural gas development, a widespread and still-expanding land use worldwide. My primary goals were to identify any generalities in species’ responses to development and summarize remaining gaps in knowledge. To do so, I evaluated the directionality of a wide variety of responses in relation to taxon, location, development type, development metric, habitat type, and spatiotemporal aspects. Recent Findings Studies (n = 70) were restricted to the USA and Canada, and taxonomically biased towards birds and mammals. Longer studies, but not those incorporating multiple spatial scales, were more likely to detect significant responses. Negative responses of all types were present in relatively low frequencies across all taxa, locations, development types, and development metrics but were context-dependent. The directionality of responses by the same species often varied across studies or development metrics. Summary The state of knowledge about wildlife responses to oil and natural gas development has developed considerably, though many biases and gaps remain. Studies outside of North America and that focus on herpetofauna are lacking. Tests of mechanistic hypotheses for effects, long-term studies, assessment of response thresholds, and experimental designs that isolate the effects of different stimuli associated with development, remain critical. Moreover, tests of the efficacy of habitat mitigation efforts have been rare. Finally, investigations of the demographic effects of development across the full annual cycle were absent for non-game species and are critical for the estimation of population-level effects.

Past testate amoeba communities in landslide mountain fens (Polish Carpathians): The relationship between shell types and sediment

The Holocene ◽  
2021 ◽  
pp. 095968362199464
Author(s):  
Katarzyna Marcisz ◽  
Krzysztof Buczek ◽  
Mariusz Gałka ◽  
Włodzimierz Margielewski ◽  
Matthieu Mulot ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Testate Amoebae ◽  
Mineral Matter ◽  
Testate Amoeba ◽  
Run Off ◽  
Number Of Factors ◽  
Depth To Water Table ◽  
Polish Carpathians ◽  
The Relationship

Landslide mountain fens formed in landslide depressions are dynamic environments as their development is disturbed by a number of factors, for example, landslides, slopewash, and surface run-off. These processes lead to the accumulation of mineral material and wood in peat. Disturbed peatlands are interesting archives of past environmental changes, but they may be challenging for providing biotic proxy-based quantitative reconstructions. Here we investigate long-term changes in testate amoeba communities from two landslide mountain fens – so far an overlooked habitat for testate amoeba investigations. Our results show that abundances of testate amoebae are extremely low in this type of peatlands, therefore not suitable for providing quantitative depth-to-water table reconstructions. However, frequent shifts of dominant testate amoeba species reflect dynamic lithological situation of the studied fens. We observed that high and stable mineral matter input into the peatlands was associated with high abundances of species producing agglutinated (xenosomic) as well as idiosomic shells which prevailed in the testate amoeba communities in both analyzed profiles. This is the first study that explores testate amoebae of landslide mountain fens in such detail, providing novel information about microbial communities of these ecosystems.

scholarly journals Advancement in long-distance bird migration through individual plasticity in departure

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jesse R. Conklin ◽  
Simeon Lisovski ◽  
Phil F. Battley
Keyword(s):  
Bird Migration ◽  
Population Level ◽  
Breeding Site ◽  
Environmental Constraints ◽  
Adaptive Responses ◽  
Long Distance ◽  
Direct Observations ◽  
Breeding Resources ◽  
Plastic Responses

AbstractGlobally, bird migration is occurring earlier in the year, consistent with climate-related changes in breeding resources. Although often attributed to phenotypic plasticity, there is no clear demonstration of long-term population advancement in avian migration through individual plasticity. Using direct observations of bar-tailed godwits (Limosa lapponica) departing New Zealand on a 16,000-km journey to Alaska, we show that migration advanced by six days during 2008–2020, and that within-individual advancement was sufficient to explain this population-level change. However, in individuals tracked for the entire migration (50 total tracks of 36 individuals), earlier departure did not lead to earlier arrival or breeding in Alaska, due to prolonged stopovers in Asia. Moreover, changes in breeding-site phenology varied across Alaska, but were not reflected in within-population differences in advancement of migratory departure. We demonstrate that plastic responses can drive population-level changes in timing of long-distance migration, but also that behavioral and environmental constraints en route may yet limit adaptive responses to global change.

scholarly journals Cellular stress signaling activates type-I IFN response through FOXO3-regulated lamin posttranslational modification

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Inah Hwang ◽  
Hiroki Uchida ◽  
Ziwei Dai ◽  
Fei Li ◽  
Teresa Sanchez ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Environmental Changes ◽  
Type I ◽  
Neurogenic Differentiation ◽  
Forkhead Box ◽  
Nuclear Lamin ◽  
Neural Stem Progenitor Cells ◽  
Subsequent Activation ◽  
Methyl Group Transfer

AbstractNeural stem/progenitor cells (NSPCs) persist over the lifespan while encountering constant challenges from age or injury related brain environmental changes like elevated oxidative stress. But how oxidative stress regulates NSPC and its neurogenic differentiation is less clear. Here we report that acutely elevated cellular oxidative stress in NSPCs modulates neurogenic differentiation through induction of Forkhead box protein O3 (FOXO3)-mediated cGAS/STING and type I interferon (IFN-I) responses. We show that oxidative stress activates FOXO3 and its transcriptional target glycine-N-methyltransferase (GNMT) whose upregulation triggers depletion of s-adenosylmethionine (SAM), a key co-substrate involved in methyl group transfer reactions. Mechanistically, we demonstrate that reduced intracellular SAM availability disrupts carboxymethylation and maturation of nuclear lamin, which induce cytosolic release of chromatin fragments and subsequent activation of the cGAS/STING-IFN-I cascade to suppress neurogenic differentiation. Together, our findings suggest the FOXO3-GNMT/SAM-lamin-cGAS/STING-IFN-I signaling cascade as a critical stress response program that regulates long-term regenerative potential.

scholarly journals The Flow through the Gulf of Mexico

2019 ◽  
Vol 49 (6) ◽  
pp. 1381-1401 ◽  
Author(s):  
J. Candela ◽  
J. Ochoa ◽  
J. Sheinbaum ◽  
M. López ◽  
P. Pérez-Brunius ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Straits Of Florida ◽  
The North ◽  
Astronomical Tide ◽  
Flow Through ◽  
Sverdrup Transport ◽  
The Mean ◽  
Yucatan Channel ◽  
Range Variation

AbstractFour years (September 2012 to August 2016) of simultaneous current observations across the Yucatan Channel (~21.5°N) and the Straits of Florida (~81°W) have permitted us to investigate the characteristics of the flow through the Gulf of Mexico. The average transport in both channels is 27.6 Sv (1 Sv = 106 m3 s−1), in accordance with previous estimates. At the Straits of Florida section, the transport related to the astronomical tide explains 55% of the observed variance with a mixed semidiurnal/diurnal character, while in the Yucatan Channel tides contribute 82% of the total variance and present a dominant diurnal character. At periods longer than a week the transports in the Yucatan and Florida sections have a correlation of 0.83 without any appreciable lag. The yearly running means of the transport time series in both channels are well correlated (0.98) and present a 3-Sv range variation in the 4 years analyzed. This long-term variability is well related to the convergence of the Sverdrup transport in the North Atlantic between 14.25° and 18.75°N. Using 2 years (July 2014–July 2016) of simultaneous currents observations in the Florida section, the Florida Cable section (~26.7°N), and a section across the Old Bahama Channel (~78.4°W), a mean northward transport of 28.4, 31.1, and 1.6 Sv, respectively, is obtained, implying that only 1.1 Sv is contributed by the Northwest Providence Channel to the mean transport observed at the Cable section during this 2-yr period.

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