scholarly journals Acute bottlenecks to the survival of juvenile Pygoscelis penguins occur immediately after fledging

2020 ◽  
Vol 16 (12) ◽  
pp. 20200645
Author(s):  
Jefferson T. Hinke ◽  
George M. Watters ◽  
Christian S. Reiss ◽  
Jarrod A. Santora ◽  
M. Mercedes Santos
Keyword(s):  
Satellite Telemetry ◽  
Weight Of Evidence ◽  
Juvenile Mortality ◽  
Marine Predators ◽  
Tag Loss ◽  
Direct Observations ◽  
Order Of Magnitude ◽  
Juvenile Stages ◽  
Spatio Temporal ◽  
Free Ranging

Estimating when and where survival bottlenecks occur in free-ranging marine predators is critical for effective demographic monitoring and spatial planning. This is particularly relevant to juvenile stages of long-lived species for which direct observations of death are typically not possible. We used satellite telemetry data from fledgling Adélie, chinstrap and gentoo penguins near the Antarctic Peninsula to estimate the spatio-temporal scale of a bottleneck after fledging. Fledglings were tracked up to 106 days over distances of up to 2140 km. Cumulative losses of tags increased to 73% within 16 days of deployment, followed by an order-of-magnitude reduction in loss rates thereafter. The timing and location of tag losses were consistent with at-sea observations of penguin carcasses and bioenergetics simulations of mass loss to thresholds associated with low recruitment probability. A bootstrapping procedure is used to assess tag loss owing to death versus other factors. Results suggest insensitivity in the timing of the bottleneck and quantify plausible ranges of mortality rates within the bottleneck. The weight of evidence indicates that a survival bottleneck for fledgling penguins is acute, attributable to predation and starvation, and may account for at least 33% of juvenile mortality.

scholarly journals Small-scale spatio-temporal characteristics of accumulation rates in western Dronning Maud Land, Antarctica

2008 ◽  
Vol 54 (185) ◽  
pp. 315-323 ◽  
Author(s):  
Helgard Anschütz ◽  
Daniel Steinhage ◽  
Olaf Eisen ◽  
Hans Oerter ◽  
Martin Horwath ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Temporal Variations ◽  
Spatial Variations ◽  
Small Scale ◽  
Accumulation Rates ◽  
Order Of Magnitude ◽  
Dronning Maud Land ◽  
Spatio Temporal ◽  
Ground Penetrating ◽  
Firn Core

AbstractSpatio-temporal variations of the recently determined accumulation rate are investigated using ground-penetrating radar (GPR) measurements and firn-core studies. The study area is located on Ritscherflya in western Dronning Maud Land, Antarctica, at an elevation range 1400–1560 m. Accumulation rates are derived from internal reflection horizons (IRHs), tracked with GPR, which are connected to a dated firn core. GPR-derived internal layer depths show small relief along a 22 km profile on an ice flowline. Average accumulation rates are about 190 kg m−2 a−1 (1980–2005) with spatial variability (1σ) of 5% along the GPR profile. The interannual variability obtained from four dated firn cores is one order of magnitude higher, showing 1σ standard deviations around 30%. Mean temporal variations of GPRderived accumulation rates are of the same magnitude or even higher than spatial variations. Temporal differences between 1980–90 and 1990–2005, obtained from two dated IRHs along the GPR profile, indicate temporally non-stationary processes, linked to spatial variations. Comparison with similarly obtained accumulation data from another coastal area in central Dronning Maud Land confirms this observation. Our results contribute to understanding spatio-temporal variations of the accumulation processes, necessary for the validation of satellite data (e.g. altimetry studies and gravity missions such as Gravity Recovery and Climate Experiment (GRACE)).

scholarly journals The incursion of free-ranging dogs into protected areas: A spatio-temporal analysis in a network of giant panda reserves

2022 ◽  
Vol 265 ◽  
pp. 109423
Author(s):  
Yue Weng ◽  
William McShea ◽  
Yixin Diao ◽  
Hongbo Yang ◽  
Xiaofeng Zhang ◽  
...  
Keyword(s):  
Protected Areas ◽  
Giant Panda ◽  
Temporal Analysis ◽  
Spatio Temporal ◽  
Free Ranging

Evaluating the potential for trophodynamic control of fish by the longfin inshore squid (Loligo pealeii) in the Northwest Atlantic Ocean

2008 ◽  
Vol 65 (11) ◽  
pp. 2524-2535 ◽  
Author(s):  
Mary E. Hunsicker ◽  
Timothy E. Essington
Keyword(s):  
Published Data ◽  
Apex Predator ◽  
Northwest Atlantic ◽  
Fish Stocks ◽  
Juvenile Mortality ◽  
Fish Recruitment ◽  
Juvenile Stages ◽  
Commercially Important ◽  
A Minor ◽  
Loligo Pealeii

Many marine apex predator populations have been depleted via targeted fishing, potentially enhancing the productivity of lower trophic-level species such as squid. Squid may be predators of juvenile stages of fish stocks, so fishing could induce depensatory juvenile mortality. Here we evaluate the energetic potential of the longfin inshore squid ( Loligo pealeii ) to exert trophodynamic control on recruitment of several commercially important fish populations. We estimated the population prey consumption of L. pealeii by developing bioenergetics and population models based on previously published data. Our predictions of population consumption showed that squid consume high quantities of prey on daily and seasonal time scales. Further, comparisons between our estimates of population consumption and fish recruitment biomass indicate that L. pealeii may potentially exert a trophodynamic control on the recruitment success of commercially exploited fish species even if these species are only a minor prey item of squid. Overall, our findings suggest that the predation interactions of L. pealeii should be considered when managing and rebuilding fish stocks in the northwest Atlantic continental shelf ecosystem.

scholarly journals Subspecies discrimination in the Scandinavian beaver (Castor fiber): combining behavioral and chemical evidence

2004 ◽  
Vol 82 (6) ◽  
pp. 902-909 ◽  
Author(s):  
Frank Rosell ◽  
Øyvind Steifetten
Keyword(s):  
Gland Secretion ◽  
Castor Fiber ◽  
Anal Gland ◽  
Geographic Isolation ◽  
Geographical Isolation ◽  
Anal Gland Secretion ◽  
Direct Observations ◽  
Subspecies Discrimination ◽  
Territorial Intrusion ◽  
Free Ranging

Geographic isolation is one of several models that has been proposed to explain the evolutionary course of speciation. In this study, we examined how geographical isolation may affect subspecies discrimination in the free-ranging Scandinavian beaver (Castor fiber fiber L., 1758) by simulating a territorial intrusion by using scent (castoreum and anal gland secretion) from a con-subspecific (N = 8 for castoreum and N = 7 for anal gland secretion) and a hetero-subspecific (Castor fiber albicus Matschie, 1907; N = 2 for both castoreum and anal gland secretion). Direct observations of 33 families during evenings showed that beavers (i) sniffed castoreum but not anal gland secretion from C. f. fiber significantly longer than from C. f. albicus and (ii) responded aggressively (i.e., stood on the mound on their hind feet, pawing and (or) overmarking) significantly longer to castoreum but not anal gland secretion from C. f. fiber than from C. f. albicus. When experimental scent mounds were allowed to remain overnight, the response was significantly stronger to castoreum but not to anal gland secretion from C. f. fiber than from C. f. albicus. Gas chromatographic comparisons of castoreum and anal gland secretion from the two subspecies supported our behavioral observations for castoreum but not for anal gland secretion. These findings suggest that geographical isolation has developed discriminatory abilities in C. f. fiber. We further suggest that the proximate factors involved are of environmental origin.

scholarly journals Spatio-temporal variation of predatory hoverflies (Diptera: Syrphidae) and their relationship with aphids in organic horticultural crops in La Plata, Buenos Aires

2020 ◽  
Vol 79 (4) ◽  
pp. 15-22
Author(s):  
María F. Diaz Lucas ◽  
Lilián M. Passareli ◽  
Noelia Maza ◽  
Daniel A. Aquino ◽  
Nancy M. Greco ◽  
...  
Keyword(s):  
Buenos Aires ◽  
Wild Plants ◽  
Immature Stages ◽  
Matricaria Chamomilla ◽  
Horticultural Crops ◽  
Direct Observations ◽  
Parasitism Rates ◽  
Diplazon Laetatorius ◽  
Wild Vegetation ◽  
Spatio Temporal

Population variations of predatory hoverflies in agroecosystems depend mainly on the resources that crops and wild vegetation provides them as well as death caused by natural enemies. We identified I) aphidophagous hoverfly species in lettuce and broccoli crops in Buenos Aires, II) the seasonal variations of the immature stages and their larval parasitism, and III) the wild plants, surrounding the crops, visited by adults. Fortnightly, 30 leaves were randomly selected in both crops during 2018-2019 and immature stages of syrphids and aphids per leaf were recorded. Adults were manually collected in patches of the wild plants (during 10 min of direct observations), and plants visited by adults were determined. The hoverflies were Allograpta exotica Wiedemann and Toxomerus duplicatus Wiedemann. Only A. exotica was recorded in crops. The dominant aphids were Myzus persicae (Sulzer) in lettuce and Brevycorine brassicae (L.) in broccoli. Parasitism rates ranged between 8 and 100% and the species were Diplazon laetatorius (Fabricius), in both crops, and Pachyneuron aff. nelsoni only in broccoli. Galinsoga parviflora Cav. and Matricaria chamomilla L. were the wild plants most often visited by hoverflies. This work provides basic information for the control of aphids by hoverflies in the framework of conservation biological control

scholarly journals Accounting for body mass effects in the estimation of field metabolic rates from body acceleration

2021 ◽  
pp. jeb.233544
Author(s):  
Evan E. Byrnes ◽  
Karissa O. Lear ◽  
Lauran R. Brewster ◽  
Nicholas M. Whitney ◽  
Matthew J. Smukall ◽  
...  
Keyword(s):  
Body Mass ◽  
Predictive Models ◽  
Scale Dependence ◽  
Metabolic Rates ◽  
Body Acceleration ◽  
Mass Effects ◽  
Order Of Magnitude ◽  
Field Metabolic Rates ◽  
Free Ranging ◽  
Modelling Process

Dynamic Body Acceleration (DBA), measured through animal-attached tags, has emerged as a powerful method for estimating field metabolic rates of free-ranging individuals. Following respirometry to calibrate oxygen consumption rate (MO2) with DBA under controlled conditions, predictive models can be applied to DBA data collected from free-ranging individuals. However, laboratory calibrations are generally performed on a relatively narrow size range of animals, which may introduce biases if predictive models are applied to differently sized individuals in the field. Here, we tested the mass dependence of the DBA-MO2 relationship to develop an experimental framework for the estimation of field metabolic rates when organisms differ in size. We performed respirometry experiments with individuals spanning one order of magnitude in body mass (1.74–17.15 kg) and used a two-stage modelling process to assess the intraspecific scale dependence of the MO2-DBA relationship and incorporate such dependencies into the coefficients of MO2 predictive models. The final predictive model showed scale dependence; the slope of the MO2-DBA relationship was strongly allometric (M1.55), whereas the intercept term scaled closer to isometry (M1.08). Using bootstrapping and simulations, we evaluated the performance of this coefficient-corrected model against commonly used methods of accounting for mass effects on the MO2-DBA relationship and found the lowest error and bias in the coefficient-corrected approach. The strong scale dependence of the MO2-DBA relationship indicates that caution must be exercised when models developed using one size class are applied to individuals of different sizes.

scholarly journals A Puzzling Disagreement between Observations and Numerical Models in the Central Gulf of Mexico

2013 ◽  
Vol 43 (12) ◽  
pp. 2673-2681 ◽  
Author(s):  
Wilton Sturges ◽  
Alexandra Bozec
Keyword(s):  
Gulf Of Mexico ◽  
Numerical Models ◽  
Surface Flow ◽  
Return Flow ◽  
Mean Flow ◽  
The West ◽  
Near Surface ◽  
Direct Observations ◽  
Order Of Magnitude ◽  
The Difference

Abstract Two large, independent sets of direct observations in the central Gulf of Mexico show a mean near-surface flow of ~10 cm s−1 to the west, concentrated in the northern and southern Gulf. Numerical models that the authors have examined do not produce this mean westward flow. The observed speeds appear to be almost an order of magnitude larger than the estimated errors; this paper studies the observations to estimate carefully the possible errors involved and compares the observations with model results. The flow to the west in the southern Gulf is presumably wind driven on the shallow parts of the shelf, and, in slightly deeper water at the outer edges of the shelf, is possibly the result of southward Sverdrup interior flow driven by the negative curl of the wind stress. In another possibly related issue, long-term deep current-meter observations in the northern Gulf at ~1000 m and below find flow to the west, whereas some models find flow to the east. The flow proposed here assumes a mean flow to the west above roughly 300 m, with a required return flow in deep water. The difference between the deep observations and the models will produce a slope of pressure surfaces of the opposite sign below 1000 m, reversing the direction of upper-layer geostrophic flow in the models.

Spatio-temporal resolution of primary processes of photosynthesis

2015 ◽  
Vol 177 ◽  
pp. 547-562 ◽  
Author(s):  
Wolfgang Junge
Keyword(s):  
Energy Demand ◽  
Solid State Reactions ◽  
Oxygenic Photosynthesis ◽  
Excitable Systems ◽  
Order Of Magnitude ◽  
Molecular Machinery ◽  
Laser Sources ◽  
New Methodologies ◽  
Spatio Temporal ◽  
Life On Earth

Technical progress in laser-sources and detectors has allowed the temporal and spatial resolution of chemical reactions down to femtoseconds and Å-units. In photon-excitable systems the key to chemical kinetics, trajectories across the vibrational saddle landscape, are experimentally accessible. Simple and thus well-defined chemical compounds are preferred objects for calibrating new methodologies and carving out paradigms of chemical dynamics, as shown in several contributions to thisFaraday Discussion. Aerobic life on earth is powered by solar energy, which is captured by microorganisms and plants. Oxygenic photosynthesis relies on a three billion year old molecular machinery which is as well defined as simpler chemical constructs. It has been analysed to a very high precision. The transfer of excitation between pigments in antennae proteins, of electrons between redox-cofactors in reaction centres, and the oxidation of water by a Mn4Ca-cluster are solid state reactions. ATP, the general energy currency of the cell, is synthesized by a most agile, rotary molecular machine. While the efficiency of photosynthesis competes well with photovoltaics at the time scale of nanoseconds, it is lower by an order of magnitude for crops and again lower for bio-fuels. The enormous energy demand of mankind calls for engineered (bio-mimetic or bio-inspired) solar-electric and solar-fuel devices.

Do primates flexibly use spatio-temporal cues when foraging?

2020 ◽  
pp. 174702182097072
Author(s):  
Cinzia Trapanese ◽  
Hélène Meunier ◽  
Shelly Masi
Keyword(s):  
Brain Size ◽  
Seasonal Pattern ◽  
Temporal Distribution ◽  
Primate Species ◽  
Temporal Cues ◽  
Large Brain ◽  
Sapajus Apella ◽  
Average Proportion ◽  
Spatio Temporal ◽  
Free Ranging

Foraging in seasonal environments can be cognitively demanding. Comparative studies have associated large brain size with a frugivorous diet. We investigated the ability of three semi-free-ranging primate species with different degrees of frugivory ( Ntrials: Macaca tonkeana = 419, Macaca fascicularis = 197, Sapajus apella = 346) in developing a mental representation of the spatio-temporal distribution of food using foraging experiments. Forty-two boxes were fixed on trees, and each week (“season”), some of them were filled with fruits which were either highly preferred, or less preferred. Spatial (geometrical panels) and temporal (peel skin of the available fruit) cues were present at each season to indicate where (food location), what (which food) was available, and when. To test the flexible use of the cues in primate foraging behaviour, we first removed the spatial and temporal cues one at a time, and then, we manipulated the “seasonal” order of the available fruit. We compared the foraging performances in the absence and the presence of the cues and during the usual and unusual seasonal order. The average proportion of baited boxes chosen by the subjects in presence of both cues was high (between 73% and 98%) for all species. The primates seemed to remember the spatio-temporal food availability (or used other cues) because no difference was found between trials with or without our spatial and temporal cues. When the usual seasonal pattern was changed, they flexibly adjusted the feeding choice by using the provided temporal cues. We discuss these results also in view of a possible experimental bias.

scholarly journals Temperature effect on the sensitivity of the copepod Eucyclops serrulatus (Crustacea, Copepoda, Cyclopoida) to agricultural pollutants in the hyporheic zone

2015 ◽  
Vol 61 (4) ◽  
pp. 629-640 ◽  
Author(s):  
Tiziana DI Lorenzo ◽  
Walter D. Di Marzio ◽  
Marco Cifoni ◽  
Barbara Fiasca ◽  
M. Baratti ◽  
...  
Keyword(s):  
Surface Waters ◽  
Hyporheic Zone ◽  
Effect Of Temperature ◽  
Concentration Addition ◽  
Order Of Magnitude ◽  
Juvenile Stages ◽  
Agricultural Pollutants ◽  
Increasing Temperature ◽  
Whole Life Cycle ◽  
Copepoda Cyclopoida

Abstract The sensitivity of freshwater invertebrates to agricultural pollutants is supposed to increase with rising temperature due to global warming. The aim of this study was to measure the effect of temperature on the lethal toxicity of ammonia-N, the herbicide Imazamox and the mixture of the two chemicals, in the adults and the juveniles of a population of the copepod Eucyclops serrulatus. This is a widely distributed species found in surface waters, in transitional habitats between surface water and groundwater, and in genuine groundwater environments. We tested the sensitivity by short-term bioassays (96 h) at 15°C and 18°C, respectively. Our results highlighted the following: (1) increasing temperature affected the sensitivity of the adults to ammonia-N and of the juveniles to the mixture, all of which were more sensitive to its detrimental effects at 18°C; (2) the juvenile stages were more sensitive than the adults to all toxicants, and (3) for all combinations of chemicals and temperatures, the effects were synergistic and approximately one order of magnitude greater than those expected according to a concentration addition model when comparing the LC50 for each chemical in the mixture with the LC50s of chemicals individually assayed. Overall, in a context of global change, ammonia-N and mixtures of agricultural pollutants may affect the survival rate of species that spend a part or the whole life-cycle in the hyporheic habitat, with detrimental effects to biodiversity and ecosystem services provided by the hyporheic biota.

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